When undertaking a residential survey, it’s always a really sad moment when I open a loft hatch and discover that, at some point in the past, the homeowner has had spray foam insulation installed to the underside of their timber roof structure.
Put simply, the problem with spray foam as that it will encase some or all of the timbers that form the structure of your roof. This encasing restricts the process of ventilation. And when there is insufficient ventilation, condensation or other sources of moisture can get out of hand and that’s a problem as moist roof timbers are susceptible to rot and insect attack.
Some spray foam products are of course better than others. There are ‘open-cell’ breathable spray foam solutions that are much better at maintaining breathability and don’t inhibit ventilation to the same extent but, in some ways, that’s just not the point. The real point is simply this: at the moment, spray foam in a roof makes mortgage lenders nervous. And if mortgage lenders don’t want to lend on a property, then the market for that property is much reduced, and the value is adversely affected. By the same token, releasing equity on a property fitted with spray foam is much more of a challenge.
So, even if the energy efficiency benefits of spray foam insulation are impressive, and in some cases they are, you should think very, very carefully before opting for this technology in a roof space. You could end up with a warmer house, but also one that is structurally compromised and worth a lot less money.
If you’d like more information, Which? have published an excellent guide to spray foam insulation.
You can read that here: Which?: ‘Spray foam insulation explained’
And if you would appreciate some independent advice on how you should improve the energy efficiency of your home in ways that are right for your particular property, then please consider commissioning an Energy Report from Stephen Michael Surveying.
Please feel free to Contact Me for a no obligation initial chat or free quotation (and no hard sell).
