MatthewPike Posted November 16, 2020 Share Posted November 16, 2020 Hi People, I have a problem, long story short we laid a new concrete floor (a week ago) in the kitchen we are renovating (30m2)... all to building regs insulation membranes etc etc. Now the problem is I need to get the tiled floor down or my wife will have my guts for garters. So my solution is as follows. 1, Prepare concrete floor inc primer and pour self levelling compound MAPEI ULTIMATE LEVELLER 1210 SELF-LEVELLING FLOOR COMPOUND ( this is my area of concern as the floor will continue to shrink below) I'm aiming to only hit the low spots with this rather than a complete surface but not sure how doable this will be in practice. 2, Lay Ditra matting adhering to SLC with ARDEX AF 200 PLUS (I'm hoping this will allow the concrete floor to continue to dry out and the shrinkage will not affect the tiles) 3, Lay Ceramic tiles with flexible tile adhesive. Kwik Flex Grey Floor Tile Adhesive No underfloor heating as i'm too tight my wife says and I say that's why slippers were invented. Any other solutions greatly received. 1 Link to comment Share on other sites More sharing options...
PeterW Posted November 16, 2020 Share Posted November 16, 2020 Get an industrial dehumidifier and get it running ASAP. Floor moisture level needs to be dropped but move the unit around so you don’t dry and crack one area. How thick is the screed..?? Link to comment Share on other sites More sharing options...
nod Posted November 16, 2020 Share Posted November 16, 2020 9 minutes ago, MatthewPike said: Hi People, I have a problem, long story short we laid a new concrete floor (a week ago) in the kitchen we are renovating (30m2)... all to building regs insulation membranes etc etc. Now the problem is I need to get the tiled floor down or my wife will have my guts for garters. So my solution is as follows. 1, Prepare concrete floor inc primer and pour self levelling compound MAPEI ULTIMATE LEVELLER 1210 SELF-LEVELLING FLOOR COMPOUND ( this is my area of concern as the floor will continue to shrink below) I'm aiming to only hit the low spots with this rather than a complete surface but not sure how doable this will be in practice. 2, Lay Ditra matting adhering to SLC with ARDEX AF 200 PLUS (I'm hoping this will allow the concrete floor to continue to dry out and the shrinkage will not affect the tiles) 3, Lay Ceramic tiles with flexible tile adhesive. Kwik Flex Grey Floor Tile Adhesive No underfloor heating as i'm too tight my wife says and I say that's why slippers were invented. Any other solutions greatly received. Don’t use Ardex 200 onto concrete It’s for sticking the matting to timber Use flexible tile adhesive with a 6 mil notch 1 Link to comment Share on other sites More sharing options...
MatthewPike Posted November 16, 2020 Author Share Posted November 16, 2020 just found my solution I think https://ardex.co.uk/product/arditex-na/ Link to comment Share on other sites More sharing options...
MatthewPike Posted November 16, 2020 Author Share Posted November 16, 2020 26 minutes ago, PeterW said: Get an industrial dehumidifier and get it running ASAP. Floor moisture level needs to be dropped but move the unit around so you don’t dry and crack one area. How thick is the screed..?? understood, 100mm. Link to comment Share on other sites More sharing options...
nod Posted November 17, 2020 Share Posted November 17, 2020 As Peter has already pointed out You must get the moisture content down in the floor, If it’s not dry the tiles will lift Link to comment Share on other sites More sharing options...
Russell griffiths Posted November 17, 2020 Share Posted November 17, 2020 Tell your wife to wait. 1 1 Link to comment Share on other sites More sharing options...
PeterW Posted November 17, 2020 Share Posted November 17, 2020 100mm would normally take 100 days to properly dry (and cure) so you have a while to wait. Ideally you shouldn’t get the moisture out too quickly as it will weaken the concrete - force drying after 14 days should be ok if this is only a screed but it will still take at least another two weeks with a dehumidifier to get it anywhere close to acceptable. Forcing it too quickly could also make the slab curl so be very careful and move the dehumidifier about. How big are the dips and humps that you need to use SLC..? Link to comment Share on other sites More sharing options...
MatthewPike Posted November 17, 2020 Author Share Posted November 17, 2020 12 hours ago, Russell griffiths said: Tell your wife to wait. ?? 1 Link to comment Share on other sites More sharing options...
