Best plan for Slate & UFH?

[peegee tips]

Hi peeps,
A bit of advice would be handy please.
So the customer wants to have slate with UFH on a screeded subfloor.
Now if the customer was to choose insulation boards, would Ditra mat still be needed?....& if they didn't want the insulation boards would Ditra be advisable?
Your thought are appreciated,
Thank you.

 

[david campbell]

what size of floor is it?
using both will increse the height of the floor

 

[peegee tips]

Its 30m2 & initially I was thinking maybe 6mm boards to keep the height down a bit.

 

[peegee tips]

Any inputs would be appreciated....thanks.

 

[doug boardley]

I'd use insulation board and decoupler peegee, here's one I did recently, (just going to give it a final coat of sealer tomorrow, now that it's been grouted and cleaned)
tilersforums.com | Tile Forums | Tiling Forum - doug boardley's Album: slate job

 

[peegee tips]

Thanks Doug, Looks a very nice job mate. Like the tile layout pattern. Is it a 4tile pattern?

Also is that calibrated slate & the genesis decoupling membrane? How does that compare to ditra? I've still been using ditra at the moment as I can wangle it at a very favourable price, but i'm sure soon it will be too expensive to use it anymore.

 

[doug boardley]

Thanks Doug, Looks a very nice job mate. Like the tile layout pattern. Is it a 4tile pattern?

Also is that calibrated slate & the genesis decoupling membrane? How does that compare to ditra? I've still been using ditra at the moment as I can wangle it at a very favourable price, but i'm sure soon it will be too expensive to use it anymore.

it's a 3 tile pattern peegee, 600 x 600, 600 x 400 and 400 x 400, all uncallibrated bolivian slate. The decoupler is dural ci, it's same as ditra only yellow

 

[DJS]

I'm doing a honed slate floor with UFH at the moment. I'm putting it in and tiling the walls this coming week, so I'll treat you guys to some pics as I do it.

I also went with insulation board and DITRA. My understanding was the insualtion board will improve the efficiency of the UFH. Whilst the DITRA should protect the tiles from any subfloor movement and expansion/contraction from the UFH.

My job is also 3rd floor flat en-suite bathroom, so the 30mm marmox should also help absorb some of the sound too. To prep the floor I had to remove 22mm chipboard with 8mm sound insulation, that was just floating. On removing that I discovered 25mm plywood randomly nailed down to the joists, so all I have to do is screw that down and remove the dust, prime it and build upward from there with the marmox, UFH, DITRA and tiles.

I'm looking forward to it, as it's my first UFH job, but it means I'm working B.holiday Monday too :smilewinkgrin:

Good luck with yours

 

[peegee tips]

Sounds like you have it well under control mate, flats can be a bit of a mare with all that lugging around of gear up loads of stairs! Is it empty or you having to move your gear every day?

Just a thought, as you have 25mm of ply on the joists, could you not screw down 6mm insulation boards to keep the height down a bit instead of the 30mm boards?

Hope it all goes well anyway, look forward to the photos.

 

[The Legend; Phil Hobson RIP]

I'm doing a honed slate floor with UFH at the moment. I'm putting it in and tiling the walls this coming week, so I'll treat you guys to some pics as I do it.

I also went with insulation board and DITRA. My understanding was the insualtion board will improve the efficiency of the UFH. Whilst the DITRA should protect the tiles from any subfloor movement and expansion/contraction from the UFH.

My job is also 3rd floor flat en-suite bathroom, so the 30mm marmox should also help absorb some of the sound too. To prep the floor I had to remove 22mm chipboard with 8mm sound insulation, that was just floating. On removing that I discovered 25mm plywood randomly nailed down to the joists, so all I have to do is screw that down and remove the dust, prime it and build upward from there with the marmox, UFH, DITRA and tiles.

I'm looking forward to it, as it's my first UFH job, but it means I'm working B.holiday Monday too :smilewinkgrin:

Good luck with yours

Is the 25mm ply exterior grade?

 

[DJS]

Cheers for the reminder Phil. Now you mention it I'm not sure it was. Do you have any tips on how can you tell, without ripping the floor up to see if its been stamped somewhere?

That said, I've also used WP joint tape on the marmox, and it will also have a layer of DITRAMATT over it, and tanking in the shower enclosure, so now I'm just hoping no water will be able to penetrate once completed!!

PGee, thankfully the couple move in once I finish, so all tools can stay overnight and are in the un-furnished/un-decorated bedroom next to where the en-suite is situated. And wet-cutting can take place on the balcony.

The rest of the floor throughout the flat is 25mm ply on joist, 8mm sound insulation, 22mm chipboard, then 2mm of wooden flooring insulation and approx. 20mm of new natural wooden flooring. By taking out the chipboard & insulation in the en-suite, I had about 45mm to get back to the existing floor level in the rest of the flat!!

I'm making it sound more complex than it is, but I'll do you some pics later. Indeed, taking all the tiles and materials up 6 flights of stairs nearly killed me!!

 

[The Legend; Phil Hobson RIP]

Cheers for the reminder Phil. Now you mention it I'm not sure it was. Do you have any tips on how can you tell, without ripping the floor up to see if its been stamped somewhere?

That said, I've also used WP joint tape on the marmox, and it will also have a layer of DITRAMATT over it, and tanking in the shower enclosure, so now I'm just hoping no water will be able to penetrate once completed!!

PGee, thankfully the couple move in once I finish, so all tools can stay overnight and are in the un-furnished/un-decorated bedroom next to where the en-suite is situated. And wet-cutting can take place on the balcony.

The rest of the floor throughout the flat is 25mm ply on joist, 8mm sound insulation, 22mm chipboard, then 2mm of wooden flooring insulation and approx. 20mm of new natural wooden flooring. By taking out the chipboard & insulation in the en-suite, I had about 45mm to get back to the existing floor level in the rest of the flat!!

I'm making it sound more complex than it is, but I'll do you some pics later. Indeed, taking all the tiles and materials up 6 flights of stairs nearly killed me!!

You can usually tell by the colour/ texture, pics would help

 

[DJS]

Cheers Phil. I just started my own thread with some progress pics.

You will see it is pretty dusty in the first few pics, then much darker in another pic, from after I swept, vacuumed, cleaned with a sponge and water, then let it dry and then primed it with PrimerG, diluted 50/50 with water. Let me know what you think!!