It is often stressed that the loft hatch should also be insulated and draught proofed to match any loft insulation that is installed, but is it really worth making a big effort to insulate it when it is quite tiny compared to the area of the loft. So after putting a bit of draught proofing strip around the edges, I put it off because if seemed to involve a few hours making a frame to fix the insulation to the back of the loft hatch cover and couldn’t be that effective because there would still be leaving a fair amount of uninsulated space around the frame.
When I came across a piece of discarded foam insulation during a cold snap I had another idea which didn’t need making any frame and would completely fill the loft hatch void. It promised to be quick and effective. I was also lucky enough to have access to a thermographic camera to see if it made much of a difference.
The loft was just a square hole in the ceiling with a plywood door. There is a special latch on the door which is pushed with a pole to open. To close, the door is just pushed shut and the latch will operate. The ladder is hinged to the edge of the hatch and slides down by pulling the rung with a hook on the pole. Probably the simplest type of loft ladder there is.
This is the loft hatch with no insulation. The ceiling temperature in other rooms was about 13 degrees. The loft hatch had a dramatic effect with the door surface at 3.4 degrees, the adjacent ceiling was at 8.5 degrees climbing to 13 degrees much further away.
The foam was cut to be about 1 cm wider than the hatch opening. The extra centimetre squeezes the foam ensuring that it not only stays in place but fits snugly in the loft hole and effectively keeps any draught out. The foam was surprisingly easy to cut with an old handsaw but unsurprisingly the finish was a bit rough. However this should not hamper its performance.
With the foam in place the hatch door can be closed. We now have to get a chair to remove the foam whenever we want to go up into the loft but we only have to go into the loft very rarely.
24 hours later with exactly the same conditions, the loft hatch area is at the same temperature as the surrounding ceiling which shows how effective it is