Levelling a floor - Crazy idea?

[Monsoon]

I have a project to level a workshop floor.
It is approx 4m X 6m

The floor is nearly 70mm lower in the middle than around the perimeter.

I intend to use a self levelling compound mixed with granite chippings.

The problem is the floor is covered in old linoleum tiles and initial test prove it will be a real pain in the ass to remove the tiles and the tar like adhesive. The floor is bone dry and I wonder if these tiles/adhesive are also acting as a secondary dpm.

So the question is:-

Is it a crazy idea to fix Expanded metal lath to the floor and then pour my self leveller over the top?

I've seen this done when a cement render is applied to the outside of a building and the EML provides a mechanical bond to wall below.

 

[mattysupra]

well there is only one way to find out!

 

[Monsoon]

Yikes - I dont wanna be a lab rat

Have you never come across this as a solution to the age old labour intensive problem of having to remove a previous floor covering?

The plasterer also use an adhesive product which has aggregate added. You brush it on non porous surfaces, leave it to dry and then you have a rough key to apply the coating.

Maybe this could also be used

 

[mattysupra]

the filled mix bit is o.k but as for metal bits im not to sure. Never done this myself and to be honest im not a 100% sure what you mean.!

 

[Monsoon]

The stuff Ive seen used on walls is sheets of metal mesh. They attach it to the wall and then apply their sand & cement render over the top.

The mesh provides a strong key for the render to bind to.

If I pour a water based self leveller onto the tiles I'm pretty sure it will fail.

Here is a pix of the mesh:-
http://www.expamet.co.uk/product/plasterers-accessories/lathing-and-accessories

 

[mattysupra]

i see what you mean now. Well i have never seen it used with smoothing compounds before and also you need to take the lino tiles up and use the correct primer etc to go with the compound.

 

[WoodYouLike]

The stuff Ive seen used on walls is sheets of metal mesh. They attach it to the wall and then apply their sand & cement render over the top.

I've seen that being used on one of the Grand Design episodes. There (on the outside walls) it worked rather well.

 

[Monsoon]

i see what you mean now. Well i have never seen it used with smoothing compounds before and also you need to take the lino tiles up and use the correct primer etc to go with the compound.

Taking up the lino tiles is what I want to *avoid* for 2 reasons:-

1. They are stuck really well with a tar like glue. Presumably even if I get the tile up, I also need to remove the glue as well.

2. The lino tiles/tar like adhesive may well be acting as Damp proof membrane as there is no evidence of damp. Of course the concrete slab may well have been DPM'ed anyway.

The plan was:-

1. Roller on 'Thistle Bond it' this is an adhesive/aggregate mix which sticks to non porous surfaces
http://www.sheffins.co.uk/products/show_prod.asp?ProdID=2358&CatID=21&SubCatID=184

This stuff leaves the surface like sand paper when it drys.

2. Fix aforementioned mesh to the floor by nailing into the concrete below.

3. Prime surface and then apply a water based self levelling compound

Edit: Just to add. I understand this may not be a standard approach to the problem but it's interesting to see how products from other trades have solved the problem of getting adhesion between a smooth non porous substrate and a cement based product above.

 

[Monsoon]

The stuff Ive seen used on walls is sheets of metal mesh. They attach it to the wall and then apply their sand & cement render over the top.

I've seen that being used on one of the Grand Design episodes. There (on the outside walls) it worked rather well.

From what I understand they use it quite often where the wall they are rendering is painted (often oil based) or over old pebbledash.

 

[mattysupra]

i dont want to coment on your planned method. Maybe you should contact the tech guys of which ever product you decide to use.

 

[noseall]

when a render is applied to e.m.l., it does not matter whether or not there is a solid substrate behind, as the strength of the render and e.m.l. is enough to sustain its needs, i.e. paint etc. being hollow behind will not matter.

if you try and replicate this on a floor, and the render happens to 'lift', then the fact that it is hollow beneath, will matter a great deal.

a failure on a floor will have more serious consequences, because we put heavy things on floors, like human beings.

 

[Monsoon]

Just an update to say I've shelved the master plan and gone back to old fashioned, tried and tested hard work.

Following a weekend of graft - I'm clear of the tiles and back to the concrete slab.

As the property is old, I intend to put down a 2 part epoxy resin DPM (F75).

Is it OK to screed over the top F75?
Should I prime st then screed?

My screed is going to be made up of 2 part granite chippings, 2 part sharp sand, 1 part portland cement (as per the recipe I got from a previous post by Noseall (cheers))

The reason for the granite chippings is the screed will thin to a little over 20mm in places.

I'm surprised that granite chippings are not used as part of a standard screed if they make a stronger formula. I thought cost may have been a factor but I paid the *same* price for the chippings as the sand.

 

[Monsoon]

Is it OK to screed over the top F75?
Should I prime st then screed?

I've had a re-read of the liquid dpm sticky and it does indeed advise priming.

I've also read f ball website, again it advises priming after applying the F75.

This seems a bit strange as the reason giving for priming prior to applying your self levelling compound is to prevent an absorbent concrete base from drying the compound.

Surely the F75 will be almost non absorbent?

Is it OK/recommended to throw a sprinkling of dry sand onto the 2nd coat of F75? (I'm sure I've read this somewhere)