How level does my floor need to be?

by Iain


How level does a floor need to be before laying new engineered boards over it?

I'm about to start laying a wood engineered floor over my existing floorboards at home.
Although we can make the surface fairly level itself there is a bow or dip to the floor at one end of the room with the existing floorboards being lower at the walls than they are in the middle of the room.
The difference could be as much as 2cms rise and fall over 3-4 metres.

Is this something that the new floor boards will deal with or do I need to somehow completely level the original floor before I can start the new one?

Hope you don't mind the question, I just came across your carpentry site looking for an answer and thought you'd probably be a good person to ask!

Many Thanks,


Comments for How level does my floor need to be?

Click here to add your own comments

Nov 16, 2010
by: Iain

Hi Gary,

Thank you so much for the reply, it's really helpful.

We are fitting the skirting board as well which sounds like it will help, and there's a particularly bad dip at one point which I should be able to lift the boards on and even out before I start.

Again, really helpful, and I will let you know how I get on.

Many Thanks

Nov 16, 2010
Levelling out existing floor ready for engineered click together boards
by: Anonymous

Hi Iain,

That's a really tough one for me to answer without seeing the room! If it's a gradual fall you'll be fine, if it's quite sharp dips it might cause you problems.

Engineered floor boards are quite thick and because of the ply layers they're really strong. Saying that, I laid engineered oak in my bathroom, but nailed it down to the joists like traditional floor boards. It's not meant to get wet, and the joists were all over the place. It still looks brand new though, 3 years later. Theres no bounce, and its solid.

There are a few factors that I would consider when deciding whether or not to justify the extra work the levelling would take. Although the manufacturers instructions would insist you level the floor within 2-3mm, i've laid floors over much worse. I'm pretty sure the floor would be fine, though i'd glue all the joints together really well even if it was a glueless click together floor. The main thing you want to avoid is having a low spot that dips down when you walk on it, as this will eventually weaken the joints.

So, it's definately a good thing that the middle of the room is higher than the wall. If the middle of the room was low, i'd recommend levelling first because it would get the most traffic and be up and down like a yo yo.

Is the low part going to be covered by furniture that will hold it down?

If you are replacing the skirting boards that would help. When you put the new skirting round you can push the floor down tight to the old floor so it can't move up and down.

To do this, use a 1200mm long offcut of skirting and rest one end on the top edge of the skirting. Then kneel/stand on the middle of it to push the board down tight while you fix.

I had to level out the floor in my lounge and dining room when I knocked the two through into one because they were all over the show. The easies way I found was to lift the boards up and simply screw new joist timbers onto the side of the low ones. You could try that, it would be easy if its just a small area that needs levelling.

If the floor is screed/concrete oversight it probably needs to be latexed with a self levelling compound to level it out.

Hope this helps. Basically to sum up, as long as you can keep the flooring kept pushed down so the joints don't weaken over time you should be ok.

Good choice of flooring!

Best regards,


Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Q&A.