Levelling a Concrete Floor before a wood floor is fitted.

sooty&sweep

Hi

We've had an extension & we're due to have a wood floor fitted in a couple of weeks.
The concrete floor is roughly level but has a few dips & lumps & bumps so we're considering using some sort of self leveling flooring compound to even it out.
Has anyone used this stuff ? How easy it to apply ? Any recommendations on a brand to use ?

The wood floor will have an underlay. How much will this take out in terms of lumps & bumps ?

Cheers

Jen

tacpot12

I've tried using a self-levelling compound and it was quite difficult to use. It can set quite quickly.

Ultimately I ended up with a floor that was pretty level, but it is one job I would recommend contracting out to a specialist. I'm pretty handy when it comes to DIY.

Davesnave

Your flooring company should probably do the levelling.

It's not a terribly difficult job, but like many other skills, not worth experimenting with. Our floor fitters came in the day before, laid the self-levelling compound and were gone within an hour or so. Added very little to the cost.

EssexExile

You say you're having the wood floor fitted, won't the same people prepare the surface? I'd be worried that if anything goes wrong the floor fitters will blame your preparation.

Edit: I had some self levelling put down in a small extension & they had three goes before it was good enough for carpet!

FreeBear

Did a small area (1.4m x 2.4m) myself a few months back - Really not that difficult, but you must follow the instructions on mixing. On reflection, I should have used a notched trowel for spreading the stuff instead of a regular large plasterers float, but even so, it ended up nice & smooth.

On large areas, it would pay to have two people - One to pour, and the second mixing so that the whole floor can be done quickly. The stuff goes off very quickly, so speed is essential.

As the OP is paying someone to fit the flooring, get them to do the prep work so that there is no questions over liability if things go wrong.

Tom99

I glued 3mm mdf to a concrete bathroom floor and it worked very well.

The other option was, as above, to have the fitter level the floor.

TheCyclingProgrammer

I would expect a decent fitter to do any preparation needed including levelling of any dips and bumps before laying the floor (and for this to be reflected in the price of course).

Doozergirl

You'll need a liquid DPM too if the extension is brand new. The concrete will not have fully cured.

sooty&sweep

Hi
The fitter has seen the floor & he thinks it's OK.
The floor isn't 100% level but the unevenness is a couple of slight lower points. You struggle to spot them unless you look hard.
There was also a channel cut through the concrete & refilled. That refilled channel is slightly raised.
The fitter has seen the floor & his view was that although it wasn't 100% even the unevenness was very gradual, if that makes sense & so the underlay would sort it out.

The fitter comes highly recommended from where we've purchased the floor from.

Our builder however is concerned & thinks we should level it.

Any advice ? How level does a concrete floor need to be ?

Jen

TheCyclingProgrammer

If he thinks it’s fine and he’s guaranteeing the job then go with his recommendation.

Tall_Tone

The aim for a subfloor is +/- 3mm over 3 meters. Trying to do this with an underlay on a wood floor when outside of this tolerance will mean the boards can move when stepped on and possibly squeak. For the sake of a few £ and 24 hours drying it is always worth levelling. As mentioned earlier, if the floor is new you will need a DPM top protect from moisture.
Wood floor adhesive would be better as by using a 6mm notch trowel it means the floor is fixed all over and will not move.