Floor leveller on concrete floor.

[frenchman96]

Hi There

I have just stripped the kitchen floor in my daughters house, it was laid with porcelain tiles on top of a concrete floor, that had a self leveling compound on it.

I noticed that the leveling compound is thin, and scrapes up easy, so I have decided to scrape it up, clean up as much as I can, will even hoover, and intend to apply a Latex floor leveler.

Not done this before, so I have a few questions.

1-its a concrete floor, quite level, but a few shallow pits, should I cement them first to level, or let Latex do it for me.
2- As skirts are removed, exposing wall, should I lay a 2x1 baton all around the room.
3-do I need to apply a unibond first if concrete like to be absorbent or/and dusty
4- room measures 4200 x 2800 or can I call that 4 x 3 mtrs = 12 square mtrs.

hope questions are not daft, only a 72 yr old novice trying to save daughter money.

[Wes]

Hi Frenchman,

1 - Depends on the self levelling you use and how shallow the pits are? A lot of self levelling will go up to around 10 mm, some go up to 50 mm. Just assess how thick you will need to go and buy the relevant self levelling for your purpose. Ardex NA is excellent stuff.
2 - Don't need to lay battens. Either use a mastic around the room and a batten across the doorway (if it comes into play) or prepare a stiffer mix with the self levelling and create a small dam round the perimeter. To clarify, put some of the levelling powder in a bucket and add a little water till you get a grainy workable lump. If it goes to the consistency of self levelling then you've added to much water. Apply the grainy mix with a trowel around the perimeter. It doesn't have to be tall or wide as there not going to be put under that much pressure. Don't worry if some of the levelling escapes when you pour. It's no big deal.
3 - If the concrete is porous, you will need to prime it. Generally 1 part primer to 4 parts water for porous surfaces but follow the instructions on whatever primer you use. It may need two coats. The dust won't stop. Just give it plenty of primer and clean the surface best you can. Slightly dampening the surface will do no harm.
4 - If you're levelling the entire room, you'll need to do it in stages, in my opinion. When pouring self levelling in stages, try and make sure the last pour hasn't dried. You want the self levelling to fuse together as one. So keep busy. You'll need a flexible bucket, a mixing padle (not the best but it'll do the job) and a drill. A spiked roller comes in handy but aren't essential. Just make sure the concrete is primed properly as if not, the concrete will suck the moisture out of the self levelling and you'll have pin holes everywhere.

As a last point, you can stand in the wet self levelling if you need to. Wear smooth soled shoes or trainers (the pro's would use spiked shoes but for one job there's no need for that).

Hope that's of use frenchman

[frenchman96]

Hi Wes

Thanks for that, great help, great site, and I suppose like most people, I look on here, do a Google for replies, use my judgement who to listen to, and get on with it.

When you talk about a primer, will my PVA Unibond (made by Everbuild) do the job, and should I dampen floor even before the PVA.

[Wes]

PVA Unibond should be fine but check with the levelling compound (just my likle disclaimer ). The primer is there to soak into the concrete and seal it, preventing pin holing.

If you used Ardex NA, that stuff would bond to Patrick Stewarts head after it had just been greased up by Elton John..

Slightly dampening the floor isn't essential. It just keep the dust down while you're working..The primer will to the same job with calming the dust down. Out of interest, what floor covering are you fitting afterwards? We're in the tiling forum so is that a clue

If the levelling compound starts pin holing you may need to apply a feather finish afterwards. That's really just to give strength back to the surface. Make sure it's not to hot in the room. If the levelling dries out to quick, it can crack, leaving you with a duff surface. Very small hairline cracks aren't a problem unless the surface is riddled in them.

Just use Ardex NA and you'll be a happy chappy

[m3 fitter]

PVA primer should not be used, as creates a plastic membrane on the substrate that can blow.. use an acrylic based primer, and the substrate will absord what it needs to and the excess will disapate. PVA in general is dieing out in most trades as failures are occurring, the tiling trade initiated this 8 years ago and slowly builders are also swaying towards acylic primer, like Dukkaboard and cement board as opposed to plywood. Good luck

[Wes]

It's not my thread but I found your answer helpful m3

I spent an hour today speaking to the technical department at Ardex regards a job I'm due to start and was informed that no primer is required for Ardex NA. Simply dampening the concrete is enough to prevent pin holing.

If you're going to use any other self levelling frenchman, the priming instruction will be on the side of the packaging..