Flattening a concrete garage floor

[The Bear]

I tried posting this on another forum but no one there had any knowledge so I'm hoping there's a bigger audience here and someone will have experience. Sorry if this is in the wrong section, but I will stand some woodwork machines on it when its done!

I want to flatten my garage floor. Its too rough for moving small casters and wheels on. Its also got a few places where there are raised bits, and a large section has had what looks like self levelling compound poured on (which is also not level) raising it 3mm higher than the rest of the floor. I don't mind a slope, but I want it to be flatter, and I understand SLC doesn't take paint. There also seems to be in a few places something black embedded in the SLC like old roof underfelt, very weird.

This will be a temporary workshop space so I don't want to buy materials to board it out and insulate, but I've seen the rough prices of floor grinders and epoxy paint and the investment in these will still be relevant when it becomes a garage again in my mind, so thats the way I'd like to go.

So my question is, has anyone any experience of hiring and using a floor grinder, types of heads to use, technique, anything really.

A few years ago I saw some guys do our hanger floor at work and I believe what I want to do is achievable but in need of some guidance if anyone can help before I visit the hire shop please.

Cheers

Mark

 

[scholar]

Hire a concrete floor grinder - I used a set up like this and it will get your floor nice and smooth, say for painting (I needed epoxy sealing), but make sure you get the proper dust extractor as the dust is unbelievable. http://www.brandontoolhire.co.uk/en/dus ... acuum.html

Cheers

 

[siggy_7]

I'm faced with a similar problem. I'm looking at hiring a grinder to start with as my floor appears to have been laid by a blind man, although the costs are quite high. If you've not got too many big high spots you're worried about knocking off, I would seriously look at levelling compounds instead - by the time you've hired the grinder etc you can buy a fair few bags of levelling compound, and using a compound will be much quicker and cleaner. For garages, most people recommend Cempolay ultra - it's got a very high compressive strength, and it takes paint.

 

[Monkey Mark]

I'm faced with a similar problem. I'm looking at hiring a grinder to start with as my floor appears to have been laid by a blind man, although the costs are quite high. If you've not got too many big high spots you're worried about knocking off, I would seriously look at levelling compounds instead - by the time you've hired the grinder etc you can buy a fair few bags of levelling compound, and using a compound will be much quicker and cleaner. For garages, most people recommend Cempolay ultra - it's got a very high compressive strength, and it takes paint.

Hadn't heard of that one but good to know for the future.
A 25kg bag covers 5m sq @ 3mm, so not bad coverage.

http://www.builderdepot.co.uk/cemen...evelling-compound-internal-external-25kg.html

 

[The Bear]

Scholar
That is the sort of thing I'm looking at hiring, and yes I will hire the dust extractor. Having watched our hanger floor at work being done I wouldn't contemplate it without. Can you remember what types of head you used (diamond, carbide etc). Also did you experience any problems using it, is there a best technique?

Siggy
Part of my problem is the previous owner has put SLC over half the floor and made a right dogs dinner of it. I have no idea if its suitable to drive on or paint( too much rubbish piled up on that bit of the garage at the moment) so would be faced with building up the other half of floor to the same level, then trying to get another layer across the whole thing to get it smooth. Which I think is also a hell of a lot of work as we all know SLC doesn't really level itself. I notice the instructions say there must be no rising damp, there is no DPM under my floor, and free of oil, which my floor isn't and grinding would remove the worse of that. But I'll research it some more, so thanks for the suggestion.

Mark

 

[RossJarvis]

I was involved in a build a couple of years back where the new slab wasn't particularly flat. One of the guys suggested grinding the floor to reduce the amount of levelling compound needed. After spending about £500 (tool rental and several hours labour) the floor ended up being re-levelled with some fairly easy flowing stuff, at further cost, due to the levels not being consistent and a fairly rough surface as the aggregate stuck up from the cement.

It may be cheaper and easier to just level the entire lot with compound.