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Amelia
07-08-2001, 11:40 AM
Hi Rob, hope you're having a wonderful Sunday! the shower pan will be installed over the plywood subfloor. Although we will need to install some sort of Vapor barrier I assume, correct? thanks for your speedy reply Rob! Talk with you soon.

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Rob Z
07-08-2001, 03:26 PM
Hi Amelia

This is the way I have installed countless shower bases, and the efforts will result in a solid, creak free base that is level (helps with the tiling) regardless of the subfloor (frequently NOT level).

Follow the rough in direction for location and size of hole in the subfloor to accomadate the drain.

Staple down roofing paper or 6 mil poly with expanded metal lath over that. Leave the hole for the pipe uncovered.

Test fit to make sure the opening is correct for clearance, square condition, etc.

Mix sand and portland cement in the ratio of about 4 to 1 (or use a premix like Sakrete Sand Mix) to a very wet consistency. How wet? If you are using a mason's hoe with two holes in the blade, when you push it into the wet mud, "fingers" of mortar will push through like Play-Do.

On a flat surface, temporarily prop or shim the base so that it reads level. Look underneath to estimate how much space needs to be filled - it may be as little as 1/2" at the drain and as much as 1 1/2" at the edge. It will vary based on the brand that you buy.

Trowel out the wet mud in amounts slightly more than needed to fill the space estimated from before.

Set the base down in the mud. Stand in it, press on it, push it in so that you can get the base level in all directions. If it ends up just a little off the subfloor it's okay. If it is more than 1/2" or so off the subfloor, pull it up and remove a little mud and reset. Strike off any mud that has oozed out of the front. Mud that has oozed out the sides or back is okay to leave alone.

At this point you will know whether your mud was wet enough or is too dry. If the base can't be pushed down, it is too dry !

Stay off the base for a day and let the mortar harden.

Next step-hooking up the drain!

Rob

Rob Z
07-08-2001, 03:33 PM
Amelia

Have you bought the base yet? If so, what brand is it?

Is there access from below? It is easier that way, and slightly changes the explanation.

Rob

Amelia
07-08-2001, 09:31 PM
Hey Rob! O.k..... yes we have purchased the shower stall already, and no, there is not access from below. Yhe shower stall that we purchased is from American Shower & Bath (ASB) and it's a Neo-Angle Shower Enclosure kit 36" X 38". My husband has already replumbed, so that the drain hole is in the right spot and we put the "shower pan part" down to be sure everything fit properly, and it does.(just to see if it fit, not permanent or anything, we haven't done anything permanent except plumbing) SO, basically, we need to know what to do next. We will be tiling the floor and the back walls of the shower to match. the kit already provides the front enclosure portion with lovely glass doors. We purchased this kit at Home Depot. I REALLY, REALLY appreciate your help Rob!!

Rob Z
07-09-2001, 06:19 AM
Amelia

I'll check in today when I get home. Get ready to be a plumber.

Rob

Rob Z
07-09-2001, 07:56 PM
Hi Amelia

I'm not familiar with the brand you have, so I don't know if it has an integral drain (built in) or one that you have to assemble onto the base. If it has the type that you assemble, then follow the directions and use clear silicone on the underside of the drain flange. Apply it gerously, and use mineral spirits to clean up the excess that oozes out after tightening.

You may need a large pair of slip joint "Channel Lock" style of pliers to tighten the big nut on the underside of the drain. Don't forget the rubber and the fiber washer.

Most of the drain fittings I see are made of ABS (black plastic) and can be broken by over tightening.

Hopefully, your trap (below the floor) is braced or other wise supported. When you lower the pan down over the pipe it can push down a bit on the trap.

Set the base in mud as discussed before. Let the mud firm up before the next step. Make sure there is enough pipe coming up into the drain.

Lubricate with liquid soap the rubber gasket that came with the drain and slide it down over the pipe in the area formed between the drain and the pipe. You may have to use a flat bit screwdriver or a small block of wood to coax it down tight. Sometimes it's a battle getting them in, sometimes it's pretty easy.

