Microcement shower

[shirebuild]

Wow, @simonD this thread was *exactly* what I needed!! Thanks so much for taking the time to post. We are just gearing up to microcement (also using Cemher) our own bathrooms and are getting particularly worked up over how to get the join between the shower tray and the walls suitably watertight.

 

I would be really grateful if you could share some more detail of your experience to help me out - getting this area well-sealed is obviously crucial!

 

Our proposed buildup is as follows...

FROM FLOOR UP: 
Cabershield
Plywood (6mm)
Mapei waterproofing membrane (lapped up the walls 150mm - distance chosen somewhat arbitrarily - happy to be corrected if anyone has views)
Stone resin shower tray (fixed in with flexible tile adhesive)

 

WALLS - the whole bathroom is already boarded out in Fermacell 
Additional layer of Fermacell (15mm) will go in the shower enclosure once the tray is in place, coming down to meet the shower tray and be sealed with silicone bead.

 

We were proposing to put Fine Surface Treatment on the second layer of Fermacell, then prime and microcement per the instructions.

 

Any input warmly received! Photo below..

 

[SimonD]

On 07/06/2022 at 13:29, shirebuild said:

how to get the join between the shower tray and the walls suitably watertight.

 

As you've already suggested, you've tanked the critical areas and you're installing the boards to go over the top edge of the shower tray and be sealed. If you're putting the sealant on, apply it to the top of the shower tray and then fix the boards on top of that so that the sealant is squidged between the board and tray and then clean it up nicely. I went extra by also having a final silicon bead at the bottom of the microcement/shower tray but is probably not necessary at all going by the installation guidelines.

 

+1 to using the fine surface treatment to fill all the screw holes and joints before applying primer and mesh and do use scrim tape for the corners rather than the base layer mesh. I've just done this on my new kitchen worktop and it was so much easier.

 

Are you doing it yourself?

 

Microcement kitchen worktop although i decided on this occasion not to make the sink out of microcement too - just couldn't muster the energy for that much. (It looks more blue on the photo than it is, which is a 'silver' grey).

Edited June 9, 2022 by SimonD

[tck1985]

@SimonD @shirebuild thanks for the really useful posts. I'm about to start on our bathroom using microcement (Cehmer) for the walls behind the bath and the shower enclosure. I am also getting worked up about how to get the interface between the bath and particularly the shower tray completely watertight. I'm using 12 mm NoMorePly cement boards as the wall substrate. If I was tiling I would use  a rubber adhesive vertical upstand on the wall edge or top edge and use tanking compound to stick this to the backer board. Products like classiseal (https://waterproofyourbathroom.com) or no more leaks (https://www.nomoreleaks.co.uk) respectively> However because microcement is so much thinner than tiles + adhesive I'm not sure this will work. I don't think I have the option to drop another board onto the tray / bath edge.  I'm wondering about finishing the microcement below the bath edge and then sticking the bath to the finished microcement with CT1 adhesive and then run a finishing bead of silicone. I could potentially do the same for the tray but I feel the risk of leaks is higher for the shower area. Any comments / other ideas gratefully received. Do you think the CT1 approach is reasonable? Do you think a tanking membrane approach could work and ? be feathered in with tile adhesive and then covered in the Microcement?

[Nickfromwales]

If using cement boards on timber studs, I strongly recommend using CT1 / similar on the face of the studs immediately before final fixing the board. NOT gripfill though!

[sean1933]

@SimonD

Really great to see someone using this product - are you a tradesman with experience of such products/plasting or is this a first attempt? If the latter, recon its DIY friendly on a floor (and to a high standard) or does this fall within the realms of plastering, ie leave it to the pro's unless its behind some furniture! 

 

We've committed to microcement on our floors for the entire downstairs of our house (240m2). Originally planned on giving topcret a go myself in the garage but now seems they only sell with installation and the prices are eye watering. Do you have any experience of the Cemher floor product?

[SimonD]

22 hours ago, sean1933 said:

@SimonD

Really great to see someone using this product - are you a tradesman with experience of such products/plasting or is this a first attempt? If the latter, recon its DIY friendly on a floor (and to a high standard) or does this fall within the realms of plastering, ie leave it to the pro's unless its behind some furniture! 

 

We've committed to microcement on our floors for the entire downstairs of our house (240m2). Originally planned on giving topcret a go myself in the garage but now seems they only sell with installation and the prices are eye watering. Do you have any experience of the Cemher floor product?

 

This is my first attempt and I'm not a tradesman with plastering or similar products, just what I've learned through the self building experience. It's a tricky product to get to a high standard of finish, particularly a floor, so it depends on how much you're willing to practise and risk yourself. Many of the suppliers are selling with installation which is understandable as there's so much that can go wrong when you've got so many layers to complete to get it right.

 

If it were for a large floor area, I would recommend getting someone in to do the work. At 240m2 it'll be both back and knee breaking!