hi all, i have a cold workshop/garage that i am going to heat with a blown air heating system taken from a block of flats. the walls are single brick wide so i will probably be cellotexing them, but the rafters which are exposed..what is the best/cheapest/least labour intensive method to use? (erring on the side of frugalness)
Steve
Same thing. I used 50mm Celotex fitted to the surface of the rafters because I didn't find losing a little space next to them. The other option would be to fit pieces in between. I used long drywall screws with large washers to fit the sheets to the rafters and then taped the joints with foil tape.
One important point is to make sure that there is ventilation behind. My roof construction is such that there are soffits under the eaves in between each pair of rafters, so I drilled a hole and put a vent in each on each side. For the walls, I made stud frames fitted to a pressure treated timber Rawlbolted to the floor (DPC under it) and bolted to the joists at ceiling height. This left a 20mm or so gap behind and then the Celotex is fitted in between and ply to the surface for the walls. THis means that things can be fitted easily anywhere. So the ventilation ports ventilate behind both the wall and the roof insulation.
When I did the calculations, the walls were the largest heat loss followed by the roof, and the floor was not a great deal.
Don't forget to do the doors and also try to draughtproof the doors a bit.
The result will be quite cosy.
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