Author Topic: Leaks, Water Damage, and Mold (Read 5417 times)

mrFinpgh · « **on:** August 01, 2022, 03:04 PM »

For those who don't want to read the backstory:

My kitchen ceiling has some water damage from a leak in the bathroom above. It's drywall laminated to plaster with asbestos in the mix. I'm going to need to get a portion of it removed just to get the plumber access to the lines buried below the 4" concrete slab in the bathroom. I would assume it's a smart idea to remove any of it that's wet. How much should come out? And what should I do in terms of drying/preventing mold once it has been removed?

A couple weeks ago, I saw a puddle on my kitchen floor after I had used the shower (located directly above the kitchen). The puddle came out from beneath my range, which was odd.

Despite my best efforts, I could not identify any clear source of water or leaks from above. The location seemed improbable, as the water didn't appear to be coming from anywhere at all. When my wife got home, i had her run the bathtub for about 10 minutes and we couldn't replicate the issue. So we agreed to keep an eye on it and see if it happened again.. a week of daily use went by and nothing. But my curiosity/confusion got the best of me last week, so I rented a thermal camera and had her run both the tub and sink with hot water (so it would show up clearly on the image). Sure enough with both things running, after about 3 minutes the camera started to show some serious contrast.

Soon thereafter, I saw a pinhole leak in the ceiling above the range hood, and noticed water accumulating in one of our surface mounted light fixtures.

. The puddle under the stove appeared again. When I pulled the fixture, it was full of water but still worked. I think I'll be replacing it.

So. Obviously, there's a leak somewhere in the plumbing in our bathroom. It doesn't seem to be a consistent leak (good?) or at least it doesn't show up as a visible issue unless a lot of water is going through the pipes.

It seems to me like the ceiling is going to have to come out in the kitchen to both 1. replace the water damaged drywall and 2. to provide the plumber with access to the plumbing, as the bathroom floor is a 4" slab of concrete with tile over it.

To remove the ceiling is a bit of an ordeal. Aside from being our kitchen, the ceiling is drywall laminated to old plaster with asbestos in the base coat. So I'm going to have to get someone to come in and take it out. Expensive stuff.

What I'm trying to determine now is what else I need to do, besides the obvious (remove ceiling, have the plumber come and fix the leak).

I know mold is a consideration with drywall - so far there's no visible signs of mold (on the front of the drywall at least) and that the joists themselves must have gotten wet at some point. What I'm not clear on is where the cutoff is for removing drywall that gets water on it. Is there a moisture reading that indicates 'remove' as opposed to 'let dry out'?

Should I take the opportunity to dry things out for a certain period of time? Should I treat the joists with some kind of anti-fungal or encapsulant? Anything else I should be accounting for? For what it's worth, this is an old and very leaky house (I doubt you could even measure ACH50 in here), so there is probably more opportunities for drying than a new home.

Thanks,
Adam

Tombombadil · « **Reply #1 on:** October 10, 2022, 08:01 AM »

Water infiltration in to the structure is a health hazard. Most U.S. jurisdictions say that you have an implied warranty of habitability.

Sparktrician · « **Reply #2 on:** October 10, 2022, 09:01 AM »

By all means, get everything fully dried out and any mold remediated ASAP! The Esso Bee that built my house did a crappy job with the plumbing, but even worse was the tile job in both bathrooms. This bozo laid tile directly over drywall in both showers using poorly applied mastic, not thinset. To make matters worse, he left zero gap between the tiles, so any grout was superficial, at best. I touched (not grabbed) the grab bar one morning and it fell off the wall. The grab bar had been attached to this mess of tile and drywall using plastic anchors, and was not attached to any framing members. When I stripped down the wall, the insulation was soaking wet. I had to leave the area open and under forced ventilation with dehumidification to reduce the humidity and dry out the insulation. Then came remediation of any remaining mold. I'm right now rebuilding that bathroom, and when this one is done, I have to do the same for the other bathroom. What a mess!!!

Cheese · « **Reply #3 on:** October 10, 2022, 11:54 AM »

I wonder if a wood moisture meter would work to at least locate the area that's the wettest. Then start in that wet area and remove a small section of drywall for a look-see as to what other issues may be in store. The wet drywall should keep any asbestos fibers contained so that they don't become airborne. Mask-up and have a good HEPA vac at the ready so that you can explore what your options are.

