# Forum Home Renovation Waterproofing  Some Waterproofing Questions.

## mgt

All, 
I have so many different questions in regard to waterproofing going through my head at different times.  So I thought I would start a thread to go through them all as they come to me and hopefully receive some guidance in relation to them.  (I find things like this keeping me up at night even though I am not up to this stage as yet in my reno)  *Question 1:*  *Can I use SikaflexFC as a bond breaker?* 
I think I understand the principles of waterproofing.  But could I use SikaflexFC in the wall/wall and wall/floor joins, - as long as I don't stick the waterproofing tape to it? 
I know the membrane will stick to sika (while not to silicone).  But if I used Sika for my joins, could I then use the polyester tape in the joins and paint the membrane on underneath the tape - making sure I do not paint over the sika, and then paint over the entire top of the tape?  So in essence, the sika would not be adhered to the membrane tape allowing independent movement (which I think is the idea of a bond breaker), of the membrane and the join.  Sika is supposed to be flexible - so if I do not 'stick' the tape to it, the joins should be able to flex separate to the membrane. 
I have read elsewhere that some people just use sika for the joins and paint membrane straight over the top (sometimes without the tape).  Is this used in practise and is it acceptable? 
I would appreciate your thoughts. 
Cheers,
MGT.

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## goldie1

Yes  you are essentially correct. A bond breaker is just two surfaces which are not stuck together 
at a point which is subject to movement.  Its basically a slip joint and there are several way of  
achieving it. The fabric tape is required  at wet area wall to wall joints and wall to floor joints. 
So yes you can use Sika  as long as the tape does not stick to it at the corner of the right angle 
If you use Sika in the corner and then paint membrane on to it they would stick to each other  
and you would not have a bond breaker and this is not acceptable

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## wspivak

Also make sure that the Sikaflex is fully cured before working on it.  Waterproofing Products, Waterproofing Supplies. The Waterstop Shop

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## Oldsaltoz

> All,  *Question 1:*  *Can I use Sikaflex11FC as a bond breaker? 
> Hi Mgt,* 
> I think I understand the principles of waterproofing.  But could I use SikaflexFC in the wall/wall and wall/floor joins, - as long as I don't stick the waterproofing tape to it? The simple answer is to use a layer of Silicon sealant or a silicon based tape over Sikaflex11FC.
> Craft tape is the stuff you are looking for about 5 bucks a 40 foot roll. 
> I know the membrane will stick to sika (while not to silicone).  But if I used Sika for my joins, could I then use the polyester tape in the joins and paint the membrane on underneath the tape - making sure I do not paint over the sika, and then paint over the entire top of the tape?  So in essence, the sika would not be adhered to the membrane tape allowing independent movement (which I think is the idea of a bond breaker), of the membrane and the join.  Sika is supposed to be flexible - so if I do not 'stick' the tape to it, the joins should be able to flex separate to the membrane. Save yourself the worry, Use Fika and silicon tape or a silicon sealer. 
> Note: You need bond breakers in the shower wall to floor joints as well. 
>   Appreciate your thoughts. 
> Cheers,
> MGT.

  Good luck and fair winds.   :Smilie:

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## mgt

Thanks guys, 
Sounds like it is going to be easier (and cheaper) to just use silicone instead of sika. Then my painting of membrane will not be a tricky affair when putting the membrane fabric tape on.  
Is silicon considered to be strong to hold two things together? (ie. the wall boards in the corners). I think i was leaning toward sika because of its bonding strength.  
Cheers
MGT.

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## goldie1

> Thanks guys, 
> Sounds like it is going to be easier (and cheaper) to just use silicone instead of sika. Then my painting of membrane will not be a tricky affair when putting the membrane fabric tape on.  
> Is silicon considered to be strong to hold two things together? (ie. the wall boards in the corners). I think i was leaning toward sika because of its bonding strength.  
> Cheers
> MGT.

  Silicon is very strong but its not there to bond the two wall sheets. The wall sheets are fixed to the wall frame 
The silicon is there as a flexible filler and sealant for the 6mm  movement gap which is left in the corner

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## atregent

> _The simple answer is to use a layer of Silicon sealant or a silicon based tape over Sikaflex11FC._ _Craft tape is the stuff you are looking for about 5 bucks a 40 foot roll._

  This may be a silly question, but what purpose does the Sika serve in addition to the silicone? Could just silicone be used? That would certainly work out cheaper than Sika + Tape, or Sika + Silicone.

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## mgt

*Question 2: Waterproofing around tap penetrations* 
All, 
How do I waterproof around the mixer tap penetration and the threaded spout outlet? 
Do I use sikaflex, then use membrane tape and waterproofing membrane to 'strengthen' around the penetration?  Or do I use one of those rubbery prefabricated things i have seen on some YouTube vids? 
Obviously I need to waterproof the gap between the villaboard and the threaded spout and the larger mixer tap body (which as a protective plastic cover).  Speaking of that cover, how do I get this off when/if i sikaflex around it to waterproof the area?? 
Thanks in advance,
MGT.

