Leveling split level floor

[hamd01]

Hi guys
I'm currently converting an old outbuilding into a usable room. The room has a step and I'd like to bring the floor level and get some 50mm insulation boards installed. The room is 6m x 5m, with the step roughly at the middle, around 15cm.

I was thinking of using c16 45 x 195mm, with OSB boards on top of the lower side, and 45 x 70mm on the upper side of the room.

However that will still leave a step of around 3cm.

I'm basing it on what c16 sizes I can see on the Wickes website.

Could anyone advise if the above is structurally sound, and if cutting the timbers down by 3cm is the right solution to even it up, or if I should shim up instead of cutting down?

Cheers

 

[cdbe]

If it's a solid floor you might be better just screeding on top of the insulation, you could use cheaper polystyrene on the deeper section. If it's a timber floor a floating floor on top of the insulation.

 

[^woody^]

If you are using timber, why can't the floor be constructed to the exact height?

 

[hamd01]

If you are using timber, why can't the floor be constructed to the exact height?

Thats what my question is.... but specifically if the timber Im proposing to use is suitable, and if I should shim up, or cut down in order to achieve a level.

 

[hamd01]

If it's a solid floor you might be better just screeding on top of the insulation, you could use cheaper polystyrene on the deeper section. If it's a timber floor a floating floor on top of the insulation.

Thank you. Yes it is a solid concrete floor. So you mean to put the insulation down, then OSB ?

 

[cdbe]

To do that successfully the original floor needs to be flat. You can get different thickness of insulation to make up the levels and even a bit of hardboard for fine tuning, and t&g boards.

Personally I'd never bother with a timber floor again - DPM, PIR then screed on top is the easiest, quickest and probably cheapest. When I say screed, for a DIY job it's more likely to be concrete. In my area you'd be looking at around £500 for 30sqm x 75-100mm thick barrowed in. Leveling (to form a finished floor) is achievable, but a bit of work so it may need a leveling compound on top.

 

[hamd01]

To do that successfully the original floor needs to be flat. You can get different thickness of insulation to make up the levels and even a bit of hardboard for fine tuning, and t&g boards.

Personally I'd never bother with a timber floor again - DPM, PIR then screed on top is the easiest, quickest and probably cheapest. When I say screed, for a DIY job it's more likely to be concrete. In my area you'd be looking at around £500 for 30sqm x 75-100mm thick barrowed in. Leveling (to form a finished floor) is achievable, but a bit of work so it may need a leveling compound on top.

I suppose I could do that, but just a question.... Ive already installed a stud wall all the way around. Supporting the base of the stud wall are treated timber joists. Would be be acceptable to concrete up to these?

 

[Ivor Windybottom]

A floating floor would give the best insulation, also the lowest cost and quickest. I replaced mine in my work room, I have literally tons of stock in here on steel shelves. I'm pleased and surprised to say it's rock solid, hasn't collapsed and isn't like a bouncy castle.

Use whatever thickness of celotex or similar and 22mm t&g chipboard, glue the joints and put a vapour barrier sheet under.

You need the concrete to be flat, you don't need it to be smooth. If there are bumps knock them off with a chisel. Then skim the whole lot just with dry kiln-dried sand, the sand will fill the voids and remains mobile so is free to move about as needed.

If you need precise alignment against the higher side you could pack under the new floor or screed the original.

 

[hamd01]

A floating floor would give the best insulation, also the lowest cost and quickest. I replaced mine in my work room, I have literally tons of stock in here on steel shelves. I'm pleased and surprised to say it's rock solid, hasn't collapsed and isn't like a bouncy castle.

Use whatever thickness of celotex or similar and 22mm t&g chipboard, glue the joints and put a vapour barrier sheet under.

You need the concrete to be flat, you don't need it to be smooth. If there are bumps knock them off with a chisel. Then skim the whole lot just with dry kiln-dried sand, the sand will fill the voids and remains mobile so is free to move about as needed.

If you need precise alignment against the higher side you could pack under the new floor or screed the original.

Do you mind me asking... I'm going to be running the radiator pipes around the permitter of the room....did you have to deal with that in your install? Im assuming you'd just leave a gap at the edge of the insulation to fasten the pipes to the actual floor, with some brackets to support the OSB?

 

[Ivor Windybottom]

I don't have a radiator so didn't need to worry. But I have run plumbing pipes under, I just left a channel in the celotex, just loose-laid the pipes in this, put masking tape and polythene over the surrounding celotex then squirted a can of expanding foam either side of the pipe. This all puffed up proud of the surrounding celotex. The next day, I used a sharpened building trowel to slice it off flush with the celotex. My method only, not approved by anyone. But it's a mains pressure cold water pipe, I haven't made a fountain!

However you do it, ensure you don't bond the pipes to the floor, e.g. where it comes up through it. The floor needs to be able to move a mm or three without making the pipes move. Make the hole through the chipboard over-sized. I used plastic pushfit, it's less bothered by a bit of movement. Decent John Guest fittings and pipe, all tightly locked so they can't work loose.