# New Build - Expanded foam cavity wall insulation



## Faszero (7 Sep 2011)

I am a keen self-builder and between an outer skin of clay brick and a concrete block inner wall I would like to use 100mm of expanded foam insulation to bond both external walls together without the need for wall ties on my next new 2 storey house.

Also, I would like to be able to omit the need for all window and wall closures or the need for any DPC's by finishing the foam flush at the openings.

Does anyone know if this construction method will be successful?


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## threebedsemi (7 Sep 2011)

While I applaud thinking outside of the box, I can't see how this would work on any level. I am not aware of any foam which would meet any of the criteria required to meet the requirements of the building regulations.

www.studioplustwo.com


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## onq (8 Sep 2011)

Hi Faszero

Lack of wall ties contravenes Part A Structure
Lack of the ope closers contravenes Part B Fire
You can seek dispensation, but you are unlikely to get it.

Rockwool, which is fire resistant needs wire reinforcement and is not THAT rigid.
Insulation that is rigid like expanded polystyrene is flammable and not THAT rigid.
You could look at a SIPS or ICF system, both each have their good and bad points.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                    as a defence or support - in and of itself - should     legal        action    be      taken.
Competent legal and building professionals should be asked to advise in                    Real Life with rights to inspect and issue reports on    the         matters    at      hand.


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## RKQ (10 Sep 2011)

Faszero said:


> Does anyone know if this construction method will be successful?


 
In answer to the question, your proposed construction will collapse. It be be damp & very dangerous before it collapses. Wall ties are not for decoration - they are a structural element.


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## onq (11 Sep 2011)

We probably need new building control legislation in this sector.
Enforcing self-builders to take professional advice.
Before a house collapses and kills someone.


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                      as a defence or support - in and of itself - should       legal        action    be      taken.
Competent legal and building professionals should be asked to advise in                      Real Life with rights to inspect and issue reports  on     the         matters    at      hand.


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