installation guide jul 08[1]

polarwall INSTALLATION GUIDE


ContentsPage No

1 Overview……………………………………………………………….….. 22 Polarwall Components…………………………………………………... 3,43 Essential Tools…………………………………………………………… 54 Pre-Planning……………………………………………………………… 65 Foundation Requirements………………………………………………. 76 Wall Assembly……………………………………………………………

i. First stage……………………………………………ii. Second stage……………………………………….iii. Third stage…………………………………………..iv. Fourth stage…………………………………………v. Fifth stage……………………………………………vi. Sixth stage…………………………………………..vii. Do’s and don’ts…………………....................…….

891010,11121314

7 Forming window & door profiles………………………………………... 15,16

8 Window & door fixing…………………………………………………….. 179 Utilities connections……………………………………………………… 1810

Angled & Radius Walls……………………………………………….…. 19

11

Party wall & T Intersections…………………………………………….. 20

12

Creating a brick ledge…………………………………………………… 21

13

Creating a lintel…………………………………………………………… 22

14

Floor attachment………………………………………………………….i. Timber floor………………………………………….

Face mounted…………………………….. Sat on wall…………………………………

ii. Pre-cast & beam & block…………………………..iii. Cast in place…………………………………………

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15

Roof attachment…………………………………………………………..i. Truss roof…………………………………………….ii. Cut roof………………………………………………

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16

Damp proof course………………………………………………………. 26

17

Gable construction………………………………………………………. 27,28

18

Basement construction……………………………………………….…. 29,32

19

Check list………………………………………………………………….. 33

20

Concrete……………………………………………………………………i. Pump and concrete access……………………….. 34

Document IG/Aug05 Revision No 10 Issue date 10/07/08 Page 1


ii. Ordering the concrete………………………………iii. Concrete specification………………………………

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Placing the concrete into the formwork…………………………………i. Boom pump placement…………………………….ii. Placing concrete above ground……………………iii. Placing concrete below ground……………………iv. Placing the concrete into gables…………………..

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22

Consolidation & Compaction……………………………………………. 39

23

Other methods of placing the concrete………………………………… 40

24

Making repairs and adjustmentsi. Fractures……………………………………....……..ii. Corner out of square.....................................…….iii. Formwork not level.......................................……..

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Internal finishes……………………………………………………………i. Cutting service chases……………………………..ii. Hanging heavyweight items onto the wall………..iii. Plasterboard & plaster……………………………...iv. Tiling…………………………………………………..

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Exterior finishes……………………………………………………….…..i. Thin coat renders……………………………………ii. Sand & Cement renders……………………………iii. Brick veneer with cavity…………………………….iv. Stone veneer with cavity……………………………v. Brick slips…………………………………………….vi. Finishes on battens…………………………………

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Health & Safety…………………………………………………………… 47

Drawings

PWD 001 – Foam / Rail Splice Alignment

PWD 002 – Typical H & U Rail Ladder assemblies

PWD 004 – Beam & Block floor construction detail

PWD 005 – Fixing masonry outer skin to Polarwall

PWD 006 – Joist Hanger Flooring

PWD 008 – Roof plate options for truss roofs

PWD 009 – Basement construction detail

PWD 010 – Alternative basement construction detail

PWD 011 – Forming basement slab with kicker & waterbar

PWD 012 – Lintel support and cavity tray

PWD 013 – Alternative method for fixing masonry to Polarwall



PWD 014 – Strip footing with ground bearing slab

PWD 015 – Roof plate options for cut roof

PWD 016 – Polarwall Xtra Range

PWD 017 – Window opening formation

PWD 018 – Restraint strap connection for truss roof

PWD 019 – Formation of wall with cement fibre board finish

PWD 020 – Strip footing with beam & block suspended floor

PWD 021 – Typical wall roof connection

PWD 022 – Typical parapet wall construction

PWD 023 – Typical sill detail

PWD 024 – Typical jamb detail

PWD 025 – Typical fixing for timber cladding on battens

PWD 026 – Strip footing with cement block foundation

PWD 027 – Insulated party wall construction

1. Overview

Polarwall has two parallel walls of polystyrene held in place by a series of PVC rails.

Concrete is then pumped between the walls to create a monolithic concrete structure.


155mm

206mm

251mm

302mm


Crossties are attached to these PVC rails (shaped U and H), keeping the polystyrene walls at the correct distance to resist the outward pressure of the concrete.

2. Polarwall Components

1. Rails : There are two rail types; the H and U Rail. They are made of extruded PVC, and come in lengths of 1524mm.

2. Crossties : Crossties are made in several lengths to allow different thickness of concrete wall to be created. They are:


U-Ladder Section

H-Ladder Section

H Corner External H Corner Internal U Corner


3. Corner pieces : Corners for the H-Rail are manufactured for both internal and external corners. They can be identified by the fact that only the internal H Corner has the arrowhead male tie connector. The U-Corner is only available in the external version.

4. Polystyrene : Extruded polystyrene is used with Polarwall

Extruded (XPS): High thermal Performance Good mechanical Robustness Very moisture Resistant

There are 4-board thickness’ 50mm, 75mm, 100mm & 150mm. Boards thicker than 50mm have a slot cut into this dimension so it can be placed over the rails.

5. Concrete : Concrete needs to be fluid enough to be pumped and properly compacted within the formwork. Concrete has exceptional qualities under



compression but is poor in tension. When concrete is under any tensile stress such as a basement, it needs reinforcing steel to provide the necessary tensile strength.

Excessive use of reinforcement in the design should be avoided as it can hinder the compaction of the concrete pour.

A suitably qualified structural engineer must calculate the sizing of the walls and requirements for reinforcement.

6. Bracing : These braces attach to the horizontal rails to support both the corners and the walls. The adjustable legs allow the walls and corners to be easily adjusted into a true and straight position.

