"Repairing" bumpy garage floor.

knipex

I am getting a steel shed erected and in advance poured the concrete slab.

I also decided to pour the finished floor before the shed went up (I was provided with dimensions but left it 1" short to allow for errors) as I figured it would be easier to screed and float without the shed beign up.

I had 2 mates give me a hand with the main slab and both came back for the finished floor. However about 15 minutes in I got an emergency call from work the two guys told me to head away and they would finish it.

Mistake.

They didn't make a bad job of screeding it but what I didn't realise was they had never laid a floor before so because I didn't float the main slab they didn't realise they had to float the finished floor. As a result its bumpy as hell.

Also I had a plank running down the centre of the floor to help with screeding which I pull up as I went, back filled and then screeded with a bit of 4 x 2 stuck to the end of a shovel. Guys obviously didn't get the hang of this as there are a number of bumps along the centre of the floor.

It going to be a garage and workshop (I work on old cars) so a pretty floor isn't critical but this just looks ugly.....

I had planned on hiring a floor grinder but the guy at the hire shop told me its more for polishing and would ride over the bumps rather than remove them (although he freely admitted he never used the machine and only rented it once) and advised self leveling compound.

My fear is that I only plan on painting the floor is that self leveling compound wont survive the rigours of use.

Any advice ?

FesterBeatty

Levelling compounds typically have a compressive strength in excess of that of concrete, so dont worry about robustness. Give the lads in <SNIP> a shout...This is more an engineering concern than an architectural...

mickdw

I would get a floor grinder if there are high spots in it otherwise it will cost a fortune on levelling compound. A proper floor grinder will take down concrete no problem. When reasonably level /flat, you can put compund on for a great surface.

antiskeptic

knipex wrote: »

My fear is that I only plan on painting the floor is that self leveling compound wont survive the rigours of use.

If going the self-levelling route then make sure to check that it will indeed take the hammering it's likely to get. I made the mistake of using too thick a layer on an uneven floor and had to remove it. I had no problem breaking it up into chucks with a lump hammer. It came away from the original floor completely cleanly.

Can you not just cast a new slab over the old and float it nicely this time?

AckwelFoley

Floor levelling compound cant be used as a finish for a floor.

The first mistake was leaving only 1 inch of a screed for a finsih floor as 50mm is the min screed thickness for a sand cement render.

There are floor grinder and floor scabblers available, the scabbler will be more severe than the grinder,however there are various types of grinders available, ones that have brick type drinding stones and ones that are diamond tipped.

The other option is to possibly lay 50mm dry mix screed after the shed is up?

Is this possible?

knipex

snyper wrote: »

Floor levelling compound cant be used as a finish for a floor.

The first mistake was leaving only 1 inch of a screed for a finsih floor as 50mm is the min screed thickness for a sand cement render.

There are floor grinder and floor scabblers available, the scabbler will be more severe than the grinder,however there are various types of grinders available, ones that have brick type drinding stones and ones that are diamond tipped.

The other option is to possibly lay 50mm dry mix screed after the shed is up?

Is this possible?

The final screed (or finished floor) is just over 50mm thick with a DPM underneath. The 1" gap is around the side of the shed. (I was told the finished floor would be say 29' 11" x 20'1" so I poured the finished floor 29' 10" by 20'. I will use a sand cement mix to fill this gap after the shed is erected.


We poured the main slab in the morning 2' wider and longer than the finished slab, 6" thick with rebar mesh, As soon as it was solid enough to walk an without leaving serious marks (about 4 hours hours) we set up our form and went to pour the finished floor.

As the slab was so wide I couldn't pour and screed in one go so I put in a temporary central form that we could use to screed the finished floor with the plan of using an easy float to finish the entire floor.

By the time I got back from work the concrete had set too hard to float (I was only supposed to be 20 minutes max ended up being almost 3 hours).

I can only find one company renting a floor grinder and its a very small one. it uses diamond inserts but the surface is so small that I suspect (as does the rental company) that it will just ride over the bumps rather then grind them away.

The floor isn't actually that unlevel there are a few slight humps where they back-filled after removing the temporary central form but the surface is typical of what you would expect after using a 4x2 to screed the surface. More ripply than bumpy and it just looks bad.

I cannot pour a second screed as the floor would just be too high. Plus the shed is going in today...