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Loft Conversions
Boarding a loft: how to board rafters from the inside
Hi,
I plan to board my loft to use it as a storage. I think I have a good idea how I want to board the floor but I'm not too sure about the roof. I would like to board the floor and the roof to reduce the amount of dirt coming from outside.
Floor: There is a Rockwool laid down between joists. I would need to run additional timber to ensure ~25cm gap for the insulation. Then I plan to cover it with 11mm OSB boards.
Roof: As the floor is already insulated I don't need to insulate the roof - especially when only plan to used it occasionally for storage. My plan was to either:
Attach 9mm OSB boards directly to rafters
OR
Attach insulation foil directly to the rafters (not between them)
这两种方法会pra吗ctical and correct? I want to make sure I don't do anything that could damage roof long term.
4 Answers from MyBuilder Loft Conversion Specialists
Best Answer
Foil insulation to underneth rafters would be a good idea cross battern with 2x1 lats to allow roof to breathe also great insulation cutting down on fuel Bill's then you could board it with osb or plaster boards would be cheaper also
Make it lighter and more like a room
Answered 15th Apr 2022
I would use 18mm moisture resistant board for the floor. OSB can degrade over time with foot traffic and temperature variation which is more acute in loft spaces. I wouldn't bother foil boarding the roof if the if you have 300mm of mineral wool in the floor/ceiling.
Answered 5th May 2022
Be careful with regards to moisture build up if putting up foil insulation, sealing any area without adequate ventilation can make the timbers sweat and rot. Air will only travel up to 3 to 3.5lm dependent on existing vent and without a vented ridge could cause moisture build up without it being able to breathe. I'm not a fan of creating spaces in lofts that haven't had the necessary timbers and calculations made as the loadings were calculated on it only holding tiles and the possibility of snow. Excess loadings without correct support could cause failure in the timbers. Also if you are planning to board over the existing insulation there are companies put there that supply stilts so the existing insulation isn't crushed because if it is crushed it doesn't perform as it should and isn't as efficient.
Answered 6th May 2022
You shouldn’t use 11mm osb on the floor this should be at least 18mm and preferably t&g chipboard flooring if you can fit them through the loft hatch use 600 x 2.4 size boards.The roof rafters will be fine with a foil insulation of some sort stapled over which will help with warmth but worth cross battening as theis can sometimes fall down in places if it’s just stapled.
Answered 9th May 2022
