Covering mineral wool insulation in loft

[sams93]

My loft is insulated with the horrible fluffy glass wool Stuff. It is on the floor and also in between the rafters.

I have boarded the floor over the insulation there.

I want to cover the insulation between the rafters as the wool drops down onto everything in the loft and it is rather annoying for storing anything up there.


I was originally thinking of using lining paper as it is cheap. My grandfather used brown paper for his and it seems to have been fine for 30 years or so since he did it.

Would my lining paper idea suffice?

 

[Tris]

Seems odd to have it in both places. Are the eaves ventilated?

This seems pretty cheap and should staple up well:
https://www.eufabrics.com/fire-reta...lstery-base-lining-fabric-fire-retardant.html

 

[Bingy man]

How about landscaping fabric- available in different lengths and widths , it will allow the roof to breathe, I’m not sure of the properties of lining fabric but this too is worth considering but the cost could be a factor. I personally wouldn’t use paper for obvious reasons..

 

[sams93]

Seems odd to have it in both places. Are the eaves ventilated?

This seems pretty cheap and should staple up well:
https://www.eufabrics.com/fire-reta...lstery-base-lining-fabric-fire-retardant.htmlY

Yes, landscaping fabric might be a good idea, it is woven, so presumably breathable. I will see how cheap I can get hold of that..

I have scrapped the paper idea, as that actually sounds like an unnecessary fire risk! What drew me to that is that I could buy lining paper for £1.50 a roll of 50 m.

I looked at the upholstery stuff, but that was £2 per meter, so I think it would be quite expensive

Currently my favourite option is some roofing membrane or underlayment as I keep seeing it’s called. Looks like it comes in 1.5 meter rolls about 50 m long, which I think should be enough to cover my loft. They are about £40 new, but I have messaged a couple of people on Facebook, who have some a bit cheaper.

 

[Tris]

I thought about landscape fabric but it melts and gives off unpleasant smoke when burned. Having said that so does my sheen flamegun! Very organic

 

[sams93]

Good point! Landscape fabric off the menu then!

Looks like i'm just down to roofing underlayment now!

 

[Bingy man]

I thought about landscape fabric but it melts and gives off unpleasant smoke when burned. Having said that so does my sheen flamegun! Very organic

Good to know , I assumed most materials today were non toxic when burned , mind you not many gardens in Wolverhampton are set alight ( the crims are too busy burning stolen cars ..

 

[dephill]

I have added an extra 100mm of polyester wool insulation on top of mine and that keeps down the glass wool. Not particularly cheap but adding insulation so all good. You might be able to buy it in 50mm thickness to keep costs down a little.
Just Google no itch insulation.

 

[sams93]

Never seen that no itch stuff - looks quite good!

My rafters are already overspilling with the super-itch stuff so I don't think I have the room for that, nor the inclination to spend more on it than i need to.

I'm hopefully getting some of the underlayment membrane on tuesday so all being well this will solve my problem!

 

[MarkAW]

I've not heard of insulating between the rafters, but between joists.

You can add more insulation on top of the old stuff, usually at right angle for better insulating (joists aren't as good as insulating). If you've boarded you can get 'loft legs' which are plastic stilts to raise the boards up to accommodate for insulation that's higher than the joists.

My loft is part boarded, with nothing in the rafters, but everything still gets covered in the dust from the insulation

 

[sams93]

Yeah I don't really know why it's in the rafters. I do know that if I ever decide to do the same in a future house to use a foam board type of insulation rather than loose mineral wool!!!

 

[trvlr]

if/when one insulates between the roof rafters - the bits that support the woodwork which supports the slates/tiles etc. - ensure there is an air gap between the underside of the roof itself and the actual insulation material; regardless of what is used. I seem to recall it has to be something like 75mm or possibly a wee bit less, say 50mm.

 

[Agent_zed]

You seem to have a mix of roofing systems that could potentially cause you issues in the long run.

Normally if you have insultation between the floor joists the attic space would be cold and vented. Any moisture can naturally escape.

If you put insulation between the rafters then the attic space is normally warm, but you need air gaps between the insulation and the felt to prevent condensation rotting out your beams.

Ive seen various gaps recommended down to 25mm. This will also depend on the membrane used under the tiles. If it is a modern breathable membrane that is tight then 25mm is likely ok. If it's old tar felt that is sagging then it's going to touch the insulation and problems will ensue.

If I were you and wanted to leave the insulation in the rafters I'd use breathable roofing membrane. It's not completely correct for the job but hard for insurance to argue it was a hazard as it is used in the same location. If you use other random fabrics then they might have a case to say you used something that caused a problem if your house was to catch fire.

To get anywhere near the current regs the only way I can see to do it on my roof (only have 100mm rafters) is 3 layers of multilayer foil, but that is expensive.