Bathroom Puddle flange

Morning all,

Looking for a definitive answer on installing a puddle flange.

I have seen a heap of videos on YouTube, and also read a heap of posts on Google in regards to puddle flanges and I get more and more confused each time. I had it in my head that a puddle flange is to be installed on top of a sloping screed in a bathroom and also waterproofed so that any water that may seep through the tiles etc can escape through the puddle flange. I have just recently started following a guy on YouTube that shares videos of tiling jobs and waterproofing, and he has told me that the puddle flange needs to be installed under the screed to the house substrate/slab. Does anyone know for sure if this info is correct? Watching gripset tips and tricks videos and he states it's either one or the other, and if the house slab has a puddle flange then the screed by code has to have one too.

Any info and opinions much appreciated.

Thanks
Geoff,

Depends on where your waterproof membrane is, if it is under the screed then yes the puddle flange needs to be under the screed.

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Originally Posted by droog

Depends on where your waterproof membrane is, if it is under the screed then yes the puddle flange needs to be under the screed.

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Thanks for the reply.

I'd imagine the waterproof 9 times out of 10 it goes on top of the screed?

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Originally Posted by garfield

I'd imagine the waterproof 9 times out of 10 it goes on top of the screed?

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Don't know, but that's how I did mine. Hasn't leaked in 20 years. :)

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Originally Posted by garfield

Thanks for the reply.

I'd imagine the waterproof 9 times out of 10 it goes on top of the screed?

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With the building industry 9 out of 10 will be screed over. Reason being screed needs to dry in order to apply membrane, quicker turn around if you membrane then screed.

Plenty of discussion, pros and cons as well as membrane above and below on the old forum.

The usual process is the membrane goes under the screed so the the area is tanked , the puddle flange if required will be under the membrane
As Droog said part of the reason is so the tiler does not have to attend site twice but I think it is more common in Victoria

On first floor bathrooms we used to set up all our angles and membrane as per the code before the tile bed but had an arrangement with out tiler to membrane the screed also before gluing the floor tiles down for good measure and to stop the bed from getting waterlogged

Before the screed

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Originally Posted by Beardy

...had an arrangement with out tiler to membrane the screed also before gluing the floor tiles down for good measure and to stop the bed from getting waterlogged

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That's why I applied the membrane over the screed. You need to make sure the tiler uses the appropriate tile adhesive though. Some aren't suitable for use on a membrane. That was the case 20 years ago at any rate.

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Originally Posted by jack620

That's why I applied the membrane over the screed. You need to make sure the tiler uses the appropriate tile adhesive though. Some aren't suitable for use on a membrane. That was the case 20 years ago at any rate.

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There are a lot more products and options to choose from now, some of the glue manufacturers also do membranes so you don’t have compatibility issues

When I redid my bathroom, I waterproofed under, then put the screed in, waited a few weeks for the screed to cure properly, then waterproofed over the top as well.
Not everyone will have the luxury of being able to wait that long, but we just used the ensuite for the duration of the main bathroom reno. No kids at home .

When we reno’d the ensuite a few years previous, got a tiler in to do the job and I TA’d for him. He waterproofed under the screed, then tiled 2 days after the screed was laid, I am not keen on that method, as I reckon the screed is constantly wet now. It hasn’t caused any problems yet, as far as I know.

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Originally Posted by garfield

Looking for a definitive answer on installing a puddle flange.

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Here's the relevant section of a certain document that you should find useful. :)

Thanks for all of the replies guys, really seems like there is mixed views on how it should be done.

I thought the waterproof was done on top of the screed which caught any water seepage that would possibly get through the grout, the water could then run down as a secondary water catch. If the waterproof was on the house slab and waterproofed into the puddle flange beneath the screed and tile bed how would the water get away, as the house slab isn't slopped to allow water to seep into the puddle flange?

My current bathroom I have just started demolition and it was built in 1998, the shower section is the old style brick hob down the bottom, ask I started trying to lift the floor tiles it came off in sections because water must have been getting through for some time, underneath it was fibreglass, well the amount of water that was pooled up and had nowhere to go because the slab that was fibreglassed was not slopes to the drain, obviously as the drain pipe with the grate is higher than the fibreglass.