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## Oldsaltoz

> *Question 2: Waterproofing around tap penetrations* 
> All, 
> How do I waterproof around the mixer tap penetration and the threaded spout outlet? 
> Do I use sikaflex, then use membrane tape and waterproofing membrane to 'strengthen' around the penetration?  Or do I use one of those rubbery prefabricated things i have seen on some You Tube vids?  Sikaflex11Fc will be fine, run a bit of masking tape around the mixer body leaving about 5 mm exposed, lay a bead of sealant on the tape and work it into the gap. remove the tape as soon as you are happy with the seal. 
> Obviously I need to waterproof the gap between the villaboard and the threaded spout and the larger mixer tap body (which as a protective plastic cover).  Speaking of that cover, how do I get this off when/if i sikaflex around it to waterproof the area??  for the shower spigot, lay the tape flush with the wall sheet and again remove when happy with the finish.  Also seal all fixings and sheet joints. 
> Thanks in advance,
> MGT.

  Good luck and fair winds.   :Smilie:

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## mgt

> Good luck and fair winds.

  
Thanks oldsaltoz, 
Masking tape.  Of course.  Makes feel silly for not thinking of it. 
I have used the 'Gyprock Wet area Joining compound' for the fixings and other board joins. (i.e. 'other' meaning - other than the wall/wall and wall/floor joins which will be silicone and membrane tape). 
If the gap around the penetration is a bit big (say 10-15mm) Do I just 'build up' the sika or use some other method? 
Cheers,
MGT.

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## mgt

*Quick one - Question #3: 
Do I have to wait the full cure time for my Silicon Bond Breaker before I place membrane and tape? * 
I am using 'Selleys Wet Area Speed Seal Silicone Sealant' as my bond breaker on the wall/wall and wall/floor joints.  I plan on doing the joins tonight (about 7:30pm) and then undertaking the waterproofing membrane and polyester tape in the joins tomorrow morning (about 9:30am).  That would be a curing time of 14 hours. 
Do I need to wait the 48 hours to "full cure" as stated on the tube, or will 14 hours be enough for me to do the next waterproofing stage of the membrane and tape. (tube also states waterproof after 2 hours) 
Cheers,
MGT.

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## Oldsaltoz

> *Quick one - Question #3: 
> Do I have to wait the full cure time for my Silicon Bond Breaker before I place membrane and tape? * 
> I am using 'Selleys Wet Area Speed Seal Silicone Sealant' as my bond breaker on the wall/wall and wall/floor joints.  I plan on doing the joins tonight (about 7:30pm) and then undertaking the waterproofing membrane and polyester tape in the joins tomorrow morning (about 9:30am).  That would be a curing time of 14 hours. 
> Do I need to wait the 48 hours to "full cure" as stated on the tube, or will 14 hours be enough for me to do the next waterproofing stage of the membrane and tape. (tube also states waterproof after 2 hours) 
> Cheers,
> MGT.

  To be brutally honest with you I would have to say "I am not a user of Silicone sealants at all"  so am not in a position to advise you on this one, but suggest you follow the manufacturers directions. Though the "apply waterproofing after 2 hours seems reasonable. 
Good luck and fair winds.   :Smilie:

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## mgt

*Another Quick one - Can I prime over the Waterproofing membrane?*  
I am using Davco Ultraprime and K10 Plus waterproofing.  I only primed all my joins (wall/wall, wall/floor etc.) early today in preparation for waterproofing and reinforcing all those joins later today (which I did).  I did not prime the whole substrate as I was not going to be able to waterproof the whole area today (going to wait for the joins to dry first) - and the Davco Ultraprime states only prime an area if it is going to be covered within 24 hours.
So,..... as I put waterproofing on the joins over the primed area - I have painted the membrane all the way to the edge of the primed area (and a bit over in some spots........). 
My question is - as I prime the rest of the walls and floor in preparation for the first full coat of membrane, can I prime up to and slightly over the waterproofing membrane I have just applied to the joins?  Or will this cause a drama.  Also - I suppose I should wait the 6 hours for the membrane to dry before I prime? 
Any help appreciated. 
Cheers,
MGT.

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## Pulse

Don't prime over the waterproofing, the 24 hour warning is most likely because dust etc accumulates with time, you would have been better priming the whole lot then coating the whole lot. 
Cheers
Pulse  
Sent from my iPhone using Tapatalk

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## mgt

> Don't prime over the waterproofing, the 24 hour warning is most likely because dust etc accumulates with time, you would have been better priming the whole lot then coating the whole lot. 
> Cheers
> Pulse  
> Sent from my iPhone using Tapatalk

  
Pulse, 
I know Priming all at once would have been the best option - but as stated, I was trying to follow the manufactures instructions of "going over" the priming within 24 hours.  You are correct, probably due to dust and particle accumulation degenerating the primed surface. 
I primed the 'non-primed' areas last night, and only went a little over the edge of the waterproofing in some spots.   
On thinking about it, Priming prepares a surface so it can readily receive a coat of another substance - so am I right in thinking that the primer on the edge of the membrane won't do any damage and might just make the next (first full coat) membrane coat "stick" to it better??? 
Cheers,
MGT

