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Expert Answers
Are My Drain Weep Holes Plugged?
QUESTION
Are my Drain Weep Holes Are Plugged? We are a homeowner who recently had a small shower renovated in our home. It was hot-mopped with porcelain tile on the walls and floor. After 5 days of grouting, I sealed the grout with Stonetech Grout Sealer applied only to the grout lines with a narrow sponge brush. I called Stonetech, and they told me this was a correct sealer to use in the shower and was would breathe. After the first shower (not lengthy), we noticed the 3X3 tile on the floor had dark wet grout for about 6-8" all around the drain. I assumed this was normal and would return to it original color in a few hours when dried. The shower is now 5+ days unused, and the wet grout remains even with a fan put in the shower for a day and the door left open. I wiped down our shower door, walls, and tile after the first shower.Our contractor is licensed, but he tells us the constant wet grout is "normal" and will eventually spread so all the floor tile grout stays wet. I asked about the weep holes, and he said he found some rocks outside to put over them. We briefly filled the shower about 1" by plugging the drain to see if we could see any drainage by the weep holes after the shower drained by using a dental mirror. We couldn't see any, but I don't know if this is a valid test. The wet grout around the drain spread a little further after we did the water test, but its still only around the drain.
We are at a loss to know what to do, as our contractor is maintaining that a constantly wet shower pan and grout is totally normal. The hot-mop installer does only this and has 15 years of experience. The hot mop pan seemed sloped, and the floor is definitely sloped now with all water going down the drain and other outer tiles having dry grout. The contractor assured us the pan was sloped by the hot mop installer. To me, it seems this might be a weep hole issue, but I'm not an expert.
We're afraid to use that shower if water is staying under the tile, and that is why I'm concerned.
ANSWER
ANSWER - Having wet grout around the drain does suggest that the weep holes at the waterproof membrane level might be plugged. Water below the tile that can't readily drain through the weep holes, into the drain, causes the tile assembly in that area to be saturated with moisture. It will then take longer for it to dry out. There should be either pea gravel or tile chips or a plastic weep hole protector around lower drain connections in order to keep the weep holes from plugging when the mortar is placed on top of it. Even when there is drain weep hole protection, over time the weep holes do tend to become plugged from calcium build up.Cementitious grout can appear wet around the drain when the weep holes are plugged, but it might actually just be a shade variation in grout color near the drain due to how the grout was installed and cured. You would have to perform a moisture survey with a digital moisture meter to determine whether it is an indication of high moisture or just a shade difference in the grout color.
The test you performed by flooding the shower pan might not be valid if it was a brief test. I would plug drain and fill for overnight, and then after it had been drained for 30 minutes or so, look to see if there is any moisture weeping from the weeps holes within the interior drain. You can also use an awl tool, with a hooked end, to stick into the interior drain weep to see if it is open, and if it isn't, it might open it.
This damp condition is not detrimental to the performance of the shower or is it likely to result in significant collateral damages, unless there are other deficiencies in the shower assembly. It may cause some of the porous cementitious grout to appear damp longer than it would otherwise.
The grout and underlying mortar will always get wet from using the shower and it will take time for it to dry. Some showers may never dry entirely if they are used daily. What can happen if there isn't good air circulation in the shower area, is the wet tile assembly can develop a musky odor.
That is why I always recommend installing a secondary waterproof membrane over the mortar bed and adhering the tile directly to the membrane. This will keep the moisture out of the mortar bed and allow the grout to dry faster. This isn't an industry requirement, but it is an option that will increase the cost of the shower installation, but provide more protection over time.
22 thoughts on “Are My Drain Weep Holes Plugged?”
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I thought the secondary membrane (red guard/kerdi) would be cool too —but with a traditional weep hole drain, (and after much mental modeling) I figured out the membranes would have to “divet down” to the weep holes, correct?—Ive thought not doing this will cause water to gather at the drain as it cant “jump” over the metal ring of the drain if you paint a liquid membrane (for example) all the way to the drain on a mortar bed made lower to accept a tile flush to the drain. Ive since seen examples of this on the web (first time I mentally concluded or induced a solution already solved). But it was so hard compared to just having a Kerdi drain that didn’t have weep holes in the first place that I only do Kerdi now
The ideal method would be to have a traditional hot mop or sheet membrane under the mortar bed over a pre-sloped substrate as the primary waterproof membrane. The membrane would tie into the two-part drain. The weep holes will be protected with gravel or a plastic weep hole protector.
Then a secondary liquid applied waterproof/crack isolation membrane is installed over the mortar bed up to the top drain flange. An ASTM C920 sealant will be used to flash from the drain flange to the membrane. This keeps the water out of the mortar bed. If for some reason there is a breach in the secondary membrane then water still has a way out.
If you use the liquid applied membrane as the primary waterproof membrane then it goes over the mortar bed. Per the manufacturers’ directions, you bowl out around the drain so the membrane will be clamped in the two part drain. Weep holes are protected. Then we patch the bowled out area with mortar and then apply the liquid applied membrane over it to keep a continuous membrane on the surface of the mortar bed.
