PVC pan liner flood test

[soultraveler]

Hi everyone.
i am curious how people pass the flood test doing the tradition pan linear shower.
normally, people set their preslope first, then pan linear, then caulk around the drain base and install the clamping flange, and let it dry then run the flood test.

my concern here is that when i run the flood test, water will sweep through the bolts. and the only thing that is stopping the water from going further out to the drain and preslope is the caulking between drain base and PVC liner. And caulking doesn't last long.

i read a post by this forum membe johnfrwhipple
https://terrylove.com/forums/index.php?threads/setting-a-showers-flood-test.57898/

he states that use NobleSealant 150 instead of 100% silicon could achieve a waterproof seal.
has anyone tried this? does this work like a PVC glue where it chemically bond the {PVC pan linear to the drain base?

Thanks

 

[Sylvan]

Hi everyone.
i am curious how people pass the flood test doing the tradition pan linear shower.
normally, people set their preslope first, then pan linear, then caulk around the drain base and install the clamping flange, and let it dry then run the flood test.

my concern here is that when i run the flood test, water will sweep through the bolts. and the only thing that is stopping the water from going further out to the drain and preslope is the caulking between drain base and PVC liner. And caulking doesn't last long.
View attachment 51709

i read a post by this forum membe johnfrwhipple
https://terrylove.com/forums/index.php?threads/setting-a-showers-flood-test.57898/

he states that use NobleSealant 150 instead of 100% silicon could achieve a waterproof seal.
has anyone tried this? does this work like a PVC glue where it chemically bond the {PVC pan linear to the drain base?

Thanks

 

[Sponsor]

 

[Sylvan]

When I install a shower drain ( I use sheet lead not plastic) after making the pan (box) I place a plug in the drain and fill the pan with waterr and let it stay over night to be sure there are no leaks

 

[hj]

And how many OTHER people do you think will install a lead pan, or would even be capable of doing it, these days?

 

[Jadnashua]

To do a flood test on a shower pan with a standard clamping drain, you must buy and use a drain plug. This gets installed deep enough down the drain line so that it is below the weepholes. Some have success using a party balloon, but blowing it up while nearly standing on your head can be a bit of a problem for some. When sealing the liner to the bottom of the drain, you only put sealant below on the top of the drain base. The holes in the liner allow the bolts to go through, and the combination of the sealant, the liner, and the pressure, create a waterproof seal.

Why anyone would use a lead pan these days is somewhat beyond me.

Personally, I much prefer to build a shower that not only has the pan waterproof, but also the entire thing. That requires a different kind of drain and a surface waterproofing material. With a conventional drain and shower pan construction, you have a minimum of 1" or more (industry standards call for minimum of 1.5", but many get away with less) as the top, tile setting surface. Neither the tile nor the grout is waterproof, and moisture WILL get below the finished surface. That's why there are weepholes. It's a first in, first out (FIFO), so that moisture is constantly being flushed through, albeit slowly, if and only if you do everything else right in the build to include mixing the mud right so it remains porous, not blocking the weepholes, and getting the slope correct without any dips or pockets that will accumulate stagnant water.

 

[soultraveler]

To do a flood test on a shower pan with a standard clamping drain, you must buy and use a drain plug. This gets installed deep enough down the drain line so that it is below the weepholes. Some have success using a party balloon, but blowing it up while nearly standing on your head can be a bit of a problem for some. When sealing the liner to the bottom of the drain, you only put sealant below on the top of the drain base. The holes in the liner allow the bolts to go through, and the combination of the sealant, the liner, and the pressure, create a waterproof seal.

hey jadnashua, thanks for the reply.
sometimes even a bathtub drain gasket can not create a waterproof barrier if you are not tighten it hard enough, let alone the 4 bolts and thin layer of pvc.....
i know in real application, the shower drain will hardly get back flowed and water sweep through the pan liner. but i just want to make a shower that is as seamless as possible.

i am curious, instead of caulking around the drain base, would it be better to apply pvc/abs solvent around the drain base? this would chemically bond these two surface together right?

what other methods are you talking about?

