Floor tiling

[nod]

I finally made a start on the floor tiling this afternoon 

I really could do with a week off to get on with it 

 ut paid work has to come first

[MikeSharp01]

@nodWhat us the orange stuff under the adhesive, looks like a great job and you are a brave man taking that amount of tilling on or are you a closet pro!

[Jeremy Harris]

  On 24/08/2018 at 21:06, MikeSharp01 said:

@nodWhat us the orange stuff under the adhesive

 

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Ditra decoupling mat.

[Alexphd1]

What the benefit of the decoupling mat?

[CC45]

Limits or elimates chance of cracked tiles due to floor movement.  About £10/m2.

 

I started our tiling last night - lot less progress than that though!

[Onoff]

  On 24/08/2018 at 21:50, CC45 said:

Limits or elimates chance of cracked tiles due to floor movement.  About £10/m2.

 

I started our tiling last night - lot less progress than that though!

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Tell me about it...

[nod]

  On 24/08/2018 at 21:06, MikeSharp01 said:

@nodWhat us the orange stuff under the adhesive, looks like a great job and you are a brave man taking that amount of tilling on or are you a closet pro!

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  On 24/08/2018 at 21:06, MikeSharp01 said:

@nodWhat us the orange stuff under the adhesive, looks like a great job and you are a brave man taking that amount of tilling on or are you a closet pro!

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Thanks Mike 

I served my apprenticeship plaster and tiling Back in the day it was the same job

Long before flexible adhesives 

We used to screed in the morning and lay boards on it in the afternoon and tile with a cement mix 

The matting is a must for UFH

25 mtrs down this afternoon 125 to go

Though I’ve just finish our last bathroom With a total of a 110 mtrs used between the three

[CC45]

25m2 - bugger, I need to get a shift on, 1/10th of thats about my daily target! Backs buttered as well?

[Pete]

Just buy large format tiles and you soon cover some area. 

[MikeSharp01]

  On 24/08/2018 at 23:47, nod said:

The matting is a must for UFH

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That's interesting, our UFH is in the slab and as we now intend to Tile,  as the power float polish failed,  do we need it?As things stand I was intending to tile directly to the slab after the failed polish is scabbled off.

[Onoff]

  On 25/08/2018 at 09:41, MikeSharp01 said:

That's interesting, our UFH is in the slab and as we now intend to Tile,  as the power float polish failed,  do we need it?As things stand I was intending to tile directly to the slab after the failed polish is scabbled off.

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F**cking hope not!

 

I thought that's what flexible adhesive was for on a concrete floor. Isn't decoupling mat a must if your tiling say a ply topped floor?

[Jeremy Harris]

The matting isn't needed at all for a modern, low temperature, UFH system with tiles laid on to a slab with embedded UFH pipes, as there will be zero relative movement from any temperature differential.  The use of this matting harks back to the old days when poorly insulated houses needed UFH running at over 30 deg C in order to give enough heat output, so there was a significant temperature differential through the floor.  No new build today, even one just built to meet building regs, is going to need UFH anywhere near that hot.  The floor will get much hotter from the sun shining on it in summer than it ever will from the UFH.

 

For example, it used to be that UFH installers would work on the basis of being able to get around 50 to 60 W/m² of heat from a UFH installation, sometimes more, maybe up to 80 W/m².  That equates to a floor surface temperature of around 26 to 28 deg C for a 21 deg C room temperature, and a UFH flow temperature of around 30 to 35 deg C or so.  No new build today is going to need that much heat, our house, for example, needs at the very most a floor surface temperature of less than 23 deg C, and there's no way whatsoever that 23 deg C is going to cause the slightest problem with relative movement - that's only 2 deg C warmer than the room.  We never need a flow temperature that's higher than about 25 deg C, and that's only in the very coldest weather.  

 

I've measured floor surface temperatures of over 30 deg C in sunny areas in our old house, which doesn't have UFH, but does have tiles laid directly on a concrete slab and they've not cracked or moved in over 40 years.

 

 

[newhome]

I have an anhydrite screed over UFH so the matting was recommended due to the screed type more than the UFH. 

[nod]

  On 25/08/2018 at 09:41, MikeSharp01 said:

That's interesting, our UFH is in the slab and as we now intend to Tile,  as the power float polish failed,  do we need it?As things stand I was intending to tile directly to the slab after the failed polish is scabbled off.

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Virtually all our tiling jobs are specified for crack matting with UFH

Your taking a chance without it 

Also you can get away with less movement joints

Most screeds and Slabs move and crack regardless of UFH If the screed moves it will at the very least crack the grout 

It’s personal choice 

 

I’ve just been out to a newly built house with a hairline crack across the large kitchen floor The builder is saying the tiler gave him no guidance 

Tilers saying builder said keep the price down 

In any case the tile will have to come up 

[Jeremy Harris]

If our reinforced concrete slab moves we're in BIG trouble, least of all will be the travertine laid directly on it!

 

It's a question of horses for courses here.  The low temperature differential, plus the reinforced slab, means there is zero risk of relative movement.  A non-reinforced, non-structural screed may possibly move a bit.

 

Both the two posters above and our own house have a reinforced concrete slab that isn't going to move at all relative to stone or tile flooring, but the same may well not be true for those using a screed that's non-structural.

