I live in a 1960s/ 70s detached house by the coast, I've recently increased the loft insulation to about 350mm the house can be drafty at times with air coming from behind light switches and under bedroom doors, can I fill the void under the bedroom floors with something like glass mineral wool or do I need to leave an air gap ?
Insulation under bedroom floorboards.
- Thread starter clayton
- Start date
From floors, draughts are mostly round the edges of a room.
This is because
- there is a gap under the skirting
- hidden defects in the walls, under the floor, like gaps in brickwork, or round joists built into the wall, allow cold air in
So if you want to block them, start at the room edges, at external walls.
An upstairs room that has a ceiling of another room beneath it will not have many other sources of draughts. There may be gaps round pipes, cables and light fittings.
If there is the roof of a bay window or extension against the wall, this is often uninsulated and a severe source.
There is no heat loss through a floor by convection. Loss by radiation and conduction are tiny. So you are left with draughts.
This is because
- there is a gap under the skirting
- hidden defects in the walls, under the floor, like gaps in brickwork, or round joists built into the wall, allow cold air in
So if you want to block them, start at the room edges, at external walls.
An upstairs room that has a ceiling of another room beneath it will not have many other sources of draughts. There may be gaps round pipes, cables and light fittings.
If there is the roof of a bay window or extension against the wall, this is often uninsulated and a severe source.
There is no heat loss through a floor by convection. Loss by radiation and conduction are tiny. So you are left with draughts.