 

[Jadnashua]

When you cut the liner, it is continuous to the drain with the exception of the holes for the bolts. Adding the sealant underneath the liner at the drain when done properly, essentially seals that path into the preslope. So, any weepage just runs along the liner, through the weepholes and down the drain IF you keep the weepholes clear, which is why the sealant must go beneath the membrane, not above, or you'd seal them off. There are weephole protector devices that you can install under the final setting bed that help prevent clogging up the weepholes where the alternatives are some cracked tile pea gravel, or an engineered screen of which, this is one example http://noblecompany.com/products/positive-weep-protector

The only things the sealant beneath the liner on the drain base is doing is protection for the path around the bolts, and if the drain backed up, preventing it from getting underneath the liner. If you do a decent flood test, you'll verify things are tight. To do that, you need to make a seal beneath the weepholes in the drain.

My preference is a totally different waterproofing scheme

 

[soultraveler]

Hi jadna, thanks for the reply.
Have you tried noblesealent150 for the drain base before?

Initially, I was thinking about using Kerdi for the shower. But after I saw a video on YouTube a guy did a testing on Kerdi and it did not do good. So, im second thinking if I should use Kerdi or not.

 

[Jadnashua]

I don't build conventional liner showers...so, no, I"ve not used one. I know of others that have, and swear by them. I don't do this very often, either.

I don't care what you use, if you do not follow the directions and use good workmanship, you can have problems with any shower build method. You can see that the seams were not done properly...too much thinset, notches still visible, leaving direct pathways for water to leak through the seam. For a seam to be waterproof, just like on setting a tile, you must ensure you embed it properly which, when done right, you've spread ALL of the notches out, and also moved all of the excess thinset out. There won't be much IF you use the properly sized trowel and the proper thinset, mixed well. If you use a LFT mortar, like the guy in that video did (not the recommended thinset), it, by design, does not flow as well as a premium unmodified...it is designed to hold up large tile, not to embed a waterproof membrane, which means it's harder to flatten, and ends up thicker than it should. The seams become water tight because the fleece on the membrane ends up essentially touching with thinset fully embedding it on the top and bottom sheets. The thinset must be fine enough (small particles of sand and cement) to flow around the fleece fibers. A LFT mortar by design uses larger particles, almost guaranteeing a bad end result.

Like everything...you have to follow the instructions. WHen you do, it works fine. That product has been around nearly 30-years and is used internationally. If it didn't work, they wouldn't still be in business and growing every year.

You shouldn't believe everything you read or watch on the internet...including me, unless you do some research. There are a bunch of knockoffs of Kerdi that came out in the last few years, but not all copies are quite the same for one reason or another...one of them being cost savings that makes some changes that have not been proven through decades of use in the field.

I can point you to other installers that have left water in their Kerdi pans for over a week while waiting on the plumbing inspection that showed no signs of leaking anywhere and no water depth change. Do it right by following the instructions and it works.

I took a class at the Ceramic Tile Institute a long time ago...they had a cardboard box that they waterproofed with Kerdi using the specified thinset type and good workmanship. They used that box as a drink cooler for over a year before some idiot poked a hole in it with a knife. Used nearly every day, full of ice, water, and drinks. The cardboard never showed any evidence of getting wet. As I said, the stuff works IF you install it properly.

 

[soultraveler]

I don't build conventional liner showers...so, no, I"ve not used one. I know of others that have, and swear by them. I don't do this very often, either.

I don't care what you use, if you do not follow the directions and use good workmanship, you can have problems with any shower build method. You can see that the seams were not done properly...too much thinset, notches still visible, leaving direct pathways for water to leak through the seam. For a seam to be waterproof, just like on setting a tile, you must ensure you embed it properly which, when done right, you've spread ALL of the notches out, and also moved all of the excess thinset out. There won't be much IF you use the properly sized trowel and the proper thinset, mixed well. If you use a LFT mortar, like the guy in that video did (not the recommended thinset), it, by design, does not flow as well as a premium unmodified...it is designed to hold up large tile, not to embed a waterproof membrane, which means it's harder to flatten, and ends up thicker than it should. The seams become water tight because the fleece on the membrane ends up essentially touching with thinset fully embedding it on the top and bottom sheets. The thinset must be fine enough (small particles of sand and cement) to flow around the fleece fibers. A LFT mortar by design uses larger particles, almost guaranteeing a bad end result.

