Levelling a concrete floor for the kitchen

Mr_Vee

Having read the threads on floor levelling on here i can't seem to be able to find a quick and simple (simple enough!) solution to my kitchen floor levelling problem.

The kitchen floor is concrete and the deviation is from about 5-10mm on one side to about 1.5-1.75 inches on the other side. (i.e. a pretty steep slope.) I know levelling compound can be used for depths of about 12mm or less and screed (sand and cement mix) can be used for depths of about 5cm or more.

As you can see, I'm stuck somewhere in between the two!

With my limited knowledge!! I've sort of narrowed it down to two options:
1) on the deeper side (i.e. 2inch deep) lay down 18mm plywood and bring to level using levelling compound and just use levelling compound on the shallow side... relatively cheap! but effective?? i dont know??

2) dig deeper into the existing concrete floor throughout and then get the builders in to lay down a 2inch screed... pretty tricky, definately messy and probably about £500-600 worth of work!??

Anyone have any comments on this or have any better suggestions at all?

Much appreciated as always... Cheers :A

Ted_Hutchinson

Have you considered using a lightweight concrete mix such as vermiculite.
See details here LIMPET TOP COAT

Having vermiculite in the mix makes it warmer to walk on and less likely to attract condensation. Very easy to work with and presumably you are intending to tile or use kitchen flooring over it as well and this may need a chipboard flooring base.

Mr_Vee

sorry, yeah its going to be tiled on top.

thanks for the vermiculite tip... im looking into it. sounds great stuff! although, i still have the problem with the levelling itself due to the varying depth. Even the builder who came to give me a quote was like: "hmm... not quite deep enough to screed and too shallow for levelling comp"

AAARGH the dilemma eh!

HugoSP

You can actually use a fine sand screed and lots of PVA.

When putting the final screed on a floor I usually use sharp sand. This is coarser than building sand, which is why you'll neen a 50mm plus depth.

However, if you want to level out less than this might I sugget the following approach.

Identify the areas that need to be levelled out and apply a 50 50 PVA Water mix onto the surface using a soft broom.

Then simply use a 3 to 1 building sand (BS1200) /cement mix and level this off using a straight edge checking its horizonal of course! Then gently float this off using a flooring trowel.

Repeat in all the areas this needs to be done. Finish the job and assess the quality of the floor for tiling.

If it's still not perfect for tiling, use self levelling compound to take out the minor indentations. The finished surface will be fine for tiles.

H

Mr_Vee

HugoSP wrote:

You can actually use a fine sand screed and lots of PVA.

When putting the final screed on a floor I usually use sharp sand. This is coarser than building sand, which is why you'll neen a 50mm plus depth.

However, if you want to level out less than this might I sugget the following approach.

Identify the areas that need to be levelled out and apply a 50 50 PVA Water mix onto the surface using a soft broom.

Then simply use a 3 to 1 building sand (BS1200) /cement mix and level this off using a straight edge checking its horizonal of course! Then gently float this off using a flooring trowel.

Repeat in all the areas this needs to be done. Finish the job and assess the quality of the floor for tiling.

If it's still not perfect for tiling, use self levelling compound to take out the minor indentations. The finished surface will be fine for tiles.

H

thanks a lot... that all sounds good to me!

that PVA is some magic stuff eh... :j

just to confirm: 3 parts sand to 1 cement and this will definately stick to the concrete and not crumble at depths of less than 5cm?

could you clarify how "wet" the screed should be and also if a DIYer like me would be able to do this? i'm very handy with DIY, a bit building work and tiling, etc. but never carried out any floor levelling before...

cheers H

Alan_M_2

There are specialst compounds available for this problem, forget the cement and woodglue (sorry - PVA), it;s not thick enough and will break up.

You need product produced by a company called Ardex, they have two self levelling compunds
K15 - a regular self leveller
K15B - for bulk filling areas before a top coat of K15 is applied. Upto 35mm thick in one hit.

For thicknesses over 20mm add granite chippings to the mix to give it some strength

http://www.ardex.co.uk/

Give ardex a call for details of your nearest stockist.

HugoSP

Alan_M wrote:

There are specialst compounds available for this problem, forget the cement and woodglue (sorry - PVA), it;s not thick enough and will break up.

You need product produced by a company called Ardex, they have two self levelling compunds
K15 - a regular self leveller
K15B - for bulk filling areas before a top coat of K15 is applied. Upto 35mm thick in one hit.

For thicknesses over 20mm add granite chippings to the mix to give it some strength

http://www.ardex.co.uk/

Give ardex a call for details of your nearest stockist.

The above method has worked fine for me in the past but this is probably a better product for the job. Next time I have a similar problem I may use this. Thanks Alan.

However I would reittarate that there is PVA and PVA. What you would use here is the PVA that is for adhesion for concrete surfaces, renders and the like. Yes a 3 sand to 1 cement mix would do it.

However in light of what Alan has said I would probably follow his advice and give Ardex a ring.

H

Alan_M_2

PVA is poly vinyl acetate or sometimes poly vinyl alcohol, it is the single most misused product in the consruction industry. I've absolutely no idea why it's so commonly used as a primer/sealer becuase on a chemical level it actually does neither particularly well.

There are specific polymer and plasticising products specially produced for these uses, usually SBR or APD based products.

Mr_Vee

HugoSP wrote:

The above method has worked fine for me in the past but this is probably a better product for the job. Next time I have a similar problem I may use this. Thanks Alan.

However I would reittarate that there is PVA and PVA. What you would use here is the PVA that is for adhesion for concrete surfaces, renders and the like. Yes a 3 sand to 1 cement mix would do it.

However in light of what Alan has said I would probably follow his advice and give Ardex a ring.

H

thanks guys... me being the moneysaver i am, would probably go for the cheaper option! :rotfl: and i strongly suspect that the ardex stuff is at least twice as expensive as cheapo sand and cement screed.

i mean if it worked 4 you hugo then it should be a sound method... but then again the ardex stuff is probably simpler and less likely to be mixed wrongly for a DIYer like me...

ooh i dont know... more confused than i was before i posted now! :cool:

decisions decisions...

Alan_M_2

Sand/cement screeds shouldn't be used at less than 75mm, in certain cases with reinforcement at 50mm.

You need a self levelling compound or remove the existing screed and start again (actually the better option)

Mr_Vee

think i will go for the ardex... it might cost a fair bit but the simplicity will outweigh the price of it. plus, i will only need the expensive ardex stuff for approx half of the kitchen (the deeper half) i can use normal, wickes levelling comp for the shallow side. Many thanks for your help alan.