Can someone help with code language

[randynavarro]

I'm trying to visualize the code requirements for a shower receptor- specifically a mortar and tile shower pan.

P2709.1 "Shower receptors shall have a finished curb threshold not less than 1" below the sides and back of the receptor"

I can't picture what that looks like.

Next:

"The curb shall be not less than 2" and not more than 9" deep when measured from the top of the curb to the top of the drain."

Does this mean the curb has to be at least 2" taller than the top of the drain?

Then in P2709.2 it says:

"The lining material shall extend not less than 3" beyond or around the rough jambs and not less than 3" above finished thresholds.

To me, this contradicts the previous cite: this says the threshold should be at least 3" higher?

I've got a shower curb that is only about 1/2" higher than the tiled shower floor and about 3 1/2" above the bathroom floor. I'm trying to figure if it's right or wrong.

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[Brandon Whitmore]

A raised shower-- weird.

I'm trying to picture how they can properly install a shower pan with no curb in place. I've seen handicap accessible showers, so I know it's possible.

"The curb shall be not less than 2" and not more than 9" deep when measured from the top of the curb to the top of the drain."

Does this mean the curb has to be at least 2" taller than the top of the drain?

Yes, that's how I read it.

I can't visualize the first code cite either.

[Rocon]

First off P2709.2 the 3 in. is referring to the lining material. This is your waterproofing layer that can be either a vinyl liner, hot mop or a glass fiber reinforced fluid applied membrane. It just has to turn up the wall 3 in. above the threashold.

P2709.1 I do not have an understanding of what they are saying.

In 2005 I had to put a number of wet rooms into some condos in Venice, CA. Extremely modern live work lofts. At the end of the day there was only 1/2 in. raised threshold at the door. How we accomplished this is we removed the 2 in. lightweight concrete topping and creating the slope needed for water to flow to the drain with mortar. The area around the bi-level drain body was locally depressed to give good flow to the weeps and then filled with filter fabric and thinset for the stone tiles.

How we got this passed was to do a volume calculation which is (or used to be) an exception. I cannot remember a code citation for this but it is how FHA and ADA get by.

[randynavarro]

First off P2709.2 the 3 in. is referring to the lining material. This is your waterproofing layer that can be either a vinyl liner, hot mop or a glass fiber reinforced fluid applied membrane.

Understood. But is says it needs to run 3" above finished thresholds. How is that possible? If the threshold stops, the liner needs to run 3" higher. . . ?

[Richard Moore]

It means that the liner (or other membrane) needs to be at least 3" higher than the height of the threshold at the jambs either side of the threshold.

I also had no idea what that first part of P2709.1 was saying until I googled "shower receptor" and realized they were talking about prefab shower pans.

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In your case, could the metal frame count as part of the "curb" if it's totally sealed? It seems unlikely.

[Jim Katen]

I'm trying to visualize the code requirements for a shower receptor- specifically a mortar and tile shower pan.

P2709.1 "Shower receptors shall have a finished curb threshold not less than 1" below the sides and back of the receptor"

I can't picture what that looks like.

It means that the front curb has to be at least an inch lower than the side & rear curbs. So that if you fill it with water, the water will run out the front before it runs over the sides. This section is referring, I believe, to pre-manufacturered receptors.

Next:

"The curb shall be not less than 2" and not more than 9" deep when measured from the top of the curb to the top of the drain."

Does this mean the curb has to be at least 2" taller than the top of the drain?

Yes. They want at least 2" for water to back up before it overflows the curb. They don't want more than 9" because that would be too tall to be an acceptable step.

Then in P2709.2 it says:

"The lining material shall extend not less than 3" beyond or around the rough jambs and not less than 3" above finished thresholds.

To me, this contradicts the previous cite: this says the threshold should be at least 3" higher?

This cite is talking about the liner on a site built receptor. The other site is saying that the front threshold (not the liner) has to be lower than the sides & rear. On a site built receptor, the front is alway lower anyway. The two cites are talking about different things.

I've got a shower curb that is only about 1/2" higher than the tiled shower floor and about 3 1/2" above the bathroom floor. I'm trying to figure if it's right or wrong.

Looks wrong. I'd say that even a site built receptor should have at least a 2" curb. The exception would be for an ADA accessible shower. They don't require any curb, though I prefer to see collapsible dams used in those cases.

[randynavarro]

Thank you kind sirs.

I think I've got it now.