Like everything...you have to follow the instructions. WHen you do, it works fine. That product has been around nearly 30-years and is used internationally. If it didn't work, they wouldn't still be in business and growing every year.

You shouldn't believe everything you read or watch on the internet...including me, unless you do some research. There are a bunch of knockoffs of Kerdi that came out in the last few years, but not all copies are quite the same for one reason or another...one of them being cost savings that makes some changes that have not been proven through decades of use in the field.

I can point you to other installers that have left water in their Kerdi pans for over a week while waiting on the plumbing inspection that showed no signs of leaking anywhere and no water depth change. Do it right by following the instructions and it works.

I took a class at the Ceramic Tile Institute a long time ago...they had a cardboard box that they waterproofed with Kerdi using the specified thinset type and good workmanship. They used that box as a drink cooler for over a year before some idiot poked a hole in it with a knife. Used nearly every day, full of ice, water, and drinks. The cardboard never showed any evidence of getting wet. As I said, the stuff works IF you install it properly.

Hey Jadnashua
Thanks for your explanation. The guy in the video actually used the laticrete 317 unmodified thinset. Do you think drying time is the factor here? since some of the thinset are bonded between two impervious kerdie membrane.

 

[Jadnashua]

Unmodified actually gets stronger when it can't dry...the chemical reaction called curing (unmodified doesn't need to dry, and some modified thinsets don't, either). The water gets chemically combined with the raw cement and grows crystals. So, curing between waterproof layers actually makes the ultimate bond stronger...same is true with bonding say porcelain...the cement has all the moisture it needs to cure to its best advantage. A latex based modified will not achieve full strength before it dries, meaning that the tile can still move around, breaking the infant crystals prior to the stabilizing effect of the modifier is achieved.

If you let things skin over before embedding, or it is not mixed properly, then it won't flow. The thinset does not 'stick' to the Kerdi (or any of these type) membrane...it creates a bond because it must flow around the fleece. Once it cures, it locks things all together - think pouring hot wax on fabric...once it solidifies, it's almost impossible to get out. If there's excess thinset, it's skinned over, it's too thick to flow when embedded, or you leave trowel marks, you will not get a waterproof seam. Once you figure it out, it's actually quite fast and easy. The best thing for someone new is to avoid trying to use large sections AND, also pull back a corner to verify proper coverage. If you do that, it goes back up with no effort. If you don't have good coverage, adjust the thinset or your technique. Prior to curing, you can wash the thinset out of the membrane and start over. Tear off the fleece, and you need new membrane since there's nothing left for it to create a bond. It's fairly easy to peel back a membrane like this for maybe as much as a week or more, but that puts the maximum stress on a very thin line...industry standards call for a minimum shear strength of 50psi, and done right, Kerdi easily exceeds that.

FWIW, if you've done it properly, it will be water tight after 24-hours. But, yes, it does get both stronger and more resistant once the thinset fully cures. Industry standards call for 28-days. While cement continues to get stronger almost forever, they had to stop somewhere, and once it gets to that timeframe, the changes become VERY slow. Most of it happens in the first few days, and after a week, it slows down even more. The longer it cures, the longer and more dense the interlocking of the crystals becomes, blocking moisture. If you've done it right, the gaps don't allow liquid water through. It will wick through thinset if it's too thick...the fibers in the fleece help to break up the capillary action, but that doesn't work if the layers are too far apart.

 

[soultraveler]

Unmodified actually gets stronger when it can't dry...the chemical reaction called curing (unmodified doesn't need to dry, and some modified thinsets don't, either). The water gets chemically combined with the raw cement and grows crystals. So, curing between waterproof layers actually makes the ultimate bond stronger...same is true with bonding say porcelain...the cement has all the moisture it needs to cure to its best advantage. A latex based modified will not achieve full strength before it dries, meaning that the tile can still move around, breaking the infant crystals prior to the stabilizing effect of the modifier is achieved.