If you're lucky, you may even be able to see where the plumbing leak is by looking for any mineral deposits on the pipe.

If that moisture meter does work, you could then probe the ceiling area and get a feel for how much drywall you're going to need to replace.

cpw · « **Reply #4 on:** October 10, 2022, 01:11 PM »

There are fairly cheap pinless moisture meters that have a drywall setting. You should be able to see what is "soaking wet that way", but if you already know you have a problem and are opening up that ceiling anyway, I would think that pulling drywall and a flashlight, your fingers are probably just as good to get the boundaries of your problem area.

https://www.homedepot.com/p/General-Tools-Professional-Digital-Pinless-Moisture-Meter-with-Backlit-LCD-MM8/205519129

mrFinpgh · « **Reply #5 on:** October 10, 2022, 02:04 PM »

I've been dealing with this for a bit, and forgot about this post. :-). Here's an update.

We had an abatement crew come out and remove about 40 sf of ceiling. They work faster and more aggressively than I expected - in and out in less than 2 hours. By contrast, any time I've set up for RRP, it takes me about a day just to get everything tented off. They did indicate that the ceiling was pretty well soaked.

I sprayed the framing and adjacent plaster with some mold control and we ran a dehumidifier for the next month, to try and dry it all out as much as possible. No visual or olfactory indications of mold, and I'll probably spray again before I close it all back up, just to be safe.

As it turns out, the leak was about a 1/8" hole in the top of the old lead line leading to the vent. How there was water in the vent is a bit of a mystery. Unfortunately, that lead line, the leak, and the connection to the stack were all encased within that 4" thick layer of concrete. So in addition to removing the kitchen ceiling, now they need to jackhammer out the bathroom floor in the area where all the lines are run.

If you couldn't predict where this was going, once they started accessing the lines, they actually uncovered a couple other defects w/ the cast iron waste line as they were removing the lead pipe running into it. And the old brass water supply piping might as well go while they are up there, etc. To replace the tie-in to the vent, they cut out a few portions of the wall behind the sink, etc.. Once they actually finished the plumbing work, they poured a new concrete floor about level with the previous substrate.

The flange and closet bend got replaced with ABS. With the ceiling out right now, everytime somebody flushes it sounds like a waterfall in the kitchen. I'm thinking I need to put some sound dampening up there before I close it back up. I have a good amount of room in the joist bays below, so I might do 6" of something like safe n' sound to try and muffle things.

The good news is, insurance covered pretty much everything except the actual plumbing repairs. So the asbestos work and time spent on actually getting to the leak is covered. They will also cover the work & materials necessary to return everything back to original condition. So while the total bill of work is about 3.5x what I initially anticipated, I'm basically on the hook for about what I initially expected. Since I'll be doing the restoration work myself, that should help reduce the absolute cost a fair amount too.

@Sparktrician About 7 years ago, when I removed the old tub surround from this bathroom, the grab bar was installed using toggle bolts, two of which went right into a buried j-box with live wiring in it.

What are you going to use for a tile substrate? I did hardi topped with redguard, but I know a lot of folks having been moving to the membrane based systems, which seem like they might be a little more robust.

Sparktrician · « **Reply #6 on:** October 10, 2022, 02:35 PM »

Quote from: mrFinpgh on October 10, 2022, 02:04 PM

@Sparktrician About 7 years ago, when I removed the old tub surround from this bathroom, the grab bar was installed using toggle bolts, two of which went right into a buried j-box with live wiring in it.

JAYZUS!!!

Quote from: mrFinpgh on October 10, 2022, 02:04 PM

What are you going to use for a tile substrate? I did hardi topped with redguard, but I know a lot of folks having been moving to the membrane based systems, which seem like they might be a little more robust.

@mrFinpgh, I'm using Kerdiboard for a number of reasons.

It's far lighter to haul around than cementboard.
There's no huge cloud of cement dust when I'm cutting it to fit a specific place.
Cutting Kerdiboard requires only a utility knife and a straightedge.
Custom cuts around plumbing and valves is a piece of cake.
The membrane is built in.
Covering the screws and their plates is very easy with the supplied roll of membrane.
Cleanup is so very easy.

