puddle flange needed on new floor waste (Concrete Floor)?

3simon · Oct 07, 2020 9:30 pm

Background:
- Renovation done on second floor bathrooms with concrete floor substrate
- Changing the layout of the bathroom, so new floor wastes will be core drilled in.

My general understanding is in the case of building a new house, where pipe is laid first, and concrete floor is filled after that, then puddle flange is not needed, as there won't be any gap surrounding the floor waste pipe (is this a correct understanding?).

But what about if I were to core drill a new floor waste into the concrete floor? I'd imagine the new hole and the new floor waste pipe won't be completely sealed (i.e. there will be a bit of a gap), therefore I'd imagine a puddle flange is needed in this case even if substrate is concrete, is that right?

Thanks!

chippy · Oct 07, 2020 9:40 pm

Hi Simon.
The puddle flange is the interface or joining method between the waterproofing and the drain.
You always need it.
Technically if you could waterproof all the way into the drain pipe you wouldn't need the puddle flange but in practice that is impossible to achieve without leaving small openings that water will get into. The drain pipe will also move at a different rate to the drain pipe so will crack the waterproofing.
The puddle flange gives a large surface area for the waterproofing to interface with the drain and also allows for the new shower grate to sit in such a way that any water that gets to the waterproofing can still escape down the drain.

3simon · Oct 07, 2020 9:44 pm

chippy

Hi Simon.
The puddle flange is the interface or joining method between the waterproofing and the drain.
You always need it.
Technically if you could waterproof all the way into the drain pipe you wouldn't need the puddle flange but in practice that is impossible to achieve without leaving small openings that water will get into. The drain pipe will also move at a different rate to the drain pipe so will crack the waterproofing.
The puddle flange gives a large surface area for the waterproofing to interface with the drain and also allows for the new shower grate to sit in such a way that any water that gets to the waterproofing can still escape down the drain.

Thanks for the quick reply! That makes sense.

Could you elaborate a bit on what you mean by 'The drain pipe will also move at a different rate to the drain pipe so will crack.'? Thanks!

chippy · Oct 07, 2020 10:10 pm

Hi Simon. Meant to say the drain and the screed.
Typically you would screed up to and around the drain pipe.
The screed always cracks very slightly around the PVC drain so any waterproofing at that point would fail.
The puddle flange removes that junction.

moudzj · Jan 20, 2021 11:38 pm

Absolutely don't need a puddle flange re concrete sections as per AS4654. However, if would be preferred for the reasons chippy listed.

Compliance can be achieved by sealing around the pipe seam with a mastic sealant, and waterproofing the floor 100mm or so into the waste.

Weakest link however is the pipe seam (joint interface with concrete), which the flange would protect. Can get rubber flanges for only afew bucks for this.

If you want to waterproof over the screed, then the flange would also be beneficial for the reasons chippy listed, however below the screed is always better.

Goodluck

3simon · Jan 21, 2021 5:40 am

I see. Thanks all. That’s really helpful!

Doozer1905 · Jan 21, 2021 8:03 pm

moudzj

Absolutely don't need a puddle flange re concrete sections as per AS4654. However, if would be preferred for the reasons chippy listed.

Compliance can be achieved by sealing around the pipe seam with a mastic sealant, and waterproofing the floor 100mm or so into the waste.

Weakest link however is the pipe seam (joint interface with concrete), which the flange would protect. Can get rubber flanges for only afew bucks for this.

If you want to waterproof over the screed, then the flange would also be beneficial for the reasons chippy listed, however below the screed is always better.

Goodluck

Your calling up the wrong Australian Standard you need to look at AS3740, in that standard it stipulates the follow

Membrane to drainage connection requires that all floor wastes installed in an area
requiring a WPM are required to have a drainage flange, and the WPM is required to be terminated at or in the drainage flange to provide a waterproof connection.

Huey79 · May 03, 2021 11:11 pm

chippy

Hi Simon.
The puddle flange is the interface or joining method between the waterproofing and the drain.
You always need it.
Technically if you could waterproof all the way into the drain pipe you wouldn't need the puddle flange but in practice that is impossible to achieve without leaving small openings that water will get into. The drain pipe will also move at a different rate to the drain pipe so will crack the waterproofing.
The puddle flange gives a large surface area for the waterproofing to interface with the drain and also allows for the new shower grate to sit in such a way that any water that gets to the waterproofing can still escape down the drain.

Just jumping on to this thread please as we are currently renovating our ensuite. The builder put a puddle flange in the shower but NOT in the floor waste or toilet drain. My husband is adamant it is required in both due to the movement of the pipe as Chippy mentioned. They have tiled over the screed (waterproof was done on top of screed) already and now the pipe sits 60mm below the top of the screed, then the tiles on top and no flange - they are wanting to put just the metal drain insert and tile piece and polyglot in. This will leave a void below wherethe flange enough have attached the two - should I get them to rip up the tile and insist the flange be installed? Will this ruin the integrity of the waterproofing??
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sk90 · Jul 11, 2024 10:50 pm

Hi did you get an answer to this/what did you end up doing? My tiler has just done the same thing. I brought it up with him and he's adamant the puddle flange wouldnt fit, pipe old is his excuse, said hes waterproofed down the pipe instead but I feel concerned that I'm paying a licensed person to do it right and they're not??

Bimbob · Jul 12, 2024 6:44 am

You must have a puddle flange at EVERY floor waste.

It’s in the code