Spray Foam Insulation in Attic: Should I keep?

noodler · 20-04-2021 4:22pm #1

Hi,

I'm in a new (very old) house where the previous owner installed open cell spray foam insulation in the attic.

My surveyor's report said it all needed to go as there was no provision for ventilation. Another builder said he could feel a breeze.

I can see by the guarantee left by the company in question that it is open cell and, according to the website, has a breathable vent card.

Is there another expert one can ask on this? I put a Google next thermostat up there for a night and there was a constant humidity rating of 60% (not sure if that is RH).

It is a cold house, the foam was expensive and it would be a shame to remove unless absolutely necessary.

Tefral · 20-04-2021 4:29pm

noodler wrote: »

Hi,

I'm in a new (very old) house where the previous owner installed open cell spray foam insulation in the attic.

My surveyor's report said it all needed to go as there was no provision for ventilation. Another builder said he could feel a breeze.

I can see by the guarantee left by the company in question that it is open cell and, according to the website, has a breathable vent card.

Is there another expert one can ask on this? I put a Google next thermostat up there for a night and there was a constant humidity rating of 60% (not sure if that is RH).

It is a cold house, the foam was expensive and it would be a shame to remove unless absolutely necessary.

If theres a vent card installed then you are ok. Get a can of expanding foam from a builders providers. Remove a hand sized amount next to a rafter all the way up to the top to see if there is indeed a vent card, you will see it stapled to the rafter. If its there, your ok. Use the can you bought to spray back in the hole you left. If not then it needs to be removed.

Theres was alot of spray used here called Icynene and thats supoosed to be ok to spray right to the felt, but to be honest that never sat right with me. It has no NSAI cert and is against building regs, so maybe thats whats in and maybe thats why he is saying remove it.

noodler · 20-04-2021 4:35pm

Just from the company's website:

When insulating a roof, the objective is to cover the entire area, i.e, every nook, cranny and gap whilst ensuring that the wooden timbers within the roof maintain their ability to breathe. This is achieved by installing a breathable card membrane or Vent Card between the rafters.

Open cell insulation is then sprayed onto the membrane of the vent card to the appropriate depth ensuring that an adequate level of heat retention is achieved.

This card creates the 50mm air gap required by building regulations.

noodler · 20-04-2021 4:37pm

Tefral wrote: »

If theres a vent card installed then you are ok. Get a can of expanding foam from a builders providers. Remove a hand sized amount next to a rafter all the way up to the top to see if there is indeed a vent card, you will see it stapled to the rafter. If its there, your ok. Use the can you bought to spray back in the hole you left. If not then it needs to be removed.

Theres was alot of spray used here called Icynene and thats supoosed to be ok to spray right to the felt, but to be honest that never sat right with me. It has no NSAI cert and is against building regs, so maybe thats whats in and maybe thats why he is saying remove it.

Ok, useful to know it can be checked even if it is probably beyond me!

Would the card be on every part?

Tefral · 20-04-2021 4:41pm

noodler wrote: »

Ok, useful to know it can be checked even if it is probably beyond me!

Would the card be on every part?

Yes. It should be running the whole way across the rafter and from ridge to eave.

Calahonda52 · 20-04-2021 8:54pm

You must be satisfied that the card is breathable

MicktheMan · 20-04-2021 11:03pm

noodler wrote: »

It is a cold house, the foam was expensive and it would be a shame to remove unless absolutely necessary.

The following comment is assuming the spray foam has been applied to between the roof rafters on the slope.

If it was my house I would remove the foam, end of.

Why?

1. I don't trust any spray foam in contact with structural timber in a cold space (outside the thermal envelope) where condensation regularly occurs. The risk of timber rot is just too high for me especially if I have no idea of what product was used and how well it was installed.
2. In any case, it is more than likely doing little or nothing to address the real reason why the house is cold. I say this because I regularly come across exactly what you describe and when tested for heat loss, its effectiveness is akin to an astray on a motorbike.

noodler · 21-04-2021 12:14am

Thanks for that.

It was installed just over two years ago and the company in question left an 25 year guarantee for any damage arising from faulty installation of up to 12.5k.

I might see if they can send someone to have a look and reaffirm their handiwork.

social butterfly 2020 · 04-12-2022 1:23pm

How did you get on With this?

noodler · 09-12-2022 12:38am

Left it in place, been about 18 months.

