Three Methods To Fill Gaps In Wood Flooring

If you’re having trouble with gaps in your wood flooring, you’re not alone.  Wood floors are essentially made up of strips of wood which are butted together, which may, or may not be nailed or glued into place.  Gaps in wood flooring are caused by the long-term expansion and contraction of the wood.  Although significant gaps in relatively new wood flooring are relatively uncommon along the lengths of the board, you may find that newer floors develop gaps at the ends of the boards.  Old floors on the other hand are likely to have gaps, both along the lengths of the boards as well as at the ends, due to the years and years of expansion and contraction the floor will have faced.   Gaps in wood floors not only look unsightly, they can be the cause of drafts and energy inefficiency.

So how can you get rid of the gaps in your wood flooring? If your floor isn’t fixed to the subfloor, you could try sliding the boards back into place, working around the perimeter of the room, where an expansion gap will have been left.  If necessary, once you’ve managed to manoeuvre the boards back into place, you could introduce some pegging around the edges of the room to prevent future sliding.  You can also reduce the movement in your floor by avoiding sliding furnishings and heavy items across the boards.

If that doesn’t resolve your problem, or if your gaps reappear, there are three main methods of filling gaps in wood flooring, which are:

  • Using a dust and resin filling.
  • Introducing filler strips.
  • Inserting a colour-match acrylic filler.

Here’s an outline of how to do each.

Using a dust and resin filling.

This is one of the most commonly used ways of filling smallish (less than 5mm) gaps in a wooden floor.  What you need to do is to get your hands on some sawdust that is of the same, or at least a similar colour to your floor (unless of course you still have some from when your floor was installed).  Once you have your sawdust, you need to mix it with a clear resin filler, which you’ll be able to get from any DIY shop or your wood floor supplier.  The consistency you’re aiming for is a bit like a thick putty, which you then introduce into the gaps using a spatula.

This method of gap filling has the advantage of providing a smooth and colour-matched end result and it dries quickly.  The downside is that the mixture can fall through gaps where the floor is laid directly over joists and it often becomes fragile with significant floor movement.

Introducing filler strips.

Filler strips are essentially very fine batons of the same species and colour of wood as your floor that you insert into the gaps.  The great advantage of this method of gap filling is that there is no risk that the strips will fall through, because they too will be able to rest on the joists.  What’s more, filler strips also create a very stable and attractive end result.

At the end of either of these two filling processes, you’ll need to sand over the filled gaps to smooth the floor out and prepare it for refinishing (if required).

Inserting a colour-match acrylic filler.

Colour-matched acrylic fillers are easy to source, either from a good DIY shop or your wood floor supplier and are arguably one of the most straightforward ways of filling gaps in wood floors.  Essentially a mastic, this method is fast, efficient and doesn’t require sanding at the end.  All of that said, the greatest challenge you’re likely to face with this solution is getting the colour spot on, so do be prepared to experiment.

Table Comparison of Gap Filling Methods in Wood Flooring

 

MethodProcessAdvantagesDisadvantages
Dust and Resin FillingMix sawdust with clear resin filler to a thick putty consistency. Introduce into the gaps using a spatula.Provides a smooth and colour-matched end result. Dries quickly.The mixture can fall through gaps where the floor is laid directly over joists. Can become fragile with significant floor movement.
Filler StripsInsert very fine batons of the same species and colour of wood as your floor into the gaps.No risk of falling through as they rest on the joists. Stable and attractive end result.Needs extra process of sanding after filling to smooth the floor.
Colour-Match Acrylic FillerInsert a colour-matched acrylic filler into the gaps.Fast and efficient. Doesn’t require sanding at the end.Challenging to get the colour match perfectly. May require experimentation.

FAQ

1. Why are there gaps in my wood flooring?

Gaps in wood flooring are caused by the long-term expansion and contraction of the wood. This can be more noticeable in old floors, which are likely to have gaps along the lengths of the boards as well as at the ends. Newer floors may develop gaps at the ends of the boards.

2. Can gaps in wood flooring cause drafts and energy inefficiency?

Yes, gaps in wood floors can look unsightly and also cause drafts and energy inefficiency. This is because the gaps allow cold air to enter the room from the spaces below the floor.

3. What can I do to get rid of gaps in my wood flooring?

If your floor isn’t fixed to the subfloor, you could try sliding the boards back into place, working around the perimeter of the room. You could also introduce some pegging around the edges of the room to prevent future sliding. Alternatively, you can use a dust and resin filling, introduce filler strips, or insert a colour-match acrylic filler.

4. How can I fill the gaps in my wood flooring with a dust and resin filling?

To use a dust and resin filling, get sawdust of the same or similar colour to your floor, mix it with a clear resin filler, and introduce it into the gaps using a spatula. This provides a smooth and colour-matched end result and dries quickly.

5. What are the other methods of filling gaps in wood flooring?

In addition to dust and resin filling, you can introduce filler strips or insert a colour-match acrylic filler. Filler strips, which are very fine batons of the same species and colour of wood as your floor, create a stable and attractive end result. Colour-matched acrylic fillers are easy to apply and don’t require sanding at the end, but getting the colour spot on can be challenging.

Jonathan Sapir

Jonathan Sapir has over 17 years in the flooring industry. As an authority on flooring, he infuses his extensive knowledge and passion for quality products into every article. Jonathan's expertise helps readers make informed decisions for elegant and durable flooring solutions.