Just done this on a workshop and garage floor. We used the international sealer and floor paint products (from DIY sheds). The sealer can be used on it's own, as can the floor paint. But if you seal first the floor paint will spread easily and goes much further. The sealer will also reduce, but not eliminate, oil stains leaching through the paint. Things to know are...
- The areas given on the can for coverage are pretty accurate.
- Sealant and Paint best applied with a standard roller on a long stick.
- In these temperatures sealant will takes a couple of days to dry and stinks, paint a bit quicker and not so smelly.
Clubber - the painting technique only works on fairly smooth finished concrete surfaces (like a garage floor). If you've got really rough finish then you might want to strub it or powerwash it first to lift the mud then screed it to a flat finish (look for a self levelling screed product). Might be less effort to fit workshop tiles.