Thread: Bathroom Puddle flange

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.

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.

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

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

Post/reply #4

Originally Posted by rambunctious

Post/reply #4

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

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.

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

Originally Posted by rambunctious

Post/reply #4

Correction- post/reply #11.

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)

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?

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?

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?

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?

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

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?

To clarify, if I was ever building again (which I won’t be ), 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.

Originally Posted by jack620

To clarify, if I was ever building again (which I won’t be ), 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.

Do you attach pics Jack? I cannot see them

Post #4.