8. Tie Snapper: The Snapper allows the installer to assemble “ladders” of rail quickly and efficiently. It sets the Crossties at the correct distance on centres.

9. Plywood & timber : This is good to have on site as it used to form shutters for openings and can be useful to prevent breakages in the wall.

3. Essential Tools

Other than standard tools, the following will make installation progress more quickly and easily.

Above grade structures:

Sliding/adjustable chop/mitre saw – cutting polystyrene and plastic rails

Keyhole or reciprocating saw –for cutting awkward holes into the polystyrene

String or Chalk Line

Transit/Surveyor’s Level

Scaffolding or trestle supports – Essential to provide easy access to the top of the formwork when pouring the concrete



Basement or retaining structures:

Cable Ties or Tie Wire

Rebar Bender/Cutter

4. Pre-planning

Before materials are delivered to site check the following.

Sufficient storage for the polystyrene and plastics inside the structure footprint ensuring efficient installation

Access location for polystyrene delivery, concrete trucks & pump vehicles

Co-ordination of services through wall

Co-ordination of all concrete inserts, i.e. anchor bolts, etc.

Confirmation of all rough opening sizes for doors and windows etc.

Confirmation of rebar requirements, particularly for lintels



5. Foundation requirements

It is important to ensure that when establishing footings, that they are constructed within a tolerance of ±6 mm of level. Using level profiles will help make this job a lot easier.

For footings that are out of level, shims can be used to bring the formwork to level.

Alternatively H-Rails can be used instead of U-Rails. A small section of polystyrene can then be placed onto the underside of the H Rail and cut to take up any unevenness in the foundation. The H-Rail will be mechanically fixed to the footing as usual.

Care must be taken not to increase the depth of the polystyrene too much, and it is advised to have no more than 20mm below the base of the H Rail.



It is good practice although not essential, to provide steel rebar protruding from the footing or raft foundation. Use of steel dowels will help to provide a solid connection of the wall to the foundation/raft.

Ensure the rebar is centred to the middle of the formwork, as any placed off centre will interfere with the shutter.

If foundations are not level then this will cause the initial course of formwork to be uneven, resulting in subsequent lengthy alterations to the formwork.

6. Wall assembly

First Stage

Mark out the corners according to the specified measurements on the plan.

Set out the building line with a chalk line or string line. This can be protected with a clear lacquer to avoid washing from rain.



Begin at a corner, and nail the U-Corner to the footing. Only one 40mm concrete nail or other suitable fixing at the centre point is required

A U-Corner is needed on the outside corner only – the inside corner is to be formed by allowing U rail to meet on the inside corner.

Second stage

Pre assemble pairs of U-Rails into “ladders” using "Polarwall Tie Snapper".

Ensure wall layout area is swept clean of any dirt or debris.

Always start in a corner; build walls from corners in, never from the centre out.

**A U-Corner is needed on the outside corner only – the inside corner is to be formed by allowing U rail to meet on the inside corner.**

Align the outside of the U-Rail to the building line on the footing. Then using one fixing per pair of U-Rails, fix the outside rail to the footings. This can be accomplished by hand nailing, using a ramset or by pre-drilling holes with a hammer drill and a 3mm bit and inserting nails.

When placing U rails from the corner ensure the inner rail is cut to size. This will make certain the join or splice at the end of the rails finish opposite each other.


Splice ends opposite each other

Inner rails cut to suit the dimension


Complete the whole layer before inserting 1st course of polystyrene.

Third Stage

Start the wall construction by inserting polystyrene into the U-Rail, starting at the corners and working towards the middle.

Fourth Stage


Always ensure the rail ends finish opposite each other.


After the first layer of polystyrene has been installed, the next step is to install the H-Corner brackets and H Rail course.

Ensure the Internal H Corner is placed on the inside of the wall and ties are clipped on at the internal corner

sections

As with the U Rail, the first H-Rail Ladder from the corner will need one rail shortened to accommodate the length of the internal H-corner.

Once the H-Rails are in position it is recommended that a length of timber is inserted into the top of the H-rail and firmly hit with a hammer to ensure a good fix between the polystyrene and rail.

When placing foam at each corner alternate the butt-joints.


H Rail cut to suit

Rail splices opposite each other


Fifth Stage

After the 1st layer has been installed (U-Rail/polystyrene/H-Rail) use a level and plumb corners.

Then install outside corner braces on every corner. Make sure corner braces are plumb and cross measurements taken from top of brace are within tolerance.



Level the brace and secure supports. Check braces periodically to make sure they haven't moved.

All braces should be screwed into the rail and screws should always be set at the top of the aperture to allow for possible settlement when the concrete is poured.

Continue to build the formwork always working from a corner inward, alternating the polystyrene and rails as the wall increases in height.

Sixth Stage

After the 3rd course has been installed the internal bracing should be attached to the wall.

Each wall brace should be no more than a maximum of 2 metres from each other. Position the first brace from the corner no more than 500-600mm from the internal corner point.



Align the formwork with the braces to give a true & vertical wall

Carry on installing alternate polystyrene and rails until the desired storey height is achieved.

Always screw braces to the rail in the top of the screw slot

Attach screws to each horizontal rail the brace is in contact with, but do not over- tighten.

Do’s and Don’ts

DO’S Rail splices should finish directly opposite each other, except in corners and

intersections. Leave a 5-10mm gap between rail end splices. (see diagram B) Both rails and polystyrene on each course height should be bonded. Do not

finish



Polystyrene splices need to be at a minimum of 100mm from any rail splices. (see diagram D)

Ensure that a Crosstie is attached from the inside H-Corner to the outside rail on all levels

Leave a gap between the polystyrene planks of between 1mm to 2mm. (see diagram C)DON’T

Never place a polystyrene splice and a rail splice at the same location above each other in the wall. (see diagram A)

7. Forming Window & Door profilesOpenings are constructed so the head and cheeks of the window or door have polystyrene surrounding it.

