Thread: acid etch before painting concrete slab (workshop)?

Don't think its necessary.
What do the instructions on the paint can say?

Yes, you will indeed need to acid wash the slab, then put a sealer on before the paving paint. I would not be in such a haste to paint it there is still a lot of moisture content in the slab which needs to get out somehow.

Originally Posted by echnidna

Don't think its necessary.
What do the instructions on the paint can say?

acid etch first but I dont want to roughen the surface, this defeats the purpose of painting it in the first place

JDub, I have never acid etched a slab before painting and have never had paint lift and I am talking about public spaces too.
Mind you I always use top quality paving paints from NuTech.
Even when I paint the inside of water features I don't acid etch, but once again I use good quality epoxy/polymer paints

Originally Posted by Guy

I would not be in such a haste to paint it there is still a lot of moisture content in the slab which needs to get out somehow.

I was going to do it not this weekend but the following one, that makes 6 weeks since the slab went down and its been pretty hot lately , I was told 6 weeks should be fine......? I wanted to do it before the shed went up.... alot easier that way

Originally Posted by Bleedin Thumb

JDub, I have never acid etched a slab before painting and have never had paint lift and I am talking about public spaces too.
Mind you I always use top quality paving paints from NuTech.
Even when I paint the inside of water features I don't acid etch, but once again I use good quality epoxy/polymer paints

Bleedin,

Are you talking about the two part systems or just standard paving paint?

When looking into it originally, I thought the two part systems would be a bit of an overkill for a backyard workshop floor.......

Joel

Hi JDub,
Just spoke to Nutech and they always recommend acid etching. So don't listen to me.
They also recommend thinning the first coat, this I do.
They have a product called pavecoat, a urathane one, a waterbased 2 pac paint and a one pac epoxy.
I usually use the pavecoat and you can get it in any colour you wish, which is a bonus as I dont think that the Bunnies paving paints can be tinted...I may be wrong though.
I guess that as my work is outside the paving usually gets a water blast before painting which would take that thin sheen of concrete off the surface. I dont think you will be waterblasting in your shed so it may be better to follow the instructions even if this may be a code violation.
I wouldn't worry too much about the acid wash roughing up the slab too much, wet the slab well before you start, keep the batch weakish and dont leave it on too long.

I would be concerned about it being too smooth, you may want add antislip beads to your paint.

I put paving paint down on a concrete slab for my workshop. It works well - except where I drop something on it and it chips.

It was not acid etched - but it was 15 years old and did have a coat of sealer on it once.

I sealed my new shed floor about 8 months ago. The concrete was less than week and a half old. Couldn't be stuffed painting it, was more worried about dust and stains........

I used the Crommelin concrete floor sealer,available from Bunnings. If you want it can be tinted using the Crommelin floor stain too. All the info is here http://www.crommelin.com.au/listPro.php?id=6

For the record, I acid etched the slab on the weekend.

I just used a commercial product from the hardware store and followed the instructions on the tub... sorry for the code violation (thats two in one week )

I dont know that its made a huge (hardly any really) difference to the texture of the slab to be honest but at least now I can say I did it properly.... and now I have the right to bitch and moan if the paint lifts

I will paint it on the weekend.

Joel

G'day Joel

Good to hear some movement happening, I have stalled on mine for the moment, suppose I could put the spouts ups .

Originally Posted by JDub

For the record, I acid etched the slab on the weekend.
Joel

Ops, you've done it already. The guys at Bunnings told me it is really necessary only when you paint really used up concrete surface - like a driveway with lots of oil stains. So, to remove the stains, even the toughest ones that acid thingy is used.
They also told that stuff stinks badly.

JDub,
I'm currently researching paving paints etc. You did the right thing by acid etching. Acid etching apparently dissolves "latience" which I understand to be a thin layer of weak, powdery concrete that rises to the surface of a new slab during the curing process. Paint won't stick properly to it. So you're good to go. By the way, are you using a water based or solvent based paint?
Cheers.

Oil based paving paints are reputed to still be better than water based, just not quite as user-friendly (cleanup, etc)