loft boarding

[ria]

Hi,

Sorry to ask but I need it spelt out for me.

Our loft is insulated. But the insulation isn't thick enough according to today's standard. If we get more laid down, the joists will have to be raised in order to have enough clearance over the insulation to board over it.

I want to know - do we raise first or insulate first?

A small area is already boarded - any thoughts whether to leave alone with less insulation or take it up and do the whole thing at once?

Thanks, Ria

 

[JohnD]

raise first.

 

[ria]

Thanks.

So, if I raise : then I get 3x1 (this is what you mean by counterbatten?) lay it flat across (not along) existing joists at intervals suitable for the boarding width, right? Assuming the existing joists look like they'll take the additional weight and using long screws. So I will end up with a grid and will have to tuck the insulation in between criss crossing joists and 3x1 - is that right? And I'm aiming to board over this but leaving 5 cm clearance? (will the additional 1" give me enough room) Is this right?

I know it's mostly all there in the preceding posts but like I said I need it spelt out for me.

Thanks, Ria

 

[JohnD]

personally I wouldn't use 3" x 1"

If you need a bit of extra height (plus an airspace between the top of the insulation and the bottom of the boards) consider how much extra depth of timber you need.

For example your old ceiling timbers might be 100mm high, and you might want 150mm of insulation, so you need a 60 or 70mm thick counterbatten. I would hesitate to go for 250mm of insulation unless you are compelled to for some reason, you get diminishing returns on additional thickness and it will not be easy to get such depth if you want to be able to walk about up there.

It's useful to have one at least 50mm wide so you can put the boards on it easily. If you use a high and narrow batten it will fall over while you are trying to fix it.

When I re-did mine, I put 100mm between the old timbers and ?75mm? running the other way between the counterbattens (it will squash down where it crosses other timbers or pipes). Running it cross ways reduces any cold spots where you have gaps or thin parts. Have a look at the thickness of your old stuff, you can re-use it or run it the other way.

 

[ria]

thanks.
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