Its time for me to think about the internals of an attic in a traditional British one and a half storey cottage.

Picture of 1st floor inside cottage

enter image description here

Note this is just spare bits of timber sarking as a temporary floor. The floor will be 22mm T&G chipboard.

Looking at various videos online I am not sure what is the best / correct way to go about it.

So, do I put my chipboard flooring on first, then the studwork frames?

Is it ok for the studwork partitions to be screwed onto the chipboard flooring, or do they need to be directly fixed to the joists?

Here is a diagram of my thinking, two ways

enter image description here

Any other suggestions or advice welcome!

  • Please limit your questions to 1 question at a time. Without some editing, this feels like it's too broad and needs some focus. For Q1 - how would you propose holding up the flooring while you're assembling the framing below it, if you were to attempt this method? I've never heard of anyone trying to put down flooring before installing the framing to hold it up? – FreeMan Mar 10 at 12:47
  • @FreeMan updated my question to be a bit more clear. Essentially do I build studword partitions onto the joists directly or can I lay the chipboard floor first, then fix the partitions onto the chipboard. – tomaytotomato Mar 10 at 15:04
  • Is "chipboard" OSB? Industry terms are most clear. – isherwood Mar 10 at 15:14
  • Its called Caberfloor, its definitely not OSB. Not sure what the equivalent in USA is. norbord.co.uk/our-products/caberfloor/caberfloor-p5 – tomaytotomato Mar 10 at 15:22
  • 1
    Interesting, that Caberfloor is what I'd call T&G OSB with a particle board surface. At 22mm (about 7/8") it seems to be reasonably thick, and if it's water resistant, then I guess all is good. – FreeMan Mar 10 at 15:44

You'll want to put in your floor joists, lay down the sub floor, then build partition walls on top of that.

It's unlikely that all your partition walls will fall exactly on a joist, so without subflooring you'll be going through all sorts of gymnastics to support the wall. Since none of your partition walls will be load bearing, you won't have to worry about walls bearing on joists - just use standard dimensional lumber with stud spacing to match your national standards.

Also, I believe that "chipboard" means different things in different parts of the world. So long as the stuff you're using is rated for flooring use, you should be fine. (Here in the States, what I think of when I hear "chipboard" would not be suitable for flooring.)


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