We are seeing a lot of cases of Renotherm roof insulation at the moment - and have bitter experience of many past cases.

Spray foam roof insulation is death to your roof.  It is also toxic.  It is a fire hazard.  It destroys your roof.  It massively devalues your home.  

OK - did you get all of that?

Spray foam insulation, or Renotherm as some call it, is PIR foam sprayed onto the underside of the roof.  It is non-breathable and toxic as hell when it burns - releasing cyanide gas. It is the same chemical as the foams that burned in the Grenfell Tower disaster.  What killed people in Grenfell was not so much fire, but smoke - toxic, cyanide laden smoke.  

Renotherm traps moisture - it sticks slates and tiles to together, making maintenance impossible - if one of them cracks or spalls, you can't remove and replace it.  Everything is stuck together in a horrible foam impregnated mess.  Water that does get between tiles and slates is then held against the timber battens, rotting them.  It is sprayed over rafters, and traps water into the rafters too.  We have seen entire roofs rotted, and totally unrecoverable.  Normally slates and tiles can be re-used.  When renotherm is used, none of the materials can be used again, and the entire roof is scrap. This puts up the cost of re-roofing dramatically.

Our advice to ANYONE buying a house - DO NOT BUY if there is foam insulation sprayed under the roof.

DO NOT even consider spraying foam insulation under your roof - you will devalue your home by the amount that a new roof will cost, and more.

We dealt with one roof recently, sprayed with renotherm, under diminishing Westmoreland slate.  All of the timber battens were in varying stages of rotting.  Foam had stuck all the slates together, making it impossible to recover them when the roof was stripped. Foam had stuck leadwork to tiles, and timber to lead.  All of the leadwork was scrap - nothing could be recovered, and the roof had to be lifted off in slabs and smashed up.  Total cost of the roof was nearly £200,000 - new diminishing Westmoreland slates had to be sourced from the quarry at huge cost, none being recoverable, and approximately £25,000 worth of lead was skipped because we couldnt strip it out of the foam.  The house was initially on the market for £1.8 million, and price dropped to £900,000 before it sold, the new owner being of the opinion he could save the roof.  He then had to sell the property after running out of money to finish the roof when our predictions about the damage caused by the renotherm were shown to be correct.

DO NOT use spray foam, sometimes sold as Renotherm - on your roof - it will cost you dearly, and you will have a massive inherent fire hazard above your head.

Damp and Condensation
Recent News
RICS prove they don't understand damp

I've just seen this staggeringly incompetent blog on the RICS website.  This is the kind of mis-information that is being fed to homeowners all over the country - and...

Pete's on BBC Radio 4 now!

Pete recently did an interview on BBC Radio 4 - You and Yours - which investigated a case history of failed cavity wall insulation.

An Irish client and his magnificent restoration blog

Our client, John, wanted help with this restoration - it led to this great blog.

It's Condensation Season!

The phone is running off the hook with calls about condensation. Find out how to solve your issues.

The Haynes Manual for Period Property

Ian Rock has written another of his great books.  This one is even better - We've helped Ian with this one and there's loads of photos of our guys doing timber frame work.  A great book, with lots of practical information you need if you have an old home.  Treat yourself and buy this - you won't regret it!

Share this page

If you've found this site useful, please share it with your friends!

Website by twoclicks