Loft space insulation

[Strac72]

Hi, any advice on this matter would be greatly appreciated. The loft space i have is very dirty and dusty, i would presume this is because there is no felt or suitable material under the roof tiles. What would be the best solution to stop dirt coming in and also act as insulation. I have been told i could put celotex between the rafters or i have seen a foil backed material which looks like you just attach to the rafters, or is there a better solution.
Many thanks.

 

[mointainwalker]

Unless you are going to use the space in the loft as habitable space, there is very little point in insulating between rafters and you should insulate on top of the ceiling.

Any type of moderately strong plastic sheet will minimise the dust coming in.

 

[Strac72]

Hi, thanks for the reply, I have no plans at the moment to make area a living space at the moment, the loft floor is already insulated so if the polythene option is much cheaper than the foil ( I think it may be called Therma wrap) I will go with this, if the cost difference is minimal would I be better off with the Therma wrap ?

 

[mointainwalker]

i don't know the product, but it is very unlikely that there is minimal cost difference as these foils sell as premium products although their efficiency is highly disputed.

 

[Strac72]

Thanks for your reply, I will make further investigation but looks like I may go with the polythene. I seem to remember seeing the rolls at around £30 for 0.65m x 13m so probably looking at 7 - 8 rolls of the stuff.

 

[freddiemercurystwin]

A breathable membrane would be best eg http://cgi.ebay.co.uk/Vent-3-Light-...958437&cguid=1402fa9212e0a47a2eb773e7fe60163c

 

[Strac72]

Thanks for your advice, i had a look at the link & the membrane looks like it would do the job, have you used this membrane yourself ? If so is a case of attaching it under the rafters ?

 

[freddiemercurystwin]

You need to be using a breathable membrane to allow the roof to breathe rather than polythene which won't. Staple it to the U/S of the rafters. Personally I wouldn't take it all the way down to the eaves for good measure.