[Onoff]

TF for A142 mesh!

[nod]

That ok 

 

once over if we had a problem with tiles lifting and we’d used something like Bal The rep would come out and they would stand the cost of relaying Now exspecially with UFH They will state that a suitable matting must be used in conjunction with there fleable 

 

[Ian]

  On 25/08/2018 at 11:24, nod said:

Virtually all our tiling jobs are specified for crack matting with UFH

Your taking a chance without it 

Also you can get away with less movement joints

Most screeds and Slabs move and crack regardless of UFH If the screed moves it will at the very least crack the grout 

It’s personal choice 

 

I’ve just been out to a newly built house with a hairline crack across the large kitchen floor The builder is saying the tiler gave him no guidance 

Tilers saying builder said keep the price down 

In any case the tile will have to come up 

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+1 

 

I agree completely with @nod

 

All new concrete and screed will shrink and crack to some extent, even if it has reinforcing mesh. If you go into any large retail shed with an exposed concrete floor such as B&Q or Costco you will see that the floor has some kind of movement joint at approx 6 metre intervals in both directions. If there’s no designed movement joint then you’ll see a ragged crack (or sometimes both!)

 

Older concrete and screed floors like @Onoffwill have finished with any shrinkage movement so anything you put on top should be okay if there’s no existing cracks.

[Onoff]

There's the answer chaps, wait three years before tiling!

[Alexphd1]

  On 25/08/2018 at 12:01, Onoff said:

There's the answer chaps, wait three years before tiling!

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2 years long enough?? 

 

Is that big sheds (b&q, costco etc) just not a thin screed aswell? 

[Ian]

  On 25/08/2018 at 12:04, Alexphd1 said:

 

2 years long enough?? 

 

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Yes, 2 years is long enough even with a power floated slab.

 

The easiest way to tell if your slab or screed has finished curing and therefore finished shrinking is to measure its relative humidity. The target value is 75% RH

Edited August 25, 2018 by Ian

[Jeremy Harris]

  On 25/08/2018 at 11:51, Ian said:

+1 

 

I agree completely with @nod

 

All new concrete and screed will shrink and crack to some extent, even if it has reinforcing mesh. If you go into any large retail shed with an exposed concrete floor such as B&Q or Costco you will see that the floor has some kind of movement joint at approx 6 metre intervals in both directions. If there’s no designed movement joint then you’ll see a ragged crack (or sometimes both!)

 

Older concrete and screed floors like @Onoffwill have finished with any shrinkage movement so anything you put on top should be okay if there’s no existing cracks.

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All I can say is that it's not the case at all for our slab - no movement at all, not even a fraction of a mm, in the five years since it was cast.

 

@Onoffs concrete was down a couple of years or so before being tiled, IIRC, and is also reinforced.

 

Our old house had the slab tiled not long after it was built in 1986 and there's been no movement there, either, and that's not even a reinforced concrete slab, and the area by the front door get's very hot from sun coming in through the glazed panels.

 

I can understand the problem with large areas in a warehouse, particularly given that they probably tile those places out before the slab has even had time to properly cure, but remain wholly unconvinced that the significant extra expense of decoupling mat is warranted on reinforced concrete slab that's pretty well cured before it's tiled.

[Ian]

  On 25/08/2018 at 12:04, Alexphd1 said:

 

Is that big sheds (b&q, costco etc) just not a thin screed aswell? 

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No, they are all power floated concrete slabs reinforced with steel mesh.

[Onoff]

  On 25/08/2018 at 12:20, JSHarris said:

 

 

All I can say is that it's not the case at all for our slab - no movement at all, not even a fraction of a mm, in the five years since it was cast.

 

@Onoffs concrete was down a couple of years or so before being tiled, IIRC, and is also reinforced.

 

Our old house had the slab tiled not long after it was built in 1986 and there's been no movement there, either, and that's not even a reinforced concrete slab, and the area by the front door get's very hot from sun coming in through the glazed panels.

 

I can understand the problem with large areas in a warehouse, particularly given that they probably tile those places out before the slab has even had time to properly cure, but remain wholly unconvinced that the significant extra expense of decoupling mat is warranted on reinforced concrete slab that's pretty well cured before it's tiled.

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Remember the wet room corner has only just been done this year, with my home brew, SBR laden mix!

[nod]

  On 25/08/2018 at 11:51, Ian said:

+1 

 

I agree completely with @nod

 

All new concrete and screed will shrink and crack to some extent, even if it has reinforcing mesh. If you go into any large retail shed with an exposed concrete floor such as B&Q or Costco you will see that the floor has some kind of movement joint at approx 6 metre intervals in both directions. If there’s no designed movement joint then you’ll see a ragged crack (or sometimes both!)

 

Older concrete and screed floors like @Onoffwill have finished with any shrinkage movement so anything you put on top should be okay if there’s no existing cracks.

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Ian makes a good point with expansion joints While I would put them in doorways 

Private custermers don’t want them all over there new floors 

Ditra will allow you not put as many in 

 

My wife asked me will the tiles definitely crack if I don’t spend £1100 on matting tgat I’ll never see I replied probably not

She then said What’s the worse that can happen

I replied Your £5000 worth of tiles would have to be redone 

She Replied order the matting 

It’s a bit like insurance your paying for sonthing that may not happen