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Filling a dent in a concrete floor
scudderfish - 12/1/22 at 02:41 PM

I'm trying to make my garage warmer. I've just had some nice thick automated doors fitted. However my floor is not flat and level and one of the doors won't seal against it leaving a gap about 5mm high and 150mm wide. What would be a suitable way of building the floor up in this area? The floor isn't damaged, it's just craply made.

coyoteboy - 12/1/22 at 02:57 PM

I have no experience directly, so may be talking out of my behind. However I would assume you can screed over too thin, so you might have to chisel out Xmm depth right out to the level area, then fill it. If you just screed the surface, it'll likely flake.

That said, there may be epoxy coatings that will handle it.

nick205 - 12/1/22 at 03:13 PM

An alternative to patching the floor, could you not fit a weather bar/strip of some sort for the garage door to close against. Our roller shutter door at work has a rubber weather strip in a metal channel screwed to the floor across the door way. Stops wind and rain blowing under the door in the winter (and heat escaping). Check with a local garage door fitting company and see what they suggest (obviously buy and fit yourself). 5m/37019

[Edited on 12/1/22 by nick205]

SteveWalker - 12/1/22 at 03:20 PM

Floor levelling compound? It is made for the job and can be tapered to a very thin layer.

roadrunner - 12/1/22 at 03:40 PM

As Steve says.
Not bad stuff for leveling an uneven floor.

pigeondave - 12/1/22 at 05:09 PM

Bewarned Not all levelling compounds are the same. Some have a max thickness of 3mm, others will go down to a feathered edge.

Something from sika will probably fit the bill. Whether levelling compound or screed will depend on how much you have to build up

jacko - 12/1/22 at 07:27 PM

Car body filler and Iím not joking I read it on a garage forum

scudderfish - 12/1/22 at 07:30 PM

Originally posted by jacko
Car body filler and Iím not joking I read it on a garage forum

I'm tempted as it's only a small area and all the levelling compound I can find online is 20kg for multiple m^2. I guess I can always remove and try something else if it fails

BenB - 13/1/22 at 02:28 PM

In a similar position previously I used some waterproof tile adhesive I had knocking around. did the job.

Sanzomat - 13/1/22 at 04:45 PM

Originally posted by BenB
In a similar position previously I used some waterproof tile adhesive I had knocking around. did the job.

+1 for that. I've got a half bag of quickset waterproof tile adhesive (the powder type) I've been using for small render repairs. I chucked a bit of sharp sand in to make it a bit more "aggregatey" and it has worked a treat. Feathers back nicely and now into its second winter and holding up no problem. I have found that floor levelling compounds don't like getting wet and the ones that are made for external use don't feather thin enough.

motorcycle_mayhem - 13/1/22 at 05:05 PM

I've used epoxy concrete repair products for that exact job, removing shallow imperfection.
They don't like damp, loose substrates, but if the floor is good, dry and contamination free it's good stuff. If one of those conditions doesn't hold, neither will the epoxy.
Expensive, but what price a puddle-free floor..

Products like (e.g.) Toolstation Epoxyset 105.

scudderfish - 14/1/22 at 09:27 AM

Thanks all, I'll let you know how I get on

Steef74 - 14/1/22 at 01:27 PM

Yes Floor levelling compound, be sure to primer the floor and clean. After that a nice layer of epoxy which is gasoline and oil resistant