Filling gaps between floorboards in bathroom

[Chris_T]

Hi

I've got old timber floorboards in my bathroom near the shower which have quite large gaps between them (~2mm). They end up with a lot of dust and dirt in them, and I'm concerned about water getting in and pooling - and I was considering filling the gaps - but found a lot of conflicting advice on Google about whether filling gaps is a good idea at all. There were also lots of conflicting suggestions about what to fill them with given there's likely to be future expansion/shrinkage. In addition to that, there wasn't really any advice specifically about wet areas. 

Alternatively I wondered if I could just recoat the boards in that area with a layer of varnish to seal them a little? The original varnish near the shower base is pretty rough now (I've only had the house a short time but I'm guessing decades of moisture have played a part).

Thanks!

Chris

[Jason]

Hi again @Chris_T,

Can you please tell us whether you can access under the house? It might be helpful for members to see some photos from the other side of this gap to see if water is getting through and if so, what damage it might have caused.

Once you've let us know I would be more than happy to tag some helpful members to share their thoughts on how they would tackle this job.

Thanks,

Jason

[Chris_T]

Thanks Jason 

I went for a bit of a crawl and got the below pic - the orange arrows point to the board with the gaps (the lighter board in the earlier photo). Doesn't seem to be any signs of water damage or leakage. Also revealed that the boards here seem to be newer than the boards in the rest of the bathroom (you can see one of the older boards on the left in the image below are much darker and have old water stains).

[Jason]

Many thanks for the photo @Chris_T, I think that will be helpful to other members to see what you are working with. It's great that there's no signs of water damage.

Let me tag helpful and experienced members in @JDE, @Mathy and @tom_builds for their thoughts on next steps. @EricL will also be happy to assist as soon as possible.

Jason

[JoeAzza]

Hi  @Christomk,

I have used Selleys No More Gaps to fill in gaps on baltic pine floors, however, my floors are painted not varnished like yours, Bunnings do sell a coloured version of No More Gaps, see below.

Selleys 380g Baltic No More Gaps Timber Floors Gap Filler - Bunnings Australia.html

[Chris_T]

Thanks @JoeAzza - to be honest there have been a few dodgy patches done over the years in this bathroom, so an absolute match probably wouldn't be a disaster. I'm more focussed on trying to give it as much water resistance as I can right now to give the floors a little longevity until an inevitable full bathroom reno!

[Chris_T]

As I'm currently not able to go in to a Bunnings store, does anyone know if these no-more gaps products have a colour reference in store? I was thinking of online ordering but I'm just going to be guessing the colour but if there's a reference in store I might wait until stores open again...?

[TedBear]

Hi @Chris_T , if you are planning to reseal the floor, you could 'almost' fill the gaps with gap filler, then sand the floor keeping the surface dust. (Empty the sander's dust bag first, so it only contains the dust from the boards.)  This will provide a filler of the right colour which mixed with a small amount of clear lacquer can be wiped into the top of the (now shallow) cracks. Then reseal it all.

[Chris_T]

Thanks for the tip @TedBear - I had heard that approach mentioned in DIY videos but couldn't find any videos of someone actually doing it... But this bathroom is probably the best place to try it out - maybe I'll make my own video! Actually when I was under the house I found a few offcuts of the flooring timber, so I might even be able to sand some sawdust off those. 

[TedBear]

That sounds great... making your own video of the process will give others the confidence to go ahead.

Also good news that you have some boards to convert into correct coloured filler.

I have used this technique when I made a kitchen bench-top out of floor boards a few decades ago and needed a continuous, smooth surface.

I just mixed the wood dust with a little water based wood glue to make a filler. It was strong enough since I was lacquering over it.

(That was before we all carried video cameras as phones, so I didn't video the process either, but the outcome was excellent.)