concrete question for tiling?

**benlovesnuk** · 29-02-2012, 10:49 PM

We have a concrete floor that is going to have a terracotta tile put ontop of it. However though mostly level it isnt smoothe and has dips etc. Its 155m2 what are my best options with budget well in mind?
I will try add a pic.............

Could i just get them to screed or concrete over with a thinbed mix?
Cheers

**dirtydog** · 29-02-2012, 10:54 PM

No need to screed, they will use cement to lay the tiles anyway.

**benlovesnuk** · 29-02-2012, 11:06 PM

Is that also with clay tiles? What would be the thickness of the concrete bed? Does it not need a special mortar?
Cheers:-)

**adzt1** · 29-02-2012, 11:18 PM

any tiles.
Thai style is a 10-20(at most)mm bed . soft sand n cement. wet.
not the best in the world but it works.

**dirtydog** · 01-03-2012, 01:06 AM

Originally Posted by adzt1

Thai style is a 10-20(at most)mm bed

No it isn't, you will find most concrete floors in shop houses etc have a 3 to 5cm dip in the middle, the tiles need to be level throughout, so your 10 to 20mm wild guess is way out, if the dip is too large then it will have a pour done first to bring it up to level, but up to 6cm of cement is fine for tiles.

**nigelandjan** · 01-03-2012, 02:29 AM

The Thais will love to tile on top of that mate ,, I have seen some superb jobs done from much worse bases to work from.
I am sure you will be well pleased

wuron · 01-03-2012, 05:12 AM

Nigelandjan is right. We like to tile a nice smooth surface, but the Thai are used to a rough surface, and the right man will do a damn good job. When I was ready to have floors poored I told them I wanted a nice smooth surface, they told me they don't do smooth. I told them to hit the road and poored my own floors.

**DrAndy** · 01-03-2012, 07:51 AM

Ben, you may want a slight incline on the tiles so that any water will run off in the direction you specify

I will be tiling my roof terrace in terracotta and what DD said is it

**benlovesnuk** · 01-03-2012, 08:07 AM

Thanks everyone. I wasnt too sure whether i might need self leveling adhesive but if you say theyll crack on with it, thats seems fine to me. Dr A sorry a little misleading picture, if you now look in the house thread you can see this will have a roof and be covered by walls etc. But thank you for the tip.
I think i read they should prepare the tile first so when grouting it comes off easier when wet, also that finishing i should use a porous stone oil like linseed and the clear bees wax? any thoughts?

**dirtydog** · 01-03-2012, 08:10 AM

Originally Posted by wuron

I told them I wanted a nice smooth surface, they told me they don't do smooth. I told them to hit the road and poored my own floors.

Cement sticks to rough surfaces a lot better than smooth surfaces.

**DrAndy** · 01-03-2012, 08:18 AM

Originally Posted by benlovesnuk

I think i read they should prepare the tile first so when grouting it comes off easier when wet, also that finishing i should use a porous stone oil like linseed and the clear bees wax? any thoughts?

if your quarry tiles are the old fashoned type which are porous, yes

you can buy types that are presealed now, much better unless you need the porosity (they used to be laid direct on earth and needed to breathe)

**adzt1** · 01-03-2012, 08:49 AM

Originally Posted by dirtydog

Originally Posted by adzt1

Thai style is a 10-20(at most)mm bed

No it isn't, you will find most concrete floors in shop houses etc have a 3 to 5cm dip in the middle, the tiles need to be level throughout, so your 10 to 20mm wild guess is way out, if the dip is too large then it will have a pour done first to bring it up to level, but up to 6cm of cement is fine for tiles.

50mm dip in the middle? not too sure about that. I see no drainage in the pic.
maybe a fall to one side or to the entrance .

I've never seen thais use a semi dry bed(screed). Its always been near on wet. if its near on wet the bed don't travel . I.e you push one down n another will move if the bed don't travel.

so a near wet bed is always thinner .
who'd wanna knock up 50 mm of bed? for what.? remember the budget..

u can have semi dry beds . they travel down well when tapping the tiles but only needed if the floor height is to be mm perfect or the initial concrete pour is out.

the problem with semi dry beds are if its not tapped down right . the floor will go hollow. ( tap it with a broom handle).
it won't last if its hollow. if not hollow uve more chance of not cracking a tile if u drop something on it.

**DrAndy** · 01-03-2012, 08:53 AM

I am not sure why they use such a thick cement bed here but it works unless you have low ceilings!

I suppose proper tile cement (the type you spread thinly and then comb out) is more expensive and needs a flat base

**adzt1** · 01-03-2012, 08:55 AM

on sealing. if u can find it here. or order it online ,LITHOFIN. its the best ur going to find.

**dirtydog** · 01-03-2012, 09:10 AM

Originally Posted by adzt1

50mm dip in the middle? not too sure about that. I see no drainage in the pic.

I said 3cm to 5cm, that is quite normal dips here, do you have drainage in your living room? Although I assume your living room is tiled or something and not rough poured concrete.

Originally Posted by adzt1

who'd wanna knock up 50 mm of bed? for what.? remember the budget..

Cement, sand and water, things really don't get cheaper than that.