I use an inflatable rubber balloon and stop up the pipe and fill the base with water. Any leaks around the rubber gasket will reveal themself in the form of tiny air bubbles.

A 2" inflatable balloon by Cherne ( the brand I buy) costs about $20. It inflates to 40 psi with a bicycle pump. Even if you buy one of these for only this project, it may be worth it to catch a leak before water ends up downstairs.

I hope this helps. Let us know how you did...

Rob

Amelia
07-14-2001, 03:43 PM
Rob, Hi again. I'm not sure we are on the same page as far as the shower pan is concerned. The shower pan is prefab fiberglass and my husband already plumbed the drain and is in the process of installing the "braces" for the shower doors and plumb the shower head. The shower came as a whole shower kit from Home Depot and the directions didn't say anything about setting the fiberglass base onto mud?? I am mostly concerned about tiling the back walls and floor, so it's water-tight. See it's a corner shower kit, so it sits in the corner of the bathroom and you can tile the two walls that make up the back of the shower and then the doors close out the front of the enclosure. Do you see more what I mean? How far above the shower head should I tile as well? I hope you get this, thanks so much for your advice and keep it coming!!!

Bud Cline
07-14-2001, 04:24 PM
Just want to stick my head in the door to say that setting the base in mud is a good idea. You may not agree now but give it two years.

John Bridge
07-14-2001, 05:24 PM
Hi Amelia,

Bud is right. Using a little mortar under the pan will keep it from flexing while you stand in it. Even the best of acrylic bases will experience fatigue after a while.

Amelia
07-22-2001, 04:56 PM
Rob, Hi again! and thank you John and Bud for adding your comments as well. O.k.... we are currently ready to put the mud bed down to set the shower base in, but I have a couple of questions first. In you first entry where you told us how to set the shower base in a good, level, mud bed, you said to "Staple down roofing paper or 6 mil poly with expanded metal lath over that."
1. What the heck is "expanded metal lath."???
2. We will be stapling the 6 mil poly all over the bathroom floor and walls, but should we also put the "expanded metal lath," over that as well; everywhere we put down the 6 mil poly?

Amelia
07-22-2001, 06:10 PM
OOps! I forgot to ask you something on my previous thread. What is the best way to cut the cement backerboard to get the most accurate cut?? We have every kind of saw pretty much and if you could recommend a particular blade (diamond coated, etc.)OR do you recommend cutting it by hand? Please try to be pretty detailed, my husband gets irritated if I'm ever vague at all. He's a "black and white" guy and I'm a "grey" girl for the most part.

Rob Z
07-22-2001, 06:28 PM
Hi Amelia

I cut cement board with a grinder with a dry cutting diamond blade. It's very accurate. You can get an el-cheapo Dewalt grinder at HD with a dry cutting wheel for about $100. If not, use a carbide scoring tool made for cement board and a rub brick to clean up the edges. Cost for the two: about $10-15.

Expanded metal lath is a nasty product that is galvanized and requires tin snips to cut. The pattern of the grid looks like little diamonds about 1/4" across. Don't be surprised if the experts at HD don't know what it is or where it is. You need to install the poly and lath anywhere that you are floating mud. Poly can be installed behind cement board on shower walls. Poly is never installed behind / under cement board on a floor.

See if this sku number works at your local HD for lath (722-000). I have to tell them each time I go in to buy it cos they dont know what it is or how to look it up.

Keep us posted!


rob

Don't despair. Christina is gray and I am definately black and white about most things, as well.

Bri
07-22-2001, 06:57 PM
I'm Lost...if Amelia is putting in an acrylic shower base..then why is she putting wire lath? If the wire is for the mortar under the shower basin, then all I have to say to that is "Good Grief"!!...talk about over kill. I'm all for doing the best job possible..but let's not get silly.

