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

[EricL]

Hello @Chris_T

It's great that you've received excellent advice from @TedBear. His recommendation is perfect and is a great way to fill and colour match at the same time. If you think you will need a more substantial filler, I suggest using Timbermate 250g, Pine Wood Filler, this filler comes in many timber colours. I recommend getting one that is the closest match to the colour of your timber floor. Combined with TedBear's sawdust technique, you should get a near-perfect match filler. Please keep us updated. I'm sure our members would love to see a video of your timber gap-filling process.  

If you need more advice or information, please let us know.

Eric

[Chris_T]

Thanks - @EricL - I do have some Timbermate from an earlier patch I did in the bathroom, so eager to try the sawdust trick out.

Also I've been reading about Cabots CFP Floor and wondering if that's an easier way to revarnish the area after I've filled the gaps (the no sanding version) - but just not sure because it's water-based whether it would be suitable for a wet area like this?

Cheers

Chris

[MitchellMc · Accepted solution]

Hi Chris (@Chris_T), 

It's great to see you've been receiving some excellent advice from our knowledgeable members. 

You could use Cabot's CFP Water Based in this application. However, you'll find it gets a bit slippery when water sits on it, so I would suggest Intergrain 1L Slip Resistant Ultrafloor instead.

For the best results, I'd advise giving your floor a sand to remove imperfections.

Please let me know if you have any questions.

Mitchell

[Chris_T]

Thanks @MitchellMc - I'll go with the intergrain - can't hurt to improve the safety while improving the aesthetics!

Chris

[Chris_T]

Quick update on fillers - I tried a few options (See image below). 

I used Selleys No More Gaps Timber floors. On the left I pressed in raw sawdust on top after applying, the middle is just plain No more gaps and on the right of that I added a little Feast Watson maple stain. The most surprising was the wood glue/sawdust mix. It dried really really dark, which was kind of unexpected. I'm going to leave for 24 hours and see if that changes, but I think the best result appears to be the no more gaps with stain (especially when you're not looking at it from 10cm away with lots of light as in the photo below!)

But wondering if anyone knows what I'm doing wrong with the wood glue/sawdust? It's 1:1 sawdust and Tarzans grip wood glue - maybe I should be using a different wood glue?

Just to see it in context without all the horrific macro detail.

[MitchellMc]

@Chris_T,

That No More Gaps with stain is looking fairly close to the coated floor colour. Bear in mind that with the raw sawdust, you are replicating the uncoated, natural timber colour, and it will need to be stained/coated to resemble the coated boards.

I'm really not sure what has gone wrong with your PVA/sawdust mix. It's much darker than what I would expect. You didn't add stain to it at all? Using that method, it should come out almost identical to the raw timber colour. I've got an example drying for you at the moment to illustrate. All PVA glues are white and dry to semi-translucent. I can't imagine where this brown colour came from.

Mitchell

[Chris_T]

Did another test last night - same issue - maybe the ratios are wrong? I'm doing about 1:1, maybe it should be more 2:1 (more sawdust?) 

[MitchellMc]

Hi @Chris_T,

Thanks for the follow-up. Try hitting that dried sample with some sandpaper. I believe you'll find once done, it will be much lighter. My sample has also become much darker overnight, but after sanding, it has revealed a lighter shade. Your sample in the floorboards is a bit too deep to sand, but try it on the sample you've just posted. Use something similar to 120-grit.

Mitchell

[Chris_T]

Thanks @MitchellMc - sanding does help! 

Cheers

Chris

[MitchellMc]

That's great to hear, @Chris_T.

I believe the PVA is creating a coating that needs to be opened up to see the true colour. Keep us update on your progression.

Mitchell