Replacing undermount bathroom sink

[branimal]

I have a rental with a double vanity and the tenants cracked one of the sinks. I got an exact replacement from the manufacturer. I'm not sure of the material (porcelain, ceramic)??? The countertop is quartz.

The manufacturer suggests cracking the sink with a hammer and then grinding the remnants under the sink to get a clean surface. (It's not installed with undermount clips). The reattachment process calls for using bathroom silicone. I'm not sure how to brace the sink until it's fulled adhered. Maybe use a scrap 2x4 and a small bottle jack???

I watched a youtube video on the process and the guy uses a stiff putty knife to wedge b/w the sink and the countertop. He then shoves in black plastic shims and works his way around until the sink releases. It's a 2 person process. He cleaned the underside with a sander and denatured alcohol. Then he used black mamba sink adhesive.

How do you guys suggest I proceed? Thx

 

[mike93lx]

2x4 across the opening with something to pull up on the sink through the drain hole

 

[cgrutt]

I'd obviously follow manufacturer’s instructions but would think you want to use 100% silicone adhesive for this as opposed to a sealant which has stuff added for flexibility etc. Haven't done this before but would be inclined to cut the existing adhesive with an oscillating tool before cracking and grinding. First off the grinding will likely make a mess and secondly you may crack your countertop in the process. I bought windshield blades (which were ridiculously expensive) that breezed through the urethane adhesive on my windshield that would be my first choice. They also make flat scraper blades that I used to cut silicone out of windows before with no problem. I think even an ordinary multipurpose blade would work fine. As far as clamping I'd use a bar clamp and 2x4 as suggested above. Make sure you put some blocking underneath. Maybe a towel or cardboard between the 2x4 and countertop. Let it set for as long as indicated on instructions probably 24 hrs minimum would be my guess. Also make sure you clean the sink and quartz with denatured alcohol or mineral spirits before gluing. Good luck.

 

[LXCam]

I used the scissor jack out of my truck when I did mine.



Then proceeded to have a blowout the very same day and no Jack with me to fix it…..but I digress

 

[nadogail]

I generally replace under mount kitchen sinks with Surface Mounted Stainless sinks set in 40 year Silicone Caulking, I put 2X4 boards across the sink and hold it down with 5 gallon pails of water.

 

[The Cobbler]

a board on top of the counter as shown in post #2 with a clamp or all thread to clamp it would be my go to. easy peasy to clamp & see that the sink is in line with where you want it to be.

 

[mike93lx]

I generally replace under mount kitchen sinks with Surface Mounted Stainless sinks set in 40 year Silicone Caulking, I put 2X4 boards across the sink and hold it down with 5 gallon pails of water.

Replacing with a top mount was my first thought, too, especially in a rental, but he already has the new sink and seemed determined to go that route. Can't fault it, the quality of the rental may dictate that repair, plus it will likely look better and will avoid cutting the countertop

 

[cannuck]

Nice to see a thread that reminds me why I hate undermounts with a passion. Had to re-mount a failed bond in little kid's (now sold) house. SS sink on plastic countertop - clamp type mounting. Cleaned mechanically, then alcohol and back in place with urethane on 2 clamp places. Braced with mechanical props from below. Didn't think it would hold, but did fine until waving goodbye to that HORRIBLE (9 YO developer-built) place. In our house (43rd year) we had top mounts in bathrooms, went with one piece plastic castings - dated but extremely happy with their simplicity, ease of cleaning, safety from failure, etc. When I did our 2020 Covid kitchen remodel (as I imagine 1/2 of all GJ did as well) everything in our open kitchen/living/dining uses granite countertops, fireplace, island, etc. that I cut and finished in our front yard. NO WAY I was going to carry our fairly large kitchen counter with 2 x 90 degree "arms" and sink in the middle - would have to be 2 pieces simply because of size anyhow - so I solved the weakness of big hole with little left behind by designing to suit an extremely large apron double bowl that went all of the way back to the wall (i.e. NO HOLE - just countertop on either side) that I top mounted. 100% easy to handle tops and 100% safe unless the whole lower cabinets were to collapse - and that's fairly unlikely (even though I made most of them),

It never fails to baffle me why people tolerate nothing but styling trends to do really stupid things with homes, vehicles, etc.

 

[branimal]

So I tried cutting the alleged silicone seal with a knife. It didn't feel like I was cutting anything. I looked under the sink from inside the cabinet and it seems the sink is attached with mortar or cementous type adhesive. It was very hard and rough to the touch. I tried my oscillating saw and that didn't do anything either. The blade got stuck in there good a couple times so decided to abandon that approach.

I can't think of what else to do, so next time I'm there I'll start chipping away at it with a hammer and chipping chisel.

Any other suggestions.

Pic of the sink to quartz top seal:

 

[branimal]

Talked to another guy at the sink manufacturer. He said it is indeed a cementous type material. He suggested removing the entire top. Laying it upside down on the floor. Crack out the sink and then grind the surface smooth with a diamond grinding wheel. Then reattach with silicone and undermount clips. He said there are a type of clips that don't require holes. I have no idea how that would work. Nor could he give me the name of the clip.

 

[mike93lx]

Talked to another guy at the sink manufacturer. He said it is indeed a cementous type material. He suggested removing the entire top. Laying it upside down on the floor. Crack out the sink and then grind the surface smooth with a diamond grinding wheel. Then reattach with silicone and undermount clips. He said there are a type of clips that don't require holes. I have no idea how that would work. Nor could he give me the name of the clip.

I have to say, I'd replace the counter entirely at that point

 

[branimal]

I have to say, I'd replace the counter entirely at that point

Yeah, that's certainly an option. An expensive option b/c it's a 72" double vanity. My tenants are not going to be happy about that, but I have more than enough deposit on hand to cover the job.