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## Pulse

The membranes are meant to be applied in complete layers, and multiple costs to form one complete thick membrane, putting primer between them is probably not desirable for that reason. Probably won't matter though  
Sent from my iPhone using Tapatalk

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## mgt

> The membranes are meant to be applied in complete layers, and multiple costs to form one complete thick membrane, putting primer between them is probably not desirable for that reason. Probably won't matter though  
> Sent from my iPhone using Tapatalk

  Thanks Pulse, 
I agree, a complete layer would be the best.   
Given that my primer only went over the edge of the waterproofing on my joins, and then after the joins dried I then applied three complete membrane layers after that, I am hoping that I will be ok and that the integrity of my membrane will be solid. 
Cheers,
MGT.

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## mgt

*​Question #4: Can the Aluminium angle to separate the end of the tiles be a waterstop angle?? * Background:  I understand what a waterstop angle is and why it is necessary.  However after calling a number of tiling stores and asking if they stocked water stop angle I was met with "What is waterstop angle?".  I was shocked to say the least (Although I am a complete neophyte with this stuff - I have researched heaps).  After explaining what it was I was usually met with; "no need for that - water doesn't get through the grout" or "we don't bother installing that" or " you don't need that".  I have even asked Tilers who also stated that they did not use them. 
So my question is - Can I use the Aluminium trim/angle that separates the end of my tiles (to step down to floorboards) as a waterstop angle if I Sikaflex it down ensuring that the sikaflex covers its base and sides completely - before using tile adhesive and tiling as normal? 
Thanks in advance,
MGT.

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## phild01

Strange you are met with such responses.  No hard rules about angle type, can be brass, stainless, aluminium or plastic.  Fullerprene 303 about the best, 11FC is good too.  Just be sure to do it before the waterproofing.

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## Oldsaltoz

> *​Question #4:*  Can I use the Aluminium trim/angle that separates the end of my tiles (to step down to floorboards) as a waterstop angle if I Sikaflex it down ensuring that the sikaflex covers its base and sides completely - before using tile adhesive and tiling as normal? 
> Thanks in advance,
> MGT.

  Hi Mgt, 
Watertops are part of the waterproofing standards, as for people saying they do not use, take their and do not use the-to do any tiling, ever. 
Yes you can and should install a waterstop angle, the bunnies people would tell you have tile angles in stock' same thing. 
Take a bit of estra time to make sure the floor is clean before applying the Sika 11FC, Line it up and re cheack after firmly pressing down alond the full length, let it cure for about 10 or 15 minutes, then return and run a small bead between the floor and the wet side of the angle, smooth it out like a small ramp. Then sika both ends on the wet side mking sure it gets into the joints between the ends and the door jamb. 
There is huge range of water stop / tile end angles available and well worth a look if you want a professional finish, they cover a large range of colours and pattern finishes.  
Also available for floor covering changes like tile to carpet etc. 
Good luck and fair winds.   :Arrow Up:

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## mgt

Thanks guys, 
I have a piece of Alu angle and will get to work on Using the Sika to put it down. 
If I have already waterproofed - is it ok for me to Sika the angle down then waterproof over the Sika and angle where required? 
Cheers,
Mgt

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## Oldsaltoz

> Thanks guys, 
> I have a piece of Alu angle and will get to work on Using the Sika to put it down. 
> If I have already waterproofed - is it ok for me to Sika the angle down then waterproof over the Sika and angle where required? 
> Cheers,
> Mgt

  Most definitely yes, this is good practice. 
Good luck and fair winds.   :Smilie:

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## mgt

Great. 
What size Alu angle would you use for 10mm thick tiles?  I am using a 12mm notch trowel for the adhesive on the floor. I have some 15mm angle but think it might be too high.  I want to get this right before I stick a bit down. 
Cheers,
Mgt.

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## phild01

It might come down to your trowel technique and whether you back batter.  I might expect 14mm but you can adjust the adhesive to suit.  These angles come in a variety of sizes from good tile outlets.
Edit Just did a check.I did mine with a 10mm and back battered. Tiles are 10mm porcelain and the finished height is 13.5mm.

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## Oldsaltoz

> Great. 
> What size Alu angle would you use for 10mm thick tiles?  I am using a 12mm notch trowel for the adhesive on the floor. I have some 15mm angle but think it might be too high.  I want to get this right before I stick a bit down. 
> Cheers,
> Mgt.

  
I would think at least a 12 mm, try putting the angle alonside the first few tiles you put down to give you some idea of the glue thickness you are using. 
Good luck and fair winds.    :Smilie:

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## mgt

Thanks Phild01 and Oldsaltoz, 
I will be giving the tiles a light back butter/scrape and use my 12mm trowel.  I will check the height of the tiles I have already laid (in the ezilay shower tray) to try and get an estimate. (or do a practise with an off cut of the Alu angle).  May also give the tile shops a try to see if they stock a size between 12mm and 15mm. (mine came from bunnings and from memory they only had 12 and 15) 
Cheers,
Mgt.

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