PART D · Toxic substances
Is cavity wall foam insulation safe
Cavity wall foam insulation should be assessed as a specific system in a specific wall. The word foam covers different products. You cannot determine safety or building regulations compliance from that description alone.
Which material is being proposed
Ask for the manufacturer's name, product identification and supporting technical information. Approved Document D deals particularly with urea formaldehyde foam and precautions against toxic fumes entering occupied areas.
Do not assume that guidance on one foam system applies unchanged to another. The installer should explain the relevant requirements and the evidence supporting the selected product.
Is the wall suitable
Ask how cavity condition, exposure, existing defects and moisture risks will be checked. Also establish whether there are obstructions or earlier insulation in the wall.
For example, a contractor should explain how the proposal deals with a cavity interrupted by debris or unexpected construction. Simply injecting more material is not a design explanation.
What should the quotation include
The quotation should identify the system, preparatory work, installation responsibilities and the certification route. Ask what happens if the initial survey finds the wall unsuitable.
Check that the installer is competent for that system. Product evidence and installer competence are different questions; both deserve attention.
Does a guarantee prove compliance
A guarantee sets out a contractual promise. It does not replace the building regulations assessment or show that the installation matches the product's intended use.
Retain the wall survey, product evidence and installation records. Establish whom to contact if there is a concern after completion.
If unfamiliar odours or other concerns arise, report them promptly and obtain appropriate professional advice. Avoid diagnosing the cause from an online description. The relevant investigation needs to identify both the material and the way it has been installed.