The downside (if you can call it such) is that the materials are ~2x the cost of a similar cementboard installation. That's offset by the lack of back strain incurred by hauling the materials into place. I'll deal with less back strain!

squall_line · « **Reply #7 on:** October 10, 2022, 03:55 PM »

We just had the tub area in our bathroom redone from a failed caulking job on an old insert. The tile guy used Kerdi board for pretty much all of the exact same reasons that sparktrician mentioned. Something to the effect of "at my age, why bother humping cementboard around when Kerdi has so many other benefits?"

GoingMyWay · « **Reply #8 on:** October 10, 2022, 06:03 PM »

Quote from: mrFinpgh on October 10, 2022, 02:04 PM

I sprayed the framing and adjacent plaster with some mold control and we ran a dehumidifier for the next month, to try and dry it all out as much as possible. No visual or olfactory indications of mold, and I'll probably spray again before I close it all back up, just to be safe.

@mrFinpgh what mold control did you spray?

Quote from: mrFinpgh on October 10, 2022, 02:04 PM

The good news is, insurance covered pretty much everything except the actual plumbing repairs. So the asbestos work and time spent on actually getting to the leak is covered. They will also cover the work & materials necessary to return everything back to original condition. So while the total bill of work is about 3.5x what I initially anticipated, I'm basically on the hook for about what I initially expected. Since I'll be doing the restoration work myself, that should help reduce the absolute cost a fair amount too.

Does that mean the insurance is paying you for your labor to do the restoration?

mrFinpgh · « **Reply #9 on:** October 12, 2022, 12:45 PM »

Quote from: Sparktrician on October 10, 2022, 02:35 PM

@mrFinpgh, I'm using Kerdiboard for a number of reasons.
It's far lighter to haul around than cementboard.
There's no huge cloud of cement dust when I'm cutting it to fit a specific place.
Cutting Kerdiboard requires only a utility knife and a straightedge.
Custom cuts around plumbing and valves is a piece of cake.
The membrane is built in.
Covering the screws and their plates is very easy with the supplied roll of membrane.
Cleanup is so very easy.

The downside (if you can call it such) is that the materials are ~2x the cost of a similar cementboard installation. That's offset by the lack of back strain incurred by hauling the materials into place. I'll deal with less back strain!

Kind of the Zip System of shower surrounds

I think I remember John Bridge had a series of posts where he not only built the surround using Kerdi Board, but also a bench in the shower out of the same.

In addition to the hauling issues, you probably also save some time compared to applying two coats of a liquid applied waterproofing or using thinset to place the membrance on drywall. I'm sure it's also much easier to 'trim in place', as opposed to, say taking a piece of cement board outside because the house is occupied and you probably don't want to run the grinder indoors.

mrFinpgh · « **Reply #10 on:** October 12, 2022, 12:49 PM »

Quote from: GoingMyWay on October 10, 2022, 06:03 PM

@mrFinpgh what mold control did you spray?

Concrobium. I had a bottle of it because I had a bit of mold in my basement due to an unrelated water leakage issue. It worked very well down there, so I saw so no reason to try anything else.

Quote from: GoingMyWay on October 10, 2022, 06:03 PM

Does that mean the insurance is paying you for your labor to do the restoration?

Apparently so. I've never had to file a homeowner's claim before, so I was not really sure how any of that would work. But I guess they will reimburse you for the cost of the restoration work based on whatever proprietary algorithms they use for figuring out how much it 'should' cost.

Sparktrician · « **Reply #11 on:** October 12, 2022, 01:44 PM »

Quote from: mrFinpgh on October 12, 2022, 12:45 PM

think I remember John Bridge had a series of posts where he not only built the surround using Kerdi Board, but also a bench in the shower out of the same.

Mike Holmes has YouTube videos out showing the use of 2" Kerdiboard slabs to create a bench that 400# of two of his employees could stand on - without support underneath.

Quote from: mrFinpgh on October 12, 2022, 12:45 PM

In addition to the hauling issues, you probably also save some time compared to applying two coats of a liquid applied waterproofing or using thinset to place the membrance on drywall. I'm sure it's also much easier to 'trim in place', as opposed to, say taking a piece of cement board outside because the house is occupied and you probably don't want to run the grinder indoors.

No liquid waterproofing is used at all, but there is a need to use Kerdiband (membrane) with thinset to cover joints and screws to ensure a full waterproof experience before applying another layer of thinset to adhere the tile after the first layer dries.

