loft boards

[FluffySheep]

Hi all

I'm eyeing up my next big job for the house, and it's boarding the loft. usual problem, the insulation is far higher than the rafters.

I bought a couple stilts from B&Q to do a small area a few years ago, but they are all 'wobbly'. The joists in the roof are 35mm (1 1/2 inches) separated by 42cm (16 1/2 inch) gaps, but the stilts look like they are designed for 50mm joists. Have I got 'strange' stilts, or are my joists narrower than normal? If they are narrower than normal, will they be able to support stilts, boards, etc? I've walked on them in the past, but never had a long term static load up there (not massive, about 25kg/m^2 I'd guess will be max I'd use)

Thanks in advance
FluffySheep

 

[Teknobry]

You can DIY it and add more wood on top of the joists to raise the height to then board over.
You can buy solid insulation (kingspan etc) which can sit across the joists and you then board over that.
There is another version of loft legs, called loftzone. it's not cheap though.

I've boarded out 28m squared using wool fibre between the joists up to the height of them, then 120mm solid insulation across the joists followed by 18mm t&g boards over that. Been hard work but worth it.

 

[Maccapacca]

Don't use solid insulation unless you have taken account for the reduced level of breathing the building will be capable of.

Solid insulation generally and especially if it's foiled acts as a vapour barrier and your ceiling acts as one big dehumidifier, sealing this off could lead to moisture build up below if you haven't got any sort of mechanical ventilation.

Nothing is ever simple

 

[FluffySheep]

Cheers for the replies.

I'm Ok with the insulation, as it's already down and set. AS in the OP, my question is are my rafters narrow than normal, of so are they wide enough to support a floor?

Fluffysheep

 

[Maccapacca]

Cheers for the replies.

I'm Ok with the insulation, as it's already down and set. AS in the OP, my question is are my rafters narrow than normal, of so are they wide enough to support a floor?

Fluffysheep

Problem is if I say yes and it all crashes down you can come after me through my Professional Indemnity Insurance. The answer I'm supposed to give is you need someone to make a calculation that is experienced and qualified.

You haven't provided enough information about the structure.

I don't think there is anyone on this forum that can give you the answer from what you have provided apart from someone saying 'it'll be all right mate'.

The fact that the shoes are wider than the joists you have is worrying and 1.5" is on the lower end.

 

[Teknobry]

Don't use solid insulation unless you have taken account for the reduced level of breathing the building will be capable of.

Solid insulation generally and especially if it's foiled acts as a vapour barrier and your ceiling acts as one big dehumidifier, sealing this off could lead to moisture build up below if you haven't got any sort of mechanical ventilation.

Nothing is ever simple

Oh joy.

Well the rigid insulation isn't foil backed.

All the ceilings are plasterboarded and now recently plastered, am hoping it won't allow moisture through.

 

[FluffySheep]

Ta maccapacca. Never thought about any comeback if it all goes pete tong. I'd never do that! The big thing is your last line that 1.5" is in the thin end. I guess 2" joists are the common width?

FluffySheep