Constructing the shutter for the opening

Window and door profiles should be pre-constructed prior to the ICF walls being assembled.


If rail splices or polystyrene splices are not properly bonded then vertical plywood strapping should be added to reinforce the weakness.

A B C D

Min. Rail Length100mm

Min between Rail Splice and Board Splice – 100mm

AB Gap

from 5 to 10mm

Gap allows check on whether polystyrene is seated correctly and if concrete is poured

1 to 2mm gap

between planks

C D

DON’T ALLOW RAIL & POLYSTYRENE SPLICES TO BE LESS THAN 100mm APART

Min Plank length is 150 mm

Min from Rail splice to

Polystyrene Splice=100mm


This is done by constructing a timber shutter, the outside dimension of the shutter being the rough opening of the window, including sill height.

The depth of the shutter to cheeks/jamb and head should match that of the concrete thickness including the internal and external 50mm of polystyrene.

The bottom section of the shutter needs to be left open to allow concrete to be pumped beneath the window. This can be done by placing 2 sections of timber to act as spreaders.

As soon as the formwork reaches the desired opening height, locate the shutter into position on a ladder of U-Rails

After the pour and when the concrete has set the plywood profile is removed for re-use.

Constructing the formwork around the opening

Construct the formwork around the shutter. The H-Rail should be left approximately 55-60mm short of the shutter with the polystyrene extending beyond this, allowing it to but up against the shutter. This is completed until the wall reaches the head of the window.


Typically 18mm shutter ply

Bottom of ply frame left open to allow access for concrete

4 x 2 Timber to act as stiffening to the ply frame


The gap left between the rail ends and the ply frame is now wide enough to slide a closer plank of polystyrene down the side of the opening.

Slide this closer plank down inside the wall ensuring it is long enough to match the full height of the shutter.

Along the head of the window place a plank of polystyrene long enough to cover the width of the shutter. Immediately above this place a U-Rail ladder, the same width as the wall formwork, and screw through the ply frame, polystyrene plank and U-Rail, connecting all pieces together.

A polystyrene plank can now be placed onto both H Rail courses either side of the head of the window to complete the formwork construction.

Always screw through the ply frame so it can be unscrewed and removed once the concrete has cured around the window.

8. Window & Door fixing

Once the concrete has cured, the area to the reveal and head of the window/door provide a fixing medium to attach a window or door frame.


Concrete

Leave H-Rail approximately 55-60mm short of polystyrene end

Ply shutter and timber strengtheners to hold reveal in place and to form out the window and door opening

A gap between the two leaves of polystyrene is created into which a cut down polystyrene board is slid down and held in place

Ensure a crosstie is placed as near to the reveal as is practical


A window/door is mechanically fixed into position using the concrete substrate to provide the fixing.

A low modulus silicone or other appropriate sealant is used to seal the window/door and polystyrene to provide a watertight finish.

If the Xtra Insulation is used and the window/door position is not located in line with the concrete, straps or fixing plates can be used, screwed into the concrete and brought into line with the window position to provide the fixing point.

9. Utilities & Service connection


Plastic pipe completely through polystyrene and plywood

Plywood strap to both sides to strengthen weakened board

Concrete

Facing brick

Fixing strap into Polarwall

WindowFramefixed to strap

Seal

Fixing


Utility ducts will need to be penetrated through the exterior walls.

These openings should be installed prior to pouring the concrete.

Use PVC pipe to mark circle for the hole then cut out with a keyhole saw on both sides and run the pipe through.

Where the board has been cut there is now a weak point and this should be reinforced with a plywood strap to both sides with an appropriately sized hole- see the above diagram.

When poured, the openings will be sealed around the exterior to prevent any

moisture leakage.

An alternative cutting method is to grind one end of the plastic tube to give a cutting edge.

10. Angled & Radius Walls Almost any corner or angle can be constructed using Polarwall. The

following steps are necessary to construct a corner are:

Step 1. Cut through inner part of U-Rails and H-Rails to



create the desired angle. Special attention should be taken not to cut entirely through the rail.

Step 2. Build a jig that matches the desired angles Then use this jig to position the crossties onto the rail, mark position of ties and put ties on all other H-Rail in the same location to hold all rails to the same angle.

Step 3. Nail the bottom U-rail onto the footing. Use an adequate number of concrete nails to hold the rails into position at the proper angle.

Step 4. Cut the polystyrene to the proper angles and position into U-Rails.

Step 5. Put the first row of formed H -Rail onto the polystyrene.

Step 6. Attach braces on all exterior sides of the corner. Screw to the U-rail and H-rail and plumb.

Step 7. Continue placing polystyrene and rails, attaching each row of rail to the braces for each level.

To construct a radius corner run H-Rail vertically instead of horizontally.

Suitable ply should be attached horizontally to the interior and exterior H-Rails to hold the polystyrene in the proper radius. This ply should be positioned at regular intervals up the wall. If necessary extra vertical supports can be positioned to provide extra support to the wall during the concrete pour.

Care should also be taken to ensure the crossties are not forced out of position by the concrete pour.

11. Party wall and T-Intersections T-Intersections are constructed to ensure there is no break in the concrete

between external and internal walls. This is important when considering the effects of sound transmission and fire between adjoining properties.

Only use Inside H-Corners in a T -Intersection to allow for the Cross- Tie connection.

A brace must be placed on the outer wall facing the T-Intersection.



Where a ‘T’ intersection is built that is not a party wall, i.e. it is not a wall separating 2 dwellings, the formwork can be constructed differently.

U-Rails can be fixed vertically to the external wall, where the line of the internal wall is to be placed. The area of polystyrene between the U and H Rail can be cut and removed to expose the cavity of the external wall. This will allow the concrete to flow into both wall faces.

