Plywood or Floorboards and insulation

24 Feb 2007
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United Kingdom
I was hoping if someone can help / advise?

I have 1930's house and the floorboards are 5" T&G; I am struggling to find the same size. Someone suggested that I use structural Hardboard Plywood and it can be cut to make joints where I have electrics, gas water pipes running to make it easily accessible should we need to lift it in future.

I have seen there are a lot of 18mm options for different types available. Can anyone suggest if this is a good idea and it wont bend due to daily traffic in the house?

Also, currently I do not have any insulation below the floorboards, given the fact that there are electric, gas and radiator pipes running all over beneath the floorboards, is it a good idea to have the insulation (thinking for the fire risk perspective) and if insulation between empty spaces between joists, is it good to have the wool insulation or insulation boards to retain the heat and sound proof the room.

Many thanks
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Why would you need same size? Just need to be same depth .
Hi Foxhole, the reason I am looking at the same size so that I do not have to change all the floorboards.

As I need to change a few floorboards, I thought it would be better if I rip all the floorboards and replace them with 18mm structural hardwood Plywood sheets and make the joints where I have pipes and wires so that whole boards do not have to be lifted in the future.

I am not too sure about the insulation as there are hot water pipes and wires running beneath the floorboard voids and hence seeking advice.

Many thanks,
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Structural HW ply is suitable for flooring. 18mm is sufficient if your joists are on 16in/400mm centres. In terms of access, if you own a router the Trend Routabout access hatch system is excellent for making neat service accesses

In terms of sound insulation your best (affordable) bet is probably mineral wool batting.

Copper pipes are often insulated with a mineral wool sleeve with an outer facing of aluminium foil, so they should be OK with mineral wool

Electrical junction boxes should not be insulated over and areas above built-in downlighters (where heat build up can occur) should be protected with a purpose made heat cap (they look a bit like an Egyptian fez)
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