Advice for DIY install of bathroom and waterproofing walls - can I tile a dot and dabbed wall?

Buffman · 16 Jan 2022 at 13:43

What's the thoughts on 6mm boards fully tile adhesive combed onto walls + mechanical fixing?

Run out of 10mm boards for last brick wall however I'm thinking to use 6mm for this then hardi back instead for the floor. I could alternatively buy more 10mm boards.

Thoughts @Simon @200sols
?

Buffman · 16 Jan 2022 at 17:58

200sols said:
Dot n dab is for 12.5mm boards minimum as per the marmox guide already linked before, 6mm boards you can use a full comb of adhesive yes, mechanical fixing is not required with full bed either but doesn't hurt. Spankers are for dabs only.

Aye i figured adding spankers to a fully combed wall isn't a bad idea /going to hurt?

Buffman · 16 Jan 2022 at 18:02

Simon said:
Tilebacker suggest 6mm can be on walls with do LR and dab. Isn’t that what he’s using but has ran out of 10mm. I’d go for getting more 10mm to be honest. Especially if an external wall and he’s going to have to make up the rest of the gap

Nah its an internal wall (the unfinished one in attached)

Dry fit of tray went fairly well (1400*800 stone tray 36kg), gonna take it up and prime floor for a second time another day, I'm knackered :cry:

Buffman · 16 Jan 2022 at 19:54

200sols said:
Belt and braces.

The tray looks good, I would seriously consider using a classiseal.

https://www.amazon.co.uk/Classi-Seal-Flexible-Waterproof-Upstand/dp/B0078MK2QA

Ah cool, yep the whole job become a bit belt and braces tbh!

I was instead going to use marmox waterproof tape which I've ordered but now come yet (shockingly expensive at £45 per 10m) plus the pre fabricated corners

Wondering wether I should just get the last wall dabbed on by my plasterer when he does the ceiling (got loads of boards downstairs as I had another 2 rooms knocked back to brick). It's not in a "wet" area other than near a toilet :cry:

. Could also just rob some plasterboard and dab it on myself. I would probably put a spanker in after regardless as its fairly easy to do.

Buffman · 17 Jan 2022 at 12:15

200sols said:
The marmox tape and corners are not for these shower trays, they are for use with the marmox shower trays which are tiled over. The marmox tape you will still need for the walls though.

Hmm I'll double check but I presumed it would be suitable for this and a bath, by just edging up to the corner of the bath/shower and be concealed by the tiling (and silicone after)

Buffman · 17 Jan 2022 at 20:31

200sols said:
No, it isn't the right product for this job.

I'll double check with the supplier.

200sols said:
You just multi bond and tape them.

I presumed that putting silicon over the spankers seems like something that isn't in reality likely to Leak through? I don't really get if it's meant to be applied to the hole as you put it in or over it once it's on? Seems an unlikely position for leakage (particularly as you're going to have to trowel adhesive over the spankers :confused:

)

Not sure if it even requires tape?

Buffman · 18 Jan 2022 at 12:45

Participant said:
Are 'spankers' considered the best mechanical fixing of tile boards onto brick and concrete then? Combined with an appropriate adhesive? What about self tapping brick screws?

I think you could use these or wall plugs plus screws (e.g. Red rawl plugs) but the spankers will be quicker

I've never got on well with brick screws to be honest.

Buffman · 18 Jan 2022 at 15:12

dLockers said:
You'd presumably need washers, rawl plugs and screws versus just spankers.

Aye sorry that's what I meant. (spankers probably same cost of washers alone, it's all ridiculously expensive stuff)

Whats the thoughts on using some dow corning rather than marmox multibond on some joints (ran out of marmox).

https://www.screwfix.com/p/dow-785-bacteria-resistant-sanitary-silicone-white-310ml/58308

Buffman · 18 Jan 2022 at 19:03

200sols said:
Dow Silicone is a good choice as well although a tad more expensive than multibond. CT1 would be an equivalent to multibond but is like £10 a tube.

Ah cool might go for this

https://www.screwfix.com/p/ob1-multi-surface-sealant-adhesive-clear-290ml/434jf

Buffman · 18 Jan 2022 at 22:24

Sin_Chase said:
For the price of a tanking kit.....just tank it.