GoingMyWay · « **Reply #12 on:** October 12, 2022, 01:47 PM »

Quote from: mrFinpgh on October 12, 2022, 12:49 PM

Concrobium. I had a bottle of it because I had a bit of mold in my basement due to an unrelated water leakage issue. It worked very well down there, so I saw so no reason to try anything else.

Thanks! I bought some RMR-86 and RMR-141 for some mold removal, but I haven't had a chance to use them yet. I wonder if Concrobium is better or more or less the same thing.

Quote from: mrFinpgh on October 12, 2022, 12:49 PM

Apparently so. I've never had to file a homeowner's claim before, so I was not really sure how any of that would work. But I guess they will reimburse you for the cost of the restoration work based on whatever proprietary algorithms they use for figuring out how much it 'should' cost.

That's interesting. I would have thought they'd only want to pay a licensed contractor to do the restoration work, but I guess they already have a dollar amount in mind so maybe they don't care as long as the cost doesn't exceed what they've budgeted.

Sparktrician · « **Reply #13 on:** October 12, 2022, 02:14 PM »

Mold Armor (available at The Borg) is also a decent product for mold remediation.

Tom Gensmer · « **Reply #14 on:** October 12, 2022, 02:25 PM »

Quote from: GoingMyWay on October 10, 2022, 06:03 PM

Does that mean the insurance is paying you for your labor to do the restoration?

Apparently so. I've never had to file a homeowner's claim before, so I was not really sure how any of that would work. But I guess they will reimburse you for the cost of the restoration work based on whatever proprietary algorithms they use for figuring out how much it 'should' cost.
[/quote]

It has been my experience that the insurance companies use software that assigns values to repairs. For instance, "X" dollars per square foot to remove carpet, "Y" dollars per square foot to remove pad, "Z" dollars per lineal foot to remove tack strip , "T" dollars per yard for disposal, etc.... Pricing is regional, frequently informed by your zip code. It has been my experience that, as a general contractor, it's next to impossible to hit their (insurance) pricing, so the only way to reasonably perform a restoration at insurance pricing is to hire one of the specialized storm/water/fire companies, who are familiar with navigating the insurance landscape and have crews that are willing to work at the wages indicated by the insurance company software.

Peter Halle · « **Reply #15 on:** October 12, 2022, 02:25 PM »

As someone who has to handle many, many insurance claims thru my one career, I am sure that the insurance company will offer a payment based on what they have in their databases. I would strongly urge the use of professionals for the mold removal part. All too often the scope of work creeps larger and having them deal with the insurance carrier is advantageous. Additionally, if their are future issues with the work performed the homeowner has someone to go back on. Insurance carriers usually skeptical if there would be an additional claim in the future because all too often homeowners will claim to have done the work but then they just pocket the claim money and either don't do the work or else do it improperly.

None of what I wrote is meant to imply that would happen in this case.

Peter

mrFinpgh · « **Reply #16 on:** October 15, 2022, 07:03 PM »

Quote from: Sparktrician on October 12, 2022, 01:44 PM

No liquid waterproofing is used at all, but there is a need to use Kerdiband (membrane) with thinset to cover joints and screws to ensure a full waterproof experience before applying another layer of thinset to adhere the tile after the first layer dries.

Does every screw get taped? I was thinking they would have some sort of fluid/caulk for covering those up, kind of like liquid flash/fast flash?

Still, I think I had to tape the joints on the hardi, so I think it's a net savings in terms of labor to use Kerdiboard.

mrFinpgh · « **Reply #17 on:** October 15, 2022, 07:08 PM »

Quote from: Peter Halle on October 12, 2022, 02:25 PM

As someone who has to handle many, many insurance claims thru my one career, I am sure that the insurance company will offer a payment based on what they have in their databases. I would strongly urge the use of professionals for the mold removal part. All too often the scope of work creeps larger and having them deal with the insurance carrier is advantageous. Additionally, if their are future issues with the work performed the homeowner has someone to go back on. Insurance carriers usually skeptical if there would be an additional claim in the future because all too often homeowners will claim to have done the work but then they just pocket the claim money and either don't do the work or else do it improperly.

Peter, I appreciate what you're saying and it makes a lot of sense. I was concerned about the mold issue, but so far I have not found any evidence of mold in the joists or adjacent plaster/drywall I've looked pretty comprehensively and can't find anything. As a precaution, I sprayed mold control after the ceiling was opened up. To be extra careful, I sprayed it again, focusing on anything that could be a possible source of food for mold.