The internal wall can now be built into the vertical U-Rail.

Bracing is carried out as outlined above.

12. Creating a Brick Ledge

A brick ledge is used allowing a brick skin exterior to be constructed above a basement construction. This can negate the need for a separate block wall to be built to carry this brick skin above.

The size of the brick ledge required can be achieved by using the nominal length crossties or by joining two of the crossties together. For example if the basement wall is 250mm and the brick ledge needs to be 450mm, a 250mm & 200mm crosstie can be joined to provide the necessary width. Refer to Polarwall Technical Department for further details.


Party wall 200mm

External wall

Brace here

Brace here

Brace here

Inside H Corner


Brace underneath the brick ledge at suitable centres to prevent it from tilting when the concrete is poured. This will also stop concrete from escaping from the underside of the ledge.

A waterproof barrier between the brick and the ledge should be created.

13. Creating Lintels

Lintels are created by inserting horizontal steel reinforcement bar above the opening and on occasions to the side of the opening as well.

All reinforcement requirements will be designed and specified by the project engineer.

There are two ways to place the steel in the formwork:

- Suspended off the Polarwall crossties



- Sat on rebar chairs

Lintels over larger spans may require four steel reinforcing bars to be used to form a cage. Again this can be installed as above.

14. Floor AttachmentsVirtually any flooring type can be used with Polarwall and there are several common methods: 1. Wood Joist Floor

Face Mounted Joists Where joists span into the wall

replace a full inner course of polystyrene with suitably sized timber.



Anchor bolts are fixed through the timber prior to the pour so that it is cast back into the concrete.

To ensure the planks are flush with the interior wall wedges are inserted behind the timber into the rail and screws can be inserted through the rail to assist in pulling it to the front.

Face mounted joist hangers are then attached to the timber.

If the timber is undersized, say 250mm instead of 300mm, then the polystyrene board to the exterior should be cut to the same size.

See Detail Drawing PWD006

Bearing onto the wall Bear the timber joist onto the wall; ensuring at least 90mm of support is

taken by the concrete core.

Ensure insulation is placed between the joists and attached to its opposite face.

The joist ends should be treated and sealed prior to concrete placement.

2. Pre-Cast Concrete Floor

Place the floor on top of a poured wall and before the assembly of the second story formwork.

If using “beam and block” floor on an internal wall the beams can be staggered to allow full bearing on the wall to be achieved. The installation should follow the manufacturers instructions.

Closer blocks must be inserted on the end of each section to prevent concrete seepage when pouring from the storey above.

Building regulations require a minimum of 90mm of concrete to provide the bearing.

See Drawings PWD003.

3. Cast in-place Concrete Floor (structural metal deck)

The formwork is placed upon the top course of the floor and braced underneath. Reinforcing steel dowels can be bent at the perimeter into the concrete wall thus creating a very strong unit.



15. Roof Attachments

At the top of the final story a wall plate is cast into place using appropriate anchor bolts or it is affixed after the concrete has set.

If the angle of the rafter is such that it coincides with the Polarwall polystyrene, a double height wall plate can be used or the outer polystyrene layer can be cut to accommodate the line of the rafter.

A d.p.c can be placed in the wall prior to the plate being attached.



Truss strapping can be fixed into the concrete after cure, or can be cast into the concrete during the pour.

Rock wool or mineral fibre insulation can be placed into the cavity area to act as a thermal seal.

Alternatively, the polystyrene can be extended up to the rafters and cut to the appropriate angle to form a thermal seal.

See Detail Drawing PWD008 and PWD015.

16. Damp Proof Courses

Waterproof Concrete – an approved waterproof additive can be added to the concrete. This is used to fill the formwork to a minimum of 150mm above the external ground level. The pour can be continued above this height with a standard grade mix.

Refer to Polarwall Technical Department for product specification



If a dpm is required this can be used by lapping the membrane underneath the rail and down inside the concrete core. Continuation of the dpc and dpm is required.

See detail drawing PWD014

A d.p.c can also be included at the top of the wall at the uppermost story underneath the sill plate and around window openings. See drawing PWD021

Waterproofing around openings is best created by using a mastic seal as detailed in the window installation Detail Drawing PWD024

17. Gable Construction Gables will generally have to be pumped separate to the formwork

underneath it, as the maximum pour height is 3.0m.

Ensure that where the gable is to be constructed the formwork is left with H-Rails to provide the connection for the gable above.

There are two methods for forming the gable



i. As a free standing structure before the roof trusses are attached

ii. After the roof trusses are attached the gable can then be formed.

To give an accurate line and angle of the gable the latter method will allow an easier construction.

Once the roof trusses are in place start assembling the formwork, course by course. The 1st course will represent the same length as the wall underneath, with subsequent courses constructed in a stepped formation following the line of the rood truss.

Using the truss nearest to the gable as a guide, snap a line down the formwork and cut both the plastic and polystyrene to match.

On the cut edge now place U-Rail ladders, which will hold the formwork in place and provide a fixing point for the ply outer shutter

If purlins are introduced into the roof, these can be brought through the formwork by cutting a similar shape in the formwork.



Pouring concrete into the gable is completed by a rolling shutter and is considered in Section 23 of the manual



18. Basement Construction Polarwall is ideal for basement construction. The larger crossties (250

and 300mm) are specifically designed to provide a greater mass to resist the hydrostatic pressures of the soil and the water.

Basements, like all Polarwall structures, need to be designed by a suitably qualified and experienced structural engineer.

It should be recognised that certain aspects of basement construction, such as applying the tanking, may require specialist contractors. The Polarwall Approved Installer should sub-contract this work to the specialists if he is has not received the necessary training, or is lacking the expertise in these fields.

The surrounding sub strata will have an influence on the size of formwork, and adoption of methods to exclude water from the basement.