Originally Posted by adzt1

u can have semi dry beds . they travel down well when tapping the tiles but only needed if the floor height is to be mm perfect or the initial concrete pour is out.

The initial concrete pour is always out, laying tiles, if not perfect then you don't get paid, people want their floor tiles level or sloping to a run off point.

**adzt1** · 01-03-2012, 10:08 AM

^ahh so ur a builder now are u?.

ur arguments are just ur opinions.

I gave my opinions and that's let the OP read as he wants.

Unless u want to quote me Industry Standards
there is no Bible on house construction in Thailand( unless uve a copy)so different methods are often the case.

The op will benefit if he understands most ifnot all methods ..

**Zone** · 01-03-2012, 10:19 AM

quote="adzt1"] 50mm dip in the middle? not too sure about that. I see no drainage in the pic.
[/quote] I said 3cm to 5cm, that is quite normal dips here,

...???... 50mm & 5cm were the same, when I last looked...

**dirtydog** · 01-03-2012, 10:35 AM

Originally Posted by Zone

...???... 50mm & 5cm were the same, when I last looked..

Is 3cm to 5cm the same? No, it isn't, it is 30mm to 50mm.

Originally Posted by adzt1

ahh so ur a builder now are u?

Yes I am, I ran a construction company here in Thailand for over 15 years.

**DrAndy** · 01-03-2012, 10:55 AM

Originally Posted by dirtydog

The initial concrete pour is always out, laying tiles, if not perfect then you don't get paid, people want their floor tiles level or sloping to a run off point.

Originally Posted by adzt1

^ahh so ur a builder now are u?.

yes, that was a big fall

**david44** · 01-03-2012, 11:48 AM

DD and others have made good points.Remember if doing a roof terrace to plan your water run off be it gutter or a slight slope for cleaning ,storm water etc.If you allow it to run from a sloped roof (which will be full of dirt,then across the terrace then down your nicely painted white walls the summer monsoon rains will stain walls with roof mess.Guess how I know? A gutter or gulley and a collection tank to recycle the surplus? Good luck

**DrAndy** · 01-03-2012, 11:59 AM

Originally Posted by david44

Remember if doing a roof terrace to plan your water run off

Originally Posted by benlovesnuk

a little misleading picture, if you now look in the house thread you can see this will have a roof and be covered by walls etc

same again

**InKorat** · 01-03-2012, 03:55 PM

The method we use often on floors that require leveling, is to first spread a mortar mix that has more sand and less water than normal to establish the grade. The mortar needs to have enough sand in it and be dry enough, so you need to trowel it flat and then place the tile to check and establish the grade.

If you can continue to tap on the top of the tile and grade level goes down, you have too much water in the mix. You should also be able to easily lift the tile without excessive sticking or disturbing the motar placed below the tile to check that the whole area under the tile is filled properly.

Once you have the grade established on the dry mortar mix, you can then place a softer rich mixture of tile cement (no sand) directly on top of the dry mix and tap the tile down for final placement.

We have been using this method for many years on marble and granite floors and it works well on tiles with no quality issues ever arising.

Once you get used to the method, it is fast and easy.

**adzt1** · 01-03-2012, 04:32 PM

^ correct.
u can always "butter" the back of the tile for a better stick.

my original point though was that the Thai style I've seen is to have a wet mix.
a wet mix won't travel therefore a thinner bed is needed... I.e up to 20mm.

any good floor layer will survey the concrete first and every job can be different.

anyway good luck with ur build OP

**benlovesnuk** · 02-03-2012, 08:20 AM

Hi, thanks for everyones enthusiastic input, the wood cross beams bottom edges are currently with no tile 235cm high from floor, the top of ceiling about 250cm. Ideally i want to keep the height at or above 2.0m as much as possible. I have old wooden doors going in that i will have tied into this floor, that will give me a height of the floors frame at 35mm, so ideally 20mm pug, on 15mm tile is ideal.
In this case what is my best mix option?
Regards

**adzt1** · 03-03-2012, 09:37 AM

id say if you only have 35mm from concrete floor (SFL ) to top of tile (FFL ) a semi dry sand a cement bed won't work.

you can float over the concrete and bring it up 10+mm then use a tile adhesive , something like ARDEX X7 , but adding another layer is just another opportunity for something to fail , plus I doubt tile adhesive is cheap around here.
using adhesive is quick once u have a smooth base to start but if u have dips n the bed gets to say 20mm ,the amount /cost of adhesive sky rockets!!.

use a near on wet bed (just under wet) wet the floor and submerge tiles in water before laying ( this stops the cement drawing up thru tile , easier to clean and bonds to the bed better).

seal tiles before you grout . if not before you lay them.

I must say a wet bed is a slowish n tuff way to lay tiles but a semidry mix really needs to travel to become solid (so nothing under say 30mm maybe even 40mm).. the only other option is Adhesive .
a wet bed gives a solid and tuff finish ,
survey the SFL first to find the highest point ,the bed should be no less than 10 mm at that point

hope this gives you some idears

Adzt1 , specialist natural stone floor layer of 19 yrs.
not such a big fall eh DrBrownnose/Andy

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