# New Concrete Floor levelling and finishing



## joncooper27 (28 Aug 2022)

I have had a new concrete slab laid in the hot weather for my Workshop/ Biomass Boiler room. The floor was done on one of the hot day and the builders struggled levelling before it set and did not float it flat!!! 
Any ideas to level and seal if self levelling compound what one is best then what to seal it? Or is there something that would level and seal? The building is 9m x 6m so a big area to do?


----------



## Bingy man (28 Aug 2022)

I recently laid a concrete base for a large shed, I decided to delay the job due to the 33deg weather. The concrete company were extremely helpful. Re-arranged it to a better day 18 to 21 deg. Slab wes 26ft x10 ft and I still struggled by the time I got to the end . How much are we talking about when you say your builder didn’t level out the slab -a few mm or is it a lot more ? Is it generally uneven all over? Photos would help . However as with other posts with similar issues to yours you need to sweep the entire slab to remove loose dust and particles. Seal the floor with SBR and let it dry . From this point you have a few options- levelling compound standard or laytex, there are several other types of floor treatments but most are expensive and can be tricky to apply. My choice for this issue is a 1.1/2 or 2 “ layer of floor screed ( concrete sand / cement mix ) as it’s a large area split it into manageable sections and apply the screed . As the screed is very fine bits of grit and not large aggregate you can achieve a very flat surface, it can be then floated with a trowel to a finer surface. I think your builder could of taken steps to prevent your situation in the conditions he was working in . Was it his decision to lay the floor - did he explain that the concrete was likely to set before he finished the floor - did he advise to lay concrete on a cooler day - or was it your decision to go ahead with the job. I ask all this because your builder could be held responsible for your uneven floor and as a result should put it right if he took the decision to go ahead given the weather conditions. Hope this is helpful.


----------



## Jones (28 Aug 2022)

Are you talking surface roughness or not flat over a distance? Also what if any covering is going on the floor? The basic choices are build up, grind down or decide it doesn't matter.


----------



## joncooper27 (29 Aug 2022)

Hi thanks for the comments, over the whole floor when you measure with laser max deviation is 10mm. It’s mostly been tamped level and not floated flat a few holes etc up to 10mm We needed to get the floor down as the oak frame was being installed and the rest of the week was hot. To be fade the builder has been ok about it I just want best way out of it.
My intention was to have a flat surface I could paint or just seal the surface to prevent dust.


----------



## Jones (29 Aug 2022)

Use a self leveling compound suitable for use as a finish surface, not all the types are. If you want a good finish get a builder, flooring guy or plasterer to do it , your first diy attempt won't be great.


----------



## joncooper27 (29 Aug 2022)




----------



## joncooper27 (29 Aug 2022)

I have just attached a picture 
The builder will do for free just want to make sure is done well and will last
What self levellers can be used as. Finished surface most I have seen are meant to go under finished floor


----------

