what's the best self levelling compound ?

mr bosch · Post by **mr bosch** » Mon Oct 05, 2009 9:06 pm

Hi
i am looking at tiling a new kitchen floor which has had new water piped under floor heating fitted and screeded over (screed has been down for few months so is well dry now)
my query is what self levelling compound would be best for the job and does the new screed need to be primed before the compound is laid.
its a large area to do (6mx5m) so any does and don'ts would be greatly received as this is the first time i've done this.
not sure yet as to what type of tile is going down, does this make a difference as to what compound to use?

kind regards
mr bosch

tictic · Post by **tictic** » Thu Oct 08, 2009 8:50 pm

not good on computer so cut/paste ive no chance

but google BALL i use their stopgap range they will have one for ur needs mate
best of

as for using it.. just like "ronseal"

DIY_Johnny · Post by **DIY_Johnny** » Thu Oct 08, 2009 10:27 pm

I did it on my kitchen and part of the living room, its very easy mate, Like pouring thick paint on the ground. I personally don't think its as 'levelling' as they would like you to believe, but a little encouragement with a trowel is all you need.

I wasn't sure if you needed to prime it but I used BAL SBR to be safe. Lads will know better than me. I used the non-flex stuff on screed before tiling but used flexable adhesive

Compound was flat as a pancake and hard as a rock when down. Kitchen tiled but living room is still exposed. Have dropped all sorts of tools on it and not a crack in sight, down 6 months

Make sure you have all gaps covered, it will find any holes and run out the door on you and then there is a lot of this.

Also I found it hard to know how much to mix up but you can go over it i assume if you underestimate

tictic · Post by **tictic** » Fri Oct 09, 2009 9:40 am

at ur door just put a dry line of the compound along door threshold before u mix it this will stop it running out the door.

mr bosch · Post by **mr bosch** » Fri Oct 09, 2009 10:19 am

Thanks for the replies guys.
@ Newbiejohn... how thick did you lay your compound and was it the screed you primed with SBR or the compound pre tile adhesive.

i would like to try and get a thick layer of compound down (10mm) as parts of the screed are a bit on the thin side, would this be acceptable?

sorry for sounding a bit thick on the questions but i'd rather ask now and get the job done right first time.

regards

DIY_Johnny · Post by **DIY_Johnny** » Fri Oct 09, 2009 11:53 am

There is a wickes deep levelling compound that can go to 50mm but would cost a bit if you are going to that depth. i reckon thats your best bet

For the living room I ran short so I mixed building sand into the levelling compound at a ratio of 2 parts compound to 1 part sand (instructions were on the back) and tossed in a few handfuls of cement in case I weakened it. I scratched it and it was pretty hard but don't know if this is the best way to go about it.

Also I used 2 coats Bal SBR , diluted on the screed and then again on top of the compound but thats because I mainly had it left over . The 2 coats were mainly because I kept getting dirt and dust all over the screed.

I have only done this once and it seemed to work just dandy so the guys can give you their professional experence

PS its more like mixing plaster than cement. I used paddle rather than shovel

DIY_Johnny · Post by **DIY_Johnny** » Fri Oct 09, 2009 11:54 am

tictic wrote:at ur door just put a dry line of the compound along door threshold before u mix it this will stop it running out the door.

Good tip! Wish I had known that earlier

mr bosch · Post by **mr bosch** » Fri Oct 09, 2009 2:06 pm

Many thanks for the advice mate.

fortunately for me you have to step down into this kitchen so i aint got to worry about door openings.

Opus Romano · Post by **Opus Romano** » Sun Oct 11, 2009 9:07 pm

I'm not sure of the relevance now, so apologies.

My first thoughts are that if you have a fresh screed then it should not require any self levelling.

Secondly, make sure that you bring the UFH up to full temp and leave for a few days before switching it off completely. Once the floor has cooled, usually at least a week after switching off, you can start the tiling. Use a flexible adhesive and grout.

Wait at least 2 weeks before switching the UFH on and then only bring it up to ambient temp. Increase the temp by 2 degrees per day until you reach the desired temp - this will prevent any adverse adhesive contraction / expansion and ensure that you have no til or grout cracking.

mr bosch · Post by **mr bosch** » Wed Oct 14, 2009 2:13 pm

thanks Opus Romano,
the reason behind the self levelling is to add bit of extra strength into the new screed as the builder that laid the screed says that it doesn't have an even thickness of 75mm throughout the floor which was specified and in some parts its about 30-35mm thick, so to be sure he suggested putting a layer of levelling compound down

cheers for advice on UFH, it was laid back in june and tried and tested then, so would it be necessary to do that again either before or after the levelling compound has been laid?

regards

Opus Romano · Post by **Opus Romano** » Wed Oct 14, 2009 6:18 pm

I wouldn't of thought it neccessary to test the UFH again if it has already been commissioned correctly

.

I'm still not sure that a 3 to 10mm bed of slc is going to add any residual strength to the screed. Before going to the expense of applying slc or tiles I would contact a manufacturer technical helpline and ask for some detailed product advice. Two of the top manufacturers of slc are Ardex (01440 714939, ask for tech support) and Mapei (0121508 6970, ask for tech support).

Best of luck.

thescruff · Post by **thescruff** » Wed Oct 14, 2009 6:33 pm

The underfloor should be under pressure test when the screed is laid.

mr bosch · Post by **mr bosch** » Wed Oct 14, 2009 7:11 pm

thanks again Opus Romano,
i'll give them a try and see what they say.

@ Mr Scruff. thanks also..As the UFH was installed by a plumber and the screed by another builder i don't know if the screed was laid under pressure test. i take it that this is required to prevent the piping from being crushed by the weight of the screed?? but as mentioned earlier the UFH has been tested a while ago

regards

thescruff · Post by **thescruff** » Wed Oct 14, 2009 8:30 pm

Stops it being crushed, allows you to tell if it's been damaged with wheelbarrows etc. give the pipe breathing room.

mr bosch · Post by **mr bosch** » Wed Oct 14, 2009 8:41 pm

cheers Scruff