Polishing an old concrete floor
Your concrete mix and how it is poured are the most important factors when it comes to achieving a beautiful polished concrete floor. Once you get this right you can achieve almost any type of polished concrete finish.
Polishing old concrete
Ripping up your old lino and hoping to transform the concrete underneath to a gorgeous contemporary polished concrete floor is most likely not going to work out. The correct thickness won’t be there. Adhesive will have seeped into the concrete causing staining that no amount of grinding can remove. Having said that sometimes old concrete polishes up beautifully. Some of our proudest work has been transforming old concrete floors, covered in paint to stunning finishes, see our photos from Farmleigh below or our video from Clockwork Productions.
BEFORE: the concrete floor at Farmleigh before we started
Generally however the best way to achieve a polished concrete floor is to start from scratch.
Not just ‘any old builder’ will do
Ensure you get a concrete contractor who has experience pouring concrete suitable for polishing. It may work out a little more expensive but your poured concrete is your finished floor. As polishing contractors we can only work with what is there.
AFTER: the platinum finish we achieved after polishing
Tips on pouring concrete suitable for polishing
- Concrete must be laid extremely well and flat.
- Make sure your concrete is floated up to the edge of the wall.
- All rooms should be poured together and partition walls installed AFTER the concrete is polished.
- The concrete screed should be a minimum thickness of 75mm.
- The strength should preferably be 35n.
- Use control joints.These can be saw cuts or plastic crack inducers. Be selective about these and try to place them underneath closed doors and in places where they won’t spoil the look of the finished product…or alternatively make a feature of them!
- Do not have any services running through your concrete slab. Have them running through your sub floor.
- Use polypropylene fibres.
- Do NOT add water during the pour! Many contractors do this to speed up the process, but this will cause shrinkage increasing your chances of cracking.
- Use a membrane under the concrete. This acts as a debonding agent and also stops water from running away from the mix.
- Use perimeter insulation and a compressible material around rising walls.
- Do NOT tamp the concrete into place. This will leave lines in your concrete which only become visible once the grinding begins.
- Concrete should be fully compacted using a vibrating screed.
- Concrete should be power floated.
- Your concrete floor should be smooth to touch and left to cure for a minimum of four weeks before the polishing process can begin.
- Concrete is a natural substance and there is no guarantee it won’t crack. By following the above guidelines however you are greatly reducing the risk.
It is always a good idea to request a sample in a discreet corner before the polishing process begins. No two concrete floors will look the same, and it is only once the grinding starts you can reveal what lies beneath and see how your finished floor will look.