You're right. the pan DOES need to be sloped. Some areas require the plumber to install it by code. That still doesn't excuse the pan from being sloped. This is covered in SEVERAL places, including the IRC (International Residential Code), The Universal Plumbers Code, as well as ANSI Specs governing the construction of a tile shower pan. I'll post the IRC and UPC Codes:

IRC Preslope code:
2000 IRC:
P2709. 3 Installation. Lining materials shall be pitched one-fourth unit vertical in 12 units horizontal (2-percent slope) to weep holes in the subdrain by means of a smooth, solidly formed subbase, shall be properly recessed and fastened to ap-proved backing so as not to occupy the space required for the wall covering, and shall not be nailed or perforated at any point less than 1 inch (25. 4 mm) above the finished threshold.

Uniform Plumbing Code related to shower pan construction.

"412.8 When the construction of on-site built-up shower receptors is
permitted by the Administrative Authority, one of the following means shall
be employed:
(1) Shower receptors built directly on the ground:
Shower receptors built directly on the ground shall be watertight and shall
be constructed from approved type dense, non-absorbent and non-corrosive
materials. Each such receptor shall be adequately reinforced, shall be
provided with an approved flanged floor drain designed to make a watertight
joint in the floor, and shall have smooth, impervious, and durable surfaces.
(2) Shower receptors built above ground:
When shower receptors are built above ground the sub-floor and rough side of
walls to a height of not less than three (3) inches (76 mm) above the top of
the finished dam or threshold shall be first lined with sheet plastic*,
lead* or copper* or shall be lined with other durable and watertight
materials.
All lining materials shall be pitched one-quarter (1/4) inch per foot
(20.9 mm/m) to weep holes in the subdrain of a smooth and solidly formed
sub-base. All such lining materials shall extend upward on the rough jambs
of the shower opening to a point no less
than three (3) inches (76 mm) above the top of the finished dam or threshold
and shall extend outward over the top of the rough threshold and be turned
over and fastened on the outside face of both the rough threshold and the
jambs.
Non-metallic shower sub-pans or linings may be built-up on the job site
of not less than three (3) layers of standard grade fifteen (15) pound (6.8
kg) asphalt impregnated roofing felt. The bottom layer shall be fitted to
the formed sub-base and each succeeding layer thoroughly hot mopped to that
below. All corners shall be carefully fitted and shall be made strong and
watertight by folding or lapping, and each corner shall be reinforced with
suitable webbing hot-mopped in place. All folds, laps, and reinforcing
webbing shall extend at least four (4) inches (102 mm) in all directions
from the corner and all webbing shall be of approved type and mesh,
producing a tensile strength of not less than fifty (50) psi (344.5 kPa) in
either direction. Non-metallic shower sub-pans or linings may also consist
of multi-layers of other approved equivalent materials suitably reinforced
and carefully fitted in place on the job site as elsewhere required in this
section.
Linings shall be properly recessed and fastened to approved backing so
as not to occupy the space required for the wall covering and shall not be
nailed or perforated at any point which may be less than one (1) inch (25.4
mm) above the finished dam or threshold. An approved type sub-drain shall be
installed with every shower sub-pan or lining. Each such sub-drain shall be
of the type that sets flush with the sub-base and shall be equipped with a
clamping ring or other device to make a tight connection between the lining
and the drain. The sub-drain shall have weep holes into the waste line. The
weep holes located in the subdrain clamping ring shall be protected from
clogging.

*Lead and copper sub-pans or linings shall be insulated from all conducting
substances other than their connecting drain by fifteen (15) pound (6.8 kg)
asphalt felt or its equivalent and no lead pan or liner shall be constructed
of material weighing less than four (4) pounds per square foot (19.5 kg/m2).
Copper pans or liners shall be at least No. 24 B & S Gauge (0.02 inches)
(0.5 mm). Joints in lead pans or liners shall be burned. Joints in copper
pans or liners shall be soldered or brazed. Plastic pans shall not be coated
with asphalt based materials."

Thanks Mongo! What is the membrane? Is that the pan that you put the mud into? Can I ask what state you are in. I'm in North Carolina. I wonder if it is code here that it has it be sloped. I hope so.

Do you mean that the subfloor has to be sloped before the pan is put in? Because if the pan is rubber how can that be sloped? That's why you call it a preslope I guess. Does that mean that they have to redo the subfloor? Believe it or not I don't need an inspection because I'm not moving walls. So I really need to know myself what has to be done. I just hope I can find someone who does this the correct way.

Cathy

Well the law of gravity even applies everywhere, even North Carolina. So regardless of whether or not it is code, water which reaches the membrane will not drain properly unless it is sloped.

Cathy,

It looks like I messed up the link to Harry's article. Try this instead. Step-by-step photos.

The subfloor is flat.

On top of the subfloor goes a slip sheet, usually tar paper, that is stapled to the subfloor. On top of the tar paper goes metal lathe, expanded diamond mesh, that is nailed to the subfloor.

