Spray Foam Insulation - A Good Idea or Not?

Kintarō Hattori

Hi Folks,

Our attic (two end end of terrace timber frame built 2007) has no insulation other than that which was laid down nearly 20 years ago. My partner looked into spray foam insulation and it seems to be a bit of a minefield. There are plenty who recommend it but equally there are plenty who say it's a terrible idea and may damage the house or make it difficult to sell.
We had looked at getting a company called Cosy Insulation to do it. They are based in the north. They use 'Synthesia Spray Foam Insulation' and seem to have good reviews. I'm afraid I'm just not DIY minded so can't really figure out whether they are using good quality materials, whether it's likely to cause any issues etc.

I'm looking for some advice/feedback.

Calahonda52

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

muffler

Lots of previous threads in this forum on the topic and the general consensus is to avoid it. As above there are now some issues with it in the UK and whatever happens there will eventually land on our doorstep. There are other more acceptable and more efficient methods of insulating.

nachouser

https://www.theguardian.com/money/article/2024/aug/12/they-encouraged-us-to-insulate-our-home-now-its-unmortgageable

Avoid would be the best advice, I think.

Gumbo

not a good idea in my opinion.

Tefral

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

gandalfio

https://www.boards.ie/discussion/comment/122597292#Comment_122597292

https://weatherseal.ie/ apply directly to the roof without any gap. According to their website and management, their product designed to do so and has been tested, ceritifed and approved.

Tefral

https://www.boards.ie/discussion/comment/122597525#Comment_122597525

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

gandalfio

Take from their website.

'Icynene Classic Cell or  Icynene LDC-50  from Weatherseal is 100% water blown and 100% open cell. Also, it contains no harmful chemicals, agents, HFCs, HCFCs or volatile organic chemicals. Thus, Icynene open cell is the most certified product on the market having achieved KIWA Agrément Certification to 

Irish Building standards. Additionally to

 BBA and ETA approvals and certification standards. In fact, Icynene recently underwent successful testing and assessments. Accordingly, it is the only foam in Ireland certified for application to the underside of breathable and non breathable roof membranes and felts'

muffler

https://www.boards.ie/discussion/comment/122597863#Comment_122597863

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.

Lumen

(deleted, missed Tefral's post)

gandalfio

https://www.boards.ie/discussion/comment/122597932#Comment_122597932

'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?

Tefral

https://www.boards.ie/discussion/comment/122597985#Comment_122597985

I would ask them how they plan on meeting the requirements of TGD Part L 2020 B.5.2.1 R2(a) and section 2 of TGD Part F 2019 without a 50mm airgap.

I think this thread exactly demonstrates why there are so many issues with Sprayfoam in the UK and most likely also will come out here in the next 15 years or so…

Anyone reading this: DO NOT LET A SPRAYFOAM INSTALLER SPRAY ANY FOAM IN YOUR HOUSE UNLESS THEY KEEP A 50mm AIRGAP!

Biker1

https://www.boards.ie/discussion/comment/122597985#Comment_122597985

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.

Tefral

https://www.boards.ie/discussion/comment/122598086#Comment_122598086

Correct about the counterbattens which create an airgap. But only if they do the following according to their own KIWA cert.

[quote]"A Condensation Risk Analysis (CRA) is undertaken for each project specific design (see section 2.1.9);

Each project specific design is tested using software compliant with BR443, BS EN ISO 6946, BS EN ISO 13788 and BS EN ISO 13370.

2.1.9 Condensation risk
A CRA shall be completed at project specific design stage (see section 2.1.3). Roofs incorporating the Product will adequately limit the risk of interstitial and
surface condensation when properly designed in accordance with BS 5250, BRE Report 262 and BRE Digest 369. Make suitable provision for adequate
permanent ventilation proportionate to the extent of the work being undertaken, with due consideration to different warm/cold roof conditions" [/quote]

My guess not one of the installers do this, and if they did, there isn't a hope it would pass.

There is a reason its not on the NSAI Agrement and this is the primary one.