In attempting to exclude water into the structure it is sensible to adopt a “belt & braces” approach and not rely solely upon one form of exclusion.

i. Slab with drainage to the perimeter,

ii. A run-off fillet,

iii. Continuous tanking,

iv. Waterproof concrete and

v. A waterstop at the joint between wall and slab.

See Polarwall drawings PWD 009/010/011

For in-depth information on basement construction builders should refer to the following publications:

a) Approved Document – Basements for Dwellings (ISBN 0 7210 1508 5)

b) NHBC Standards – Chapter 5.1

Several British Standards contain relevant information in respect of basement and subterranean construction. These include:

c) BS 8002: 1994 Code of practice for Earth Retaining Structuresd) BS 8004: 1986 Code of Practice for Foundationse) BS 8007: 1987 Code of Practice for design of concrete structures

for retaining aqueous liquidf) BS 8102: 1990 Code of Practice for protection of structures

against water from the groundg) BS 8110 Structural Use of Concrete



h) BS 8301: 1985 Code of Practice fro Building Drainage.

Reinforcing Steel

A basement will by its nature be placed into tension from the pressure of the ground surrounding the structure.

Steel in the form of singular bars or a mesh construction is required in the formwork.

A suitably qualified and experienced structural engineer will need to design and specify the steel requirement for each and every structure.

Where individual steels are being placed into the formwork, the vertical horizontal steels can be tied onto the Polarwall crossties. The U & H Rails are snapped together as normal and the steel is placed into the formwork as the build proceeds.

Where a mesh is being used, the U & H Rails cannot be snapped together as the mesh will impede its assembly. Snapping crossties to one of the rails, feeding it through the mesh and connecting the opposite rail by hand overcome this problem.

Raise the mesh by 50mm off the ground, as this will prevent the mesh centres and the crossties from impeding each other.

Concrete Specification

Concrete in a reinforced structure must be a minimum of C35 grade.

Although this quality of concrete is considered to be water resistant, it is not unwise for the engineer to also specify a watertight additive be included in the mix. However, waterproof concrete does not in itself provide suitable protection and the external walls should also be tanked.

Waterproofing

Prior to any tanking being applied to the external face of the wall, any gaps between the boards should be stopped with an impervious seal.

Tanking should always be added to the external wall before back filling irrespective of whether waterproof concrete is used.

Before any tanking system is applied the tanking material should be checked for solvents that may be present in the material or in the primer, which may react with the polystyrene. Before any tanking is applied the Polarwall Technical Department should be consulted to check material compatibility.

We further recommend that if the Polarwall Approved Installer has not received specific training from the tanking manufacturer then he should consider appointing a specialist sub-contractor with the necessary training and expertise in that particular product.



Special care should be taken when backfilling to ensure that the tanking is not damaged and protection of the tanking by suitable board is necessary and reference should be made to the tanking manufacturer.

Tanking should be continuous and lapped with the dpm for the foundation raft/slab to provide a watertight seal.

Drainage

Place appropriate drainage at the side of the slab, whenever possible, and backfill with pea gravel or a similar material. Ideally the complete backfill should be in free draining material but to at least a minimum of 300mm above the top of the slab.

Good drainage does not lessen the need for a waterproofing tanking material to be added to the wall, but will reduce hydrostatic pressure and will assist in avoiding water ingress into the structure.

If a basement has a “walk out” area (is retaining on three or less sides) then the drain should be sloped appropriately to run off to the open side of the structure. If the basement is completely enclosed then a sump will be required.

The drain will need to be encased in a suitable material (as recommended by the manufacturer of the drain) to prevent blockage of the inlets).

Slab and Wall Connection

The joint between the wall and the slab is the weak spot in the structure for water ingress.

It is recommended that after the concrete has been poured and prior to any application of waterproofing that a sand/cement fillet is created form the bottom of the wall to the edge of the slab to assist in water run off.

If a damp proof membrane is placed underneath the slab it is good practice to oversize this and bring the surplus up the side of the walls and over the fillet. The tanking then can be placed to provide a generous overlap to this surplus.

Waterstops

The joint between the wall and the base slab is the weak point in the basement. A waterstop can be placed either by

i. Creating a keyed recess when forming the slab and place a semi-rigid waterstop into the wet concrete of the slab. The recess is necessary as the crossties on the bottom course of U-rail may impede placement of the waterstop.

Care should be taken when pouring the concrete into the wall to ensure that the waterstop remains in the correct position. It is advisable to tie this off to the reinforcing bar to



ensure it retains its correct position. The waterstop must be continuous through out the perimeter of the structure. A typical version of this product is Servitite from Grace Construction Products Ltd and is shown in Polarwall Detail Drawing PWD 009 (detail B). This method is preferred to method “C” or “A” shown on PWD 009.

ii Placing a “Swellable” waterstop at the joint between wall and slab. A putty type swellable waterstop is preferred to a rigid “swellable waterstop, though the argument has been made that the swellable waterstop may not swell in time to stop the moisture ingress so method “a” outlined above should be used where possible. A rigid swellable waterstop may be recessed into a keyway. It should be fastened (using a fixing method recommended by the manufacturer of the waterstop), to prevent it moving when the concrete is placed inside the formwork.

iii By setting H-rail into the wet concrete of the slab rather than putting U-rail onto the cured slab the cold joint is broken by the rail and the two legs of both the internal and external H-rail will act as waterbars. The H-rail should be butted together and a hydrophilic putty type waterstop should be added at the joints to provide extra protection. See Polarwall Drawing PWD010

Kicker Construction

A kicker up stand will elevate the cold joint and is sometimes preferred. The joint at the top of the kicker shall have a continuous waterstop inserted such as Servitite from Grace.

See Polarwall Drawing PWD011



19. Checklist for concrete pour

This is a good guide to use, as a check to insure the placement of the concrete will go as smoothly as possible.

