Loft Insulation

FreeBear

https://forums.moneysavingexpert.com/discussion/comment/82129823#Comment_82129823

Best not to. But if you put a sheet or two on top, the load gets spread enough so that you can walk on it.

If I do go ahead with using Celotex, I'll add some extra timber on top of the existing joists so that no weight is put on the insulation - Wouldn't want any loads transferred to the ceiling which certainly wouldn't cope.

missile

I have often wondered if adding floor boards would be as effective as Xcm of insulation?

FreeBear

https://forums.moneysavingexpert.com/discussion/comment/82130760#Comment_82130760

Probably not - There is often an air gap between the top of the insulation and the boards, so any heat will just get blown out (along with any damp air). Fibreglass has a thermal conductivity of 0.04 to 0.044 W/m²k compared to chipboard at 0.13-0.14 W/m²k. The lower the thermal conductivity, the better a material is at providing insulation. So boarding a loft improves the overall effects by an insignificant amount.

TELLIT01

https://forums.moneysavingexpert.com/discussion/comment/82129621#Comment_82129621

Headroom at the centre of our loft is about 9 feet so. although headroom would be lost it wouldn't be a major problem, and would encourage us to get rid of a load of the junk which has been up there 20 years or more.

stripling

https://forums.moneysavingexpert.com/discussion/comment/82130760#Comment_82130760

Wood is no good for insulating. You need the real insulation deal before any boards. Wooden front doors lose loads of heat as do wooden walls etc.,

Chickereeeee

https://forums.moneysavingexpert.com/discussion/comment/82129621#Comment_82129621

I used normal length loft legs, then ran wooden battens over them, to give additional height, then chipboard. This had the benefit of making the floor MUCH stiffer, while chipboard could be screwed to the battens anywhere.

missile

https://forums.moneysavingexpert.com/discussion/comment/82140783#Comment_82140783

That would be very expensive or did you DIY?

Have you done a cost comparison v energy saving?

Chickereeeee

https://forums.moneysavingexpert.com/discussion/comment/82140853#Comment_82140853

DIY, and not very expensive at all.

ComicGeek

You have to be mindful of the reducing impact of increasing insulation.

In a typical 2 bedroom semi-detached house with gas boiler and no loft insulation, you might save the following:

£240/yr with 100mm loft quilt

£276/yr with 200mm loft quilt

£290/yr with 300mm loft quilt

£296/yr with 400mm loft quilt

So the extra layers have a smaller and smaller impact. The Government recommends a minimum of 270mm, but 200mm is probably what I would pick as a minimum.

I installed 70mm Celotex boards (bought as cheap seconds) between joists (equivalent to 140mm loft quilt) in the middle 3rd of our loft under loft boards, to be used for storage - then 250mm quilt (bought on offer from a DIY store) for the other 2/3rds. No problems having different insulation in different areas, just don't ever use spray foam insulation.

I don't really see the point of spending money on loft legs, particularly when it's just creating storage space for unnecessary stuff which should be sold/donated/thrown away.

FreeBear

I don't really see the point of spending money on loft legs, particularly when it's just creating storage space for unnecessary stuff which should be sold/donated/thrown away.

Some people install their boilers up in the loft (daft idea). So you need a solid surface to walk around on when servicing it.

Others, with old vented heating systems will have header tanks up in the loft. Again, a solid surface is needed for maintenance purposes.

The rest of us bung all the old tat'n'crap up there - Yes, much of it should have been thrown out along with the plastic christmas tree & decorations.