Of course, the asbestos crew took out about 40sf of the ceiling, so it's very possible that they removed anything that was going to be moldy back in August.

squall_line · « **Reply #18 on:** October 15, 2022, 08:11 PM »

Quote from: mrFinpgh on October 15, 2022, 07:03 PM

Quote from: Sparktrician on October 12, 2022, 01:44 PM
No liquid waterproofing is used at all, but there is a need to use Kerdiband (membrane) with thinset to cover joints and screws to ensure a full waterproof experience before applying another layer of thinset to adhere the tile after the first layer dries.

Does every screw get taped? I was thinking they would have some sort of fluid/caulk for covering those up, kind of like liquid flash/fast flash?

Still, I think I had to tape the joints on the hardi, so I think it's a net savings in terms of labor to use Kerdiboard.

Here's the Kerdi installation that was done in my bathroom recently (not by me, by a tile guy). I claim no knowledge of the proper use of the system, but this doesn't appear to be done incorrectly to my eyes, either.

Yardbird · « **Reply #19 on:** October 15, 2022, 09:00 PM »

I see that furniture mat and blanket in the bathtub.

There is a site by a professional tiler called "Floor Elf"- I think he is out of Fort Collins, Colorado. One of his tips was to always put a furniture mat in the bathtub. That way you can tell the owner it is to protect the tub, but is really in case you just want to take a nap in the middle of the day. Your tiler went one better-he even has the blanket.

squall_line · « **Reply #20 on:** October 15, 2022, 10:09 PM »

Quote from: Yardbird on October 15, 2022, 09:00 PM

I see that furniture mat and blanket in the bathtub.

There is a site by a professional tiler called "Floor Elf"- I think he is out of Fort Collins, Colorado. One of his tips was to always put a furniture mat in the bathtub. That way you can tell the owner it is to protect the tub, but is really in case you just want to take a nap in the middle of the day. Your tiler went one better-he even has the blanket.

The General put the mat in there; he told me that he was tired of his subs ruining brand new tubs dropping screws and stepping on them. The tiler would have had to have put a timer on his saw to have taken a nap in there for as much as I heard the saw running when he was here.

Cheese · « **Reply #21 on:** October 15, 2022, 10:23 PM »

That looks fine…however if I were doing the job, I’d just roll out some Kerdi to cover the entire wall instead of using those small individual square patches. That way it overlaps the Kerdi at the bottom of the tub and you have a continuous “rain curtain” that prevents moisture from traveling to where it’s not supposed to be.

Sparktrician · « **Reply #22 on:** October 16, 2022, 09:03 AM »

Quote from: mrFinpgh on October 15, 2022, 07:03 PM

Quote from: Sparktrician on October 12, 2022, 01:44 PM
No liquid waterproofing is used at all, but there is a need to use Kerdiband (membrane) with thinset to cover joints and screws to ensure a full waterproof experience before applying another layer of thinset to adhere the tile after the first layer dries.

Does every screw get taped? I was thinking they would have some sort of fluid/caulk for covering those up, kind of like liquid flash/fast flash?

Still, I think I had to tape the joints on the hardi, so I think it's a net savings in terms of labor to use Kerdiboard.

All screws and seams get taped and the thinset gets left to dry before starting the tile job.

Sparktrician · « **Reply #23 on:** October 16, 2022, 09:21 AM »

Quote from: squall_line on October 15, 2022, 08:11 PM

Here's the Kerdi installation that was done in my bathroom recently (not by me, by a tile guy). I claim no knowledge of the proper use of the system, but this doesn't appear to be done incorrectly to my eyes, either.

The one thing I would do differently is in the first photo. I prefer to back-cut (in essence, rabbet) the bottom slab of Kerdiboard so that it covers the lip of the tub, but is held up above the horizontal top of the tub by 1/4". When I apply the bottom slab, I put a healthy bead of Kerdi-fix in the back-cut (rabbeted) area to seal the Kerdiboard to he lip of the tub. When the tile job is complete, that 1/4" gap is sealed once again by Kerdi-fix to join the tile to the top of the tub, but flexibly to compensate for expansion and contraction due to heat and humidity.

