how do I raise a floor

[tinno]

Hi, we have had an extension which has increased the size of the lounge. We now have two different floors in the lounge, one half made up of the new extension with a concrete floor and the other half made up from the original lounge with the old wooden floor. Problem is, the new concrete floor is aprox 8mm lower than the original wooden floor. I obviously need to raise the new concrete floor to bring it level with the old. This must happen all the time with new extensions, but I can't find any advice on the net. Would really appreciate some advice on how to go about it. BTW - carpet is going to be used - I did find backerboards which seemed to fit the bill perfectly but am I right in thinking they can only be used if you are tiling on top, I'm guessing carpet wouldn't give them enough rigidity?

 

[Deleted member 174758]

I did find backerboards which seemed to fit the bill perfectly but am I right in thinking they can only be used if you are tiling on top, I'm guessing carpet wouldn't give them enough rigidity?

You could aleways level off with screed or latex, but it would take 2 or possibly coats to give sufficient build. had a look at the backer boards - most are foam.

 

[tinno]

Thanks jobandknock for taking an interest and quick reply - I've been told by the building regs guy that you can get levelling compound for under 3mm or over 50mm - but I thought levelling compound was to level a surface not raise it?

 

[Deleted member 174758]

Thanks jobandknock for taking an interest and quick reply - I've been told by the building regs guy that you can get levelling compound for under 3mm or over 50mm - but I thought levelling compound was to level a surface not raise it?

Well al I can say is that I've seen commercial flooring guys double skim floors and thick skim to get the required amount of build on a bad floor on a number of occasions and that's how I did my own kitchen a few years back (using a few bags left over from a trade job). The brands these guys use are names like Ardex, Ball and BAL - not names you'd get from a DIY outlet. I've just looked at the technical notes on a bag I've still got here. It reckons that you can build up to 35mm, but that over 10mm thick you need to add fine aggregate. These compounds say they are self-levelling, but the reality is that you'll still need to trowel them out to somewhere near the required level. It needs to be done quickly, too, because the stuff starts to set within 15 to 20 minutes and you can walk on it in about 2 hours

 

[rjm2k]

Did you build the extension yourself? If not, why didn't the builders ensure the floors were at the same level?

 

[tinno]

Builders built the shell, I'm doing the internal stuff - electrics, plumbing, dot & dabbing!!!! All in the name of trying to save money!! Thats what I thought, the builders surely should have levelled the floor, unless they regarded that as "internal"!! I certainly regard it as part of the shell. The ceilings were way out as well, had to level those as well. I'm finding a few little things, not major, that weren't built according to building regs, for example, I had to remove the bi-fold doors at the weekend to shift the frame so I could get the cavity closers in, something the builders didn't do!!!