Spray Foam Insulation - A Good Idea or Not?

Under no circumstances allow this stuff into your house.

In addition to waht you have posted, now a huge issue with it re house insurance, big issue in UK and coming here soon.

Alos an issue with pre sale surveys/certification

Avoid would be the best advice, I think.

There is alot of issues with Spray Foam in the UK because alot of the time, they are not installed correctly.

OP, in Ireland we have the Technical Guidance Documents, these state that all roof insulation should maintain a 50mm airgap between the insulation and the roof membrane to allow airflow. Airflow will stop moisture build up, which will stop roof rot.

There are companies that are installing spray foam in Ireland right now, that are spraying directly against the roof membrane without this 50mm gap. They are going to see issues. If someone says their product is signed off for this, walk away. Id say the largest and most well advertised one in Ireland purports to be this way… which is wrong.

Spray foam has its uses, its great for dormers etc where detailing insultation with timber can be difficult.

You must ensure that anyone that installs the spray foam installs whats known as a vent card first, to maintain this 50mm gap. These are stapled into the rafters and then sprayed against.

The next thing to make sure is that a suitable vapour barrier is then installed over. Do not install closed cell spray foam to your roof, only open cell.

Next part is check that the spray foam itself is actually approved for use in Ireland by the NSAI. These guys rigorously test the products before getting approval.

The product you mention has an Agrement Cert from the NSAI. They detail the install method that is signed off. In section 2.4.3

https://www.nsai.ie/images/uploads/certification-agrement/IAB_190414_Sythesia_2020.pdf

For Clarity there are only two other makes of sprayfoam signed off by the NSAI to install in Ireland

E:Zero E500

https://www.nsai.ie/images/uploads/certification-agrement/IAB110365_2020.pdf

and PurACell

https://www.nsai.ie/images/uploads/certification-agrement/IAB160389__PurAcell_2020_1.pdf

They install the brand of foam I was referencing above. Note how it contravenes the TGDs and also doesn't have an NSAI cert….

Their BBA certification which in essence means nothing here is 9 years old or put another way, 9 years out of date.. They dont have certification from our regulatory Authority the NSAI which would set off alarm bells for me.

'it is the only foam in Ireland certified for application to the underside of breathable and non breathable roof membranes and felts'

So is this false advertising?

Yes and no. Can be sprayed directly to a breathable underlay if the roof is counter battened above the rafters and an over fascia ventilator is used to ventilate between the slates and breather membrane. When used this way, say in a vaulted roof it must also have a vapour barrier fitted on the warm side of the insulation. The average Joe soap is getting screwed as usual by these companies and the professionals that should know better remain silent.

The 50mm gap is dreamworld.

the issue is this connection which cannot be 100% protected from getting cold which condenses the WV in the open cell foam.

My neighbour in Dublin got it done and 15 years later this connection failed, roof collapsed.

I note the IFF done correctly but its simp[ly not cost effective for the spray and go brigade to do it right.

In any event too many points of failure

It's quite concerning the claims they're making given the contradictory information being said here.

Assuming OP you want to reduce your heat loss and considering it is a (2007) TF house you might well be better off (in all senses of the word) to perhaps concentrate on overall air tightness improvements.

Oh, and to give my tuppence worth about sprayfoam, don't.

No one. Self certification alive and well in this country.

Weatherseal do provide a compliance certificate upon completion of the work.

I was wondering the same thing!?

I have a Level 9 in Engineering Discipline, Level 8 in Quantity Surveying, Chartered Member of the Society of Chartered Surveyors, Chartered Member of the Royal Institute of Charted Surveyors, Member of the Association of Project Management, 18 years experience as a Construction Contracts Manager managing site teams of more than 50 personnel.

Every day of the working week I interface with Construction Products and Services and BCaR :)

Not withstanding the foregoing, all my posts here are of my opinion only.

Have you had work done by them?