Floor surface for ground floor wet room

[Moss]

Hi

This is my first time posting so hope it is in the right place.

I am renovating and old house and currently about to fit out a bathroom on the ground floor. The bathroom is currently in a bigger room and has 2 external walls and the other 2 walls will be partitioned to separate it from the bigger room.

I replaced the entire ground floor with a new concrete floor about a month ago. My plan for the bathroom floor is to do a wet room and I mentioned it to the builder who was pouring the concrete floor so he suggested that the bathroom part be poured 2 inches lower to allow a fall to be screended towards the shower drain so this is what they did.

The bathroom is 2180mm by 1500mm with a sliding door on a 1500 wall and the shower opposite on the other 1500 wall. I am currently putting up the partition walls which will have a wall hung wc and will then be ready to screed the floor but don't know what to use. The dept of the floor will 2 inches sloping down to just under 1 inch ( on top of 4 inches reinforced concrete). Is this too thin for a concrete screed? What else can I use as a screed on the floor? The 4 inch reinforced floor is down for 5 weeks now and seams very dry, should this be primed?

My plan is to have it finished for Christmas so plenty of time but I also want to allow the screed to fully dry before tanking/tiling.

Any advice would be greatly appreciated
Thanks

 

[Dumbo]

Get a preformed wet room tray and stick that down and get matching thickness tile backer board for the rest of the room and yes prime the floor .

 

[Ajax123]

More than 25mm fall? Seems a lot...

 

[Moss]

Thanks for the help above.

I had not considered a preformed tray/backing boards but it would work all right. I checked it earlier and it is reasonably level and some Self levelling compound would make it perfect.

It will work out expensive to buy the tray and backing boards but I can see how it would give a very good surface for a wet room and is probably worth it. I also checked the exact dept of it earlier and it is actually just over 1inch which would work well for the tray/backing boards but I might struggle to get a fall out side the shower area towards the drain.

The width is also around 1450mm and the walls
Are not exactly running at 90 degrees to each other but I assume that a 1500 by 800 tray can be cut back to suit.

Now that the floor is sorted, I would appreciate some ideas for the walls. My initial plan was concrete floor, cement board on partition wall and the 2 other walls (constructed with stone/lime cement) to have moisture slabs stuck on with metal fixings also. We were then going to stick a membrane over the whole thing to make it waterproof.

I assume the advice here will be tile backer board for the shower area. My plasterer advised the moisture slabs because he thinks they will stick better to the old walls, I could fit 10mm backer boards over the slabs? Any ideas?

 

[Dumbo]

What are moisture slabs . You don't need a fall outside of the wet area towards the drain as this should not be getting wet . You can fix tile backer board direct to clockwork using tile adhesive and mechanical fixings .

 

[Bond]

Aye' moisture slabs, not sure what you are referring too, is there damp / condensation issues with the external stone walls?

 

[Moss]

No damp/condensation issues, moisture proof slabs are just an 8feet by 4 plaster slab which handles getting wet better than a normal slab so is usually used in shower areas. It would be common to put membrane over the slab then to prevent water coming into contact with the slab.

 

[Dumbo]

No damp/condensation issues, moisture proof slabs are just an 8feet by 4 plaster slab which handles getting wet better than a normal slab so is usually used in shower areas. It would be common to put membrane over the slab then to prevent water coming into contact with the slab.

So basically green plasterboard

 

[Bond]

No damp/condensation issues, moisture proof slabs are just an 8feet by 4 plaster slab which handles getting wet better than a normal slab so is usually used in shower areas. It would be common to put membrane over the slab then to prevent water coming into contact with the slab.

Okay got ya, moisture resistant plasterboard, so your framing,insulating and boarding with green plasterboard and waterproofing same in shower area, that's all fine. Only need to use backerboard if the weight of the tile dictates. Cheers

 

[Ajax123]

use Wedi type boards and dot and dab them to the walls using Silane Based adhesive like Evostick Sticks like Sh*t turbo