In both cases the water is kept out of the mortar bed. Water is shed at the surface of the tile. What little moisture gets into the grout joints and thin-set will dry rapidly.
When installing a high performance resinous flooring system would weep holes be a problem.
Any drain with weep holes needs to be protected so water can readily pass through. In theory, a resin flooring coating system should be water tight particularly at the transitions so water can’t get beneath it. If water does get beneath it, then there could potentially be issues where the floor could blister or peel.
I am having a similar issue on a recently installed shower, the marble tile around the drain(about 5″) has remained wet looking even though we haven’t used the shower for 2 weeks. The contractor looked at the top weep holes and they are clear, he states the square drain cover on a round drain body has gaps and that some water is getting in the gap between the cover and drain body. The mud under the cover wet. This then is “wicking” causing some of the other mud to get wet and thus casuing the marble to be wet around the drain.
Does this seem reasonable?
The darkness could be because it is wet, but if it hasn’t been used for 2 weeks, then it is probably stained. You can test it with a moisture meter to see if there is a higher level of moisture at those darker spots.
Looking from inside the drain the weep holes may look open, but they could be plugged from the inside. I don’t see how the drain cover has anything to do with it.
I have seen where when some types of natural stone are subjected to excessive moisture that the moisture might activate or carry other minerals into the stone and cause it to stain.
If you think it is stained then you can try using a poultice to try to remove the stains.
hi
My contractor did not protect the weep holes- Is there a way to create them after the fact?
I had to pull up all the tiles on the shower floor and the first row of wall tiles at the bottom – the wall board was completely soaked and there was water all over the shower liner. Please help! I do not want to have to redo the whole shower again 🙁
The only way to open the weep holes is to remove the tiles around the drain and go down into the mortar bed to the drain clamping connection and open up the weep holes and add gravel or a plastic weep hole protector.
If the wall board is a gypsum board whether it is water resistant green board or not it is not approved for shower applications because it will deteriorate when subjected to moisture. There is a product called DensShield backer board that is water resistant and can be used in wet areas.
Sounds like it wasn’t waterproof correctly. The shower pan waterproofing should have continued up the wall at least 3 inches above the height of the dam or better yet 12 inches up or more. Then depending on the backer board used a vapor barrier or waterproof membrane should have been used to flash over the shower pan waterproofing membrane so there is continuous projection against water intrusion.
Depending on the conditions, you might be able to remove the first two rows of wall tile up from the shower and tie into the shower pan membrane; if there is one there. If you did install over regular drywall then you should remove all of the tile and redo it. The drywall when it gets wet is prone to develop microbial growths that can be problematic.
Chances are if the contractor made all of the other mistakes, there are likely more mistakes that you haven’t found yet.
When you place the stones around the drain to keep the weep holes open, do you cover those stones with Mortar so everything is sealed up to the drain opening?
Once you cover the weep holes in the drain with pea gravel or with a plastic weep hole protector then apply the mortar over it. Make sure the mortar can’t get into the weep holes. Water in the mortar will be driven to the pea gravel as the water is allowed to drain through those weep holes and those dry conditions continue to drive the moisture to it.
If water can seep through a 1.5″ thick slab of 4 to 1 Mapei bedding, then why can’t it seep through holes or grooves in a three piece shower flange that may be filled with that same 4 to 1 bedding mix, without the help/use of pea gravel?
Seeping water in this case is water migration. The water from the tile surface migrates through the grout joints and migrates into the mortar bed and will eventually migrate to the drain weep holes that in this hypothetical case is filled with the same mortar and not fully open as intended. The water doesn’t reach the weep holes until the entire mortar bed is saturated with water and it can’t hold any more water. If the weep holes are plugged with mortar then there is no space above the weep holes where there should be gravel or a weep hole protector to facilitate the flow of the moisture from the mortar bed above it. Thus the water will very slowing weep and not allow the mortar bed above it to adequately dry before the shower is used again. Thus the mortar bed never fully dries out that can cause a darkening of the tile above it and can cause musky smells.
If the weep holes in the drain are open and protected by gravel or a weep hole protector creating an open space above it for water to collect, it will draw the water into it as it becomes the path of least resistance. The more the water escapes through the open weep holes the more of a siphoning affect occurs that increases the flow of water due to the low pressure condition created by the flowing water going through the weep hole; this is a function of the physics law that high velocity creates low pressure.
That is why industry standards and the building code requires weep hole protection around drains.
I have a 16 year old shower that I’ve always struggled with mildew in.
I recently found the drain weep holes were completely plugged with either eroded mortar or calcium deposits, I’m not sure. I was able to unplug them. My question is, can I put something to protect them without pulling up the shower floor?
I do not see any loose gravel or pieces of tile or anything like that on top of the weep holes.
