I have removed the skirting boards in my new build house, as I am going to fit engineered wood floor via the floating method.

The issue I have is that after removing the skirting, I was presented with these cavities at the base of the wall. They are around 2 inches wide, but vary in size around the room.

On the exterior walls there is also a gap in the flooring at the back of the cavity.

The interior walls have do not have this gap.

In addition to the below questions I was wondering the purpose of this gap?

I'm not sure how to proceed with the fitting of the floor though.

  • Should I just lay underlay and leave the cavities as they are?
    Would this not allow a draft under the skirting?
    Would it allow too much movement of the floor?

  • Fill the cavity completely?
    Would this affect any insulation/damp-proofing on exterior walls?
    What should the cavity be filled with?

  • Fill the cavity to within half inch of floor?
    This is how the walls were when I have previously laid flooring How would I go about filling to this level?

Appreciate any assistance with this and happy to provide any more information if required.

Cavity bottom of wall

1 Answer 1


If you're putting back the skirting boards, you can get wooden beading/moulding to cover the expansion gap.

Alternatively you could use a thin bead of hidden flexible caulk underneath the skirting board if you don't mind having a gap, as this would stop drafts coming from underneath.

In my (limited) experience this 2 inch gap is normal on both plasterboarded and normal plastered walls. It seems like there's a few advantages - e.g., it avoids damp problems from the floor or spills, and also allows expansion movement.

  • I've removed the skirting to allow the flooring to fit underneath to avoid using beading. If I were to use caulk, this would attach the flooring to the skirting, which would likely either crack when the flooring expands or if it doesn't then will prevent the flooring from expanding.
    – 123
    Commented Nov 14, 2019 at 10:16
  • 1
    That's fair - I would go with your third idea of extending the plasterboard to within a half-inch of the floor then to stop the draft. You could fill it by gluing thin strips of plasterboard along the wall, or use something like polycell plaster repair. Will be interested to see what other answers suggest as I'm about to face in to the same problem.
    – Matt
    Commented Nov 14, 2019 at 11:27
  • Ye I considered filling it with hard wall (cheap) or something down to half an inch, but not sure how to stop at that height? Possibly use a piece of plywood or something and remove just before it's fully set?
    – 123
    Commented Nov 14, 2019 at 12:08
  • Most homes do have gaps at the bottom that’s what the mop boards or “trim” hides. Since you have a floating floor the trim needs to be thicker than the gap between the floor and the wall and, wider than the gap from the Sheetrock to the decking. You can fill the spaces so you can have smaller trim pieces but you will still need some trim over the flooring to hide the gap that slows it to float.
    – Ed Beal
    Commented Nov 14, 2019 at 15:20

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