Calahonda52

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

gandalfio

What if the spray foam is applied only in the storage crawl spaces of an already converted attic? (converted space would have kingspan under the plasterboard).

gandalfio

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

Tefral

@gandalfio have you had it installed?

MicktheMan

https://www.boards.ie/discussion/2058368235/spray-foam-insulation-a-good-idea-or-not

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.

gandalfio

Who inspects spray foam installations and signs off as to whether or not it complies with TGD and NSAI regulations?

Biker1

https://www.boards.ie/discussion/comment/122600277#Comment_122600277

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

muffler

https://www.boards.ie/discussion/comment/122600277#Comment_122600277

As above its basically self certification. You as the building owner are responsible for compliance with all statutory building regulations. You can of course seek the opinion of a professional who will ask you to get the relevant documentation from the company. If they can't or won't provide proper certs you may choose to notify the building control dept. of your local Council. What if anything they will do is anyone's guess. Most likely they will pass responsibility back to you as the building owner. Such is the system we have in this country.

gandalfio

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

muffler

https://www.boards.ie/discussion/comment/122600983#Comment_122600983

Compliance with what though?

Why are you actively promoting this company and its product? Have you had work done by them?

Tefral

https://www.boards.ie/discussion/comment/122601084#Comment_122601084

I was wondering the same thing!?

gandalfio

I'm not promoting anyone. Just stating what I know about that particular company and asking questions.

What qualifications do the posters replying here have? Genuine question.

Tefral

https://www.boards.ie/discussion/comment/122601489#Comment_122601489

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.

muffler

Oh, I'm just a grumpy old bastard or a retired architectural technician in other words.

muffler

https://www.boards.ie/discussion/comment/122601489#Comment_122601489

Have you had work done by them?

Tefral

A very poignant article in the Irish Times.

https://archive.ph/1VIX4

Lumen

The one angle that's not really covered is whether any type of rafter insulation is desirable.

I'm sure I've read threads like this where people are being sold a spray foam rafter treatment when some careful but cheap deep joist insulation and ceiling/hatch airtightness would do as good or better a job.

Like, what's the point in insulating an unheated ventilated space?

Muahahaha

This thread is timely for me as Im finally going to re-insulate the attic in a 1995 built timber frame house. Its slightly unusual & problematic as its a 3 bed semi but with 2 bedrooms on the first floor and the third bedroom & ensuite on a second floor up inside the attic. Its not an attic conversion per se as it was built this way. But it means each side of this top bedroom and under the pitch of the roof there are two crawl spaces, triangular in shape sloping down with a steep pitched roof of 40 degrees.

Ive had companies out here quoting in the past but never went ahead with the job as they all came coming with this spray foam solution. Im not an engineer but to me it didnt make sense to spray the rafters and insulate the two crawl spaces at roof level because where the roof and top of the wall meets (so basically near where the guttering is on the exterior) there is a gap of about 10cm with cold air coming in there and sometimes birds too. So it always seem pointless insulating at rafter level when Ive this ventilation that is 10cm wide and runs the width of the building, about 4.6 metres. So even if I went for the spray foam Ive still got this gap with cold outdoor air coming into the attics crawl spaces. Ive never understood if this is normal construction or why it is that way, I know attics need to be ventilated but I would have thought it would be some small holes rather than a 10cm gap running the width of the building? Any comment much appreciated as Ive never understood this about my house.

Im hoping others here can advise but my impression of how to do this job correctly is that I actually have two insulation jobs. One is to insulate the floor of the crawl spaces with 300mm rockwool so the heat in the two bedrooms below them cant escape quickly. And then the other job is to insulate the envelope of the top bedroom which is best described as a cube inside the attic. So the bedroom walls would be insulated from the attic side of it with 300mm rockwool. The tricky part is the bedroom ceiling- the top of that has no access from the crawl spaces because the rafters run close to the apex of the cube. So the only way I can think of it getting done is for a hole to be cut in the bedroom ceiling and the installer to go up there and lay insulation above the ceiling and then to replaster the ceiling. And if I dont do that bit above the bedroom ceiling the heat is still going to escape from the ceiling upwards and the entire job would be a waste of time. Am I correct in thinking like this, i.e that the entire cube needs to be insulated both walls and ceiling?