What do you mean? It's all going to have waterproof tape applied in all areas, just boards are supposed to be bonded together with silicone /adhesive underneath (belt and braces)

Buffman · 18 Jan 2022 at 22:43

If interested all, the total cost of all the tanking gubbins Inc boards, niche, fixings/washers/ spankers/primer and tile adhesive(s) approx £800.

The cost of materials has gone mad, but I'm sure I could have certainly done it cheaper too to be fair.

Includjng :
26*marmox 10mm boards
7x marmox 6mm boards

Buffman · 20 Feb 2022 at 16:46

Not made much progress on this other than having the ceiling plastered and now painted. Been busy doing jobs on the rest of the house. Just put the spankers in today.

Got a tiler sorted to come too and he noted that it wasn't entirely level but would be able to sort it. He seemed very competent and recommend but pretty expensive to tile it all at 2.7k. Going to do some fancy bits like mitre the tiles in the niche too.

Buffman · 26 Feb 2022 at 19:50

Got my shower tray finally bedded in (put it on mortar but tbh it was thin

Also got lights in (2 in shower are small ones and there is 2 bigger ones above bath/sink, seems enough)

Put my shower drain in and for some reason I recall reading /seeing online to put silicone on it as you tighten the ring..... Then read after it says don't use acetoxy silicone.... Doh. I used Dow corning 785

Also got to put in the decoupling membrane (6mm marmox boards n the floor of the bathroon - after priming floor twice then prob use the 8mm trowel I have). Would you put them underneath the bath? @200sols ?

Buffman · 27 Feb 2022 at 22:18

Bug One said:
Did you use cement under the shower tray?

Mortar mix yes (ready mix to be fair)

Buffman · 28 Feb 2022 at 15:39

Bug One said:
Cool. I laid mine straight onto the floor boards first time, and it ended up cracking.

I didn't factor in that the underside of the tray wasn't flush to the ground, and one half of the tray was incredibly thin (about 3mm!). I've replaced it now and added various sized blobs (according to the depth) so the underside of the tray is supported consistently.

I used a mix of ready mix cement + extra sand + PVA. Looked very similar colour to yours.

Oh dear! Was it a cheap plastic tray?

This is a stone tray and to be fair not uniform underneath so can see ive weighed some areas down with tiles to ensure contact on the edge and also applied silicone.

The manufacturers (mira) suggests either silicon or mortar for this and to be fair they can be supported from stand up legs in four corners so it should(!) be fairly capable of supporting its own weight.

Doesnt seem to wobble now that I've put it in at least!

Buffman · 18 Mar 2022 at 18:56

Going to put the decoupling membrane (6mm marmox boards) on the floor this weekend. Going to primer twice then put it in.

Will be putting it in with 8mm fully combed tile adhesive then 25mm screws - I want to avoid longer screws as there are so many services under my bathroom! From reading marmox advise it seems to suggest screws aren't even necessary?

Should I put this decoupling membrane under the bath also? Suppose its extra "waterproofing"?

Thoughts @Simon @200sols
?

Buffman · 18 Mar 2022 at 18:59

Simon said:
Are you tiling under the bath

Nope!

Just edited my other post. It will be tiled up to the edges around the bath though and covered with a cover panel

Buffman · 18 Mar 2022 at 20:05

Sound, cheers both just bought this bath mixer but it doesn’t tell me if it’s 15mm bsp or 1/2 inch threads onto it. Got it 70quid new on eBay

https://www.mirashowers.co.uk/taps/mira-honesty-bathshower-mixer/

Buffman · 18 Mar 2022 at 20:15

Simon said:
Prob crap flexi with a tiny bore anyway so might end up replacing them ? I used solid tails on mine

If it’s 15mm I found ones that are 10mm bore, should be okay. To be honest will be very very irregular use until/unless I have kids.

Buffman · 19 Mar 2022 at 23:07

Only thing I can't work out is if I need to screw the boards down after fixing them with cement based adhesive

The marmox technicalguide suggests its not necessary and even suggests its counterintuitive for some applications (floorboards/plywood). Seems to stay silent on chipboard.

Any thoughts @Simon @200sols ?

Primer on

Boards cut to size