Slate paving slabs indoors?

[jblack]

Hello All,

I've got an area of 60sqm to tile. I have been offered a good deal on a load of 600x600 Marshalls patio slates. These are obviously thicker (20-23mm) than indoor slate floor tiles. We're also having wet UFH which will be screeded to suit the finish.

Is there any reason not to use these slates? Would I need to bed them on a mortar or use a tile adhesive?

Cheers, J

 

[Karis]

I assume were talking about a solid concrete sub-floor here! 20mm over your wet UFH isn’t exactly going to compliment the warm up/reaction time of your heating system although once it's warmed up, you will have a good thermal store! With UFH you need to use a flexible adhesive or it won’t last, thermal expansion/contraction caused by the UFH will crack it all to hell.

Won’t it look a bit like an indoor patio? Just a thought!

 

[tpt]

assuming they are slabs and not actual slate...
depends on how much of a good deal they are - i'd question it to be honest. You'll use a LOT more adhesive & grout, you'll spend a grand on sealer (you'll need something like lithofin multiseal) and they will take more heating.

What sort of thickness are they and what sort of deal have you been offered?

 

[tictic]

Ok...first things first...
The screed what type is it....sand/cement....gyvlon screed...?
How thick is the screed?...70-75mm it will be sand/cement...40mm it will be gyvlon screed(little more prep needed)...

20-23mm thick slate....not a problem...are they calibrated or uncalibrated???

Dependant on screed,this will need to be commissioned first...I.e. mfr instructions on the heat up time...

60m2....area there will need to be exspansion joints inc. in this size off area every 6-8m2 bays....

Then when wet ufh commissioned,you will need to look into a de-coupling membrane...ditra ect?..
Then set out with exspansion joints...if not using ditra ect...


How's yer knees ....

 

[tictic]

Ps
Ptb adhesive will do the job...

Pourable thick bed....adhesive.....

 

[jblack]

They're real slate. I thought they'd just be a thicker version of a standard slate floor tile. They're the Marshall Midnight Blue 600x600mm.

http://www.building-supplies-online...0-4653-p.asp?gclid=CIHYwteRhrECFQQhtAodcVgz-g

The screed over the UFH pipework would be 65mm concrete. If a standard 10mm tile is used that'd take it to 75mm. I'd just take the screed down to 55mm if I used the thicker ones.

 

[tictic]

What is it your fixing the tiles onto.....

Domestic...commercial?

Is there exspansion joints incorporated in the screed?

I.e what sort off traffic will be going over the area?

 

[tictic]

On I-pad so can't open your link to tiles....



Are they calibrated or uncalibrated?...

 

[tictic]

IMO keep the screed to 65mm....min

 

[jblack]

Just the ground floor of a 3 bed semi. The screed has not been spec'd with expansion joints, just the standard perimeter expansion.

I can't see any info on the calibaration of them.

 

[tpt]

i would have thought you'd be better off with a calibrated 10mm slate. i can get you a good price on them and then you could just use a more normal adhesive. a solid bed addy is gonna add a fair bit of cash and you'll need at least an s1 flexi if not an s2

what kind of screed is it? if its anhydrite then you need to be careful which addy you use, especially over UFH as the thermal expansion on that gypsum screed is huge. Most addy manufacturers will push you toward an s2 such as granfix rapidset flexi with additive over 2 neat coats of acrylic primer. you've also go to make sure the screed is perfectly dry.

tictic....i've been thinking that karis feels familiar. out of interest why are you suggesting using ditra? to get around the thermal expansion?

dunno if your interested but i have a load of very good *honed* slate seconds, they have very slight honing scratches that the sealer generally covers unless your 150mm from the face - i have 600x300 and 600x600.

Read more: //www.diynot.com/forums/tiling...n-wooden-floors.329496/#2448141#ixzz1zt3XGhJe

 

[tictic]

Perimeter...yes
Door thresholds ...yes

And an area off 60 m2 there should be bays off every 6-8m2 exspansion joint.......better have a word with yer .....architect...builder...ect....


Tpt
Wet ufh and stone...
Me...to cover ma arse.....ditra.....

Does as it says oon the tin...


As you say....client being to ....let's say.....eager...equals ....


Thermal shock...in/on the screed....


To eager to get the job done....seen it a few times...

 

[tpt]

yeah i spose it does cover a multitude of sins. We have had a couple fail due to being laid when the screed was wet...patience is a virtue. dont you agree richard, sorry Karis

 

[tictic]

Or fix with....



Green screed....


What ya think......



























Rich...........

 

[tictic]

Just the ground floor of a 3 bed semi. The screed has not been spec'd with expansion joints, just the standard perimeter expansion.

I can't see any info on the calibaration of them.

Is it a self build ?
How big is the areas off the rooms?

If its just the one big pour,and your tiling it all(even with stud walls ontop)

You will still need exspansion joints incobarated into the pour mate..


Again get back to your architect ect and get it in writing what they plan to do...