# Forum Home Renovation Waterproofing  screw heads compressed cement flooring

## dmsantam

Hi, 
My bathroom floor is 15mm compressed cement. The sheets were screwed in flush with galv screws. The joins were then sealed with poly sealant that is safe for waterproofing. The same sealant was used over most of the screw heads, but a few were missed, and one coat of crommelin shower waterproofing was applied, with bondbreaker bandage on all wall/floor joins and wall/wall joins in the shower. I am using wondercap flanges for the shower waste, and floor waste. The wondercap was seated with the same poly sealant, and a bead was put around the interface between it, and the compressed cement sheet. It is recessed flush.  
Questions: 
1. Should I use bandage on all the compressed cement floor joints?
2. Should I use bandage on the screws? Or at least the screws that did not have poly sealant put on them?
3. Should I use bandage on the wondercap to compressed cement floor joins?
4. If the answer to any of the above is yes, can I put that bandage on now (one coat already done), and then do another coat on top of all that? 
The bathroom is small, so it's easy for me to put bandage on screws, joins, etc at small cost.  
I appreciate any input.  
cheers, 
Dan

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## phild01

You need to bandage the floor joints with a bond breaker,  screws don't need it.

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## Marc

Why only one coat?

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## Oldsaltoz

> Hi, 
> My bathroom floor is 15mm compressed cement. The sheets were screwed in flush with galv screws. The joins were then sealed with a poly sealant that is safe for waterproofing. The same sealant was used over most of the screw heads, but a few were missed, and one coat of crommelin shower waterproofing was applied, with bond breaker bandage on all wall/floor joins and wall/wall joins in the shower. I am using wondercap flanges for the shower waste, and floor waste. The wondercap was seated with the same poly sealant, and a bead was put around the interface between it, and the compressed cement sheet. It is recessed flush.  
> Questions: 
> 1. Should I use bandage on all the compressed cement floor joints?
> 2. Should I use bandage on the screws? Or at least the screws that did not have poly sealant put on them?
> 3. Should I use bandage on the wondercap to compressed cement floor joins?
> 4. If the answer to any of the above is yes, can I put that bandage on now (one coat already done), and then do another coat on top of all that? 
> The bathroom is small, so it's easy for me to put bandage on screws, joins, etc at a small cost.  
> I appreciate any input.  
> ...

  1-Yes. In case of movement
2-Yes. To avoid corrosion that will cause a swelling and leak.
3-Yes. But keep 25mm away from the hole and run it 50mm past the outer edge.
4- Read the manufacturers recommendations before you do anything.
Good luck and fair winds.  :Smilie:

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## dmsantam

> 1-Yes. In case of movement
> 2-Yes. To avoid corrosion that will cause a swelling and leak.
> 3-Yes. But keep 25mm away from the hole and run it 50mm past the outer edge.
> 4- Read the manufacturers recommendations before you do anything.
> Good luck and fair winds.

  Many thanks for all the replies! I have done as per above quoted recommendations.  
As for the question about "why only 1 coat", i meant I had only done 1 coat so far.  
cheers!

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## Oldsaltoz

> Many thanks for all the replies! I have done as per above quoted recommendations.  
> As for the question about "why only 1 coat", I meant I had only done 1 coat so far.  
> cheers!

   
I Almost forgot, Check the puddle flanges, if they have any screws in them you must remove them and fill the hole with a sealant, The screw will be low grade and prone to rust, that means swelling that could damage the waterproofing.

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