Screed is obviously put down and designed to run a fall for water towards the drain. If there's water getting through the tile bed which would then seep through the screed, where and how does the water get away?

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Originally Posted by garfield

Thanks for all of the replies guys, really seems like there is mixed views on how it should be done.

I thought the waterproof was done on top of the screed which caught any water seepage that would possibly get through the grout, the water could then run down as a secondary water catch. If the waterproof was on the house slab and waterproofed into the puddle flange beneath the screed and tile bed how would the water get away, as the house slab isn't slopped to allow water to seep into the puddle flange?

My current bathroom I have just started demolition and it was built in 1998, the shower section is the old style brick hob down the bottom, ask I started trying to lift the floor tiles it came off in sections because water must have been getting through for some time, underneath it was fibreglass, well the amount of water that was pooled up and had nowhere to go because the slab that was fibreglassed was not slopes to the drain, obviously as the drain pipe with the grate is higher than the fibreglass.

Screed is obviously put down and designed to run a fall for water towards the drain. If there's water getting through the tile bed which would then seep through the screed, where and how does the water get away?

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Either drill 4x6mm holes in pipe just above or at the puddle flange,
or slot the pipe before the grate slips into place.

Before water proofing membranes and liquid sealers were introduced, copper trays were used with a flanged brass grate silver soldered to the tray.
This meant, as you have questioned, water would saturate the bed to a height of 6-8 mm but was considered at the time to be the best option.
Tilers would(and maybe still do) bed the tiles in a wet base/screed.
Last shower I did was 2003 and I did the base tiles this way.

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Originally Posted by garfield

If there's water getting through the tile bed which would then seep through the screed, where and how does the water get away?

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It doesn't. The main thing is that it can't get through the barrier to damage the underlying building materials. Barrier on top of the screed is the way to go, and if you're doing it yourself you don't have to worry about the cost of having to get the tiler back twice to complete the job.

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Originally Posted by rambunctious

Either drill 4x6mm holes in pipe just above or at the puddle flange,
or slot the pipe before the grate slips into place.

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Puddle flange adaptors are deigned so the water can pass between the puddle flange and the adaptor:

Puddle Flange To Brass Waste Adaptor 100mm - NATFW677

Just make sure you don't fill the gap with tile glue.

So would most agree then that the puddle flange is fully incorporated and waterproofed into the screed?

As Jack620 says my understanding with the puddle flange, is it cannot accept the grate to completely seal the grate to the pipe, there are like notches or teeth like looking things that are designed to allow water to seep through into the drain if there is any under the screed that way it has somewhere to drain rather than puddle up and retain moisture?

I'm certainly no expert so that is why I am seeking some opinions, but from most of the videos I've watched the screed seems to be waterproofed. I was thrown when it was suggested to me that the puddle flange goes Under the screed as I don't know how that water would escape under the screed when there is no sloping or runoff for the water under a screed.

I would forget about watching videos. The screenshot I posted above is directly from AS3740:2021 Waterproofing of Domestic Wet Areas. It is literally the bible on how to waterproof a shower in Australia.

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Originally Posted by jack620

I would forget about watching videos. The screenshot I posted above is directly from AS3740:2021 Waterproofing of Domestic Wet Areas. It is literally the bible on how to waterproof a shower in Australia.

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Which screenshot Jack I cannot see a screenshot. I did see an attachment in one of your replies but I cannot seem to open it.
Thanks

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Originally Posted by garfield

Which screenshot Jack I cannot see a screenshot. I did see an attachment in one of your replies but I cannot seem to open it.
Thanks

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Post/reply #4

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Originally Posted by rambunctious

Post/reply #4

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I see a attachment but I cannot open it... Maybe because I'm on my mobile

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Originally Posted by garfield

So would most agree then that the puddle flange is fully incorporated and waterproofed into the screed?