(And may I apoligize ahead of time if I don't know what I'm talking about)

Brian

John Bridge
07-22-2001, 07:20 PM
Bri, you have to remember that Rob was schooled by Michael Byrne. Overkill is the name of the game. I'll never accuse him of building anything that'll fall apart, though.

Rob Z
07-22-2001, 08:06 PM
It may be over kill to set a shower receptor in a base of mud (with a piece of lath to reinforce the mud), but it does solve the following problems:

1. out of level perimeter to set tile on, because the subfloor isn't level
2. creaking and flexing shower floor that causes numerous complaints from homeowners, which can't be fixed after the installation is complete
3. flexing floor that eventually causes the rubber gasket to leak

The manufacturers of the brands I have used all say in their instructions to bed the product in a bed of mortar or hard setting plaster (not drywall mud).

I think the extra hour (or less)it takes to mix some mud and set a shower receptor in (or a bath tub) is well worth the effort.

Rob Z
07-22-2001, 08:19 PM
In our new house, the flimsy Jacuzzi soaking tub is set in mud. Nice and solid.

The Florestone shower receptor is not set in mud, is out of level, holds water in the corner because it won't drain, and creaks like a bitch when I get into it.

Oh yeah, the tile is set on greenboard, and it already is starting to look bad in places. At least we agree that was done with anything but overkill.

Rob

Bri
07-22-2001, 08:30 PM
Rob, Robert..Robbie
I didn't say it was over kill to set the thing in a mud base...it's the only way to do it properly...but the wire lath does almost nothing under it...sure it only costs a couple of bucks...but then you have to buy snips to cut it...and then...well you get the picture...it's a step that can be left out without any problems.

Brian

Rob Z
07-22-2001, 08:39 PM
Now Brian, only my grandmother calls me "Robbie"

Here's my thinking on the lath. Mud that is as wet as it needs to be to get it to flow as the base is pushed down in it is somewhat weak unless reinforced. For the cost of scraps of lath (which I always have left over from bathroom floors that are five feet wide), this mud has something to grab into. I've never tried it without, so don't know if the mud will "break up" under the weight of someone getting in and out of the shower.

Rob

Bud Cline
07-22-2001, 08:55 PM
I wonder if dumping hot water on a cold shower receptor set in plaster would develope problems from condensation forming on the underside of the receptor?

Bri
07-22-2001, 09:03 PM
Well I can't see the mortar breaking up ..since it's incased in acrylic...but I thought we were talking about Amelia's shower...and I'll bet she doesn't have scraps of wire lath laying around ..or the snips to cut it...sure it can't hurt to put wire lath under...how about 1/2 inch rebar?...Sorry Rob...I must be tired..I'm getting grouchy.

Brian

Rob Z
07-22-2001, 09:17 PM
Brian

If I use the no. 4 rebar, should I have a welder come in to tack it in a grid?

Rob

Bud Cline
07-22-2001, 09:23 PM
Pigtails will do nicely! Ahhhhh! But we digress.

Bri
07-22-2001, 09:30 PM
No...wire ties will work just fine....(Geez..Amelia must really be confused...sorry)

Bud Cline
07-22-2001, 09:48 PM
Pigtails, wireties, same thing!

John Bridge
07-23-2001, 10:30 AM
Amelia,

Now see what you have done? You've got the boys all confused.

The metal lath is optional. If you have some laying around, nail it under there. If you don't have any, forget it. The mortar is the important part.

Amelia
07-23-2001, 12:47 PM
Rob, thanks for the info! I need to ask you something though. When I tore out the floor of the bathroom all the way down to the subfloor, there was plastic underneath? I just assumed since I was putting plastic under the cement backerboard on the walls, that I should do it under the backerboard for the floor as well? It certainly seems like it would be more water-resistent? OH, and yes of course you were correct about the subfloor not being level. It's was suprisingly UNlevel!

