Solid boards for loft insulation

[ban-all-sheds]

My Mum is having her loft insulation upgraded - it currently has a mix of old but sound fibreglass (about 100mm), tatty, ripped, squashed fiberglass, vermiculite and nothing.

She wants to have part of it boarded for storage purposes afterwards, and there's an obvious section where this would best be, so roll insulation running across the joists as well as between, as proposed by the installer, would be a pain in that part.

As far as I'm aware, solid foam or EPS panels (Kingspan/Celotex/Jablite/etc) are perfectly OK for walking on when there's chipboard over the top - am I right?

My idea was to have roll insulation between the joists in that part and then solid insulation boards on top of the joists.

Any problems with that?

Any recommended products?

Cost issues are distorted a bit by the fact that she'd get the roll stuff installed for nowt, but in general are the ready made insulated boards worth it, because they save the installer time, or would separate insulation and flooring be cheaper?

Access is no problem - 8x4 sheets of foam could easily be got up there.

 

[mointainwalker]

As far as I'm aware, solid foam or EPS panels (Kingspan/Celotex/Jablite/etc) are perfectly OK for walking on when there's chipboard over the top - am I right

I think that's only when they are 100% supported and if I have read it correctly you are talking about partial/intermittent support on joists so I can't imagine the Jablite would survive. As for the others I can't say but would certainly depend on thickness to some extent.

Given that PIR etc is pretty expensive and the fibre-wool is free, would not a second set of joists at 90o to existing, roll in-between and boarded on top not be a better option ?

 

[ban-all-sheds]

Yes - intermittent support by joists, but with boards on top to spread the load.

Companies make composite boards designed for use like that e.g.

http://www.insulatedloftboard.co.uk/

http://www.knaufinsulation.co.uk/press_releases/deck_it_out_with_knauf_insulat.aspx

and insulation panels designed to be used like that with your own boards on top, e.g.

http://www.space-insulation.com/board.html

http://www.knaufinsulation.co.uk/pr...oam_floor_insulation/polyfoam_floorboard.aspx

But how the insulation material differs from other foam/EPS/XPS products I don't know.

Difficult to say where the cost balance lies - probably not with cross-joists unless composite boards are expensive and regular insulation can't be used, because there's the costs of the joists, and two sets of labour activities to pay for rather than 1.

 

[mointainwalker]

Yes - intermittent support by joists, but with boards on top to spread the load.

When you write this , I am still not clear if you mean boards on top of joists. If you do then i don't see a problem,

As for these other "special" boards, don't know, never looked at them.

By the way, i think you've had your external insulation done now ( from something i read on here ). Do you want to start another thread to say how it went as it's something very few people seem to do.

 

[ban-all-sheds]

Yes - intermittent support by joists, but with boards on top to spread the load.

When you write this , I am still not clear if you mean boards on top of joists. If you do then i don't see a problem,

No - I mean boards on top of the insulation, like this:

By the way, i think you've had your external insulation done now ( from something i read on here ). Do you want to start another thread to say how it went as it's something very few people seem to do.

Still not ******* well done.

Finding it really difficult to find installers willing to do a one-off private house - they all seem geared up to doing multiples for housing associations and local authorities.

Have had 2 quotes, didn't like the system proposed by the cheaper. Found another company by chance at a home improvement show last weekend, and that's given us another route to look for companies via the trade associations(s) for external plasterers/specialist renderers instead of just the insulation association.

 

[studips]

yeah, see no probs, i was carefully walking around on 100mm celotex yesterday without boards and haven't dented on left a mark, with a ply or mdf sheet over it you'll be fine