Wall has been inspected to insure all Crossties are in place on rails and specifically the internal corners

All corners are braced with screws to the top of the aperture.

All "T" intersections are braced.

Each wall is adequately braced with internal braces at no more than 2m centres.

Scaffolding is in place to allow easy access around the top of the wall and into all points.

Ensure scaffolding is secure and does not present health & safety issues.

Ensure all walls and corners are straight, both vertical and horizontal.

All necessary reinforcement is in place to meet design requirements.

Necessary openings are made for services and braced accordingly.

Necessary tools, wall anchors and blow-out kits are on-site ready for use.

Any significant gaps between boards are filled with an expanding polystyrene

Interior and exterior is organised properly to allow delivery of concrete.

Area is clean and clear of obstacles.

Check inside of form is clear of debris and free from frost, snow, mud and water.

Safety glasses, hard hats, gloves, and waterproof boots are available.



20. Concrete Pump & Concrete Access

If the site is tight or access difficult it is always wise to get the concrete pump contractor to visit the site prior to the pour to assess the requirements for access not only into the site but for the size and specification of the pump. Sometimes overhead cables or branches may hinder the movement of the boom.

Ensure that the hopper at the rear of the pump will not be too high for the concrete to flow from the cement lorry. The pump’s hopper can be higher when the pumping is being carried out from a slope, or if the concrete delivery lorry is smaller than usual, such as a “Minimix” truck.

Ordering the Concrete Calculate the volume of concrete required using the following table.

CrosstieNominal Length

Crosstie Actual Length

Concrete Thickness in

Wall

Total Wall Width

Cu M of Concrete per Sq Meter of

Wall

100 mm 108 mm 114.5 mm 222 mm 0.1145 cu. m

150 mm 149 mm 155.5 mm 260 mm 0.1555 cu. m

200 mm 200 mm 206.5 mm 311 mm 0.2065 cu. m

250 mm 244.5 mm 251 mm 356 mm 0.2510 cu. m

300 mm 295.25 mm 301.5 mm 406 mm 0.3015 cu. m

Concrete Specification The concrete should be of capable of being pumped which means that the

slump must be a minimum of 75mm. If the slump figure is too high, the concrete will exert too great a pressure upon the formwork, so the concrete should be ordered between 75mm and 100mm slump. The slump range required is classified as S2.

The aggregate should ideally be 10mm.

The minimum grade for the concrete should be C25 for above ground construction, though if a wall is classed as reinforced, it will be need to be a minimum of C35.

The ultimate water content must be no more than 3%.

The concrete should be kept free of additives whenever possible. Ready-mix concrete suppliers will often include Water Reducing Additives/Admixtures



(WRA) to improve the workability of the concrete; they are often referred as ‘Plasticising admixtures’. The setting time of concrete using WRA is often within 90 minutes of the equivalent plain mix at equal consistence and normal temperatures (15 to 250C). This will clearly have a detrimental effect on the formwork.

At lower temperatures setting times will be extended using WRA, especially where alternative binders such as granulated ground blast furnace slag (GGBFS) or pulverised fly ash (PFA) are being used to partially replace CEM I cement. Even at normal temperatures, high replacement levels of slag may result in longer setting times.

Ideally materials such as GGBFS and PFA should not be specified, especially where a WRA is being used. We prefer to see a CEM1 mix which is a straight Portland Cement without other additives.

The use of a waterproofing additive is not recommended as there is often a tendency for such additives to have a retarding effect upon the concrete cure, and consequently there will be an increase in formwork pressures.

Water must not be added to the concrete mix once it is on site as the strength of the concrete will be weakened. Sometimes a rogue concrete truck driver may add water to the mix in the mistaken belief that if is more fluid it will pump much faster and he will finish his delivery quicker. Watch out for this happening!

We advise the use of a slump cone testing kit on site to ensure that the concrete is not too fluid.

Be prepared to refuse a delivery if the concrete is not to specification.

Be aware of increased concrete pressures, which occur in cold weather. We do not recommend pumping of concrete when the temperature is below 5oc as the set of the concrete will be too slow and the formwork pressures will be significantly increased.



21. Placing the concreteBoom pump

The most efficient way of placing concrete is through a boom pump.

A boom pump normally has a 125mm diameter pipe and this needs to be reduced to 100mm or 75mm by addition of a reducer. Under no circumstances should the diameter of the nozzle exceed 100mm.

The Polarwall nozzle adapter will slow the flow rate of the concrete into the formwork.

Ensure a bag of cement is available on site to enable the pump operator to run through his pipes as a grout liner prior to pumping the specified mix. Under no circumstances should this grout be placed in the formwork.

Some pump truck operators run a special lining gel through the pump tubes prior to the concrete pour and this gel is a retarding agent. Under no circumstances must this gel go into the formwork as it will slow the cure rate and may cause fracturing of the formwork. We advise that the concrete pump operator be asked to use a cementitious grout liner rather than the gel.

Prior to pumping all site operatives should familiarise themselves with the “Code of Practice for the Safe Use of Concrete Pumps” published by the Construction Products Association (Tel 020 7796 3366). This publication includes a page showing recommended hand signals between site operatives and pump operator. Site operatives should agree the hand signals with the pump operator prior to commencement of pour.

Start pumping at a well braced corner and travel along the formwork. As the concrete is placed it will form a slope, and allow the concrete to land on the slope creating a new slope as you go. This reduces formwork pressures.

Fill the formwork in layers up to a maximum height of 900 mm and never more than 1200mm in height. A good method is to divide the height of the wall to be poured by the number of deliveries and try to ensure that each truckload is used for one circuit of the formwork.

By the time the first lift of concrete is finished around the perimeter of the house, the initial set is occurring in the original starting point and a further lift



of a similar height can begin. A single storey is best done in three lifts with a minimum of approximately 40 minutes between each successive lift.

