"Decorative" sand cement render in bathroom/ wetroom. Help please!!

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Biller

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"Decorative" sand cement render in bathroom/ wetroom. Help please!! "Decorative" sand cement render in bathroom/ wetroom. Help please!!

Ok, merry xmas and happy new year everyone first of all!

I am in "that" place where you wish you had started bashing your head against a wall BEFORE starting "that" project which is way out of your league... Long story short: not much money>opportunity to build a studio in a humongous space with in my means arises> "just needs some work" > "so far so good" quickly turns into "cold hard reality check" > 3months in and i spent xmas eve sanding a table and new years eve plaster boarding the bathroom to be, because time is running out and money HAS run out...

Now past admitting defeat and pushing on with what ever means remain.

The current halt see's me working out what to do with the bathroom and shower walls... No money for tiles but vast amounts of sand, cement, ballast, pva, eva and sbr and some rubberised bituminous tanking left over... See where this is going?

So, saw "raw" sand cement render in a bathroom a while back and figured that might be an ok option.

Bathroom first: CAN I RENDER NEW PLASTER BOARD WITH SAND CEMENT? Using sbr as bonding and tanking?

Next up shower:
Stripped off three layers of tiles back to bare plaster with a bit of paint on, paint seems solid... Very little to no flaking, so a fairly solid substrate i should think... Walls are one external brick, one internal breeze/ cement block and one boxed off ply section. Question again is; how can i render that in sand cement? Again, ok to bond and tank with sbr and render as usual?

Any advice or instructions hugely appreciated!!

All the best and thanks in advance for any replies!

Alex
 
Hey danny, thanks for the welcome!
my apologies for diving straight in like that...!
i admit i am somewhat stressed out
which may be the reason for my mannerly oversight.

as i hint in the above post,
i am a photographer by profession since 6 years,
with a little building experience from youth working on sites occasionally for a bit of pocket money etc. But no substantial education in any particular trade.

a few months back an opportunity arose for me to lease a very large space for very little money through a friend of a friend and i took it not realising the reality of the amount of work... Most parts are fine as i have done them on site when i was young and remember a good deal... But specialist trades are of course not something i did back then, so thats where i fail... Although i have rendered walls previously, i only ever did this under supervision of someone who knows what they are doing.

so although i know i can get the mud on the wall and get it flat,
i would like it to stay there for longer than a few weeks... Hence my questions above.
the reason i am under pressure is that i have clients booked for the 6th of jan and must have a usable bathroom by then... Not necessarily "finished" but at least a functional toilet and shower... For which i need to finish the waterproofing / rendering in the shower area...

I hope that gives a bit of friendly background on my self...?
as before, any insights, ideas, instructions would be hugely appreciated!!

thanks in advance for anyones time,
and all the best,
alex
 
@Biller dont apologise buddy I know exactly wehre you are... I have been doing a renovation myself... its a ballache but is worth it... they said...lol
 
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Yea... Not sure ball ache cuts it anymore... Kinda wish i was a mole, then i could justifiably dig my self a hole!

so any insights? I'm thinking sbr cement tanking with a spot of sand, then hoping a sand cement 4:1 gauged with sbr will stick, be waterproof and stay stuck for 4 years... Thats all i'm gunning for here.
alternatively it says on the bitumen emulsion that it can be rendered over if third coat is blinded/ keyed with sharp sand. Although that will positively be water proof i'm concerned it might not be strong enough to keep even a skim of sand cement on the wall for very long...?

i need to finish this week so any input or alternative ideas VERY welcome!

cheers,
alex
 
As bobby says , render should be on to the brick work . Have a look on gumtree etc for tiles u might hit it lucky ?!?
 
Hey sorry for the delay in replying! Thank you for everyones advice and contributions!!

so the answer to sand cement render over plasterboard has through the bank been a straight "no", except for one suggestion from an, as he called him self; "bit of a macguiver"
(Seasoned plasterer none the less, according to him self) who's idea i would like to run by you... In hopes i might inspire some curiosity and opinions on everyones part and possibly even get your blessing...!

same goes for the ply and bare plaster questions; so here it goes:

1. Sand cement on pb; how it MIGHT work:
mainly it is said to be a weight issue, secondly movement.
The substrate is as follows-
PB is moisture grade 12,5mm, glued with gripfill and screwed with 50mm fixings into a 4x2 frame 60cm centers and noggins roughly every 60cm to 80cm.
macguivers idea is this:
- fill joins and screws as usual, let cure/ dry
- apply bituminous tanking around edges and floor join generously in 3 coats and blind 3rd with sharp sand. (About 5 to 10cm up the wall)
- mix SBR & cement tanking slurry according to manufacturer and add 5% fine sharp sand
- apply slurry over entire wall
- mix sand cement render 4.5 to 1 with SBR in gauging water according to manufacturer
- apply 3 to 5mm coat of sand cement render
- allow to cure for as long as feasible, minimum 3 days without drying out.

opinions yet?

2. Sand cement on bare plaster;
substrate seems to generally be accepted as good and strong enough...?

- open surface with wire brush all over then clean and free of all dust
- same bitumen tanking around edges and floor as above
- same SBR tanking slurry as above
- stronger mix though, 3.5 to 1 with SBR according to manufacturer
- apply 3mm of above as skim coat
- allow to cure 2 days min, dont let dry
- should be fine...?

...opinions?

3. Sand cement render on ply; how it might be done:
the substrate: 20mm marine ply on 3x2 frame attached directly to exterior brick wall,
all glued with gripfill and fixed with 100mm screw & plug, cavities filled with expanding foam. (Sole purpose of the box is taking the shower mixer and pipes)
according to most advice a working method should be:
- clean & dust free boards completely
- tank all edges and joins as before with 3 coat bitumen and blinded
- attach render lath (either screw or hammer staple)
- again the good old tanking slurry as before generously applied all over evenly
- sand cement render 4:1 with SBR according to instructions as before this time in two coats3 to 5 mm each
- cure as before
- should be ok...?


Trust me, if i had tiles or a way to get enough tiles within the next week...
i would definitely be tiling.
i'm confident with a trowel and hawk, but not so much with methods and procedures
as all plastering i've ever done was under supervision of others...

please if you see anyway this could work,
let me know your thoughts...
all the best, alex
 
alex no. in the netherlands they have materials that can do this, in uk no way, we are 20 years behind,, do not waste your effort.
all the tile shops will have sales on just tile it.
 
If you want to render it rip the boards off ! As said again it wont work , also you will struggle with a tight coat of sand cement , not enough strength at a couple of mil , fair dos u havnt got the money but this isnt the way to do it . By the time u want to open the place the render would have failed , get some tiles . An sure its a business you are trying to make here , you will just get problems in the future months if not weeks that way which isnt going to be very productive. As said bite the bullet and get some tiles mate
 
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