spray foam insulation

bluestrattos

Hello,

This may have been asked before but couldn't really find a straight answer.

I got my attic insulated with spray foam (synthesia from Kinspan) for the roof. The floor is fibreglass.

Our roof has grids/vents all around to let the air in, and there's also a grid near the top of the roof to let some air in, and before today, there was only felt on the roof, hence the need of insulation.

The spray foam guys covered everything, but the joists, so the wood could breathe.

Researching this issue, I get conflicting information, and I asked the guy doing the job, and he said the foam is breathable so any moisture/condensation would disappear.

Nevertheless, my question is: should the attic still have the grids/vents as before, or the breathable spray foam actually works, and we don't need to open holes in the foam for the vents?

Thanks

bluestrattos

https://www.boards.ie/discussion/2058355506/spray-foam-insulation

Can't edit, but I should add that the house is from 2005.

Biker1

https://www.boards.ie/discussion/2058355506/spray-foam-insulation

See page 8 & 9 of the attached NSAI cert for the spray foam. Despite what the installer says there is a requirement to maintain a 50mm ventilation space between the foam and felt/breather membrane and a equivalent continuous 25mm vent in the soffit. If there is no vent opening at the ridge then the foam must continue at collar tie level to allow for cross flow of air.

IAB_190414_Sythesia_2020.pdf

Doolittle51

Yes, the attic still needs to be ventilated. What was the reason for getting sprayfoam? The fibreglass on the attic floor insulates the house, so why apply sprayfoam to the roof? If the fibreglass isn't sufficient, it should be topped up or replaced. 300mm is the norm these days.

bluestrattos

https://www.boards.ie/discussion/comment/122247692#Comment_122247692

The attic already has floor boards, at least 50% of the area, and we plan to convert the attic in the next 3 years.

gandalfio

We got the eaves spaces in the attic spray foamed after the attic was converted. It vastly increased heat retention in the winter. But the bedrooms below are becoming unbearably hot and summer hasn't even begun so we're considering having it removed.