Special care should be taken around openings to ensure that the concrete is well compacted around the sides of doors and windows and that there are no voids in these areas. Party walls should also be well compacted to ensure the acoustic integrity of the wall.

The concrete lintel should all be poured in one go. Try to avoid any concrete falling into the lintel area before you are ready to pour the whole lintel. This protection can be done by covering the lintel area with scrap board.

As the concrete is being placed, workers at ground level should be watching the formwork for any bursts that may occur in the panels. These workers should also have rubber mallets to hit the rails with as they go around the perimeter, which helps the concrete to gain full compaction.

After the concrete has settled, and been compacted, the top should be levelled off with a trowel.

If the wall is continuing for a further storey it is advisable to leave the surface rough to allow a subsequent pour to bond. Also check whether any dowel bar has been specified and if so insert at this stage.

If this is the final floor then concrete anchors or J-bolts may be required to connect a wall plate.

Placing the concrete into the formwork (below ground)

Repeat the procedures outlined above, the only difference is filling the concrete in layers of no more than 500mm. This is due to the presence of steel to ensure sufficient compaction around the steel.

Placing the concrete into the formwork (gables)

Internal braces should be placed onto the inside of the wall to secure into position in the same manner as described in previous sections. Ply strapping should be fixed to the outer side of the wall running counter diagonally to the line of the gable.

A rolling shutter is constructed to carry out the concrete pour using a 1.2m length of ply shutter the same width as the formwork. This is screwed onto the U-Rails running up the gable from the bottom.

Using the concrete boom pour the concrete into the gable until the level of the concrete is just below the ply shutter. The boom pump will have to be placed at either end of the gable to ensure full consolidation.



Screw a further 1.2m length of ply onto the U-Rails above the existing shutter and continue the pour until the shutter height is achieved.

Repeat the same until the whole gable is full with concrete.

See section 17 for diagram details

Checking for true

Within twenty minutes of the concrete pour all walls should be checked for true and adjusted accordingly. As soon as walls are trued the cleanup of any spillages should begin and the bracing should be cleaned of any concrete.

IN ALL CASES THE MAXIMUM HEIGHT OF CONCRETE POUR SHOULD BE NO MORE THAN 3.0M IN ANY ONE LIFT



22. Concrete Consolidation & Compaction

Internal Vibration

We advise against the use of internal vibrators but recognize that in certain circumstances a poker vibrator will be required.

Such times may be to ensure consolidation around reinforcing steel in basement walls, and also in lintel areas.

In no circumstances should a vibrator be inserted into the concrete formwork that has a diameter greater than 25mm.

Even this “pencil” vibrator should be used with great care, in a perpendicular fashion and it is important that the vibrator does not touch the panels, the rails, or the ties.

Using larger vibrators will break the polystyrene panels and may impair concrete quality by causing segregation. Vibrators should be used in accordance with the manufacturer’s instructions and care should be taken not to “over-vibrate”.

External Vibration

The ground staff will greatly assist consolidation by giving solid taps with a rubber mallet to the horizontal rails as each level of rails is reached by the concrete fill height.

The rubber mallet is firmly hit against the rails every 75 to 100mm. A short piece of timber can be held against the rail to prevent inadvertent thumping of the polystyrene.

Other methods of external vibration may also be used apart from the rubber mallet. There are external vibration pads available on the market, for sale or rent, which can be placed on the rails to achieve good compaction. Alternatively, a reciprocating saw (without the blade) can be run along the rails, or a good SDS drill in hammer mode and not rotating, can be attached with a plate and held against the rails.



23. Other methods of concrete placement

Bucket or skip A “bucket” or “skip” is hoisted above the formwork by crane. The skip needs

to have an “elephants trunk” or it can prove very messy. Logistically, two skips are needed so that one is being filled as the other is being emptied, and they each need to have a capacity of 1 cubic metre or the fill will proceed too slowly. To be able to carry a reasonable size of skip any significant distance from the concrete lorry, a very large crane will be required which can make placement by skip very expensive. It is best considered where a crane will already be planned for the site.

Care has to be taken that the concrete doesn’t fall from too great a height or too quickly as this can damage the formwork and lead to segregation.

This method requires an experienced contractor to undertake the concrete placement.

Line Pump Where a boom pump cannot easily access the site, a line pump can be

employed.

The pump normally lies along the ground, where vertical lift it is required steel 90-degree sections are placed into position to allow pumping for a higher point.

Generally a platform will have to be set up to rest the pump on and allow it to be walked around the top of the wall.

The difficulty of the line pump comes in its handling and raising it to the required height, which can be very labour intensive.



24. Making Repairs & adjustments

Fractures of the board are relatively rare, though they can occur at any time and at any point in the wall. Consequently, it is good practice to be ready in advance for a fracture with at least one board prepared for replacement and with the necessary plywood strapping cut.

If it appears that a specific board appears to be damaged then ply wood strapping can be placed over the damaged point and screwed into the rails below and above the point of break.

Fracture repair Should a panel break during the pour, the pump should be switched off

immediately

Clean concrete residue from rails around fracture.

Cut a new polystyrene plank to length to fit into fracture void.

Cut the new replacement plank lengthwise down the middle, from one end to the other, at a 45° angle to allow for it to be re-inserted back into the opening and chamfer the back corners of the board to ease its insertion.

Insert top half of the polystyrene plank into top rail. Make sure that angle on the end-to-end cut allows the bottom half to be inserted below top.

Insert the bottom half of polystyrene plank into rail.

Secure the break with plywood strapping above and below fracture or strengthen using a dividag method. See below



Corner out of Square

Should a corner of the formwork be out of square there is no need to rebuild the wall. Simply come away from the comer about two feet and draw a true vertical line with the aid of a level. By measuring from the line to the corner find the point where the wall started to go out of true. Measure back from the top of the corner to the plumb line by the same distance as the bottom of the form to the plumbed line. Connect to create a “V” and by using a square locate the corresponding internal points. Cut this V out on both internal and external formwork. Have someone apply enough pressure against the corner until the “V” closes completely. Fasten with plywood to both sides using four screws for each rail.