On top of the diamond mesh you make your preslope from deck mud. It slopes from the walls to the drain at a pitch of between 1/4" per foot and 1/2" per foot. Those are the minimum and maximum allowed by code. That is your "preslope". Deck mud has two dry ingredients, sand and portland cement. You then add just enough water so the mix is just wet, sort of like sand castle sand. You dump it on the mesh and then "pack" it into place with a wood trowel or some other tool. It's also referred to as "dry pack".

On top of your preslope goes your "rubber membrane". It is usually 40-mils thick and actually is not rubber, it is usually CPVC or CPE. It is secured at the drain by being clamped to the drain, at the walls it runs up the lower portion of the wall about 10" and is fastened to the wall framing at the 10" height.

You can't tile directly on the membrane, so you add another layer of deck mud on top of the membrane.

Now you tile on the second layer of deck mud.

Clear as deck mud?

Mongo

Cathy,

I ran into similiar situation like yours. I was just about to gave you the link Mongo provided. He beats me. :)... Anyway, the basic idea here is to water proof the shower stall, unfortunately a lot of the tilers do not know what they are doing. I ended up using Shluter system instead. There are quite a few advantages if you read the link below. Mongo have an excellent photo step by steps if you'd like go with this route, check the thread "Kerdi Shower" in this forum.

Allex

Here is a link that might be useful: My reasons to switch to Kerdi

Thanks again Mondo! That's a great link to the step by step photos! I even got my husband to look at them. It was pretty interesting to see the way it's supposed to be done. Now I know the questions to ask. I have a feeling a lot of tilers skip that first preslope step, so I hope I can find someone who knows how to do it right. The Kerdi system is interesting Alex but I don't know that I can deal with trying to find someone to do it that way so I think I'm just going to have to find a really good tiler.

Cathy

The Kerdi system is interesting Alex but I don't know that I can deal with trying to find someone to do it that way

Cathy-- I know top notch installers all over the country. Where abouts are you?

If you don't feel comfortable posting your location, email it to me.

Sorry Bill. I wasn't ignoring you just haven't been on until now. I am in the Cary/Raleigh triangle area of North Carolina and I would love to know of a good tiler and plumber if you have that!

I spoke with my tiler (haven't hired him yet) and he puts a rubber pan (from a plumbing supply store) down over the floorboards and then puts the mud down on a slope towards the drain. That's it. He said moisture can't get through because of the pan unless there is a lead in the pan and he checks that first. There is only 1 time he puts down mud. He said he uses Bonsal products because they are the best. He knew nothing about the other steps. And he wasn't cheap. He came hightly recommended.

Cathy

The Bonsal pans are preformed pans, and they are sloped for drainage.

Though I've never used one, I think they are probably tile ready, which means that you tile directly to the pan itself.

If tile ready there's no need to pack the pan with a thickness of mud.

But again, since I'm not familiar, I'll defer to your installer. I'd at least try to peruse the installation instructions beforehand.

Mongo

From what I understand, the Bonsol rubber pan is not presloped. It goes directly on top of the floor and then he puts mud on top of it and slopes it. Then the tile does on top of that with a slope.

You understand correctly. What Mongo's talking about is a hard solid pan that's ready made for tiling over, no mud required.

Your installer's correct in that moisture can't get thru. however, without help from gravity (which is where the preslope comes in) it won't reach the weep holes, either, which means it'll just sit in the mud bed of your shower, "fermenting", with all the skin oils, dead skin, sweat, etc. that you wash off when you take a shower. now you'll have what will resemble a pharmaceutical experiment gone terribly wrong inside your mud bed, all because he doesn't want to take the time and install your shower pan the way it should be.

Then I'm thinking of a different product.

Just to confirm I did a quick google and found this:

"Bonsal Co. offers the ProForm Shower Pan, a tile-ready waterproof pan. The shower pan will not retain moisture. Installation requires a glue connection to a standard PVC drainpipe. The pans are pre-sloped to drain and tile can be applied directly to the sloped pan."

So it sounds like we have two different products in mind.

If he's not using Bonsal's ProForm pan, which is a preformed pan, then the only other thing I can think of off the top of my noggin is he's using B-6000, which is a liquid topical roll- or trowel-on membrane.

If he's applying the B-6000 to the flat subfloor, then packing in a sloped base of mortar on top of the membrane, then tiling on that, that does not meet code. And if code doesn't not apply in your area, then I'll just say it doesn't meet the basic standards for constructing a shower.

In this case the B-6000 would be considered the "membrane" or the "liner". Go back to Bill's first post and read what he highlighted in bold about the liner needing to be sloped.

If he's not using the Bonsal ProForm pan or the Bonsal B-6000, then I have no idea what he's using. I'm not sure if Bonsal markets a traditional 40-mil pan membrane. But if they do, that should be sloped as well.

Mongo

I'd be willing to bet the liner is either CPE or PVC. Either way, it needs to be presloped. End of story.

End of the "same ole story", eh?

I think you're both right. He does use Bonsal products but it couldn't be the liner because when I looked in Lowes, the liner was just a roll out liner and I know he doesn't do it the way you guys explain. Do you know of anyone in my area that does the right job?

Cathy

I'm waiting to hear back right now. I know he's in NC-- just not sure WHERE in NC.