Wall Issue When Replacing Bathroom Laminate Vanity Top and Sinks

[nukeem]

I have taken on a task of replacing my laminate vanity tops and sinks with a cultured marble vanity/sink in my Jack-n-Jill bathroom. As I was taking the old vanity top out (had to cut it) I noticed some holes in the wall on each end (the sink goes from one wall to another) where the vanity top met the wall. The back spalsh was flsuh with no holes. As I was repairing some of the wall I noticed the distance between the two walls looked different at the from of the cabinet compared to the back. Measurements showed the from to be 61-1/4 inches and the back was approximately 60-1/2 inches.

The laminate vanity top had separate tops, sides splashes, and back splash, so it would be easy for the installer to cut the backsplash to fit. But it appears they cuty holes in the wall for the top to fit instead of cutting it.

So, my problem is that I have a cultured marble vanity top/sink, which includes the back splash that is 61". The 1/4" at the from is no problem as I have the side splashes to install. What is the best way to regain the 1/2" on the back side so the sink will fit without me having to do any cutting on it?

Thanks for any help.

[Nestor]

Well, either one or both of your walls aren't straight. That is, they're not parallel.

So, this is really a two part problem:
1. What to do at the back of the counter top which is 1/2 inch wider than the space between the walls.
2. What to do at the front of the counter top which is 1/4 inch narrower than the space between the walls.

So far as the back of the top goes, then I don't think there's any good option other than cutting the counter top to fit between the walls.

If the cabinet below the top is still in place, set some drywall on top of it to simulate the top and use that surface to make a template out of poster cardboard to give you the exact shape of the space between the walls. Mark the top, bottom, front and back of that template so that if you turn the top over you can also turn the template over to ensure that corners line up and that you don't get mixed up and mark the cut lines on the counter top wrong.

"Cultured Marble" sounds like a fancy material, but it's really just Plexiglas mixed with clay or stone dust to give it opacity and a "natural stone" look (kinda). So, cutting cultured marble is really just cutting through Plexiglas, albeit more abrasive, but any circular saw will do it. But, try to get a blade with at least 40 tungsten carbide teeth for a smooth cut.

When I cut plastic laminate counter tops (and I've cut 19 of them so far) I do it with both a circular saw and a hand saw. I turn the counter top upside down so that the backsplash is pointing downward and rest it on some empty 5 gallon plastic pails (all of which are identical in height). I clamp a straight edge (I use a piece of clear fir 2X4 lumber) to the counter top so that the shoe of the saw will slide along the straight edge and the blade will cut along the scrap side of my proposed cut line. (I had this clear fir 2X4 run through a table saw on both sides to remove the rounded corners on it.)
Since a laminate top has a bullnose that sticks down about 5/8 of an inch, I have to be able to lift the saw over that lip without changing the plane of the blade. To accomplish this, I simply make two stacks of three shims each (to make a pair of "ramps") that are parallel to the straight edge to guide the saw over the bottom lip of the bullnose. A line going through the fronts or backs of each ramp would be perpendicular to the straight edge so that both sides of the saw are lifted at the same time by the ramps. I put 2 inch wide masking tape over each "ramp" to hold the shims in place.
My circular saw uses 7 1/4 inch blades and that's enough to cut through the laminate top and the bullnose, but not to cut all the way through the backsplash. So, once I cut through the flat part of the top and the bullnose, I vaccuum up any sawdust on the underside of the top, remove the clamps holding the straight edge down, adjust the position of the part of the counter top I'm cutting off slightly so that the kerf is of uniform width from front to back (thereby ensuring that the part being cut off is in the same location it was before I started cutting) and then set that same straight edge across the keft at the front bullnose of the counter top and use the clamps to clamp the counter tops on both sides of the kerf to the straight edge. That holds the two sides apart a fixed distance and prevents them from moving relative to one another.
Now, I take an ordinary hand saw:


and, holding the blade of the hand saw flat against the good side of the kerf, complete the cut through the backsplash with the hand saw.

And, I see no reason why the same procedure wouldn't work for a Plexiglas counter top.

So far as the front of the top goes, I'm thinking I'd use 2 inch wide painter's masking tape to mask off the wall and edge of the top and caulk the ends of the counter top using a putty knife
to get a nice sharp corner. Wait for the caulk to cure and then pull of the masking tape. Or, at least, I don't think any pro could do any better with this set of circumstances to deal with.

[pushkins]

Simply notch the drywall on either side to allow the vanity top to fit in, after your side splashes are installed any notching will be covered. It's a very, very common occurrence (unfortunately not all builders build square) especially with solid surface counter top installations, even square walls can lead to installers needing to notch the walls in corners as the drywall corners may have had to be built up.