Formwork is not level

Formwork should be checked periodically to ensure that it is level.

A laser level comes into its own in this respect. If formwork should be out of level boards can be trimmed accordingly at any level, though it is better to build cut them to the required height as soon as possible. If there are variations on the foundation causing the boards to be out of level then this should be rectified as the first course of boards is placed.

Cleaning up

It is good practice to use a water hose at the end of the pumping to clean the formwork and to remove any spilled concrete, paying special attention to ensuring that the alignment props are free of concrete spill.



25. Internal finishing

Cutting chases. An electric router will quickly and easily cuts through both the polystyrene

and rails.

The bit should be flat bottomed and cuts should be made vertically and horizontally.

A ply template the same size as the service channel can be used to provide a straight guide to cut the chase.

A hot knife may be used and is especially well suited for cutting the electrical boxes through the polystyrene so that they may be attached directly to the concrete core. The hot knife will not be suitable to cut the UPVc rail

Do not allow plasticized PVC material to be in contact with the polystyrene. The plasticizer in the cable sheath can migrate to the polystyrene and consequently cause the cable to become brittle.

Hanging Heavyweight Cupboards

There are several methods of allowing for items to be hung on the interior walls. These are

i. Cast J-bolts into the concrete to affix a correctly sized batten.

ii. Replace a course of polystyrene planking with a suitably sized wood plank, which should also be anchored to the concrete. (Preferred method)

iii. Attach plywood to the same thickness as the gypsum wallboard in the appropriate places. This can be screwed into the rails.

Plasterboard and Plaster Plasterboard or dry lining is an ideal internal cladding.

Screw the lining to the interior horizontal plastic rails. The fire safety of the home is enhanced by mechanically attaching the board to the rail, as it protects the polystyrene and the rail from the flames for a longer time period.

It is good practice to attach the plasterboard to the full height of the walls before attaching the ceiling boards, which should then be butted up flush to the wallboard.

Likewise it is good practice to use the skirting board at the base of the wall to help retain the plasterboard in place.



It is important to note that all joints in the plasterboard must be taped and filled, as should all screw-fastening points.

Internal walls can be fully plastered for those who require a traditional finish. It will be necessary to attach a proprietary mesh or lath to the wall to ensure the bond.

Tiling Tiles should not be laid directly onto the polystyrene as the PVC rails may

cause the tiling to be uneven. However, if thicker slotted polystyrene plank has been used or if a render can be applied (see section 28 – Render) in the interior then the tiles may be applied direct. Alternatively a suitable lining board can be attached.



26. Exterior Finishing

Thin coat Render Systems These are generally applied in two coats. A polymer modified cement base

coat is applied directly to Polarwall. This is the adhesive bond between the render topcoat and the wall.

A polypropylene mesh is embedded into the polymer base coat to act as a stable key and prevent cracking to the substrate.

The pre-coloured topcoat is then applied to the first coat.

Polarwall has undertaken testing with manufacturers of these render systems, therefore please refer to the Polarwall Technical Department for a list of suppliers.

Monocouche renders (i.e. single cost render), should not be used without first attaching a lath or mesh. With any ICF structure the substrate will tend to move according to the climatic conditions.

The render manufacturer instructions should be followed when applying the products

Sand & cement Render A traditional render may be applied.

An expanded metal lath will have to be mechanically fixed to the wall in order to provide a key for the render.

Fixing specification should be in accordance with the manufacturers instructions.

Brick Veneer Cavity wall Although it performs no structural function with Polarwall, a brick cavity wall

may be added to the exterior for aesthetic purposes.

Polarwall does not normally need to be constructed in a cavity type situation, as it is waterproof and weather tight.

Brick, though highly attractive, absorbs water like a sponge, and it is advisable to ensure that the brick is not touching the Polarwall.

The brick skin should be fastened with an appropriate tie. A suitable tying system can be secured to the horizontal rails depending upon the load of the bricks and wind loadings of the site.



If high loadings are calculated then the fixing mechanism can be affixed to the concrete core.

An alternative is to use ties designed for timber frame construction fastened into the horizontal rails or back into the concrete.

Helical screw ties directly into the concrete can be placed as the courses of bricks gain height.

See detail drawing PWD005 & PWD013

All finishing’s, ties and necessary damp proof course shall be placed as per the Building Regulations and appropriate British Standards.

The brick wall can be built off the footings or foundation, or alternatively, a brick ledge can be created as shown and referred to previously in Section 14. It is not recommended that the brick ledge be formed totally below ground level. A d.p.c will be required at the brick ledge.

Stone Finish In the same way as the brick veneer wall is created, a masonry stone wall

can be similarly built.

Brick Slip Finish There are some proprietary finishes using brick slips or tiles and an

attachment board which lend themselves to Polarwall construction.

Refer to Polarwall Technical Department for product specification and compatibility.

Finishes on Battens see PWD025

By attaching vertical battens, to the horizontal rails a weatherboard siding can be added to the exterior wall. Battens should be placed on the centres required by the weatherboard manufacturer. If preferred or required the battens can be affixed into the concrete core.

Vertical slates or tiles may require further horizontal fixing battens (counter battens) to be attached to the wall and this is best done by placing the horizontal battens on a course of vertical battens.



27. Health & Safety

Polarwall provide a risk assessment that can be used as part of the site safety assessments. This should be followed and read by all operatives who are working with or involved with the construction of Polarwall.

Please refer to the Polarwall Health & Safety Risk assessment contained within this installation manual.


installation guide jul 08[1]

Documents

issue date

polarwall

polarwall

polarwall

experienced

rigid swellable

forming window

brick skin