Concrete - anti dust ?

In message , Rick Hughes writes

I had a similar problem and went straight for the 2 part epoxy floor paint, it stopped the problem and made sweeping the floor a darn sight easier too. The only thing I would do differently if I was doing it again would be to add sand to the mix to give more grip. If the floor is wet it is somewhat slippery.

easy peasy. Use a concret hardener, works a treat

Going over it with dilute PVA will do the job cheaply - I'd probably try 1:3 PVA:Water on a bit and vary it so it penetrates rather than glooping on the top, then roller all over.

It will be shiney afterwards, but not dusty - I did the same to a bit of subfloor slab that was annoying me(!).

If you are worried about PVA becoming tacky or going weird when it gets wet, use SBR instead - costs more but will give a very stable surface and will be water resistant - also good enough to put floor paint on later if the mood takes (wouldn't fancy that with PVA in a damp environment).

PVA or SBR are surface treatments, a silicate concrete hardener reacts with the concrete & changes the surface.

Even that is overkill.

For simple dust prevention PVA will work, but its not fully waterproof. Concrete paint - not two part - is perfectly adequate for low wear areas. The epoxy is the dogs bollocks industrial grade solution. Bloody excellent but expensive.

True, but both prevent dusting

I'd go for much thinner pva than 3:1, you want to avoid that slick water soluble surface! PVA is a glue, it prevents dusting by gluing the concrete particles together, thus strengthening the top layer. The weaker your pva mix, the further it penetrates, and the thicker the top layer that gets strengthened. I'd try 10:1 first, then anything from 10:1 to 5:1, the second application after the first has had plenty of days to dry. If the slab is damp, better go for SBR.

NT

Would it do anything to stabilise concrete which is crumbling and forming craters due to the frost?

I have some TrueFix concrete PVA additaive, which was sprayed onto the screed after laying to harden the surface .... I'll give that a go. Any idea what the dilution is ?

There's a school of thought that says this is bad concrete work and nothing can fix it...

Floor paint works, but it's expensive to get one (chlorinated rubber or epoxy) that can stabilise concrete. The affordable stuff won't.

A better sealer for concrete is waterglass (sodium silicate). This is cheap(ish), if only you can find it. It's a bit obscure these days.

There's a school of thought that says this is bad concrete work and nothing can fix it...

This is a new selfbuild ... the groundworkers were supposed to wait for a dry day, pour the raft, and powerfloat finish ....... they poured in in rain, and finish was then not as good as it should have been. My fault for using a 'professional firm'

As I mentioned I had another building on site and had that power floated and it is no problem even with vehicle traffic.

Was the dry day/power float etc in the spec? If it was you should have got 'em to remove and dispose of the incorrectly laid raft and re-lay properly at their expense.

The only way "professional firms" will learn is by hitting their wallet.

It was ... however they said 'no problem' screed will take care of it ......... and could not hold off as Timber Frame was due to arrive.

The screed of course sorted out house, but not garage.

Been thinking of 'maybe' using a self leveling screed, but this may be prohibitively expensive.

It's not too bad.

But you'll still need to stabilise the surfce or the bond will fail. For that, I would soak it until it can take no more in 1:2 - 1:3 SBR:water, which is exactly what I did with some friable screed I was about to top over with compound. Worked too.

Don't know off hand, you would have to look at the can or ask the mfrs.

It reacts chemically with the surface of the concrete, so it would prolly help.