finished floor heights and units, ufh

[Martysmarty]

Hi all.

 

I have had some good help so far on this forum and i come with another issue to sort.

 

We are going to have to put our kitchen units in before tiling the floor. For a couple reasons, one my partner cant decide what she wants till its all in (women). Also the screed floor is still curing, plus the time factor as im flat out.

 

So, at the moment were looking at tiles, would i be right in thinking 15mm would be ideal builup for floor tiles? 10mm tile, 5mm bed of adhesive. Its screed and very level.  And is there any membrain materials i need to account for?

 

Proposed plans

 

Option A, set the kitchen base units 15mm heigher on the legs, plus a 3mm tolerance gap and finish with sealer. So the legs would be 168mm, with a 150mm plinth.

 

Option B, just tile up to plinths, keep units standard heights. All appliances are intergrated.

 

My problem with option A, what if we get the buildup wrong. I can cut plinths on the lower units but not the end panels or the apliance housings. Also i cant lift up the legs after as the wall cupboards would be out of alignment. i will probably have my splashbacks tiled by then too. 

 

I prefer option B, but as its wet underfloor heating, the tiles will expand. What would be best to deal with that? Leave a 3mm gap and use sealer? 

 

Thanks

Martin

Edited August 7, 2021 by Martysmarty

[Adsibob]

Generally tiles come in various thicknesses, from 6mm up to something very thick like 20mm terrazzo. But don’t buy terrazzo!

Adhesive will vary, but I would have thought 3mm is ok. So maybe identify 3 or 4 tiles you are considering and see how thick they are. You might find they are all 8mm to 10mm thick, which is a pretty common size. 2mm fiebre unlikely to make a huge difference.

 Units should have adjustable keys to give you a bit of play. 
i would have thought you don’t need to install everything in to get an idea of what tile will work with your scheme. Get a door sample from the kitchen company and take it to a tile shop. That should help narrow things down a bit.

Edited August 7, 2021 by Adsibob

[markc]

Last two kitchens I’ve installed have been before the tiles.  Build cabinets and legs as if flooring was there, then I stick the units on a piece of 18mm chip or similar.

I always leave end panels approx 5 mm above the finished floor to stop them soaking water up. As long as you have an idea of what the tiles will be, just allow a suitable thickness.

[nod]

10 mil tile will need 10 mil adhesive 

[ProDave]

And you must tile under washing machine / dishwasher space.

 

Leave end panels off until tiled and cut to length to suit?

[Adsibob]

1 hour ago, nod said:

10 mil tile will need 10 mil adhesive

I thought a 6 to 8 mm tile needs a 6mm x 6mm trowel to apply the adhesive which will leave a 3mm bed of adhesive beneath the tile. Is that not right?

[nod]

14 minutes ago, Adsibob said:

I thought a 6 to 8 mm tile needs a 6mm x 6mm trowel to apply the adhesive which will leave a 3mm bed of adhesive beneath the tile. Is that not right?

Perhaps 6 on a flat wall 

8 is quite thin for floors 

Work off the thickness of the tile 

10 tile =10 mil adhesive Should really back butter also

[Adsibob]

15 minutes ago, nod said:

Perhaps 6 on a flat wall 

8 is quite thin for floors 

Work off the thickness of the tile 

10 tile =10 mil adhesive Should really back butter also

So this might make my terrazzo nightmare even worse. We are having UFH embedded in screed and we’re going to tile directly onto that. Checking the build ups, my architect has actually only allowed 3mm of space for the adhesive which goes in between the screed and the 20mm thick Terrazzo. If this space needs to be a couple of mm bigger, that should be okay, but if it actually needs to be 20mm as opposed to 3mm I’m in a real pickle as I don’t think our front door, which is made of steel and opens inwards will be able to open.

[Temp]

You will need to talk to the supplier. Some recommend using dittra mat.

 

Guide here on what trowel to use to end up with good % coverage and required thickness. Eg 6mm x 6mm square notch or 10mm U notch should end up with a 3mm bed when properly compressed. They say the U notch is easier to compress..

 

https://www.rubi.com/en/blog/how-to-choose-the-right-tile-trowel-size-step-by-step/

 

PS I'm not contradicting @nod. Thicker adhesive is normally used on floors. 

 

Edited August 7, 2021 by Temp

[Martysmarty]

Hi all, thanks for the posts.

 

do i need to use a coupling mat when tiling onto this screed with the underfloor heating? The pipes are screed bedded, or can i just tile onto the screed with the correct tile adhesive?

 

What are peoples thoughts on tiling up to the units? Just want to weigh up my options.

 

Most tiles we picked out are 8 or 9mm, i definitly wont be going thicker.

 

Thanks

[Adsibob]

31 minutes ago, Martysmarty said:

Hi all, thanks for the posts.

 

do i need to use a coupling mat when tiling onto this screed with the underfloor heating? The pipes are screed bedded, or can i just tile onto the screed with the correct tile adhesive?

 

What are peoples thoughts on tiling up to the units? Just want to weigh up my options.

 

Most tiles we picked out are 8 or 9mm, i definitly wont be going thicker.

 

Thanks

I would tile under and either side of the appliances as suggested above (in case of any leaks), and tile to the feet of the other units. Then plinth goes on top of tiles, covering up feet of units.

[Temp]

4 hours ago, Martysmarty said:

Hi all, thanks for the posts.

 

do i need to use a coupling mat when tiling onto this screed with the underfloor heating? The pipes are screed bedded, or can i just tile onto the screed with the correct tile adhesive?

 

 

 

We have a mix of stone and tile over UFH in screed. Used flexible adhesive without a decoupling mat. 

 

Only issue we had was where we screeded and tiled through a doorway from one room into the next. The two areas of screed shrank towards their centres causing a curved crack at the doorway. This propagated through the tiles. Should have made a deliberate straight crack in the screed (aka expansion gap) and arranged for it to be under a sill or on a grout line. Or perhaps used decoupling mat in that area.

 

 

Edited August 8, 2021 by Temp

[saveasteading]

2 hours ago, Temp said:

(aka expansion gap)

 

Pedantry or precise use of terms, as you choose but:

 

It is not an expansion joint, but a contraction joint. All concrete and screed shrinks when it cures. More or less according to water content and reinforcement.

Expansion joints are for use outdoors where it may heat and expand (back to where it started usually)

If in doubt, movement joint covers everything.

 

I would tile under and either side of the appliances as suggested above (in case of any leaks), and tile to the feet of the other units. Then plinth goes on top of tiles, covering up feet of units.

You can even use cut or other old tiles under the appliances. BUT if you change the kitchen there might be awkward gaps. Unless silly expensive, it may be worth tiling the whole area. 

There is a bonus to doing the tiling first: the kitchen fitters will put the worktop at the right height, and the legs are all much the same height.

[Temp]

Well the crack was expanding:-)

[saveasteading]

26 minutes ago, Temp said:

Well the crack was expanding:-)

Touché.. I never thought of that!