Self Levelling Help - slab split into two?

[Dean A]

Morning all,

I need to prepare my kitchen floor so that it can take tumbled/chipped edge trav and need a little advise.

The area is approximately 5 x 4m2, and the current concrete slab is split into two parts. Each part of the slab was poured at different times (they were previously two separate rooms).

The slabs have been down at least 5 years, so are stable, and were previously screeded with sand/cement which came up with the previous floor tiles. The previous screed was about 50mm-70mm thick (head height is an issue is/was an issue in the room).

There is a 7-10mm different in height between the two slabs, but this varies along the full width of the join (4m wide).

My plan is to screen the whole lot in a single pour of F-Ball Stopgap 300HD SLC, and have calculated that 12 bags should do the job. The slab is quite level, it's just the height difference which will swallow quite a lot of the SLC. There is also a low point in one corner that will need probably 12mm-15mm.

I have taken some pics to try and show you the area, but they are only happy snaps - sorry about the poor quality.

Question is, is my plan to try and fill the area with Stopgap 300 and tile onto this a wise one, should I be concerned about the split in slab under the SLC moving and cracking tiles and finally, from your experience will this take more than 12 bags?

The materials involved are expensive and I want to get this one right.

Thanks in advance for your help :smilewinkgrin:

 

[nybor62]

you will need to prime the floor with stopgap p131
at the depths some of the slc needs to be 12 bags may be cutting it fine imo
you will get 5m2 at 3mm thickness approx

 

[Ajax123]

Repairr that chasm first before you lose a small herd of goats down it and they give you greif for years to come. That crack will reflect through whatp ever you put on top of it if you dont. A low viscosity resin stictch should do the trick.

 

[Dean A]

you will need to prime the floor with stopgap p131
at the depths some of the slc needs to be 12 bags may be cutting it fine imo
you will get 5m2 at 3mm thickness approx

Hmm, I thought it might be cutting it fine, I might increase to 14 bags - this is when it starts to get very expensive at £20 a bag!

I forgot to mention that I will prmie with neat stopgap p131

 

[Dean A]

Repairr that chasm first before you lose a small herd of goats down it and they give you greif for years to come. That crack will reflect through whatp ever you put on top of it if you dont. A low viscosity resin stictch should do the trick.

Thanks for the reply.

The angle of the picture doesn't help, there isn't really a chasm, the two joints butt up against each other. There is just a height differential.

I haven't seen anything about a low viscosity resin stich in my research, is it quite common to use this method? I did consida Ditra matting as I have used this before, but at 20m2 it will add significant cost.

 

[Sean Page]

Have you looked at Mapei Ultraplan Renovation Screed?

 

[Dean A]

Have you looked at Mapei Ultraplan Renovation Screed?

Hi Sean,

No but looks good, and Mapei Eporip sounds like it could do the trick with the join of the two slabs. I used Mapei Fiberplan for the bathroom and it flowed well, do you have experience with the renovation screen product?

 

[Sean Page]

Yes, I've used a fair amount of it and it can be poured to 30mm in one go if needed. I've not used Mapei Eporip before though. I would maybe go for a crack suppression membrane to bridge the join then slc over the top, but it's hard to call from a photo.

 

[Mike]

Is it not possible to have a grout line over the joint and use colour match silicon in the grout line as an expansion joint?

tapatalk on my HTC

 

[Mike]

Oh, and hello Sean, welcome back:thumbup:

tapatalk on my HTC

 

[Dean A]

Is it not possible to have a grout line over the joint and use colour match silicon in the grout line as an expansion joint?

tapatalk on my HTC

Hi Mike,

I am planning on using an opus or french pattern so not ideal!

In addition, there wasn't a split before and the other half won't understand!

 

[Rich]

That looks like a crack and a half. It will need repairing if you are planning to slc over the top of the crack or as Mike has said a movement joint over the top of it.

 

[Diamond Pool Finishers]

you can baulk-up the SLC with aggregate , and have you thought about using an uncoupling -membrane over the joint between the slabs of oversight...

 

[Rich]

How wide is the crack? Im pretty sure that a decoupler will only bridge a gap of 3mm.

 

[Dean A]

That looks like a crack and a half. It will need repairing if you are planning to slc over the top of the crack or as Mike has said a movement joint over the top of it.

Thanks for the reply.

It's not so much a 'crack', it's the join in the 2 substrates. They are stable and about 4-5" thick - just different heights.

There is no gap between the joints, the picture is very deceiving - apologies for the poor quality.