Query around PIR loft insulation and condensation

[ADringer]

Hi all,

Looking to sort out the insulation in the loft very soon and have opted for PIR between the joists as there isn't much head room to begin with. I've done a bit of research and have read some things about potential condensation when using PIR between it and the plasterboard of the ceiling below.

My 60s built house has ventilation through the eaves which is unblocked and I'm not doing any rafter insulation - is there still a concern around condensation between the foil and plasterboard, or is it enough that the loft space is generally well ventilated?

Thanks

 

[baker332]

The PIR needs to be air tight, and if possible use a membrane to help keep moisture from going above the plasterboard. There must be an air gap between the PIR and the roof tiles for ventilation.

 

[baker332]

Ah I reread this and understand now, I can't see there being a problem with this method as there is plenty of ventilation but others may chip in.