As Jack620 says my understanding with the puddle flange, is it cannot accept the grate to completely seal the grate to the pipe, there are like notches or teeth like looking things that are designed to allow water to seep through into the drain if there is any under the screed that way it has somewhere to drain rather than puddle up and retain moisture?

I'm certainly no expert so that is why I am seeking some opinions, but from most of the videos I've watched the screed seems to be waterproofed. I was thrown when it was suggested to me that the puddle flange goes Under the screed as I don't know how that water would escape under the screed when there is no sloping or runoff for the water under a screed.

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Firstly a puddle flange is only used for ( lightweight) non concrete floor construction and it’s primary function is to hold the drain pipe secure so that you maintain a good seal / bond for the waterproofing membrane to extend into the drainage pipe. Whether you decide to screed before or after the membrane does not change that the membrane must extend into the drain pipe.
In NSW I would expect that around 90% of wet areas are membraned before the screed goes down and yes they hold water, it doesn’t matter if there is fall or not as a tilers bed is a very weak sand and cement mix and holds water like a sponge regardless. (Think of a wet sponge between two non porous surfaces, it just stays wet)
The floorwaste grate that you fit into the tiles does not seal into the drain pipe to prevent excess buildup of water in the bed. Typically it just sits in the bed over the waste pipe

The best job is to waterproof before the bed which is the one that will require a mandatory inspection and then add a second one over the bed for good measure ( but is not a legal requirement)

I am referencing what happens in NSW, other states may do it differently

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Originally Posted by rambunctious

Post/reply #4

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Correction- post/reply #11.

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Originally Posted by Beardy

The best job is to waterproof before the bed which is the one that will require a mandatory inspection and then add a second one over the bed for good measure ( but is not a legal requirement)

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I've been out of the game for a long time, but why would the inspector care whether the membrane is above or below the screed if the Standard allows either?

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Originally Posted by jack620

I've been out of the game for a long time, but why would the inspector care whether the membrane is above or below the screed if the Standard allows either?

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Yeah I wasn’t quite clear there, I said earlier it can be either above or below but what I was saying there was the best job is to do both. They would want to inspect the first one as that is the one that has the mandatory critical items like width of linear flashing , sealing of shower and entry door angle or hob and the membrane turning down into the floorwaste. The second membrane on top of the bed is more a sealing of the bed and an additional belt and braces measure but does not require to be inspected as you have already satisfied the code with the first one
If you were just doing a membrane over the screed then that is one you would be getting inspected

Got the attachment open, thanks for that.

So with the puddle flange being installed under the screed directly into the shower drain in the concrete slab, does that mean only a small area around the flange needs to be waterproofed or does the whole shower cubicle need to be waterproofed even though a screed will be in top and will be completely waterproofed?

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Originally Posted by garfield

Got the attachment open, thanks for that.

So with the puddle flange being installed under the screed directly into the shower drain in the concrete slab, does that mean only a small area around the flange needs to be waterproofed or does the whole shower cubicle need to be waterproofed even though a screed will be in top and will be completely waterproofed?

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If you are electing to do your waterproof membrane on top of your screed there is no requirement to waterproof the flange itself as you will be extending your membrane down the inside face of the waste pipe
The flange will still need to be secured or glued down to hold your waste pipe securely so it doesmt move and damage the membrane

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Originally Posted by garfield

So with the puddle flange being installed under the screed directly into the shower drain in the concrete slab, does that mean only a small area around the flange needs to be waterproofed or does the whole shower cubicle need to be waterproofed even though a screed will be in top and will be completely waterproofed?

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To clarify, if I was ever building again (which I won’t be :no:), I would not do it the way I did in the photographs of my shower. I would do it exactly as is shown in the picture from the AS. I.e. I would embed the puddle flange into the surface of the bed/screed, then apply the waterproofing membrane.

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Originally Posted by jack620

To clarify, if I was ever building again (which I won’t be :no:), I would not do it the way I did in the photographs of my shower. I would do it exactly as is shown in the picture from the AS. I.e. I would embed the puddle flange into the surface of the bed/screed, then apply the waterproofing membrane.

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Do you attach pics Jack? I cannot see them

Post #4.