Celotex and loft insulation

[sparkwright]

Am currently patching up a garden shed/summerhouse that a previous occupant started working on.

It's a large wooden shed with pitched felt roof.

All the walls are lined with ply, with celotex inside.

The pitched 'ceiling' inside is partly boarded with ply and celotex. The rafters are about 3 inches and the celotex about 2 inches. 1 inch gap between the celotex and the roof board. There isn't enough celotex leftover to fill the sloping roof before fitting the remainder of the ply.

There was problems with condensation, which is probably why the boarding wasn't completed. Leaving the windows slightly open seems to have stopped it, and have been advised to fit vents low down.

My main question is how important is the celotex in the sloping roof? Would some off cuts of fibreglass loft insulation be ok? Is it ok not to bother fitting any insulation in the sloping roof?

The shed does not have to be particularly warm, the main point here is to fit the ply just to tidy it up. But I don't want to cause any 'problems' by not fitting any form of insulation. About 50 % of the sloping roof has beedn fitted with celotex.

Thanks in advance.

 

[jeds]

Is it heated? If so then with no insulation you'll be heating the street. If there's no heating then there's no point in insulating. If you do heat and insulate then the warm air will cool on the cold side of the insulation and you WILL get condensation. The only way around this is to seal the inner part of the roof on the warm side of the insulation. This must be done thoroughly and the problem area is the junction between roof and walls. The alternative it to ventilate the cold side, which is not easy with a ply felted roof.

 

[sparkwright]

The shed will probably never be heated.

There is celotex fitted on the lower sections of both slopes.

I have some off cuts of loft fibreglass, which I was wondering could be used fot the upper sections of the slopes - where the ply isn't fitted.

Just wanted to know what the best option would be for me.