An Outdoor Fountain Basin

[Montalvo]

I'm a homeowner, tackling a project that's probably over my head. My biggest asset is probably my willingness to admit that I don't know what the heck I'm doing!

I've built a concrete basin for a fountain on my front porch and would like to tile it and ensure that it doesn't leak. It'll hold water 24/7 (God-willing) but at least freezing weather won't be a problem in my location (No. California). I've built the basin with 4" of concrete and #3 re-bar on 8" centers. The basin is only 3' square by 2' deep but a) the water line will be above grade, b) there are four pipes that enter the bottom and side of the basin and c) the side walls have a seam between the concrete basin and some pre-cast concrete decorative walls. All three of these factors are making me extra cautious.

Even though I live in hot-mop land, I thought using an Oatey shower pan liner might be the best route to water-proofing this baby. I bought a liner and have read the info on this board about installation but I still have several questions:

1. What's the thinest layer of fat mud I can use as a base for the tile on the side walls? For aesthetic reasons, I'd like it to be 1/2" or thinner, including the liner and mesh. But the bag of fat mud (Dyna-Crete 730) I bought at the tile store says it should be a mimimum of 3/4" plus a scratch coat and then also mentions a one-coat method whereby the tile is actually attached to the fat mud (i.e., apparently no thinset is used).
2. In sealing the liner around the four PVC pipes, I planned to cut very snug holes, apply some of the PVC cement used to spice the liner to the liner and pipes and finally lay down a bead of silicon on the seam. Does that sound like a reasonable way to ensure a water-tight fit?
3. How do I attach the liner to the cement basin and pre-cast walls and how do I attach the mesh to the liner? I bought some PL polyurethane constuction adhesive that sounds like it'll work.
4. I have four inside corners to form with my liner, plus some additional overlaps to accommodate one of the walls that is rounded. Should I use the liner cement to glue these corners flat?

Sorry for this lengthy message. Thanks for any advice you experts can offer.

Bob

[cx]

Welcome, Bob.

1,3,4. Sounds like a perfect application for Kerdi. You can apply it directly to your concrete walls with thinset, then thinset your tiles directly to the Kerdi. Completely waterproof (save for #2), adds less than 1/8th inch thickness if you're careful, eliminates the need for the bulky liner, lath and mud.

2. Not sure you really can, but you can prolly come pretty close. First you gotta tell more about the pipes. Size? Already set inna concrete? Just raw ends stickin' into the "basin"? How far? Where are the pipes located? You got a picher? We like pichers.

My opinion; worth price charged.

[Mike2]

Hi Bob and welcome to the Forum. Glad to have you with us.

Personally I would choose a completely different method to "waterproof" this fountain base. However, seeing how you have already purchased the liner and materials, I don't want to start chasing rabbits from the git-go. So lets see what others have in the way of ideas to make you liner system work before taking off on another tangent.


Edit P.S. I see the gentleman from Boerne done snuck in ahead of me...and yes a Kerdi system and/or a roll on membrane to seal around the pipes was an alternative I was thinking about. He's done axed some good questions too.

[Davy]

I like CX's idea with Kerdi being used, not sure about sealing off around the pipes.

Not sure if Red-gard would be good for something like this or not, others might know.

I have seen a paint on waterproof sealer that is used for basement walls, might be something to look in to.

The lath, scratch coat method would build out more than you want for sure, I would use one of the other choices.

[cx]

Yeah, Davy, I use one of those sealers (Thoroseal+Acryl-60) now and again, and they're good products. My concern there would be with that cold joint he's got, which I'm not entirely sure I understand. Also the sealing around the pipes, but I don't have a good plan there for the Kerdi, either.

There is another product by Quikrete (QuickWall I think is the name) made for building dry-stack-and-fill concrete block walls. Troweled on the surface of the block, it makes it strong as hell and waterproof, by my own observation. Seems like that would handle that joint, too. But, again, there's the problem of the pipes.

The Red Guard or one of the other trowel-ons might do well, too, and may actually seal better to the pipes. Maybe Noble has something? Eric?

I'm afixin to go to the shop this minute and try to glue some Kerdi to some PVC pipe, the results of which test I will not publish here for fear of ridicule and possible stoning for heresy.

We need to know more about the pipes.

We need to

[Mike2]

Thoroseal.

I've used this to seal around ABS, galvanized, and black iron pipes.

[Davy]

Yep, Thoroseal sounds familiar, CX. Maybe we'll get some more info on those dang pipes, maybe a picher.

