Drilling ventilating holes in loft board

benawhile

I intend to board my loft floor on 7” loft legs after adding glass fibre insulation over the joists.


There are no condensation issues at present and I will continue to monitor this.


The ceiling below is plasterboard from the 1950s and there is no vapour barrier.


My question is, as I cannot verify whether standard loft board is vapour permeable, would I reduce risk of condensation under the boards if I drilled vent holes in them?


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ANDY597

Standard loft boards are about 18mm chipboard

They shouldn't be allowed to get wet or will degrade.

I don't think based on your description that condensation would occur in the area you've described.

What's more likely is the rooms below show condensation when warm air meets cold surfaces.

Ventilation downstairs, and good insulation above should see you well.

In a none habitatable loft it's reasonable for it to be cold when downstairs is warm, the insulation is doing its job.

If condensation is an issue up there, then perhaps consider roof vents as talked about in another thread over the past couple of weeks so should be easy to find.

Hope this helps
Trust this helps.

ANDY597

Ps. Don't compress the insulation, the purpose of the stilts is to rise the board to avoid compression. An air gap between board and insulation recommended

ANDY597

First Post meant to say WOULDN'T. Tried to edit but can't seem to on phone. Sorry