Is what Im describing do-able? I dont even know where to start here as any company I contact comes running with their spray foam solution which Ive decided I dont want due to uncertainty about insurance and well because even with a 50mm air gap I dont like the idea of never seeing the rafters again because if theres a roof leak they could be rotting away hidden behind spray foam insulation and by the time I realise it the roof has fallen in.

@Calahonda52 I remember you pointed me before to an NSAI document with standards for how to insulate a room in an attic/dormer bungalow situation. I cant locate it or your post due to Boards search not working well. Any chance you could re-link it as Id love to read it again and try to get some understanding of what I need to specify with an installer to get this job done correctly.

mickdw

I received a circular from my insurers I believe basically stating that where spray foam is found during Building inspections, it is to be recorded as a possible defect.

That was about 3 years ago.

Practical experience of opening up existing structures would suggest that it is a very bad idea.

https://www.boards.ie/discussion/2058368235/spray-foam-insulation-a-good-idea-or-not

look up spray insulation in reddit/uk housing. Do not allow it near your house, numerous house sales have fallen through in UK due to this fire hazard. Many have to spend thousands to get it removed, some even have to reroof their houses in order to sell their properties.

https://www.reddit.com/r/HousingUK/comments/1dneesp/spray_foam_insulation_still_being_promoted/

Gerry Sheridan

The amount of misinformation regarding Spray Foam Insulation on this post and in general is incredible, Spray Foam insulation has been around for over 60 years and has been successfully used around the world in all types of properties, the critical factor is that it is installed in accordance with the relevant product certification and manufacturers instructions, it is the safest most effective form of insulation when installed correctly. Spray foam is one of the most tested and certified insulation products on the market and must meet the strict criteria laid down in EN 14315-1 thermal insulation products for buildings.

The situation in the UK arose when cowboy operators used closed cell foams directly to the underside of tiles and slates as a waterproofing and stabilization solution, the effect this had was to trap moisture and expediate the failure of the roof, as a result of this mortgage lenders blanket refused to lend on properties with any type of spray foam, this situation is now easing as lenders and surveyors learn the difference between open and closed cell foams and according to a recent BBC report 75% of the major lenders will now consider lending where a proper paperwork trail and inspection process is on place. this is not an issue in Ireland as virtually all applications in Ireland are open cell either directly or indirectly to roof membranes and felts as per product certification. in a recent Irish Times article the major lenders have confirmed no issues in Ireland with lending

in Ireland we must comply with Building Regulations not technical guidance documents (TGD). TGD are there to do exactly what they say, provide guidance and they do stress the following

" the adoption of an approach other than that outlined in the guidance is not precluded provided that the relevant requirements of the Regulations are complied with. Those involved in the design and construction of a building may be required by the relevant building control authority to provide such evidence as is necessary to establish that the requirements of the Regulations are being complied with".

Therefore some certifications allow for direct application to felts and membranes with the use of vapour control layers where required while others require a 50mm ventilated air gap with through ventilation at the soffit and ridge. In addition there are several studies carried out by the Fraunhofer Institute on WUFI Hygrothermal analysis on the application of spray foam to roofs in Ireland and the UK In Ireland NSAI and KIWA certification demonstrate compliance with Irish Building Regulations, always make sure you use a registered brand with certification and a contractor that is approved by the manufacturer, is part of a third party surveillance scheme and has a robust Quality Management System, never use closed cell foam in your property

For clarification i have over 20 years experience in spray foam insulation with approximately 150,000 installations in Ireland and the UK with a failure rate of less that 0.0001%, i will provide accurate information to anyone that required it

Mod: Advertising removed

SwimFin

https://www.boards.ie/discussion/comment/122597292#Comment_122597292

NSAI Agrément Part 5 Conditions of Certification i.e. 5.1 "This Certificate shall remain valid for five years from date of issue or revision date"…therefore this Certificate is not valid and not acceptable under TGD D3 ©

Technical Guidance Document D – Materials and Workmanship