[Nestor]

Yes, but we're talking about a 4 inch tall backsplash that's integral with the counter top. That means you're going to have to remove the paper and gypsum to a height of 4 inches above the counter top at both ends to get the backsplash to slide in.

And, we're talking about a total of 1/2 inch of gouge depth. That's going to either require that you fill in that gouge afterward with joint compound, or it's going to look like someone wrecked the drywall at both ends of the counter top.

Finally, how are you going to make such a "notch" look civilized? The only way I can think of is to cut through the drywall paper at both ends of the counter top and then scrape the paper and gypsum down with a paint scraper, and then sand with a sanding block. But, even then it's gonna look rough enough that people are gonna think it was done with stone tools and that's if you don't end up breaking that thin 1/4 inch of gypsum remaining at each end of the counter top.

It's Nukeem's house, Nukeem's money and Nukeem's problem, but I maintain that the better way to do this job is to make a template of the counter top space out of poster cardboard and use that template to mark and cut ENDS of the Plexiglas vanity top to fit between the side walls.

The backsplash of the counter top can then be scribed and cut with a jig saw to fit against the back wall. Shucks, if Nukeem has a belt sander, then scribe the contour of the back wall onto the counter top, cut along the scrap side of that scribed line with a jig saw, and then sand up to the scribed line with a belt sander for a perfect fit of the counter top to the back wall. That's how I did all my kitchen counter tops.

Nukeem: If you do decide to cut the counter top to fit up to the walls, DON'T just cut the ends of the counter top to the right angle, throw the counter top on the existing cabinet and scribe the backsplash. That way will work, but it's hardly well thought out. Instead, if there is a front "lip" that sticks down at the front of your vanity top, then put a long piece of wood under the vanity top when you push it against the cabinet so that it gets caught between the lip of the vanity and the front of the cabinet. That way the counter top will be held parallel to the front of the cabinet by that wooden spacer.

NOW, use a piece of wood the same width or a little narrower tham the one sandwiched between the front lip of the counter top and the cabinet to scribe the contour of the back wall onto the backsplash. THAT WAY, not only will the counter top fit perfectly against the back wall, but the counter top/sink will also be installed parallel to the existing cabinet.

If you had just put the Plexiglas top onto the cabinet so that it fits between the side walls and then scribe the contour of the back wall onto the backsplash, the counter top would still look OK when viewed from above. But, if you looked at it from below, you might find that the Plexiglas top was installed crooked with respect to the cabinet.

By using a board as a spacer to hold the Plexiglas vanity top parallel to the existing cabinet, and THEN scribing the contour of the back wall onto the backsplash, and then cutting along that scribed line, not only will the vanity top fit perfectly against the back wall, but it will also be installed parallel to the existing cabinets when viewed from below.

Believe it or not, most people that install counter tops don't do that step I'm describing with the board being used as a spacer to hold the top parallel to the cabinet before scribing. The installation still looks fine from above, but if you lie on the kitchen or bathroom floor and look up, you can see that the counter or vanity top isn't installed parallel to the cabinet it's sitting on.

OK, call me a fanatic perfectionist for pointing that out, but it seems to me that the little bit of extra work it takes to sandwich a board under that top before pushing it into place against the cabinet to ensure the top is parallel to the cabinet before scribing and cutting is well worth the result of having the top installed CORRECTLY. That is, as though it was installed on the cabinet before the cabinet was installed in the bathroom. Most pros simply toss the top on the cabinet and proceed to scribe the backsplash, and that's the difference between fine craftsmanship and a trained monkey doing the work. That is, the craftsman thinks about what he's doing and does it the best way he can think of, whereas the monkey does it the way he was trained to do it and doesn't question whether there's a better way to do it.

PS: So that means that when you make your poster cardboard template, you need to align the edges of the cardboard with the front edge of the cabinet and not simply push the cardboard against the back wall. Similarily, you need to measure how far the counter top will stick out ofer the front of the cabinet, draw a line on the underside of the counter top where the front edge of the cabinet should be and put your template down with it's front edge along that line before marking the cut lines at each end of the counter top.

[pushkins]

You don't cut out a 4" tall piece for the back splash, you only notch for the thickness of the counter top, the counter top sits in the notch and the back splash sits on the counter top. If the rear back splash is molded with the top then you will notch the corner to accommodate the rear splash, again the side splashes will cover any notching in the corners.
Also you don't hack at the drywall to notch it, cut a clean line through the drywall and remove the piece. Most likely you will find it is one wall that is not square to the rear wall so you probably only have to notch one corner side. Remember to add a bead of silicon to the top edge of the back splashes as well as the joint of back splash to counter top.