[Montalvo]

Thanks for your timely responses, guys. Actually, my initial plan was to use Thoroseal, which I bought several months ago to seal some leaks in my gunite fish pond. But the guy at the tile store mentioned the "cold joint" that CX talked about and said that would cause me problems in the long run. I plan to die in this house (not soon, hopefully!) and don't want to create problems waiting to happen. The tile store guy suggested hot mop and I talked to a hot mop guy but didn't sound too encouraging and said a liner might be a better solution.

I don't understand exactly how this cold joint creates leak problems but perhaps it's associated with uneven thermal expansion/contraction between the upper pre-cast concrete and the lower poured concrete basin wall. (Fill me in, CX.) During construction, I propped the pre-cast up on some 1x2x16" concrete "sticks", tied re-bar from the bottom of the pre-cast into the grid on the basin floor and then poured concrete in a single pour, adding forms to hold up the walls and then stuffing the last few inches on concrete under the pre-cast by hand. It appears to be sturdy enough, even before mortaring the pre-cast joints, but apparently this cold joint could cause the seam on a Thoroseal coating to split and cause leaks.

As for the pipes, I've got three pipes in the floor: a 1 1/4" threaded pipe for a standpipe drain/overflow, a 3/4" pipe for an auto-fill and a 3/4" pipe that will connect to a submersible pump and carry water to the lion's head mounted above the basin. There's also a 1 1/2" pipe coming in a side wall that will carry electrical cords from the pump and a submersible light. This pipe leads to a planter where the pipe will extend vertically (above the waterline) before the wires are run over to an outlet.

OK, guys, hope that helps. I'm working on attaching some pictures, Davy.

Thanks again,

Bob

[Montalvo]

I couldn't find instructions on how to actually attach a picture but I'm assuming that I just put my file address after the http:\\. If you're not seeing anything, maybe someone can write and give me a hint.



Bob

[Mike2]

Hi Bob:

CX will be back to answer your question(s), I'm sure of that. In the way of facilitating this discussion I see three mutually interdependant issues here to address:

1. Waterproofing the overall concrete fountain base itself;
2. Bridging and sealing the cold joint; and
3. Sealing the pipe to concrete/membrane connection.

I personally don't know of one single product that will perform or satisfy all three.

[Chris the Rep]

Bob,

Knowing you've already bought your pan liner, I might suggest another option. Ultra-Set will waterproof the whole thing and will add less than 1/8" thickness, it will bridge the control joints, and will seal around the pipe protrusions. You can thin-set directly to. I've seen it used successfully in lots of fountains. Have a look at the data sheet.

http://www.bostikfindley-us.com/PDF/...t/ultraset.pdf

Chris

[Montalvo]

When I click on the "Insert Image" icon, a window asks me to "Enter the text to be formatted" and suggests I enter a URL. What do I put there to upload my photos?

In response to Mike2's summary of my concerns, I think he's done a pretty good job. But if I continue to pursue the installation of a liner, do you think it's reasonable to seal the pipes as they pass through the liner using caulk or silicon? If so, what technique and products do you suggest? one concern about the pipe/liner joint is that the standpipe will be unscrewed periodically to drain/clean the basin and the stress of unscrewing could conceivably cause the seal around that pipe to fail.

Based on the inputs so far, I'm thinking that it might be best to put down a couple of coats of Thoroseal (BEFORE installing the liner???), install the liner with a bead of some sort of sealant around each pipe, install my deck mud on the floor and fat mud over mesh on the walls, then maybe add another coat of Thorseal before thinset and tile. But if I do all this and it STILL leaks, I'll be one unhappy camper!

Bob

P.S. I just read Chris the Rep's message about Hydroment. Chris, how is that product different from Thoroseal, which makes similar claims? And won't the cold joint still create a potential for cracks?

[bbcamp]

Use the Manage Attachments button in the reply or compose message screen.

[Chris the Rep]

Ultra-Set is a urethane based material, not cement/acrylic based. Elongation is close to 400%, so if you follow the detail they provide correctly, it will bridge the control joint. It is designed to be used in tile applications only, it's not a general purpose waterproofing. You can thin-set directly to it, using one of Bostik's recommended thin-sets.

Thoro makes good products, but they are not in the tile installation products business.

Chris

[Montalvo]

OK, thanks to bbcamp, I think I'm finally able to show you some pictures of my fountain project. Regarding Chris the Rep's suggestion on UltraSet, I'd be interested in hearing from anyone who's had any experience using this product, especially in sealing a cold joint and around pipes, such as I have in my basin.

Bob