Loft insulation and boarding

[billynw]

Hi guys,
I would like to board some of my loft for storage.

I had the loft insulated last year on a Manweb grant.
They layed the insulating 10 Inches thick.

joists are small 3 inch by 1.5 inch.

Could I put boards down or do I have to raise the 3 inch joists a bit higher ?
I dont really want to put more weight up there by raising the joists higher.

Thanks guys

 

[wickerman]

HOW DID THEY GET 10" OF INSULATION IN 3" JOISTS

 

[breezer]

easy, they stacked it

 

[masona]

HOW DID THEY GET 10" OF INSULATION IN 3" JOISTS

Who said that ?

 

[billynw]

Put it this way, I cant see the Joists now becuase there is that much insulation over them

 

[masona]

This is one of the biggest problem we are now facing, this stupid government insisting on having 250mm insulation which is no real cost saving at all.

Depending on your roof layout, is to find the bearing wall and use that to build a framework with new floor joists over the 250mm insulation.

The other option is to remove the 250mm insulation and use loose fill insulation to the 65mm level leaving 10mm air-flow under the loft flooring providing the gang nail trusses ceiling joists are being supported on the bearing walls.

 

[abssm]

This is one of the biggest problem we are now facing, this stupid government insisting on having 250mm insulation which is no real cost saving at all.

Hi Masona, so what in your opinion is an adequate thickness of insulation? I am being serious, not provocative, because if 100mm is adequate then i can do my whole loft for £33.98 and then if 200mm is more than adequate then........ well you do the maths

 

[JohnD]

your "joists" are small and weak so will not take much weight.

One way to do it is to counter-batten them with extra timbers laid crossways on top of the existing ones, and lay your floor on that. then you can slice the insulation so it fits between the timbers.

space the new ones to suit the flooring.

this does not add strength overall, but it does at least help to spread your weight over several trusses when you are clambering about up there. If you use ply rather than chipboard, in the largest sizes you can get up there, and screw all the components tightly together, it will be fairly rigid.

however the roof is designed to be strong enough to hold the tiles up, so is not suitable for anything heavy, or groups of people.

 

[Phil_h]

Looking at creating a small boarded stoarge area about 2m * 2m for light storage. Want to keep the insulation close to 270mm.

1960 semi - roof joists are 400mm apart. and i think 100mm high.

When putting counter-battens across the joists what type of timber should be used?

Pressure treated etc?
Kiln Dried ?
Stud Work ?

From wickes link here...
http://www.wickes.co.uk/Timber/Sawn-Timber/icat/sawntimber

What size battens should I use?

 

[JohnD]

if you can find some 150mm-ish or 200mm-ish, that will be better because it will give the depth you want for insulation.

As the space you describe is so small, you may be able to rest them on the wallplates at each end, which will be great, as it will enable the floor to be supported by the walls instead of the ceiling, so it will have more strength and less likely to make the ceiling dip or crack.

treated yes, but no point in kiln-dried since the loft will not be very dry. Shift the timbers up there to acclimatise before you fix.

try a woodyard rather than a DIY shed.

 

[Phil_h]

Thanks JohnD