Mike Goetzke · « **Reply #24 on:** October 16, 2022, 10:50 AM »

Quote from: squall_line on October 15, 2022, 08:11 PM

Quote from: mrFinpgh on October 15, 2022, 07:03 PM
Quote from: Sparktrician on October 12, 2022, 01:44 PM
No liquid waterproofing is used at all, but there is a need to use Kerdiband (membrane) with thinset to cover joints and screws to ensure a full waterproof experience before applying another layer of thinset to adhere the tile after the first layer dries.

Does every screw get taped? I was thinking they would have some sort of fluid/caulk for covering those up, kind of like liquid flash/fast flash?

Still, I think I had to tape the joints on the hardi, so I think it's a net savings in terms of labor to use Kerdiboard.

Here's the Kerdi installation that was done in my bathroom recently (not by me, by a tile guy). I claim no knowledge of the proper use of the system, but this doesn't appear to be done incorrectly to my eyes, either.

Few years ago I remodeled our master bath. It just has a shower stall. I used cement board and the rolled Schluter-Kerdi membrane that is thin set onto the cement board. To me looks like they did a great job on your bath.

Ha - my house is about 40 years old and the original tile was just put on regular drywall.

tjbnwi · « **Reply #25 on:** October 16, 2022, 11:08 AM »

Appears all of this is handle, just want to show you what can happen if a showert is not prepped properly.

I was in Denver doing this master bath and bedroom when my SIL called, wanted her master bath redone.

https://flic.kr/s/aHskYNxce1

When I got back home I told my SIL cost and timeline for me to do the work. She told to much and to long.

First clue she had a problem was the water leaking into the kitchen....

This is what the walls behind her tile looked like after a few showers. Yep, that is plywood in the shower with no warterproofing what so ever. I did not get to this for over a month after the last shower in the space, the plywood was still soaked when I took it apart.

Kerdi board, installed and taped.

Tile installed, waiting on the granite caps.

Schluter Systems is my go to.

Tom

Sparktrician · « **Reply #26 on:** October 16, 2022, 02:33 PM »

Quote from: tjbnwi on October 16, 2022, 11:08 AM

Appears all of this is handle, just want to show you what can happen if a showert is not prepped properly.

To amplify on Tom's message, waterproofing is mandatory in the build-out. No exceptions. The photos below are from the bathroom in my own home after I opened the wall up. This is the result of putting tile directly on drywall using just the absolute minimum of mastic with NO waterproofing and NO thinset base. We are NOT amused!

mrFinpgh · « **Reply #27 on:** October 20, 2022, 05:56 PM »

Quote from: Sparktrician on October 16, 2022, 02:33 PM

To amplify on Tom's message, waterproofing is mandatory in the build-out. No exceptions. The photos below are from the bathroom in my own home after I opened the wall up. This is the result of putting tile directly on drywall using just the absolute minimum of mastic with NO waterproofing and NO thinset base. We are NOT amused!

That is rough. Almost seems like they'd have to try to do such an incorrect job.

mrFinpgh · « **Reply #28 on:** October 20, 2022, 06:49 PM »

Picking up on this thread a bit more. We're starting to put everything back together now that it's all had a lot of time to dry out and the concrete should be cured enough to tile.

It's been years since I had to do any drywall or plastering, so this took a bit longer than I would expect. These small patches where there's an obstruction every 10 inches or so are a hassle.

This weekend, the plan is to pull the (temporarily set) toilet and replace the tile that had to be removed as part of the plumbing work.
The concrete they poured is neither flat nor co-planar with the existing substrate. So first order of business will be putting down some feather finish to try to get to a flat substrate that is about the same height as the current substrate. While that's drying we'll do any cuts we need to make and triple check layout. It shouldn't take long, since it's such a small area. I'd guess we'll spend 3x as long on the substrate prep than we will on the tiling.

One thing I'm unsure of though: we have a skirted toilet (Toto Aquia), so it doesn't get fastened the way a typical toilet does using closet bolts. Instead, there are plastic anchor blocks that get screwed to the ground, and then those get drilled into from the side to actually connect everything together. When they temporarily set the toilet, they drilled into the concrete to anchor those blocks. However, we will need to remove the anchor blocks in order to tile up to the flange. So, when the toilet gets reinstalled, new holes will have to be drilled (we'll also replace the anchor blocks with new ones. The old ones can only be re-drilled so many times before they get too loose). Is there an ideal material to fill the existing holes prior to tiling over them? Something that will set up quickly and cure hard enough in 3 or 4 days time?

