Sealant for Wedi board

[pogues]

Hi all,

First post, but have really appreciated learning from this forum over last few months. Thank You. Chance now to post.

Nearly finished a project tiling down to a domestic bath. with shower mixer taps, using wedi board, wedi waterproof tape, BAL Sgle Part Flex cementious adhesive (for dot & dab and fixing tiles) and standard 7mm 8"x10" tiles. All OK, just about to grout with BAL microflex.

Trying to have a system that is dependable & low maintenance as may not be around to fix. Seem to keep finding contradicting info about which sealant is appropriate.

Please could you add any practical experience/recommendations you may have?

1. What sealants with Wedi / cement Adh / ceramic tile / / acrylic bath?

a) Vertical internal movement joints where the Wedi's meet.
5mm gap tile corner to tile corner?
b) Between Wedi wall system and top of acrylic bath?

2. With a wide gap in internal corner should I use a foam backer rod?

My Research came up with:-

Wedi:
Wedi 610 Adh/Seal (3 weeks oder) & expensive and also bonds the bath to the wedi wall. If want sealing only (not bonding) then Wedi say a solvent-free sealant must be used otherwise it eats away the board.

Dow:
Didn't recommend Dow Corning 785 as it might contact cementious substrates (wedi surface and BAL Adh). They recommend 798 which is a cold room application OK for cementious substrates, but needs special ordering. Quite expensive and poss long leadtime. Not sure of this as haven't heard anywhere else. They say it is solvent free but not written on tech sheets. Have you guys used 785 or 798 as I guess it'd be fine between tile and bath or tile to tile in corner?

Wedi Nearest Distibutor:-
Have Mapesil solvent free sealant which they sell with Wedi but didn't specifically recommend it. OK but on Mapei technical sheet says substrate needs priming with Primer FD which will be a pain. Sounds complicated and needs another purchase. Have you guys used this with Wedi?

Many thanks if anyone can add some practical experience to my research?

Ian

 

[DHTiling]

Hello and welcome..

I just use the flexible joint tape for internal joints and wedi for the straight joints .... this water proofs as recommended and then i use Silicon expansion joints in the tiling ...

 

[tommyzooom]

To stick the bath to the wedi, check out CT1 or Tec7 Sealant/adhesive. They stick like s*** to a blanket. they are a bit tricky to get a smooth bead so I use Silicon for anything visible

 

[pogues]

Thanks guys 4 fast reply,

For the waterproofing I used the Wedi waterproof tape feathered with BAL SPflex on all joints as suggested and have used BAL SPF for tiling as recommended. I didn't make it clear in my post, sorry, but I'm looking to find the compatible flexible solvent free silicon sealants (not adhesive) between the tiles at the internal corner and between the tiles and the bath without causing degradation or lack of seal strength to the background system of Wedi and cement based BAL that I'm sure the sealant will be in contact with? (hope my explanation makes sense) eg. solvent based sealants can eat away at the board.

 

[The Legend; Phil Hobson RIP]

Hi and:welcome:

 

[Max@ableskills]

Hi and welcome to the TF

 

[pogues]

Help, DIY'er needing feedback. I think my post was too over complicated. I'm just trying to do it right first time but not go spec mad.

Basically, could anyone help and please tell me what Silicon sealants they find have worked OK out in the field when sealing ceramic tile to tile and tile to acrylic when the background substrates that the sealant will touch are also Wedi tile backer & BAL SPF which have cement in them? Or common sealants that aren't good.

Has DC785, Mapesil AC solvent-free (acetoxy - acid curing), BAL microseal or Unibond etc all worked fine?

I'm done with tech sheets and solvent vs non-solvent and not knowing whether acetoxy, alcohol blah blah curing counts as solvent or non-solvent.

I just wanna seal ma barf!

Cheers
Ian

 

[steveb]

welcome