# Forum Home Renovation Waterproofing  Enclosed balcony waterproofing

## paddyjoy

Does anyone have any tips on how to go about waterproofing a recessed/enclosed balcony like below? 
I would like to keep the inside and outside levels as close as possible so that the bi fold doors will have enough clearance to open. 
The outside will be tiles. I was thinking maybe I could put a strip drain in possibly directly outside the bifolds and slope the exterior towards the interior? 
Any ideas?

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## Random Username

I'd try for a solution that didn't involve the lowest point being right next to the one unwaterproofable bit of the balcony - the doors.  All you need is one of those heavy rainfall events and you'll have water not being able to drain away fast enough, and it'll be soggy carpet time.  I'd extend the waterproofing into the room, too. 
As it is, you'll essentially have your doors as one wall of a swimming pool!  And think of how many commercial buildings get water damage because of the ever-popular-with-architects box gutters!

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## paddyjoy

> I'd try for a solution that didn't involve the lowest point being right next to the one unwaterproofable bit of the balcony - the doors.  All you need is one of those heavy rainfall events and you'll have water not being able to drain away fast enough, and it'll be soggy carpet time.  I'd extend the waterproofing into the room, too. 
> As it is, you'll essentially have your doors as one wall of a swimming pool!  And think of how many commercial buildings get water damage because of the ever-popular-with-architects box gutters!

  Fair point, we'll be having timber floors so the last thing we want would be water coming in. 
I was looking at these zero threshold drains but unfortunately at $1k per linear metre it's a bit out of budget.  The zero Threshold Drain | Creative Drain Solutions 
Maybe standard strip drain on the outside edge will be the way to go.

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## Random Username

You should note that those zero threshold drains are for secondary drainage only, and rely on a proper drain doing most of the work! 
I've seen the standard residential drains overflow too often...I'd be looking at something 150-200mm wide at least.

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## goldie1

What ever you do make sure it is over specified and have more than one outlet. You only need a blockage 
( leaves blown into with a big downpour ) and you have a problem

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## paddyjoy

> What ever you do make sure it is over specified and have more than one outlet. You only need a blockage 
> ( leaves blown into with a big downpour ) and you have a problem

  Good point, maybe it would be better if rather than having a drain I continued the balcony floor and just sloped it down into the gutter like this, then it could never overflow.

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## Oldsaltoz

G'day Paddyjoy, 
I think you will find that any domestic balcony must be 50 mm below the opening. 
Having a fall all the way to the outer edge is by far the best solution. 
By the way, I recently waterproofed 2 metres into a room that had bi-fold doors to a balcony.
Seems it was closed but not fully latched, the wind and rain pressing on the panels and caused it to open and flood the top floor. This is one of the disadvantages of Bi-folding anything. 
Good luck and fair winds.   :Smilie:

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## paddyjoy

> G'day Paddyjoy, 
> I think you will find that any domestic balcony must be 50 mm below the opening. 
> Having a fall all the way to the outer edge is by far the best solution. 
> By the way, I recently waterproofed 2 metres into a room that had bi-fold doors to a balcony.
> Seems it was closed but not fully latched, the wind and rain pressing on the panels and caused it to open and flood the top floor. This is one of the disadvantages of Bi-folding anything. 
> Good luck and fair winds.

  Thanks Oldsaltoz, the required 50mm drop is going to give me issues I think and will have to go back to the drawing board. 
Below is basically what I have to deal with. The green lines are where the external walls will be, there is a space of 2.2m for doors, the brown area is the footprint of the balcony where I was planning to put down exterior sycon sheets. 
If there was a 50mm high door cill along the purple line would that cover the drop or does it specifically require that the outside balcony level is 50mm lower than the interior floor level?

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## Oldsaltoz

> Thanks Oldsaltoz, the required 50mm drop is going to give me issues I think and will have to go back to the drawing board. 
> Below is basically what I have to deal with. The green lines are where the external walls will be, there is a space of 2.2m for doors, the brown area is the footprint of the balcony where I was planning to put down exterior sycon sheets. 
> If there was a 50mm high door cill along the purple line would that cover the drop or does it specifically require that the outside balcony level is 50mm lower than the interior floor level?

  50 mm is the Standard in Qld for domestic, mind you commercial is not.
Give you local council a call to confirm, they a lot of calls from Mr Smith. 
Good luck and fair winds.   :Smilie:

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## goldie1

> Good point, maybe it would be better if rather than having a drain I continued the balcony floor and just sloped it down into the gutter like this, then it could never overflow.

  Now your talking. I have seen plenty of unit blocks built with enclosed balconies.  Concrete balustrade and one 
small floor waste.. Even with a step down they flood with monotonous regularity. A few leaves in the drain 
and a good down pour. The usual solution is to core drill a couple of holes through the balustrade at  
floor height.

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## paddyjoy

I like the Mr Smith idea ha ha 
I think sloping it down the gutter is going to be the safest, I'll have to funnel it some how so that it can pass out between two rafter and out into the gutter somehow. 
It will pass over that steel beam also so the waterproofing will have to be pretty good in case there is an undetected leak in the future.

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