Attic floorboards

B

Birroc

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Hi,

I have just insulated the attic and I want to get some attic floorboards. Are there different types or is it simply just rough chipboard floorboards with grooves?

How much would I expect to pay and for what size?
 
Woodies sell t & g attic flooring packs, convenient to pass through the hatch, from memory I think 1 pack covers about 5 square metres and €15 per pack
 
Some of the chipboard sheets are very heavy. I noticed that 1 sheet of a lighter chipboard cost just over €8 in Woodies during the week. Seemed like bad value to me.
 
I have just started mine. Did you cut grooves in the joist for the cables? some say not to do this but there is little aternative
 
You should really put thin battons on top of the joists instead of notching them. Cutting the joists weakens the roof structure.
Leo
 
I cut a nick in my joist, this is nothing compared to the thickness of the joist, plus if you are screwing a 1/2 in thick floor on top it should be stronger because it is making a kind of box section. I must add that I am not an expert on this matter.
 
In theory your insulation should be running not only between the joists but across it i.e. perpendicular to them to meet the required standards.

So therefore you would probably be best off getting insulated rafter boards and minimising your floored areas.

Admittedly when I did it myself I wasn't aware of this and now that it's floored I can't really add additional insulation without taking it all up, so it might be in your interest to consider it at this point.
 
cbyr1983 said:
In theory your insulation should be running not only between the joists but across it i.e. perpendicular to them to meet the required standards.

So therefore you would probably be best off getting insulated rafter boards and minimising your floored areas.

Admittedly when I did it myself I wasn't aware of this and now that it's floored I can't really add additional insulation without taking it all up, so it might be in your interest to consider it at this point.
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That's right, Cbyr. I insulated between the joists with fibreglass insulation and laid 2 layers of 60mm rigid insulation across them before flooring on top of it with the B&Q tongued and grooved chipboard flooring. The flooring is very heavy alright, as Tintagel said.
 
I would prefer to insulate inside the tiles, thats where the condensation appears, and it would also help the water tank.
 
roker said:
I would prefer to insulate inside the tiles, thats where the condensation appears, and it would also help the water tank.
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If you're getting insulation in your attic, you need to increase the ventilation in the attic space.

It sounds like there is none so the warm air that's rising through the ceiling and the current insulation is not being 'flushed' out of the attic because there's little or no ventilation and when the warm air hits the tiles, the moisture in it condenses because the tiles are colder.
 
roker said:
I cut a nick in my joist, this is nothing compared to the thickness of the joist, plus if you are screwing a 1/2 in thick floor on top it should be stronger because it is making a kind of box section. I must add that I am not an expert on this matter.
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OMG! :eek:

Please do not do this!

Screwing a 1/2 in thick timber sheet on top of ceiling joists will not prevent them from bowing or failing.

Roof timbers are specified a certain thickness for a reason. Notching them could compromise their structural integrity.

As Roker said he's not an expert.

As others have suggested, laid rigid insulation across the ceiling joists, lay the chipboard on top and screw through into the joists taking care not to screw into electrical cables. Electric cables can overheat if covered by insulation so you should make ever effort to lay them on top of the insulation.
 
For years plumbers and electricians have drilled hole/nicks in joist to get pipes through etc, Are we saying that the engineering is so under engineered (calculated so fine) that a small nick will make a difference? is it not calculated to take weight for storage etc? There is already a 60+ gal water tank up there, which is nearly half a ton. When I had my Stira loft ladder fitted 8 yr ago they cut out an entire section of joist and braced it across. The stud wall underneath is also bracing the joist.

On a point of insulation, I agree with bmacintyre you must increase ventilation, but there must be no entry point for air from the house below, otherwise the warm air from the house will carry moisture to the attic, and that is what condenses.
 
If it is only going to be used for storgage why not partially floor, leaving every third floor space open or areas near the upright timbers open?
 
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