New concrete floor?

[Brizz76]

I've searched the forum for a similar problem but no joy, so sorry if this is a repeat question - I am a newbie though!

I'm taking up tiles from my kitchen floor but some are bringing up chunks of the concrete floor below with them, whilst other tiles seem to be adhered so fast that I can't get my hammer-drill chisel underneath them at all in order to get them off. Consequently, I'm having to chisel away at the concrete just below the bits of tile left behind so that all the ceramic tile comes off.

My question is, should I just patch in any deep holes and then use a latex screed to get a level base to re-tile on, or would I be better off 'digging out' to a certain depth over the entire floor area (about 1.75m x 3.5m) and then lay a new layer of concrete. If so, what depth should I dig out and what depth of new concrete should I lay?

Any advice (or a link to another post dealing with this issue) would be greatly appreciated

I'm no DIY expert, but do have in-laws who are pretty good and who have laid concrete before, so could help me.

 

[masona]

Providing there's no movement of the old floor screed then make good with sand/cement plus levelling compound, if you do deep dig you may damaged the dpm which is under the concrete level, then it will be a bigger job.

 

[Brizz76]

Providing there's no movement of the old floor screed then make good with sand/cement plus levelling compound, if you do deep dig you may damaged the dpm which is under the concrete level, then it will be a bigger job.

Sorry to be so thick, but I don't understand what is meant by "screed then make good with sand/cement plus levelling compound". When I had a similar problem with the downstairs toilet floor, I filled in the holes with mortar (about 30 or so holes, each roughly 5cm across and between 1 and 4 cms deep) and then used a latex compound over the top. That was fairly straightforward. The holes that are appearing in the kitchen are bigger and deeper - some chunks coming up attached to the back of tiles are roughly the size and shape of an apple!

 

[masona]

Normally an oversite is like this,

hardcore + pea shingles > sand > dpm > 100mm concrete (3/4 ballast) > 50mm floor screed which is cement & sharp sand. (depending on the age of your property then an insulation boards is use as well.

The exsisting floor tiles is on top of floor screed and this is what you're seeing, does it look like sharp sand?

 

[joeb99]

Sounds like you are having the same problems as i had - ex council house kitchen floor tiles by any chance??

I removed them by using a trowel (heary duty for cementing) and water.

soak the floor, leave for an hour, then use the trowel to loosen a few tiles. Now soak the floor again and repeat. After a while, the tiles become really easy to remove.

I have damp coming up through my floor cos the isn't any DPM under the screed, so that helped to remove the tiles!

 

[ronacretesimeon]

Suggest as follows:

1. clean up the sides and base of any "holes" to make sure the surfaces are hard and dense and not loose and powdery - this is because the new mortar you are putting in needs to bond to what has been left behind
2. prepare surface
3. leave clean and dry
4. if you think you need to renew the damp proofness in these areas, apply 1 coat Ronacrete Monoprufe into the prepared holes
5. allow to dry (12-24 hours)
6. mix and apply 1 coat Ronafix:cement bonding primer, mix proportions 1:1
7. while wet or sticky mix and apply repair mortar, mix as follows:
1 volume cement
2.5 volumes medium sharp sand
1:1 mix of Ronafix and water, added to cement and sand to give semi-dry screed consistency

Trowel this on to wet or tacky primer, compact and finish smooth with a trowel

Protect with polythene. Allow to cure for 24 - 48 hours.

Use the repaired areas

You now hava DPM and thin bonded hard repair mortars.

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[Brizz76]

Thanks to all for your advice. Ended up not as bad as I feared as the damaged area was restricted to just a couple of tiles worth. The rest of the tiles came up fine, so I'm just having to do a couple of small bits of patching with mortar.

Thanks very much once again.