Sanding Floor - filling cracks with sawdust and glue

[Dave Young]

Hi All,

I'm sanding my living and dining room floors this weekend. I sanded a similar floor in my last house a few years ago, and was happy with the result but regretted not filling the gaps between the tounge and groove boards. This time I'm planning to fill them with a mixture of sawdust and glue - as suggested in various postings and the faq.

I have a couple of questions, that I'm hoping someone who has actually tried this might be able to answer :

- What glue would it be best to use? I'm thinking either pva or wood glue. If pva, could the varnish make it turn white again? (I'm planning to use a water based varnish - Ronseal Diamond Hard). How about 'waterproof' pva? (saw it in Wickes next to the normal pva). Would wood glue be better? (does that dry clear?)

- I'm planning to sand down to fine grade, then fill the gaps leaving the filling proud of the gaps, then sand with fine grade again to make everything level. Anything wrong with this plan? I won't need to go back to medium grade again to level off the sawdust + glue will I?

Any other words of wisdom anyone who has tried this can offer would be appreciated!

Thanks in advance, Dave

[Andy Dingley]

I don't like this approach - although I've used it on plenty of floors. It works fine at first, but it shrinks over time and gaps open up. If your gaps are small to begin with, then it might work for you.

Screwfix offer a slightly flexible floorboard sealer in mastic gun cartridges. I might use this sometime and see if it's any better.

Cheap PVA - go to the builder's merchant and buy a gallon for almost nothing. It's also a perfectly usable wood glue. Don't let the frost at it though.

Works fine over the sawdust filler.

Personally I always use acid-cure formaldehydes on floors (Rustin's Floorcoat), but Diamond Hard should be OK.

Two things:

You can't sand the gaps until the sawdust has dried, and this takes ages. If you're doing more than one room you can do it by pipelining and filling the next room the day before you need to finish sand it. Otherwise it will slow you down considerably, just in drying time.

Secondly, you don't need it level - it'll shrink anyway. The main reason for running the sander over it again is to clean up the boards alongside, if there's any spillage.

[MikeS]

Why not cork (this may not be the correct spelling) the floors as they do on boats looks neat and does not shrink otherwise one would be in trouble at sea. Perhaps a chandlers yard may give advice? MikeS

[Pete C]

Hi,

BTW is this stuff UV resistant?

cheers, Pete.

[Andy Dingley]

Yes.

I think it's a bit iffy on gamma radiation, but it's hard against most other hazards. Stinks when you put it down, but it's a damn good product in service.

(Actually it's not perfectly resistant - if you want real heat resistance too, they do a special version for that).

[stuart noble]

IMO *saw*dust and glue looks bloody awful. If you have dust from the sander, it looks marginally better but still not remotely similar to the boards themselves. I would lift and re-fix wherever possible, or fill with 2mm or 3 mm strips if you have a sawbench handy (and the gaps are reasonably uniform), or match a proprietary filler to the finished surface (not the bare wood) as a last resort.

[Andy Dingley]

On Sun, 14 Nov 2004 12:46:00 -0000, "stuart noble" If you have dust from the sander,

Which is a fair assumption, although it does introduce the scheduling problem.

Is that a problem ? You're not trying to make the gaps vanish, you're trying to stop the draught and make it look tidy. Some minor contrast seems perfectly OK, IMHO.

I've not been a fan of strips, because I've always had tapered gaps. If they were that even, you could shove the boards up and close the lot out.

[bof]

In message , Andy Dingley writes

I've found it's not as good as bespoke PVA wood glue, the set result is far less flexible / more brittle; for those who remember it more like Cascamite than bespoke PVA wood glue.