No sign of rot but always in the back of my mind about the timbers you can't see.

Whole road has it which gave me some reassurance, the hassle of removing it coupled with the fact there is not felt between tiles and timbers has stopped me looking into it further.

social butterfly 2020 · 10-12-2022 1:28pm

https://www.boards.ie/discussion/comment/119973391#Comment_119973391

I installed humidity readers in my attic. it does provide some peace of mind

noodler · 10-12-2022 3:46pm

https://www.boards.ie/discussion/comment/119979123#Comment_119979123

Intetesting, send me a link if you wouldn't mind. What readings are you getting?

I've a whole of house dehumidifier in the hall but obviously wouldn't be helping the attic.

Part of me thinks the absolute worst that could happen is you have to get a new roof which is probably 20k?

social butterfly 2020 · 10-12-2022 7:20pm

I just bought the netamo humidity sensors. They work a treat and secondly the humidity is consistently steady and shows low levels of humidity. Have you considered installing tile vents in your roof?. That will help also

Penandgwen · 10-12-2023 11:24am

We have had a prepurchase survey carried out on an 1990's dormer bungalow. The surveyors report stated that as the attic space was insulted with open cell insulation, it was impossible to check out the roofing timbers. This job was carried out on behalf of the Vendor in 2017 and apparently a vent card was used in the process. The Vendor said a certificate was issued when job was completed. There are several questions we have regarding this type of insulation.

1. In UK and NI foam insulation has become a major issue with mortgage institutions, and lately insurance companies. In the main they a reluctant to release equity as the internal roofing structure cannot be verified as being sound. Will this become an issue here also?

2. Is there any way ingress of water via broken tiles or slates be detected before damage occurs to the roof timers

3. If insulation companies apply SEAI grant, do they have they a duty of care/guarantee regarding problems down the line.

4. If warranty was supplied to the Vendor does this carry through to the new owner? There is a noticeable draft in the main upstairs bedroon which could be as a resulat of cold bridging.

5. Should this become a Nationwide problem as in UK will the state, who are currently incentivizing this product be willing to compensate for its removal? (No answer required here!)

6. Finally, after much research into foam installation, we would ideally like to have this removed and replaced with a more traditional product but are finding it difficult to locate such a person or company. Any help regarding this would be appreciated.

Lumen · 12-12-2023 10:58am

https://www.boards.ie/discussion/comment/121478034#Comment_121478034

You're mixing together practical considerations about buying a property with a bit of a rant about banks, govt and the construction industry.

If the foam has been installed according to the detailed specifications in the NSAI cert, there should be no practical issue. Whether it's doing much useful is another question.

Broken tiles or slates shouldn't cause water ingress if the felt is intact. If water does get in through damaged felt, vent cards have been properly installed, and the felt is breathable, then it should dry out much the same as an un-foamed roof.

I would probably buy a house with foam in the attic if I could get confidence that it had been installed properly, but I wouldn't buy a dormer unless it had a well-engineered warm roof design (insulated above the rafters) or needed a complete replacement roof. Dormers are a PITA to make energy efficient. But that's just me.

greasepalm · 12-12-2023 11:13am

Interesting reads above and yes i also got my my roof tiles sprayed with Icynene long before they lined them with a barrier to stop the foam from coming out of holes.

Due to issues later with old cracked tiles under solar panels and dripping water into attic i ended up getting a new tiled roof on back of house as 50+ year old roof would end up with more issues and a barrier was put down before new tiles.

It made removing old tiles more difficult because of the foam and i do find house is warmer and i still get a breeze up there so not totally sealed

noodler · 12-12-2023 12:03pm

I'm the OP, almost three years on and I haven't done anything about this.

Somewhat heartened by the fact many of my neighbors have it and for alot longer than me.

I have a cert and guarantee from the installers when the previous owner got it done but other than that no clue if it was done "correctly".

Id say, even if you could find. someone to take it out, it would cost thousands, it might take some tiles with it and then the house could be freezing again.

I'm stuck in a kind of purgatory

greasepalm · 12-12-2023 2:53pm

I am happy to leave mine as it is.

Penandgwen · 19-12-2023 10:49am

Thank you Lumen for your coment

As we are old age pensioners we are sinking our entire savings into this property, and do not want our children to have to deal with problems down the line.

Spray Foam Insulation in Attic: Should I keep?

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