Levelling floorboards for engineered wood

30 Aug 2019
Reaction score
United Kingdom
I’ve started installing 14mm click fit engineered wood in my first floor (which has floorboards)

All I did for preparation was screwing down the loose floorboards and replacing the ones in bad shape with 18 mm plywood; I also used a sander to bring down a couple peaks in the floorboards edges (mainly where two joists meet)

I used a 3mm underlay (this one https://www.wickes.co.uk/Arbiton-Ea...Wood-Flooring-Underlay---10-2m2-Pack/p/191372) and started installing the planks parallel to the existing floorboards

After completing the first room I realised the floor squeaks when stepped over, and in some cases it even moves by 3 mm (measured using a 60cm spirit level and puttin my weight next to it)

The subfloor is clearly not levelled and maybe I haven’t used the correct underlay

I am thinking of taking the planks up (I should only break the 6 that I’ve had to glue, but save the rest) and do whatever is necessary to stop the floor from moving and make noise

I am thinking of using a planer wherever there is a step between two adjacent floorboards and then nail down some 3mm hardboard (2.5£/m2) and maybe use a different (thicker? Fibreboard?) underlay

What do you suggest?
Sponsored Links
I always screw the boards down at 400 centres with tongue tite screws. On a concrete floor, prime and glue down.
I’d change the underlay to timbermate excel. Great for wood floors.

The floor needs to be flat as any dips will cause movement which leads to squeaks in a click engineered.
Sponsored Links
I’d change the underlay to timbermate excel. Great for wood floors.

The floor needs to be flat as any dips will cause movement which leads to squeaks in a click engineered.

But how? 3 mm ply, 6 mm ply, self levelling compound?

I’ve been told to use 6mm ply, but what happens if there is a large dip in the floor below the plywood so that it is not in contact with the floorboards? I’m talking about an area of maybe 20x20 cm, not just a few mm...
Last edited:
The way we do it.

6mm Plywood the whole room. Ringnailed every 6” and 4” on joints
Then get a 2m long level / feather edge
Mark on floor low spot and screed rheum with
Uzin 196
Fball 700
Bostik flex
Ardex FA10
Tilemaster levelflex

Take a lot of time and can be hard to get everywhere flat and level.
Do I have to nail the plywood in the centre as well to be sure it’s in contact with the floorboards or just on the sides?
Cut up about 2mm short and then use gripfill or a mastic.
Was about to say put this on the flooring forum for more advice. But you have
Is it better to pour the slc on all the three bedrooms and the hallway together (35 m2) or room by room? And if so, how do I ensure they are all at the same level if done at different times?
I was thinking of using Mapei Ultraplan as slc, I’ve checked the instruction and it doesn’t say what primer or sealer to use on plywood

What do you suggest?
Mapei Prim grip

Are you sure? It doesn’t mention timber here

Eco Prim Grip is a multi-purpose, ready-to-use primer for internal and external floors and walls and may be used to improve the bond of all types of cement, gypsum and lime-based plasters on substrates made from concrete, brickwork, vibro-compressed concrete blocks, lightweight blocks and gypsum.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links