Maybe I can hire a countertop guy to do the job for me. This isn't a handyman special.

 

[mike93lx]

Yeah, that's certainly an option. An expensive option b/c it's a 72" double vanity. My tenants are not going to be happy about that, but I have more than enough deposit on hand to cover the job.

Maybe I can hire a countertop guy to do the job for me. This isn't a handyman special.

Two 36's and an epoxy joint?

 

[branimal]

Two 36's and an epoxy joint?

I'd just get a 72" from the manufacturer where everything lines up perfect. I'll call them and ask about pricing.

 

[Fav Onefour]

That's going to be a tough little fix. I can't picture any real repair that you can do without removing the countertop. It will need grinding to remove the old fastening material. Best practice is to remove all the material down to bare quartz top.
What does the contact area look like on the replacement sink? Is it a smooth flat surface? I've seen sinks that were molded rough on the top edge. Those buggers will not stay attached with a regular silicone bead.
I have not replaced sinks with the cement type adhesive. I have a couple tops with the material and it is dang hard stuff. I'm sure it will need grinding.

The last few I've done were epoxy adhesives. There are quite a few options if you go that route. I wonder if the manufacturer has recommendations for their tops?
Either way, you would have best success by removing the counter and doing the work from backside. Gravity will be your friend.

 

[cgrutt]

Is there enough room to cut the sink out with a diamond wheel and grinder? Recommend closing doors, wearing a respirator and keeping a shop vac close to blade while cutting its going to make a mess. After sink is out you may be able to flatten out residue with the diamond wheel.

ETA removing countertop would definitely make it easier but depends what's on wall (tile, etc).

 

[branimal]

Is there enough room to cut the sink out with a diamond wheel and grinder? Recommend closing doors, wearing a respirator and keeping a shop vac close to blade while cutting its going to make a mess. After sink is out you may be able to flatten out residue with the diamond wheel.

ETA removing countertop would definitely make it easier but depends what's on wall (tile, etc).

I could cut the sink out once I got it off the countertop and flipped it over. FWIR I installed the countertop with dabs of silicone. I might have been generous with the silicone. It was my first countertop. I'm pretty sure I could fanagle the countertop to a nearby empty bedroom and do the work you suggested above.

Option 2: I called the countertop manufacturer - the replacement top with pre-installed sinks is $990 out the door. 7-10 business days for arrival. They'll also refund me $125 for the replacement sink I already purchased. So net $865. I'm going to charge that to the tenants.

Maybe option 2 is the easy button.

 

[mike93lx]

 

[Fav Onefour]

I do agree with the easy button option. Makes even more sense based on the cost outlay on your part.
I will caution you on the process. I've dealt with a few companies doing large vanities. They typically ship as a whole unit and the top is packaged together. You already know that part and the fact that it isn't attached.

The replacement process is different and some just seem to have a hard time getting packaging right. LTL carriers will beat the crud out of those boxes(crates). End stacking and pallet bridging are common practice when space is tight. I had one replacement top they tried three times and we just gave up. Each time the replacement took about five weeks. That vendor was using wood crates with foam sheet packaging and the tops were not held solid. The containers also had too much flex. One showed up with a chipped corner and two came with stress cracks off the sink opening. I ended up taking the credit and made one work for awhile until I found a suitable top.

It's not just countertops. I also had a three dinger with a fancy glass door. First two rounds were 245 lb crates of cullet. Third had glass, but rails were bent. Big, heavy, and flat is just too tempting for damage.

If you go with easy button, check the new top before you commit to tear out on the old.

 

[thunderalley3]

Take and keep very detailed photos of the broken sink and the method of adhesion to the top. I can almost 100% assure you the tenant who did the damage has already scoped out a $49 sink at the big box and figures the total repair will be $100.

When you hold back the cost of a compete top replacement the next place you will see them is on Judge Judy!!

 

[branimal]

I explored OPTION 3 yesterday - Called my quartz countertop guy - very fair pricing. Once I sent him some pictures he knew what the fix was. He said it would cost $300 for the repair. He'd have to drive into Manhattan on Saturday or Sunday morning (Free parking in front of the condo on weekends). Bring the countertop outside and grind it off on the sidewalk. This is in a residential/commercial district. If the condo board members find out, they're not gonna be happy. He didn't seem so keen on the job - he stopped responding to my texts. He's given me fantastic prices on quartz kitchen tops so I'm not gonna keep pestering him.

I went with the easy button and ordered a new top with pre-installed sinks. My stress level went down immediately.

Take and keep very detailed photos of the broken sink and the method of adhesion to the top. I can almost 100% assure you the tenant who did the damage has already scoped out a $49 sink at the big box and figures the total repair will be $100.

When you hold back the cost of a compete top replacement the next place you will see them is on Judge Judy!!

100% agree on how the tenants are going to react. The history on this : years ago I went in to make a repair and noticed the sink had a hairline crack. I emailed the tenants about it and I never heard back. I didn't want to harass them on it, but I do have that email for my records.

 

[cgrutt]

Glad to hear you got it sorted out. I know I'm probably in the minority with my thinking on this but if it were me I'd probably tell the tenant that you decided to replace the entire countertop and two sinks and it cost you $*** but only charge them for the cost of the replacement sink plus quote that you got to repair it. I think this would be the "right" thing to do. If I were the tenant and you charged me for a double vanity plus two sinks for a hairline crack in one sink and no damage to the countertop I'd be pretty ticked off. This sort of thing is part of the cost of being in the rental business no? Anyway my $0.02 good luck either way.