Every one says to wait for warmer weather but we’ve got the house empty for a few days before we move in. Seems like an ideal time to do it despite the weather. Does the cold just slow down the drying/curing or does it spoil the actual adhesion with the concrete?

It’ll be fine. What’s it say on the tin? Not below 8 degrees or something.

Floor painting top tip. Start at the door and work your way back to the corner. 😉

Wear a jumper it’ll all be fine!

Multiple issues.

Adhesion will be on since the floor will be even colder than all likelihood. You might be below the dew point which will mean you have condensation and damp on the floor that will not dry up.

Cold curing plays havoc with paint. It may take longer to dry. I’ve seen products that simply won’t dry at 10C or less. Waterborne is particularly bad compared to solvent borne or solvent free.

Sometimes it may appear to dry but in reality it hasn’t properly done so and will peel and blister in a few months (vitrification rather than gelation)

If you check the labels and tech info for the paint you intend to use it should have minimum recommended temperatures and dry times/overcoat times for different conditions.

Cold is normally less than 10C so if you are desperate to do it then a free standing radiator might be enough to let you do it successfully.

It will take days. Literally days. My lbs did this on Saturday evening, thinking it would be dry by Monday morning. It wasn’t even tacky until the following monday, and was totally ruined by the time it went dry on Thursday/Friday, because they had to put cardboard everywhere to keep trading.

Indeed, if it is epoxy/amine based then my experience tells me that

40C = <2hrs
25C – 4-8 hours
10C = 24-72 hours
<10C = maybe/maybe not.

I didn’t realise weather played such an important part in the process! I had mine painted when I moved into a new house, (the floor was really dusty) and it’s just peeled off over time. Could that be due to it being done in October/November or will it be down to a lack of prep work? I’ve got another tin, but not got around to re-doing it.

if it’s really dusty I think you’re supposed to use a sealant first to give the paint a good key?

Surface prep and weather are likely to be the cause of failure of most paints in my experience.

I work with industrial stuff but to give you an example to test our products we go to the effort of applying it and exposing it around the world – Arctic, Middle east, Tropical (Normally Far East), Temperate (N America, N. Europe) etc.

Best check the weather forecast. I’ll be okay with it taking a few days but not drying would be a bugger.

Would I be better with paint or an expoy then? Not got the materials yet. Should be okay with the corner thing as there’s a door at each end.

If it’s epoxy based, could you not just add more hardener/catalyst? I usually do a lot of work on the boat over the winter, usually just add more catalyst until it sets too quickly and make a note to add less next time.

Alternatively, stick a heat lamp or three in there for the day before to get the concrete nice and warm?

Wait till it’s warmer, you’ll think it’s dry stick something heavy on it and it’ll just peel off or leave an imprint. And only way to get rid of said imprint is to sand it down and re-coat which is a chew!

If it’s epoxy based, could you not just add more hardener/catalyst? I usually do a lot of work on the boat over the winter, usually just add more catalyst until it sets too quickly and make a note to add less next time.

Is that a question or a suggestion? In either case, don’t do it, it doesn’t work like that.

Assuming a pigmented A and a clear B (hardener) adding more hardener will mess up the chemical nature of the paint (stoichiometry) it will reduce the amount of pigment (since there is none in B), it will probably increase the solvent content which will remain trapped in the film especially at low temperatures.

The B in an epoxy is not a catalyst, it is a reactive component that cross links with the epoxy. The catalyst is often contained in the B since it is often a tertiary amine and compatible with the curing agent. In any case adding more catalyst is a route to getting something that appears dry faster but is actually rubbish. Winter grade paints are often on different resins not just balanced out differently.

Having painted a concrete floor in an unheated building one cold December I’ll second that it will take foolishly long to even stop being surface tacky and will blister/flake/be a total waste of time if it gets too cold.

I’d live with it til Spring personally…

Alternatively accidently spill some really horrendously coloured paint on the floor, it will stay there forever and resist all attempts at removal…………. 8)

Would some sort of space heater be an option?

Just enough to elevate the temperature in the garage while the paint cures…