Amelia
07-23-2001, 01:03 PM
Gentleman, Gentleman, easy now. We're all friends here, no need to start swinging your..... tools around. (he he) John, if I didn't staple down the metal lath, would I just pour the mud on top of the poly? AND Rob, would I need to make sure the mud completely fills the shower base? Every nook and cranny?

Rob Z
07-23-2001, 07:14 PM
Hi Amelia

The poly is for use as a vapor barrier behind cement board on walls. It's not used under cement board on floors because the cement board is set in a bed of thinset and fastened with hot dipped galvanized roofing nails or specially designed cement board screws.

It would be great to get the mud under the shower base completely spread out and in every nook and cranny, but that's probably not going to happen. Try to get it as good as you can, and it will make a world of difference.

Did your old bathroom floor have plastic underneath it because it was a mud job? What was there before?

Rob

PS what brand of cement board are you going to use, and do you have the MFR's directions for installation?

Amelia
07-25-2001, 06:28 PM
Hi rob! The shower base comes from a mold probably, so when we lay it down, there will be space between the the fiberglass and the floor because it's not a solid piece, so I was wondering if I am supposed to put a "pile" of mud down to fill the base of the underside of the shower pan? OR do I spread out a layer of however much I need to get the base level?
There was lanoleum on the floor before, not tile, so I'm not sure why the platic was there before?

Amelia
07-25-2001, 06:31 PM
OH Yes! We are using Durock as our backerboard. It was recommended by a "pro". Is that good for you?

Amelia
07-25-2001, 06:40 PM
which side of the bacerboard goes up? the side with the letters or the "smooth side?"

Bri
07-25-2001, 07:15 PM
Rough side out, facing you.

chip
07-25-2001, 07:44 PM
I might just as well get in the argument, I have already upset the apple cart about cement backer board.

It matters not, which side you adhere to, honest.

It is easier to score and break the smooth side. only one layer of mesh on the smooth side as that side does not have the overlap for the wrapped edges.

Art

Bri
07-25-2001, 07:59 PM
Art

It only matters in my case, because the thinset tends to hold the tile up better on the rough side...a little friction goes a long way.

Bri

Rob Z
07-25-2001, 08:05 PM
Hi Amelia

Yes, Durock is a fine product. I've used 1000's of pieces of it.

Trowel the mud out on the floor and push/set the shower base down in it. Have a level handy.

For a new product I am not familiar with, I quickly shim the base level on a garage floor or driveway and look at the volume underneath. This way I can estimate how much mud to spread.

Durock does indeed specify that the rough side is for thinset and the smooth side is for mastic. Art's product (Utilicrete) is basically the same smoothness on both sides. When I do use Durock (rarely Art, I promise) I do put the rough side out.

Keep us posted.

Rob

No idea why plastic under the old vinyl floor .....

Amelia
07-29-2001, 11:40 AM
This may be a really stupid question, but what exactly is the difference between thinset and Mastic? I know other folks would like to know as well from some chats I've received lately, but are a little embarassed to ask, so I'll stick my neck out there. So, what is the difference between thinset and mastic?

Rob Z
07-29-2001, 12:34 PM
Hi Amelia

Good question, and an important one.

Mastic is a glue, either water based or solvent based. Mastics aren't anywhere near as strong, long lasting, water resistant, flexible, or any other good quality as compared to thiset mortar. Mastics don't do well in water, they can't support heavy loads, can't be built up as thick, and generally can't do anything nearly as well as thinset mortar.

The only thing that mastics are good for is their "no sag" properties. This means you can trowel it on a wall, set a tile in it, and not have to shim it against the pull of gravity.

One other thing about mastic...it's convenient cos you don't have to mix it.

Thinset mortars are portland cement based products, usually with sand in them, and are everything that a mastic is not. Thiset mortars are kind of like brick mortar in a very, very thin cross section. Most thinsets have maximum strength when only 3/32" thick. There are thinset mortars that can be built up thicker than this.

I hope this helps.

rob