By midweek, the plan is to have the toilet and sink back in place and a fully functioning bathroom. Then I'll shift my focus to the kitchen ceiling starting next weekend. My current plan is to use mineral wool insulation to muffle the waterfall-like sound of the toilet. There's about 6" of space from the wooden structure supporting the concrete to the edge of the joist. I haven't decided if I'll try to put 6" of insulation in there, or just stick with a more reasonable 3".

The joists themselves will need to be shimmed out a little bit and then I'll be putting up a double layer of 5/8 drywall to bring the ceiling flush with the surrounding. With all of that, my hope is that the kitchen will no longer have all the sounds of the bathroom.

mrFinpgh · « **Reply #29 on:** October 24, 2022, 11:18 PM »

Well, continuing the saga we tried to start tiling this weekend.

I mentioned in my other thread (on my Fein Turbo II deciding to not run all of the sudden) that there were some setbacks.

The big plug in drill I use for mixing thinset/plaster/grout went up in smoke halfway through mixing up a few gallons of thinset.
The concrete floor that the plumbers poured after doing their repairs is rather wavy in a number of directions, with a bit of an upward tilt towards the flange

So we were set back by a day or so but fortunately I've got enough overtime clocked to take Mondays off if I need to. :-) I was able to get a new drill for mixing - I went with a HF Low RPM/High Torque spade drill/mixer. As of now, I can't see myself needing to mix more than 50 gallons of stuff within the next decade, and I'm going to likely buy a new dust extractor to bridge things while I work on examining/repairing my Fein Turbo, so I figure I'll put the money where I need it.

The drill works great - it can go as slow as I can possibly tolerate and no problems mixing up some thinset exactly according to the prescribed ratios. I used to mix thinset more or less by feel, and while nothing has ever failed on me, I wanted to be extra conscientious now that I'm more sensitive to the importance of following the recipe.

In hindsight, I wish I had allocated a full day just for getting the substrate flat and in plane with the existing tile floor. While I did do a couple rounds of feather finish to fill in the hollows, the concrete itself seems to have an overall slightly downward angle to it, which made getting things even approximately flush was a lot more work than any other tiling I've undertaken. Here's what I did:

1. sponge the substrate to moisten it
2. burn in some thinset
3. with a 3/8*1/4 square notch trowel, rake thinset in one direction
4. backbutter the tile
5. press it down and wiggle it to collapse the trowel lines

The problem is, almost every tile was low relative to the ones already placed. I know those were done w/ the same trowel because it's the only square notch trowel I have.

So my solution was to pull the tile up and ice it like a cake, putting on a generous extra helping of thinset. Then I'd push this back down and check for flush w/ the adjacent tile and put a straightedge across to check for parallel. In some cases, I would get generous squeeze out, which I took as a sign that I had 100% coverage on those edges (as long as it squeezed out along the whole edge). Some were perhaps a little hit/miss. All of them were very hard to pull up - the suction from the thinset was significant.

The thing about this approach that has me nervous is, I know Versabond Thinset specs a max thickness of 1/4". I'd guess I was pushing that limit and probably a little more in some places. I also have a bit of concern that the generous layers of extra thinset might not be actually providing 100% support underneath - in other words, perhaps there are spots where the Tile-Thinset-Substrate connection didn't make it all the way down. It seems like it wouldn't be the case, but I'm keenly aware of what can happen to a tile with poor support underneath it.

The other thing that happened is that somehow the layout got off - I chalk this up to the fact that I'm trying to get new tiles woven in to existing stuff and a couple of the cuts we made (we pre-cut everything, or tried..) seemed to end up working very differently with a layer of thinset underneath them. What I tried to do in this case is just adjust the layout so the critical areas will look good and be aligned. That meant shifting a few grout lines to be smaller than the surrounding ones, but those should all end up covered by the sink and be very low visibility (the ones in front of the pex). It is a bummer to do that - I hate seeing reminders of my bad work/compromises, but we are on a very tight timeline to get the bathroom put back together so we can get out of this AirBnB. As it is, we had to extend our stay to deal with our previous setbacks.

All that backbuttering meant my thinset went off before I could get all the tiles in (yes.. 20 some tiles in 4 hours..). So tomorrow after work I'll have to come back and finish it off. I just hope nothing else goes sideways on me and I can get those 4 remaining tiles down in less than a couple hours.