I’m installing tile on a shower stall floor. The plumber’s put in a lead pan and the next step is to trowel in ever-so-carefully screeded underlayment. What kind of material should I use for this. I did it once years ago but don’t recall.
the tile is ceramic and the setting material is modified thinset.
Thanks in advance for any advice!
Replies
I do not mean to be problematic but the first step would be to remove the lead pan and replace it with a rubber membrane liner or one of the newer systems
We make a lot of money every year replacing old showers because the lead pan failed after 10-15 years.
that's good to know but the pan was the owners decision.
I think you need to try to explain to the customer why a lead pan is such a horrible idea.
I think the membrane could be easily layed over the lead. Then, a dry pack mud base trowled in.
blue
I don't think that could be done because of the drain assembly. The drain clamps down around the pvc/rubber membrane so the the lead pan would interfere.
A lead pan is a horrible out of date idea that is destine for failure. The customer said they wanted it isn't an excuse in my book. It's "our" job to educate them to the best of our ability, to give them the best product possible.
The lead will over time react with the acids in the concrete, oxidize/"rust" and fail.
Give me or the author a break! Educate teh customer? How do you know that that was not already attempted? So quick to bash. I think everyone here knows that you can only suggest?(argue) with a customer (WHO ALWAYS KNOWS BEST) so far.
I'm not bashing anyone.
Yes educate the customer, it's really not that hard and for something such as this, it would be fairly easy to come up with several sources of information that would spell out exactly why putting a lead pan liner is a horrible idea.
There is no reason it has to be an "argument" either.
If the customer is to stubborn or bull-headed to listen at that point I do not want to work for them and I would politely decline the job. It's foreshadowing for them being problematic down the line.
They can find someone else to do a half asz job.
The customer certainly does not always know best.
Well, I appreciate the discussion and I'm taking the good advice about never using lead pans in the future. Thanks for the substantive explanation of their inferiority. In this particular case I didn't have an opportunity to educate, persuade or even pressure the client as they had the plumber put in the pan before they contacted me about setting tile. I live in NYC where PVC is illegal and Kerdi drains aren't made to fit no hub. So I'll be using a trowel on membrane over the setting bed and I'll try the Orange Bag Sakrete suggestion. thanks all esp McDesign and davidmeiland
I'll be putting mine in tomorrow at 6 PM EST - maybe we can, you know, do it together!
Forrest - all about Karma now
From all the stuff I've read, deck mud is usually softer stuff than sakrete. strength is not that desirable for this application- most masons say they like to be able to shave off the humps the next day, if they didn't get it perfect. I would think that mortar mix with extra sand, mixed up dry, would be the right material.
Don't get me wrong, sakrete should work fine- it will just be less forgiving than what's usually used.
Edit: I don't know what "orange bag" sakrete is. I'm assuming it's a grade of their pre mixed concrete.
zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
Edited 11/8/2006 1:50 am by zak
Deck mud is typically 4:1 sand to portland. No lime, no gravel. You can buy it in sacks at tile stores. It's a completely different material than concrete--you can't pour it, you pack it into place. It's about right when you can make snowballs out of it.
Right, I know. Although I've seen 5:1 more often, sand to portland.
But what is the orange bag sakrete?
I see where I could have been misread- by "softer mix" I meant it has less cured strength than concrete.zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
The "orange bag" is the crack resistant Sakrete with the tiny polypropylene fibers throughout. I like it because when I pull out my screed strips and pack those slots full, I feel like the wet-to-wet join is better.
I hadn't thought about being able to shave off humps from a softer mix, but I would worry about the thinset bond strength of that to the tile.
Forrest
Dry pack is the industry standard for tilesetters who know how to do it. I have never tried to make a pan using concrete but I've seen it done. Question, though... are you doing two layers of mortar with a membrane in between, or is this one layer into a metal pan? If it's two, it's hard to see how you do the ~1" thick layer that is typical over the membrane, and is brought it to the correct elevation re the drain fitting.
I make a sloping (1/4" per foot) plywood pan first on lowered and doubled joists; usually 4 pie wedges tapering down to a center drain, then the PVC membrane in that, lapped up 10" on the walls and over the curb, and clamped with the sub-drain ring.
Then rockboard the walls down into the pan membrane, holding them up about 1/2". There has been some discussion here about holding the rockboard completely above the concrete, but I like the concrete engaging it since there aren't any fasteners on the bottom 10" or so.
Then rip four screed strips from corner to drain at the right thickness (they're not tapered, since the plywood floop under the PVC membrane is sloped); pack in concrete flush with the strips, then remove them and pack in those slots.
Forrest
That's an interesting technique. I assume you go to the trouble of recessing the floor so that you don't have such a high curb? It is a very simple matter of 20 minutes or so with drypack to get that preslope over the subfloor. There are also kits of ready-made preslope but I haven't used them. How thick is the layer of concrete over the membrane?The issue with embedding the bottom of the CBU in the pan is that moisture in the pan can wick up into the CBU and discolor the grout at the bottom of the walls. I believe Michael Byrne is now recommending holding the CBU above the pan and caulking the joint with silicone. Not sure what his fastener detail is...
Concrete is usually about 2 - 2-1/2"; as much as I can get out of the threaded portion of the subdrain assembly.
My first tile book, and bible is by Byrne.
Forrest
Sorry to hear about the lead pan. Maybe you could use Kerdi over the deck mud and save your customers some headaches and $$$ down the road.
Deck mud:
http://www.johnbridge.com/deckmud.htm
Shower construction:
http://johnbridge.com/vbulletin/showthread.php?t=5434
Billy
I agree that a sheet metal pan is hardly state of the art anymore, and should be removed if possible. Absent that, I would waterproof over the setting bed. Kerdi or one of the trowel-applied membranes would be things to look at.
The issue is not just the lead itself, it's the fact it's not pre-sloped. A mortar and tile installation into the lead pan WILL lead a certain amount of water into the pan, and since it's not sloped to the drain the water will just sit there. You might end up with a permanent nasty smell after a while. All of the current installation techniques call for a slope so that water that gets thru the grout will trickle into the drain.
Okay, ignoring the lead pan for the time being, I'm doing the same thing today. I always use the "orange bag" sakrete, the crack-resistant stuff with the fibers in it.
I've got to go put up the rockboard now; will do the mud tonight or tomorrow - the client promises to do the mixing and hauling!
Forrest
I think the problem with lead pans is that over time, the alkalinity of the cement eats through it, causing it to leak. Some water proofing products do not need the clamping assembly, but I don't think that is the best solution. A water proof membrane, fully integrated with the drain, is the best way to make the pan water tight.
You can coat the lead with a waterproof material, or simply place some plastic on top (a slip sheet) before you float.
-Bill