Crack/subsidence in concrete floor

[bigegg]

My mum's kitchen has some historic subsidence in her kitchen floor due to d••khead neighbour planting leylandii about 3ft from the wall. They were removed about 4 years ago
The floor hasn't moved in two years

There is a crack across the length of the room - about 10ft - which has dropped by about 4mm.
Just enough for her to stumble.
I/we can't afford to dig out the entire floor to replace it.
Can I just pour self levelling epoxy screed to fix it?

Recommendations for a product?

 

[pedrobedro]

Cempolay is the main solution, £8 from screwfix. It's only supposed to be laid to about 2mm but I mix it with some PVA to go a bit thicker. Your epoxy screed should do the job though if you already have it.

 

[clift_d]

I would probably go for Mapei Ultraplan that Screwfix also sell - it can do 3mm to 30mm in one application.

The way I've seen the professionals get a good level surface is to use dabs of the leveling compound to bond little stacks of plastic packers that are set at the right height at intervals across the floor. When these are set they simply pour the leveling compound between them and trowel flush with the tops of the stacks.

 

[mike os]

Use either level flex or fine flow 3000, it's all I will use these days

Use a srb primer and mix exactly to instructions. ...

You will need to fill the crack first

You can build both up,in layers if you need to.... I usually use level flex as a base and 4 to 6mm fine flow for a perfect finish use a spiked roller

 

[outofthefire]

I would probably go for Mapei Ultraplan that Screwfix also sell - it can do 3mm to 30mm in one application.

The way I've seen the professionals get a good level surface is to use dabs of the leveling compound to bond little stacks of plastic packers that are set at the right height at intervals across the floor. When these are set they simply pour the leveling compound between them and trowel flush with the tops of the stacks.

Its a lot easier to pour "self leveling compound" and allow it to find it's own level than to fanny about trying to use dabs of leveling compound which on there own will find different levels. The clues in the product name

 

[arther dailey]

I would suggest trying to find some one with the knowledge to just check the crack and give advice before going ahead, hopefully they will confirm alls well and carry on.Either way obviously you need to sort it being a trip hazard, my old mum tripped and broke her elbow last year, easily could have ended up far worse senario.Arther

 

[brightspark]

just get self levelling compound tipped on it and float over it job done worry in a few years time if it opens up

 

[Bobtail4x4]

cut across at 90 degrees bond stainless pins then overlay self levelling

 

[mike os]

Have to plug the crack or the leveller will settle in that area

 

[bigegg]

Fill the crack with?
Grind out and silicon sealer?

 

[outofthefire]

Fill the crack with?
Grind out and silicon sealer?

I'd just use cement its only to close the crack

 

[arther dailey]

If you are going to close crack with cement, first vacuum all dust you can get out, mix PVA 1 part to 4 parts water ,soak crack, then add rest of pva mix to you sharp fine sand 4 parts to 1 part cement,or 3 to 1, fill crack..

 

[mike os]

Fill the crack with?
Grind out and silicon sealer?

Depends how big... If it's hairline open out the top a bit, blow or vac out what you can prime with srb... don't use pva on cement based products. ... and pour some self leveller or cement slurry in... you won't stick the parts together but you can hopefully prevent them moving against each other

If its wide then sand cement mortar will suffice

Fill untill it's just about level with the floor so you know it's not 'leaking'

 

[arther dailey]

Why not pva?, loads of builders prime with pva, I use it all the time fixing repairs on concrete ,no problems with pieces I did 20 years ago. Anyways yes srb is also good.

 

[brightspark]

Why not pva?, loads of builders prime with pva, I use it all the time fixing repairs on concrete ,no problems with pieces I did 20 years ago. Anyways yes srb is also good.

sbr is totally waterproof and is used in slurry mix in damp proofing and does not re emulsify in damp conditions like the waterproof unibond pva does I use the sovereign sbr its over 30 quid a gallon but its the besthttp://www.sovchem.co.uk/bondingagent.html

 

[arther dailey]

interesting, I have used sbr when making certain statues etc, but it always gives me such a head ache, confined in work shop space the smell just doesnt agree with me.used to get all my admixs from a firm called Bretts, but they closed around here.
the one thing I would add in slurry is a good super plasticiser, water reducing,self levelling mix.

 

[mike os]

Pva is no longer best practice, and has not been for several years... it can fail under damp conditions

 

[arther dailey]

glad I read the post,its always good to learn!