# Forum Home Renovation Waterproofing  Waterproofing over silicone joint

## waite123

I have a joint on my roof which seals the walk on rooflight to the timber frame. I have had problems with it leaking so i have to put more down. I was wondering if there was something i could put of the joint sealing it more like an epoxy or another sealant that will stick to the silicone. The roof is fibre glassed. Any information or help would be greatly appreciated.

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## rebuildr86

unfortenately silicone is really unable to be overcoated with anything, not even silicone.
i would suggest getting a large sheet of somethi g like zincalume, and cutting a large square out of it and then a slightly smaller square out of that so i end up with a seemless frame that u can then attach to the concrete and glass.
It will have to be very flat amd pressed sown into a very thin bed of sealant.
for the sealant, i would use 2 different prodcuts.
1. for the inside where glass meets metal, id be using an acetic cure silicone, this will have good bond to both glass and zinc, and will stay good for a lo g time.
2. for the outside edge where the frame will meet concrete, go with a paintable silicone, like selleys one, and then u can apply an acrylic waterprrof membrane or primer over that and across the zincalume for a nice watertite finish.

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## rebuildr86

i recomend selleys for 3 reasons, 1.im an ex orica (duluxgroup) staff member (dulux, selleys and yates) 
2. its readily available and well stocked at bunnings
3. warrantys are actually looked after by a customer service case officer. 
for the outer silicone, use this.. http://www.selleys.com.au/sealants/h...ts/armourflex/ 
for the inner, use any good 100% aecetic cure silicone.

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## marz1

It looks like the glass is recessed down a little in the roof? is water ponding there or does it run off to a gutter somewhere?  Id suggest remove the glass raise it a little sit water doesnt sit there, prime the area around it with a waterproofing flexible compound use a bytul mastic product between glass and roof, them use a good silicone or bytul mastic flashing that has a aluminium backing, that will waterproof between both surfaces and repell water away. ive used this product and works well.                                                                                                       firstly apply a bytul mastic  like this one https://www.bunnings.com.au/selleys-...alant_p1234715
then flash over the top with this https://www.bunnings.com.au/consolid...-tape_p1100467             the tape has aluminum backing its permanently soft and grips very well to allow for movement and waterproof, just buy the coreect width tape, apply to the side edge of the glass and over the roof just press on firmly, if your not going to remove the glass then apply the tape ad make sure you have at least 25MM overlap both sides.

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## rebuildr86

i believe its an entertaining area that people will be walking over.

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## Oldsaltoz

As noted above, nothing will stick to silicone, not even a new layer of silicone will to an original. Based on that alone I would not use silicone if it was free. 
You can remove old silicone mechanically, but you also have to remove the residue or nothing will stick. Acetone will remove it but you must have good ventilation, rubber gloves and eye protection available. Only use white rags as the acetone will dissolve any dyes.  
I use Sikaflex 11FC for most applications have never had a problem. it is a fast curing sealant that remains flexible after curing. 
Good luck and fair winds.  :Smilie:

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