ᐅ Drainage of terrace / patio / deck Floor-to-ceiling windows / Full-height windows
Created on: 10 Aug 2023 14:26
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Pivi2000Here is my second question regarding my project to renovate my existing terrace:
The terrace is located in a corner of the house, meaning it is enclosed on two sides by the building, with floor-to-ceiling windows and doors on both sides. However, the doors have a threshold, so they are like regular windows rather than having a level threshold.
It is a terrace with a concrete slab foundation. Until now, it was a wooden terrace built on old paving slabs placed on sand.
I plan to lay gravel on top of the concrete slab, followed by crusher run, and then install cement slabs or porcelain tiles. I intend to set the surface level of the slab just below the bottom edge of the windows.
From what I understand, building regulations or standards suggest installing drainage channels at the windows to properly drain water, especially under snow load or extreme weather events that occur once every 100 years. Usually, these might not be necessary, but they are advisable.
There are at least two systems: those that connect directly to a pipe (e.g., ACO drainage channel), and those that drain the water away through a drainage layer (e.g., ACO facade channel). I initially wanted to use the drainage layer system, but on further consideration, it seems illogical in my case because the drainage would lie on the concrete slab and might not drain reliably. The water could collect in the corner between the house and the slab. Although I have sealed everything with multiple layers of bitumen coating and the area beneath the windows is watertight, I still have concerns. From my perspective, this approach would be worse than the current situation, so I am leaning toward either a direct pipe connection or no drainage channel at all, but definitely not the drainage layer system.
Additionally, I have two light wells that will be dismantled, and I plan to use their drains for the terrace drainage.
Am I missing something in my reasoning?
Thank you in advance for your feedback.
The terrace is located in a corner of the house, meaning it is enclosed on two sides by the building, with floor-to-ceiling windows and doors on both sides. However, the doors have a threshold, so they are like regular windows rather than having a level threshold.
It is a terrace with a concrete slab foundation. Until now, it was a wooden terrace built on old paving slabs placed on sand.
I plan to lay gravel on top of the concrete slab, followed by crusher run, and then install cement slabs or porcelain tiles. I intend to set the surface level of the slab just below the bottom edge of the windows.
From what I understand, building regulations or standards suggest installing drainage channels at the windows to properly drain water, especially under snow load or extreme weather events that occur once every 100 years. Usually, these might not be necessary, but they are advisable.
There are at least two systems: those that connect directly to a pipe (e.g., ACO drainage channel), and those that drain the water away through a drainage layer (e.g., ACO facade channel). I initially wanted to use the drainage layer system, but on further consideration, it seems illogical in my case because the drainage would lie on the concrete slab and might not drain reliably. The water could collect in the corner between the house and the slab. Although I have sealed everything with multiple layers of bitumen coating and the area beneath the windows is watertight, I still have concerns. From my perspective, this approach would be worse than the current situation, so I am leaning toward either a direct pipe connection or no drainage channel at all, but definitely not the drainage layer system.
Additionally, I have two light wells that will be dismantled, and I plan to use their drains for the terrace drainage.
Am I missing something in my reasoning?
Thank you in advance for your feedback.
bauenmk202015 Aug 2023 09:42You can install an ACO channel drain in front of the patio door and connect it to a PVC pipe. I would then connect the channel drain to a drainage hose using an adapter piece and have this end in a hole filled with gravel. You can place a geotextile fabric over it and create a small planting bed on top.
Is there a rainwater downpipe from the roof at the "L-bend"?
Water will likely remain on your concrete slab, coming through the patio surface or joints. Whether or not you drain the water into the channel drain may be negligible. However, I would still direct the channel drains away from the house as described above.
Is there a rainwater downpipe from the roof at the "L-bend"?
Water will likely remain on your concrete slab, coming through the patio surface or joints. Whether or not you drain the water into the channel drain may be negligible. However, I would still direct the channel drains away from the house as described above.
bauenmk2020 schrieb:
You can install an ACO channel drain in front of the patio door and connect it to a PVC sewer pipe. I would connect the channel drain to a drainage hose using an adapter piece and have it discharge into a hole filled with gravel. You can then cover this with a geotextile fabric and create a small planting bed on top.
Do you have a downspout from the roof at the "L-bend"?
There will likely be water standing on your slab that seeps through the patio surface and joints. Whether or not the channel drains are connected to that drainage is probably negligible. However, I would recommend routing the channel drains away from the house as described above. No, there is no downspout at the bend.
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xMisterDx18 Aug 2023 21:23In your setup, everything, absolutely everything, calls for a wooden deck.
bauenmk202020 Aug 2023 10:52The connection detail between the slab and the house wall would be interesting. How much space or gap do you have between the slab and the house base?
A channel only drains surface water. Everything that seeps through joints ends up on the slab. If the slab does not have a slope away from the house, the patio surface should also be sealed and designed with a slope of 1% to 1.5%.
I can also imagine tiles with a slope away from the house. This would likely result in a lower overall height since they are adhered directly to the slab, unlike your previous setup with a substructure and thick wooden decking.
A channel only drains surface water. Everything that seeps through joints ends up on the slab. If the slab does not have a slope away from the house, the patio surface should also be sealed and designed with a slope of 1% to 1.5%.
I can also imagine tiles with a slope away from the house. This would likely result in a lower overall height since they are adhered directly to the slab, unlike your previous setup with a substructure and thick wooden decking.
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