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Posted: Sat Apr 03, 2010 2:46 pm
by soobell
I'm a newcomer, so forgive me if I'm asking wrong question, in wrong place 
..... I'm going to paint a concrete floor (using standard floor paint from DIY place). How long should I leave the newly-laid concrete before painting it? (Is there a formula I should use - eg allow 'x' number of days' drying time for each 'y' mm of concrete depth?).
The floor is indoors (in a centrally-heated house).
Posted: Sat Apr 03, 2010 3:16 pm
by seanandruby
I would leave it at least a month. Painting a concrete floor needs a lot of preperation, it needs shotblasting, fine scabbling, scaryfying etc. You cant just apply paint to finished concrete. It will need sealing. I think you should think about it very carefully, otherwise you will be painting the floor time and time again. Maybe look up a specialist firm ???
Posted: Wed Apr 07, 2010 10:33 pm
by simeonronacrete
Hi
Waiting for concrete to dry - and waiting for the Relative Humidity at the surface (RH) to fall to a level acceptable for the intended floor coating product - is important, but not always essential. For example we have epoxy floor coatings which can be applied to damp screeds and concrete.
Seanandruby is correct, you must prepare first, or early failure is likely.
Give us a call; we'll be happy to help.
Posted: Mon Apr 19, 2010 11:50 am
by TheVictorianCobbleCo
Simple answer - the concrete needs to have a moisture content of less than 3%, 5% maximum - you hire a moisture metre for the day to test (Check with Plascon/Dulux techs). It can take a year to get to this point. Then its preparation, first degrease. then etch primer, then paint. After MANY attempts, I left the concrete for as long as posible then used a road paint. Otherwise go the Ronacrete route.
Posted: Mon Apr 19, 2010 6:02 pm
by GB_Groundworks
how was it finsihed as well, just tamped or power floated etc?
Posted: Mon Apr 19, 2010 7:18 pm
by soobell
Many thanks for the advice so far, although I've become slightly worried that this is not going to be as straightforward as I'd thought: I don't mind how long I have to wait (any advance on a year ?) ........ but I'd not expected to have to do shot blasting, acid etching or anything like that! (All beyond my capabilities and, I suspect, my budget).
The floor has been power-floated, and is nice & smooth. I'd thought my only dilemma would be whether to use a surface sealant (PVA?) or the kind that soaks in, before painting it.
Any further advice would be very, very welcome.
Posted: Mon Apr 19, 2010 9:27 pm
by 47p2
I ground the top surface of my floor before sealing it. You can read about it here