Raised Loft Boarding Q&A

There are two main reasons for this, and the first is to stop it squashing the insulation and the second is to allow an air gap between the top of the insulation and the underside of the boards.

The bit that actually works to stop the transfer of heat are the little air pockets not the wool or the fibreglass. The wool or the fibreglass is just a structure to hold the air pockets together and stop the air moving too much. The air can move and this type of insulation is called “vapour permeable” for that reason.

If you squash the wool then you also squash the air pockets so you get a lot less of them and so the insulation value reduces.

Squashing the wool down can also put pressure on the ceiling below which can damage it.

In a properly ventilated loft it’s very cold in winter. So the boarding will be very cold. Some of the heat and moisture from the room below can make it’s way through the insulation and if there’s no air gap between the insulation and the boarding the moisture will condense on the underside of the loft boards (which is called interstitial condensation) which can cause black mould to occur, and also cause a degradation of the boarding.

Lifting the boards slightly so there is some air movement will avoid this.

We build a hand made custom structure on site which takes into account what’s going on in the loft to provide the best possible support and finish to the boarded space.