# Forum Home Renovation Waterproofing  Waterproofing mesh or not?

## Timber21

Hello  
I am about to have a builder start a bathroom renovation. I have asked the builder regarding the use of waterproofing mesh/tape. He tells me it is not necessary unless there is a large gap. He says the corners/junctions of the villaboard are sealed with Sika PU and then he does 3 coats of waterproofing over. 
Am I old fashioned in thinking that the mesh should be used on all junctions? Should I insist on this before I sign off on the contract? 
Thanks
Timber21

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## intertd6

> Hello  
> I am about to have a builder start a bathroom renovation. I have asked the builder regarding the use of waterproofing mesh/tape. He tells me it is not necessary unless there is a large gap. He says the corners/junctions of the villaboard are sealed with Sika PU and then he does 3 coats of waterproofing over. 
> Am I old fashioned in thinking that the mesh should be used on all junctions? Should I insist on this before I sign off on the contract? 
> Thanks
> Timber21

  ask him to supply the manufacturers installation method details of the system he's going to use, if it's what they recommend then it's all go, if he can't come up with the details he's making it up as he goes along and you'll be paying twice to get it done properly if it fails some years later when he's long gone.

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## Timber21

Thank you for advice...will do

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## Timber21

Thank you for advice...will do

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## phild01

I wouldn't trust it.  Who is doing the work, and you want a certificate for warranty.

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## Timber21

He is a bathroom renovator with current valid license.
Am I correct in thinking that the tape/mesh is a bond breaker and not just for spanning the gap in the joint?
There are liquid reinforcing fabric material (eg Crommelin) which can apparently be substituted for the traditional tape. Anyone had any experience with this product?

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## Mike8136

The mesh versus bead of sealant requirement relates to the class of waterproof membrane.  There is class 1 to class 3. I can't remember which is which without looking it up but if he is using the most flexible type then a bead if neutral cure sealant is all that is required. 
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## JB1

I would use fabric. 
Ask him to use sealant as per normal but also use fabric on the corners. It will cost nothing in the overall scheme of things. 
It may not be needed but it will do no harm. 
If he doesn't oblige, then I'll be looking for another builder as he isn't going to provide the customer service you will want.  
End of the day, you're the customer.  
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## Timber21

Thanks Mike 
Have asked him to provide details about which membrane he is using but am inclined to ask him to tape all the joints anyway. As JB1 says...may cost me more but will give me peace of mind I think.

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## Timber21

Inclined to agree with you JB1. May be a bit of overkill but will give me peace of mind. I understand that there is a longer drying time if the fabric is used so probably puts his schedule out a bit. He seems good enough so far answering all my questions etc so hopefully he will oblige.
Would you hazard a guess as to how much extra cost I should expect? 
Cheers

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## Timber21

Builder is using Davco k10 Plus waterproofing membrane and Davco Prime X primer.
He says the Sikaflex Pro acts as a bond breaker.
He is obviously not using the Davco k5 bond breaker for some reason.
Would another brand bond breaker tape still be compatible. If so, I could ask him to add this in for extra peace of mind.

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## droog

As per the Davco K10 Plus manufacturers instructions.
All cracks / joints, irrespective of their width, must be filled firstly with K5 Bond Breaker. Then 50mm wide polyethylene / polypropylene tape should be placed over the crack, ensuring it adheres to the surface. 
I would ask why he is not intending to follow the manufacturers recommendations and if he will provide a written guarantee in place of the manufacturers warrantee as he is not installing as per their recommendations.

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