Roof

[AttM]

My roof is origonal 1940's rosemary tiles on lath and cement, with no underfelt. I'm in the process of boarding the loft out for storage and was wondering if I should put some sort of polythene sheet (visquene or some such) across the roof joists to keep the wind out. Would I create any damp problems by doing this?, or any other problems?

 

[breezer]

i am not a builder but would what you propose not seal the loft? (unless the material you suggest can breathe)
you may also want to see

http://www.diynot.com/forum/viewtopic.php?TopicID=1623

 

[AttM]

I didnt intend sealing the loft right down to the soffits, just across the joists. I thought it may end up a bit warmer up there.

 

[breezer]

Oh. in that case could you not just put down fibre glass before boarding? it would give sound insulation too.

 

[AttM]

I already have insulation on the "floor" up there, under where the boards are going to go. I was thinking of the loft space itself being better protected from the drafts etc that will get through the tiles, but it may be that stopping these will lead to damp. I'm not sure

 

[AnonymousImport]

so long as youve adequete ventilation coming from your eaves the loft space itself will be ok but polythene may sweat on the inside in the summer and cause problems. Perhaps expanding foam (used sparingly) along the joists on the worst offending areas would stop the draughts. May I suggest also laying an extra layer of rockwool before laying the chipboard, does nothing for the loft but certainly helps on the heating bills

 

[AnonymousImport]

RE ABOVE: I also recently boarded the loft. To stop the loose dirt falling onto storage, I fastened polythene to the joists, from the eave down to the purlin only. I then put plasterboard over, again only down to the purlin. Theres plenty of ventilation, but reading the above, I'm now worried. Will it be okay, or am I going to cause problems with rot, etc. I really dont want to strip it all down, but I will if I have to.

 

[AttM]

RE ABOVE, thats exactly the sort of thing I had in mind (just crap at explaining it)

 

[Graeme]

it can get pretty hot up in there in the height of summer. Perhaps during a heatwave you could remove one section and check it out and if it's the case what the previous post suggested maybe ripping it all down would be a bit extreem. Cut out small rectangular sections of each board and place a minature air vent(the ones used above toilet doors)would help the condensation.

In AttM's case, if theres that much draughts coming through the tiling, i doubt sweating would be a problem in his case

 

[kostello]

you could staple building paper to the under side of the rafters.
its like heavy duty brown paper.
aleks