Tiling over tiling etc

[Onoff]

Posting this on behalf of a mate:

 

"Lifted up the newer tiles back to the original ones. Gonna just tile
over them like what was done before.

What would you do for the back corner? Still need to take up the old
adhesive but gonna have about a 15mm deep gap where no original tiles
were. The washing machine is going there so don’t know if I’ll be able
to get away with adding extra adhesive to raise those tiles or should
use something else?"

 

 

 

I was thinking bring up to level with existing tiles, a decent self levelling "something"? Or a strong SBR laden screed levelled off. How to prep though?

 

Cheers

Edited March 9, 2018 by Onoff

[Nickfromwales]

2-part self leveller for the deficit. 

If the old tiles are sound then crack on. If there's any hint of movement then chuck a Ditra mat over it or it's a suicide mission. 

[Onoff]

  On 09/03/2018 at 23:33, Nickfromwales said:

2-part self leveller for the deficit. 

If the old tiles are sound then crack on. If there's any hint of movement then chuck a Ditra mat over it or it's a suicide mission. 

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Cheers. Any particular make of compound?

[Nickfromwales]

Any 2-part TBH, Ultra or Ardex. Ardex is expensive so try and find a BM that stocks the Ultra if you can as it's prob half the price and I can't tell them apart once laid.

 Ultra 2-part.

[Onoff]

  On 10/03/2018 at 08:38, Nickfromwales said:

Any 2-part TBH, Ultra or Ardex. Ardex is expensive so try and find a BM that stocks the Ultra if you can as it's prob half the price and I can't tell them apart once laid.

 Ultra 2-part.

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Says only up to 12mm for the Ultra or you have to bulk it out:

 

"Level IT Two can be applied at depths between 2 and 12mm. For 
deeper sections up to a maximum of 30mm, it is necessary to 
bulk out with a suitable graded aggregate filler. This can drastically 
prolong curing times so allowances must be made accordingly".

 

He's worried about the wm going on top. 

 

Or just lay to the 12mm max depth and let the tile adhesive take up the rest? 

 

(What tile adhesive will be the next question! )

Edited March 10, 2018 by Onoff

[Onoff]

Would mix No2 not do for this:

 

Mix Design’s

1.    Floor Screeding and Screed Repair (min. 6mm) 
by weight            by volume
50kg cement            1 pbv
150kg medium sand        2.5 pbv
10 litres SBR            (1:1 SBR:water 
9 litres water*        (add to consistency
Yield approx 0.1m³

2.    Heavy duty floor toppings (min. 12mm)
by weight            by volume
50kg cement            1 pbv
75kg medium sand        1.25 pbv
75kg 6-3mm grano chips    1.25 pbv
10 litres SBR            (1:1 SBR:water
9 litres water*        (add to consistency
Yield approx 0.1m3

 

3.    Waterproof Renders (min.6mm)
by weight            by volume
50kg  cement            1 pbv
125kg medium sand        2 pbv
10 litres  SBR            (1:1 SBR:water
9 litres water*        (add to consistency
Yield approx 0.1m³

 

4.    Water Resistant Concrete (min.25mm)
by weight            by volume
50kg cement            1 pbv cement
100kg medium sand        1.5 pbv
100kg 10-5mm pea shingle    1.5 pbv
5 litres SBR            (1:3 SBR:water
13 litres water*        (add to consistency
Yield approx 0.14m³

 

5.    Bonding Screeds, Plaster, New Concrete to Old
by weight            by volume
1kg cement            1 pbv cement
1 litre SBR            1 pbv SBR
Yield approx 3-4m² per litre

6.    Floating Screeds (min. 38mm)
by weight            by volume
     50kg cement            1 pbv
    150kg medium sand        2.5 pbv
    4.5litres SBR            (1:3 SBR:water
    13.5 litres water*        (add to consistency

 

[Nickfromwales]

I prefer to pour something 'pissy' when patching in. A patching screed doesn't creep and key in anywhere near as good without a load of prep and priming etc. 

£20. Mix - pour - forget. . 

[Onoff]

  On 10/03/2018 at 11:01, Nickfromwales said:

I prefer to pour something 'pissy' when patching in. A patching screed doesn't creep and key in anywhere near as good without a load of prep and priming etc. 

£20. Mix - pour - forget. . 

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So the Ultra will be OK above 12mm without bulking out?

 

Says with this Mapei stuff you can add 20 - 30% sand for thicknesses greater than 10mm:

 

latexplan.pdfFetching info...

Edited March 10, 2018 by Onoff

[Nickfromwales]

I'd just chuck in clean 6mm chippings.

 

[Nickfromwales]

Or a bag of dash if there's one handy. Adding sand dries it out. 

[Onoff]

  On 10/03/2018 at 11:44, Nickfromwales said:

Or a bag of dash if there's one handy. Adding sand dries it out. 

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Would a single layer of 10mm pea shingle first work? To bulk it out and have gaps for the compound to run between and key to the existing substrate?

 

All I could find chippings wise was this:

 

https://www.travisperkins.co.uk/Grano-6mm-Dust-Trade-Pack/p/996251

 

Edited March 10, 2018 by Onoff

[Onoff]

  On 10/03/2018 at 11:44, Nickfromwales said:

Or a bag of dash if there's one handy. Adding sand dries it out. 

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What's "dash"?

 

EDIT: JUST twigged, pebbledash! Same question as before then, how thick a layer in the bottom of the void? And should it be "gappy" to allow the muck to bond to the solid stuff underneath? Ta.

Edited March 10, 2018 by Onoff

[Onoff]

This is easiest for him to get!

 

https://www.wickes.co.uk/Wickes-10mm-Gravel-Pea-Shingle-Major-Bag/p/220128

[Nickfromwales]

10mm is a bit big if he's filling 12mm. 

Depends on how much tile adhesive is going over it afterwards.  

[Onoff]

  On 10/03/2018 at 13:12, Nickfromwales said:

10mm is a bit big if he's filling 12mm. 

Depends on how much tile adhesive is going over it afterwards.  

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He reckons he's got 15mm of depth to fill. Dunno where he'd get small bags of 6mm chippings. 

 

The TP stuff is 6mm to dust.

[Nickfromwales]

No dust !

Ordinary dash should be available in small bags, but if filling 15mm then 10mm chippings should be fine.