If you let things skin over before embedding, or it is not mixed properly, then it won't flow. The thinset does not 'stick' to the Kerdi (or any of these type) membrane...it creates a bond because it must flow around the fleece. Once it cures, it locks things all together - think pouring hot wax on fabric...once it solidifies, it's almost impossible to get out. If there's excess thinset, it's skinned over, it's too thick to flow when embedded, or you leave trowel marks, you will not get a waterproof seam. Once you figure it out, it's actually quite fast and easy. The best thing for someone new is to avoid trying to use large sections AND, also pull back a corner to verify proper coverage. If you do that, it goes back up with no effort. If you don't have good coverage, adjust the thinset or your technique. Prior to curing, you can wash the thinset out of the membrane and start over. Tear off the fleece, and you need new membrane since there's nothing left for it to create a bond. It's fairly easy to peel back a membrane like this for maybe as much as a week or more, but that puts the maximum stress on a very thin line...industry standards call for a minimum shear strength of 50psi, and done right, Kerdi easily exceeds that.

FWIW, if you've done it properly, it will be water tight after 24-hours. But, yes, it does get both stronger and more resistant once the thinset fully cures. Industry standards call for 28-days. While cement continues to get stronger almost forever, they had to stop somewhere, and once it gets to that timeframe, the changes become VERY slow. Most of it happens in the first few days, and after a week, it slows down even more. The longer it cures, the longer and more dense the interlocking of the crystals becomes, blocking moisture. If you've done it right, the gaps don't allow liquid water through. It will wick through thinset if it's too thick...the fibers in the fleece help to break up the capillary action, but that doesn't work if the layers are too far apart.

Hey Jadnashua, thanks for sharing the tips. Yeah, i will pre-cut and dry fit the kerdi and work on small section at a time before the thinset gets too dry, and also check for coverage.
i am thinking about applying hydro ban on the seams of the kerdi after it is cured. you know, just for extra protection. what do you think?

 

[Jadnashua]

ONe big thing that makes far more difference than people would think is to literally wipe the walls down with a wet sponge prior to spreading the thinset. It's not too wet unless there's liquid water on the surface. This means that all of the moisture stays in the thinset, giving you more time to deal with covering it prior to it getting stiff, which also means it can skin over, rather than being sucked out by the subsurface. This is ultra critical when using something like HardieBacker which is REALLY thirsty! Hardie may take 2-three wiping passes with a wet sponge to reach a reasonable level of saturation. SSD, saturated, surface dry is ideal - it lets the thinset spread and perform as it was designed. Wiping down also removes most any dust that might compromise the install.

IMHO, there's no good reason to paint a seam on Kerdi prior to finishing the system. While not a big factor, your actual bond strength may actually end up smaller if you do. The liquid doesn't cure as rigid as thinset, and can't lock into the seams as tightly. Check your coverage by pulling back a corner...if the sheet is fully covered with no gaps, it will work as long as you have at least the 2" required overlap. FWIW, the narrowest KerdiBand is 5", so you have some leeway when making seams...the sheets don't need to be perfect fit as long as you can get the required overlap. Depending on the size of your tile, you may just overlap the sheets rather than using the seam tape. Again as long as it's at least a 2" overlap, it will work. The advantage of KerdiBand is that it is thinner, so there's less buildup. That becomes less and less of an issue the larger your tile are since they typically also have a bigger notched trowel to set the tile...it is easier to avoid issues with keeping everything nice and flat (not that it's hard, it just easier).

Some people put the seam tape up in the corners and floor/wall connection, then add the sheets...it works either way...same with overlapping the sheets...it makes no difference if it ends up like shingles, or the other way around...all it requires is a properly done seam.

 

[soultraveler]

Hey jadnashua
i know its kind of redundant to use hydro ban on the kerdi seam. It defeats the purpose of kerdi.
thanks for mentioning pre-soaking the hardie. haha cause i have just bought the hardie and kerdi today.
i remember took me a good few pass of hydro ban to get a good layer of paint on the hardie.