MatthewPike Posted November 18, 2020 Author Share Posted November 18, 2020 On 17/11/2020 at 07:37, PeterW said: 100mm would normally take 100 days to properly dry (and cure) so you have a while to wait. Ideally you shouldn’t get the moisture out too quickly as it will weaken the concrete - force drying after 14 days should be ok if this is only a screed but it will still take at least another two weeks with a dehumidifier to get it anywhere close to acceptable. Forcing it too quickly could also make the slab curl so be very careful and move the dehumidifier about. How big are the dips and humps that you need to use SLC..? up to 10mm in a couple of places. Link to comment Share on other sites More sharing options...
PeterW Posted November 18, 2020 Share Posted November 18, 2020 So to get SLC to flow properly, @Nickfromwales advises to get the floor sopping wet and then mix the SLC “like mother’s milk...” so an extra 6-700ml of water per mix. I would get this done now and then leave it 72 hours and start with the dehumidifier 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 18, 2020 Share Posted November 18, 2020 Sopping wet with a mix of ( 25% ) flexible tile primer and ( 75% ) water to ‘size’ the new screed. Then a 50/50 mix used on a sponge to re-dampen the screed literally done as the flexible tile adhesive for the Ditra goes down. That’ll be bombproof. You should not lay tile adhesive onto a biscuit dry floor. The Ditra will indeed prevent the tiles from being affected, and should give up to 10mm decoupling ( @nod ? ). Link to comment Share on other sites More sharing options...
Onoff Posted November 18, 2020 Share Posted November 18, 2020 On 16/11/2020 at 22:50, MatthewPike said: Now the problem is I need to get the tiled floor down or my wife will have my guts for garters. Sounds a harsh woman to please! When I did my bathroom..... Main slab - Feb 2016 Wet room corner slab - April 2018 Tiling started - August 2018 ? Link to comment Share on other sites More sharing options...
nod Posted November 18, 2020 Share Posted November 18, 2020 3 hours ago, Nickfromwales said: Sopping wet with a mix of ( 25% ) flexible tile primer and ( 75% ) water to ‘size’ the new screed. Then a 50/50 mix used on a sponge to re-dampen the screed literally done as the flexible tile adhesive for the Ditra goes down. That’ll be bombproof. You should not lay tile adhesive onto a biscuit dry floor. The Ditra will indeed prevent the tiles from being affected, and should give up to 10mm decoupling ( @nod ? ). If the floor is still drying it can still lift Even with Ditra Link to comment Share on other sites More sharing options...
Pocster Posted November 18, 2020 Share Posted November 18, 2020 4 hours ago, Onoff said: Sounds a harsh woman to please! When I did my bathroom..... Main slab - Feb 2016 Wet room corner slab - April 2018 Tiling started - August 2018 ? Was the slab dried out by the time you started tiling ? Link to comment Share on other sites More sharing options...
Gav_P Posted November 18, 2020 Share Posted November 18, 2020 4 hours ago, Onoff said: Sounds a harsh woman to please! When I did my bathroom..... Main slab - Feb 2016 Wet room corner slab - April 2018 Tiling started - August 2018 ? UFH on when? 1 Link to comment Share on other sites More sharing options...
Pocster Posted November 18, 2020 Share Posted November 18, 2020 Just now, Gav_P said: UFH on when? 2024 Link to comment Share on other sites More sharing options...
Gav_P Posted November 18, 2020 Share Posted November 18, 2020 43 minutes ago, pocster said: 2024 Sporty! Highly ambitious too I’d say. ? 1 Link to comment Share on other sites More sharing options...
MJNewton Posted November 18, 2020 Share Posted November 18, 2020 5 hours ago, Onoff said: Sounds a harsh woman to please! When I did my bathroom..... Main slab - Feb 2016 Wet room corner slab - April 2018 Tiling started - August 2018 ? I envy you guys that just crack on with it... I let things drag on and on. 1 Link to comment Share on other sites More sharing options...
Ian Posted November 18, 2020 Share Posted November 18, 2020 (edited) @MatthewPike the solution to this same problem that I’ve used a lot on fast-track commercial projects is using a liquid surface applied damp proof membrane: https://ardex.co.uk/products/damp-proof-membranes/ it slows the moisture movement from the slab down to a level where it no longer causes a problem to the final floor finish. ....but it’s not a cheap solution. Edited November 18, 2020 by Ian Link to comment Share on other sites More sharing options...
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