Preparing a concrete floor for ceramic tiles.

[Will]

Hello all

If anyone can give me any advice I would be really grateful... as an expectant father I am trying to get my house sorted before the imminent arrival!

Background:

I live in a house that was converted from a farm building sometime in the last 50-100 years (?) and I want to put ceramic tiles down on the kitchen and hallway floors. I have pulled up the existing vinyl tiles that were covering the floor to expose the black adhesive (?) below. The tiles came up easily and the adhesive below is dry to touch and is well stuck to the underlying concrete floor.

The concrete floor is very unlevel and has highs and lows as well as small areas where the concrete has simply crumbled. This is probably a result of damp (?) as there is no damp proof course (!).

I want to prepare the floor properly so that the ceramic tiels lie flat and survive for a few years (I really can't afford to have a dpc fitted so I am trying to get the next best solution).

Proposal:

1. Fill the bigger holes with mortar.
2. Coat the floor with a couple of layers of bitumen paint (to stop damp getting to adhesive/tiles - the whole floor wont be coated as the areas under the kitchen units will be left).
3. Then use a leveling compound over the floor part to be tiled.
4. Apply tile adhesive and lay the ceramic tiles.

Questions:

1. Is this a goof solution or is there a better way?

1. Have I got the order above correct? For example, should the bitumen paint go on the leveling compound?

2. There is a confusing array of products available - water based/vinyl/latex etc. What types of bitumen/levelling compound/tile adhesive are compatible? Will they all bond with on another?

Basically any advice you can give would be much appreciated.

Thanks

Will

[Mark S.]

I'll leave the tiling and damp to those better qualified just a note that if you use any leveling compound at any point avoid the Wickes homebrand stuff - I've just spent ages redoing the areas I'd used it on when B&Q were out of their own brand and the Evostick stuff...

Mark S.

[stuart noble]

Treat the area with 1pva: 4 water before filling. A general purpose mortar (Readymix etc) works well. Forget the bitumen. Use a latex screed (the one that comes with a liquid additive). I'd cover the whole floor to 5mm thickness as you won't want damp getting up into the units. Not the easiest stuff to work with though. You could skip the screed and rely on the adhesive as a waterproofer but using it to pack the tiles/level the floor can become expensive and will take forever to dry. The latex is walkable in a couple of hours.

[The Natural Philosopher]

I'll take a different tack on this.

First of all stabilsie with PVA. This really does bind loose mortar together.

Then ether rescreed or use levelling compound. That gets it roughly level.

Forget DPC as teh tiles are water oproo anyway, but use waterproofing in the grout.

Lay tiles on a fairly thick bed of rapid set, using strings and levels to get the levels spot on accuarte. Tamp tiles down gently with a rubber mallet.

Wash off any tile cement immediately on laying. Rapid set mixed stiff is recommended as it doesn't slump and sets fast enough to be walked on gently in a couple of hours.

Use quality grout (I swear by Bal, YMMV) and a waterproofing additive: clean it all immedairely grouted - I use those scrubbing pads and scrub, wipe and squeesze, and finish off with a shaping tool to make teh grout look sexy.

If there is a slight damp problem up the walls, cut tiles in half for skirting, and run them up to at least 4 " above outside ground level. In general in a solid brick wall this will force the damp to rise, and it should evaporate outwards raher than inwards.

[Will]

Thanks Mark. I'll make a point of using another brand! I have read of a few people having problems with levelling compound... I wonder if it was wet enough when used??

[Will]

Thanks everyone, some realy useful tips and ideas. Luckily I have the father-in-law coming to help so I will run the options past him and see what we come up with. It seems my knowledge of adhesives needs to be expanded....

I let you all know what we decide to do and give some feedback on the results when its done... hopefully next week! LOL

Thanks again... and keep any other ideas coming as I don't plan to start the job until this Friday!

[stuart noble]

Fine for the pros. Me, I prefer to pack the tiles individually in my own time. Rapid set, strings and levels? Sounds stressful to me :-)

[Mark S.]

As others have said plus I "washed and vac'd" the bare concrete first then pva'd the lot twice just in case.

I'd laid a room and half of the compound before using the wickes stuff and that's still there so I put it down to their mix?

B&Q do own brand pva in 10 litres for less than a litre of the "branded" stuff too.

Mark S.

[Will]

"stuart noble"

[stuart noble]

IMO the low stress way is to fill the floor roughly first. Use a length of

2x1 to check levels with doorways etc and leave a little more than a tile thickness gap. Pin another piece of wood to it and you can use it to tamp the stuff down. It needs to be flat but not necessarily level.

[The Natural Philosopher]

I do pack the tils individually, but the strings and levels are what you need to get the darn things packed right!

[The Natural Philosopher]