In this video, he said he has found a new way of bonding the kerdie seam without using the unmodified thinset. All i see is that he is rolling some kind of slurry thinset like liquid on the membrane with a paint roller. He will reveal his new technique in his next video. you can skip the video to 17:10.

have you tried or seen anything like that?
Thanks again for your support.

 

[Jadnashua]

In Europe, then tend to use a product called Kerdi Coil-L. If it's that, it's not new. When they introduced Kerdi to the EU nearly 30-years ago, there were numerous national agencies that had their own way of doing things, and trying to get them all to agree how to use that new product just wasn't worth the fight. They wanted a method that was approved across the entire EU, and that took getting it through the committee of all member states (countries).

In the USA, Schluter only had to present test results to the one, national governing board...all of the states abide by that. Their test data stands on its own, done by an independent lab, recognized across the country. IMHO, it's not simpler...it's one more product to buy (it's not cheap, either!).

Install it right (and it really isn't all that hard!), and it works as instructed in their North American manual. https://sccpublic.s3-external-1.ama...98814/Shower System Installation Handbook.pdf

It will also work if you decide to use the EU method, but cost you more. Schluter sells over 100K drain assemblies in the USA every year, that's a LOT of showers. Most are installed per their instructions and do not leak. Good workmanship is expected. Pay attention to your seams, mix the thinset properly, wipe down the surface prior to spreading the thinset, and cover, then embed it before it skins over.

 

[soultraveler]

Hey Jadnashua....you are right. instead he uses the Ardex 8+9 as the final waterproofing, which is also an acrylic and cementitious powder mix. very similar as Kerdi coil-L. What do you think about this combination?

I have just put up the hardie and wet set my kerdi drain flange today. Going to do the slope tomorrow.
again, thanks for your help here.

 

[Jadnashua]

If it makes you feel better, use the stuff as it does work. If you trust your ability to install the stuff as the manufacturer, Schluter suggests, it will work fine, too, and save you steps and money. Really, it has been working with just unmodified thinset in the USA for decades. It passes all of the certification tests. It works as designed.

Hardie, as I said, is REALLY thirsty. Some go to the extent that they spray it with a garden sprayer (water only) until it doesn't absorb any more. It's not too wet unless there's liquid on the surface, and if then, you won't have to wait all that long for it to go away. It does make a difference.

 

[soultraveler]

If it makes you feel better, use the stuff as it does work. If you trust your ability to install the stuff as the manufacturer, Schluter suggests, it will work fine, too, and save you steps and money. Really, it has been working with just unmodified thinset in the USA for decades. It passes all of the certification tests. It works as designed.

Hardie, as I said, is REALLY thirsty. Some go to the extent that they spray it with a garden sprayer (water only) until it doesn't absorb any more. It's not too wet unless there's liquid on the surface, and if then, you won't have to wait all that long for it to go away. It does make a difference.

Hey Jadnashua...yah i think i will sleep better at night taking the extra step. I like the 1/4 inch Hardie. It gives me room to shim behind the stud to even out the walls.

 

[Sylvan]

And how many OTHER people do you think will install a lead pan, or would even be capable of doing it, these days?

I hired an Albanian that is in this country 4 years and has a work permit,. He just turned 31 and I am paying him $125 PER HR and he only uses sheet lead never any plastic crap and is willing to learn and work 7 days a week when needed

There are still great craftsmen available but they have to be imported from European counties.

Also the majority of roof drain we install are caulked joints rather then No Hub.

I like using lead as it last for decades

 

[Jadnashua]

Unless the pan is sloped to the drain, it does not meet the plumbing codes. Yes, many inspectors only look to see if it leaks, if they inspect it at all. The industry guidelines require the liner to be sloped.

Most of the plastic liners are pvc..the same basic material used in drain pipes, but made flexible. Do you avoid pvc pipes because you worry about them failing?

Yes, you can make a lead pan sloped. Most people don't do it. Neither tile nor grout is waterproof...the moisture does accumulate in the deck mud since it won't all drain, leading to the tile and grout showing moisture, and leading to mold growth.

High rises tend to avoid plastic pipes...CI still is probably the high quality installation, assuming it's done right. I can't see that a pvc liner, between two layers of mortar would be a fire hazard, though.