Retro Fitting Expanding Foam Insulation

30-Mar-2011

Beware – Retro Fitting Expanding Foam Insulation to un-insulated Houses

 This is where it is proposed to drill holes in your walls and with a caulking gun application, fill all the cavities between your studs and your nogs in your framed wall with “expanding foam”.

This has been a pet hate for me for several reasons:

1)    No building consent is required for this work, therefore no inspections are required, leaving the owner in a position where there is nobody to blame if it all goes wrong ie caveat emptor (buyer beware).

2)    Drilling holes through the exterior cladding, the cladding being the first line of defence for weather-tightness, then the paint – the second form of defence, are both penetrated, and on completion are left with a bogged hole with paint over it. Bog is extremely porous, which is why panel-beaters use it, then a quick slap of acrylic paint over, does NOT constitute an acceptable weather-tightness solution.

3)    If holes are drilled in every cavity from inside, then there is a major cost to fill all holes and repaint/paper all the external walls – which really means paint the whole room as you will not be able to match the colour of the remaining walls.

4)    Most old bungalows with bevel-back weather boards (their target market) do not have building paper – this means the foam will track through the gaps behind the weatherboard and more importantly, weatherboards at the lap are not water/air tight (this helps breathing) which means the foam can spew out of the outside of the cladding. So apart from the mess, and it is a very sticky substance, will probably result in the house being repainted entirely again.

5)    This is lethal to a brick veneer house. Again, older houses do not have building paper either (some do, some don’t, prior to the 80’s) which means that the WHOLE CAVITY will be filled. Obviously this can come out the washouts at the bottom and the vents at the top – not to mention that the moisture (rain + wind) now has a direct passage to travel to the framing, which was protected by the cavity but now the protection will be gone.

6)    Any electrician or plumber, builder etc that needs to re-wire or re-plumb any work in any wall with that product will have a real job on their hands as anything in that wall will now be encased in foam.

So basically, the only reason that this product is able to be sold, is that there are no controls on doing non-structural work and it does not need any council interference through any consent or inspection process. A cowboys dream.

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