[nukeem]

Thanks for all the input. I was leaning towards notching the wall, but when I really started to think about it since the vanity is wall-to-wall I will have about 10-12" from the back that I would have to notch to allow the vanity top to slide all the way back. While this is not bad for the top since the side spalshes would hide it, the back splash, which is molded to it, would only cover the 1" at the back. Then I would have to repair the wall in front of it that I had to notch to get it all the way to the back. I'm not a drywall expert and can do small patches ok, but I don't know if I could adequately fix the 9-11" and have it look good. So, I was not looking forward to cutting on my new vanity top, but that appears the best way to go. Fortunately, I have a rotozip with a diamond blade that cuts through this stuff like butter. Which is also bad if I miss on the cut. But, I have plenty of time since it is a spare bathroom and don't have to rush the job.

Again, thanks for all the input.

[pushkins]

You don't slide the top back, you install it on an angle (say left side down into the notch then ease the right side down).

[Nestor]

Nukeem:

Pushkins is correct about not sliding the top back. Your top has an integral sink molded into it, and that sink is going to hit the cabinet front when you try to slide the top in horizontally.

But, with a 61 inch long top and 60 1/2 inches between your walls at the back, the only way you can do what Pushkins suggested in his last post is to notch the drywall on one side wall a full 1/2 inch deep. That is, you're going to have a hole in the drywall on one side wall.

Go to get a sheet of 3/8 inch drywall and cut it to about 60 inches long by the depth of your counter top.

Set that on your cabinet so that it lays flat. Measure to ensure that the front edge of the drywall overhangs the cabinet front by the same amount at both ends. Use some painter's masking tape to hold the drywall to your cabinet so that it doesn't move.

Now, take a small block of wood and slide it along each side wall, marking the contour of the side wall on the drywall with a pen or pencil held on the other side of the block of wood. Do that at both ends of the drywall. Mark the top of the drywall, the left side and the right side, the front and the back.

Cut the drywall along those pen or pencil lines. I'd probably use a coping saw that allows you to turn the blade 90 degrees, or a jig saw fitted with a wood cutting blade to do the cutting here.

Now, set your counter top down, right side up on two pails of equal height.

Measure the thickness of your backsplash and cut that distance off the back edge of the drywall.

Set your drywall on top of the counter top and push the back edge of it up snug against the backsplash. Confirm that the front of the drywall is even with the front of the top. Use masking tape to hold it down to the counter top so that it doesn't move.

Now, slide that same block of wood along the cut edge of the drywall, marking the top of the counter top with a felt pen as you go. Alternatively, use masking tape at both ends of the counter top, and mark the masking tape with pen. Do that at both ends of your counter top.

Cut your counter top along those marks, complete the cut through the back splash with a hand saw.

Set your counter top on your cabinet and it should fit between your side walls like a glove. Confirm that the top overhangs the front of the cabinet by the same amount at both ends.

Look at how the backsplash fits against the back wall. If you see any gaps between the top of the backsplash and the wall, you can now scribe the backsplash to fit against the back wall. Take a small lock of wood that's just a bit wider than the widest gap and slide that block along the back wall marking the top of the backsplash as you go. Remove the top and set it on two pails. Now, cut just outside of that mark with a jig saw and sand up to the mark with a belt sander if you have one. If not, cut as close to the mark as you can with a jig saw and then caulk the joint with a latex caulk. You might have to sand the ends of your top down a bit to get the top to fit right against the back wall.

No professional is going to get a better fit than that.

Now, do you have a plan in place to fasten the counter top down to the cabinet, or is there existing hardware you can use for that?

[Nestor]

PS: You should know that since your counter top is made of the same kinda plastic that top quality nail polish is made of (it's called "polymethyl methacrylate") NEVER EVER NEVER take your nail polish off at that counter top. If you spill any nail polish remover on your top, it'll leave a permanent mark where the plastic was dissolved. Ditto for any alcohols or strong solvents like isopropyl alcohol or lacquer thinner, both will dissolve your plastic top. Mineral spirits (aka: paint thinner) is safe to use to clean gunky stuff like lipstick or plumber's putty off your top.

You should also know that your polymethyl methacrylate vanity top is made of the same kind of plastic that top quality interior and exterior latex paints are made of. In fact, if you ever see the word "acrylic" used to describe anything from furniture to floor polish to bathroom floor mats, know that all of those things are made of the same kind of plastic as you have in your bathroom vanity top. It's a very versatile plastic.