I’ve read about coffee filters used, could I do that–glue a coffee filter to the plastic (is it flange?) piece that has the weep holes and tracks that lead to them? would that help?
Thanks for any advice!!
I assume you opened up the plug weep holes from the interior of the drain, which is possible. In theory if you were able to create a void on the exterior side of the weep hole to allow water to readily pass through it might help. Although it will likely plug up again over time as the calcium and minerals from the water builds up. So you will have to clear it again from time to time.
When they installed the tile they should have had gravel or a plastic weep hole protector over the weep holes so that they would never get plugged.
I am so glad to find this article. We bought a new home and we had been complaining about an on and off musty smell from our shower floor drain. The builder just looked at it and they said there is nothing wrong with it. I told them that the weep holes were full of tar and clogged. They said as long as they do not see anything wrong, they will not fix anything. How do I prove that there is a problem since the weepholes are clogged? Does the code require weepholes to be unclogged? How can I make them fix it because all they say is that they do not smell anything and the shower is draining so there is nothing wrong with it. Whenever we use the ahower we get rashes and as soon as water hits the tile, it smells bad. Please help.
You cannot assume the weep holes are plugged without evidence that shows that they are in fact plugged. To verify that you need to remove tiles and the mortar bed around the drain to expose the weep holes to see if in fact they are plugged.
They might have installed a drain that doesn’t have weep holes? Or maybe they didn’t pre-slope the shower pan so water isn’t able to reach the drain?
We don’t know how the shower pan is configured with what products. Generally speaking when there is problem it isn’t due to a single deficiency, but rather it is due to multiple deficiencies. The only way to find out is to do the destructive testing by removing various portions of the shower pan and the wall.
You need to find evidence that correlates the smell to a defective condition relative to industry standards and product manufacturer’s directions.
To hire a forensic company like CTaSC who are experts at this it would probably cost well over $3,000.00 to inspect the shower, remove tiles, and then to reinstall replacement tiles depending on how far our inspector has to travel. Of course you need to have matching replacement tiles and grout.
Hello,
The contractor finally agreed to fix the drain and found out the weep holes were really clogged. They removed the tile and put gravel around it. After a few months, I noticed the wall tiles are getting darker and when I opened the drain, the weep holes Re clogged again with tar. I really do not k ow what to do.
Thanks
Michelle
To have tar in the weep holes then I would assume the waterproofing used was a hot mop method. Since that is the first layer of the assembly and it should be clamped in the two part drain right below the weep holes, then the tar must have been there before.
If the walls are getting darker because water is migrating up the walls then you have another problem that is compounding your problems. There should be no path for water to migrate up the walls if the shower was constructed correctly. There should be a space filled with closed-cell backer rod and filled with an ASTM C920 sealant to block any moisture migration.
One wall of my marble shower has a few marble pieces chipping off. A stone contractor stated that it appears that the weepholes are clogged and thus, there’s too much moisture in the pan, which is causing a side of the marble shower to chip off. However, a different stone contractor states that he doesn’t think that it’s the weepholes because if the weepholes are clogged, why aren’t there any chips on the other walls or the floor of the shower. What are your thoughts? Thank you.
The plugged weep hole theory doesn’t make sense for a few reasons.
To make the correlation that chipped marble tiles are caused by plugged weep holes located several inches below the marble surface without any visual evidence is a stretch. Plus marble tiles in showers and other applications like the Vermont marble installed in the 345,000 gallon Hearst Castle Neptune pool in California don’t chip due to being subjected to moisture.
If it is a true marble then per industry standards it can’t have an absorption greater than 0.2%, which is by definition impervious. So the marble doesn’t have a propensity to absorb much that would cause it to expand.
If the marble tiles are butted together without a grout joint it is possible as the tiles expand from surface moisture and temperature fluctuations it can cause chipping along the edge, which we refer to as a chattered edge. Industry standards recommend at least a 1/8″ wide grout joint, but never less than 1/16″ wide.
If the marble tiles are not butted together and there are chips, it maybe due to abuse from something dropping on it. Sometimes if two adjacent tiles have excessive lippage where one edge is higher or lower than they other, it can have a propensity to chip from various types of impact.
Thank you for your response. The side wall where the chipping off is taking place is actually a 1-piece marble. In other words, the 1-piece marble is having chips in 3 different areas of its surface. The contractor was confident that it were the clogged weepholes that were causing the retaining of moisture because I mentioned that 3 years ago when a handyman cut through the grout, a foul odor (smelled like sewage) came out of there. He immediately recommended that the weepholes be unclogged before he polishes, reseals and regrouts that shower.
Those are two different issues. The weep holes might be plugged, but you can’t verify that without removing the tile around the drain. On some drains you can see the weep holes inside the drain where you might be able to probe at it with a hooked awl tool to remove some calcium build up, but you are not going to clear the weep holes if they are plugged at the flange of the drain unless you do remove the tiles. But that has nothing to do with the chipped marble unless the marble tiles are tightly butted together.