Wood Slats for Sink Recess

This page describes one of the phases of the multi-year Master Bathroom Remodeling Project.

Inspiration

Curved Ceiling Inspiration

While browsing images during the design phase for the bathroom remodeling project, I ran across the picture at right and really liked it. I wanted to incorporate this in the design. The recessed ceiling and wall area around the sinks and vanity were a good candidate.

After designing it this way, I started to think about how this would work structurally, and I was initially not able to come up with an accepatble way to do this. I abandoned this idea for a long while to limit the project complexity. It was not until after the first two phases of the bathroom remodeling, just before beginning this one, that I came upon a an idea for doing the curve that would work structurally and not be too complicated. The key idea was to use plywood ribs to support the wooden slats.

Preparation

I began the preparation for this project in May 2016, though did not really begin it until 16 months later in September 2017. I had spent a year working two jobs so the bathroom remodeling work was put on hold. The preparation work was done just after finished the previous phase of the project which put wooden slats on the main ceiling.

The preparation consisted of removing all the insulation above the ceiling and putting a plastic sheet barrier between it at the attic. The removal of the insulation was also aimed at examining how the current ceiling and light fixtures and structures were installed so that I would have a strategy for removing them.

Existing Light Box (attic)

Light Box and Vent Pipe (attic)

Plastic Covering in Attic

Demolition

Original Sink Ceiling (north view)

Besides having the rough idea of using plywood ribs to form the curvature of the ciling, I had no idea of exactly how this would work. It was going to have to be contingent on what structural elements I had to work with in the existing walls and ceiling. The only way to find that out was to demolish the existing area and expose all the studs and beams. It was a little disturbing to demolish it without a concrete idea of how this was going to get put back together.

Preparing for Demolition

Original Sink Ceiling (south view)

Demolition in Progress

Prototype

Plywood Layout for Curved Slats

Curved Slat Layout Template

The curved ceiling was tricky enough that I needed to make a prototype so I could see if my calculations and ideas would actually work. There were dozens of minor measurement details and adjustments I had to make to get everything to align just right.

I also needed to cut the backing boards for the flat areas of walls and the ceiling because the transition areas between them were critical in ensuring a smooth final slat layout. The general idea for this work was to figure out how to position the curved pieces first and then it would be easy enough to work the flat pieces around them.

Curved Slat Rib Assembly

Prototype Curved Slat Rib (closeup)

There were two supporting curved ribs that would be mounted to a backing board with braces between the ribs for stability. There would also be a curved plywood base made out of smaller flat pieces and spanning the two ribs. This gave me something to mount to the wall studs and provided a surface to mount the mahogany slats.

Prototype Curved Slats (top view)

Prototype Curved Slats (loose fit)

Prototype Curved Slats (bottom view)

Side Wall Backing Board Fitting (north wall)

Curve Slat Backing Board (dry fit, north)

Curved Slat Rib Assembly (dry fit, south)

Cutting the Real Thing

Routing and Layout Template after Cutting

Routing Template Line Layout

For the prototype, I had just free-hand cut the curve using a jigsaw. This was not the smoothest of cuts and it also was not reproducable. It was important that the two ribs have exactly the same curvature shape or else the slats would look like a jumbled mess.

I made a fixture to be able to swing an arc with my router to achieve a uniform curve. Since the slat backing pieces are really just flat pieces of plywood, I then made little notches along the curve in the right places to make it piece-wise linear so that the 8 pieces could sit flat against the curve.

Curved Slat Rib, Pre-routing Clamping

Curved Slat Ribs after Cutting

Curved Slat Ribs, Beginning Assembly

Test Fitting all Backing Boards

With the real versions of the curves pieces and the wall and ceiling backing boards, it was time to put them all in position to see how they all lined up. Some minor adjustments were needed, but for the most part things fit well: much better than I expected.

All Backing Boards Dry Fitted (north view)

Curved Slat Backing Board (dry fit closeup, south)

All Backing Boards Dry Fitted (south view)

Light Fixture Locations

Light Fixture Positioning

At first, I wanted a light over each of the two sinks and a third light over the vanity area. To center the lights this way would result in an odd looking spacing between them. In the end I decide to just position the 3 lights uniformly across the ceiling.

Cutting and Assembling Slats

Side Wall Slat Layout

On the ceiling, I used 1x4 mahogany stock, but since this ceiling was lower and it would include the walls that were even lower still, I wanted these to be smaller 1x3 pieces. Unlike in the slats for the main ceiling, the slats here would mostly all be the same length. The only exceptions were the wall outlets (one on each side) and the slats surrounding the light fixture cut-outs.

After cutting the slats, the assembly process was much the same as in the main ceiling project where I would screw in from the back side of the backing boards so there would be no visible screws. The curved pieces, with all their support structures, were a little more difficult and I had to specially cut out some slots so I could get a drill and scewdriver at the right location and angle.

Side Wall Slat Positioning

Side Wall Slat Backside Screws

Rough First Slat Assembly

Trick of the Eye

Because the curved sections were the hardest to work out, the ceiling area's slat locations would be based upon making them line up with the slats on the curve. The curved areas at both ends, once mounted to the walls, means that the distance between them is a fixed and non-negotiable amount. What to do if this width is not an even multiple of the 1x3 slat widths (plus the 1/4'' gap)?

The odds were against it and it did not accomodate an even number of 1x3 slats. It was close, but I needed an extra 3/4'' to make it an even number. I decide that I would shave 1/16'' off of 12 of the slats and positioned them in a way to make it difficult to notice that they were thinnner. I positioned these slats as the ones that ran by the light fixture openings. The lights were already visually interrupting the even slat layout and spacing, so this seemed to place they would be least noticed. With 3 lights and 12 thinnr pieces, it worked out nicer to have the 4 slats around each light be the thinner ones.

Practical Considerations

Cutting Ceiling Backing Board

At this point, the ceiling board between the two curved assemblies, was a single piece of plywood. The less seams the better. However, after affixing all the slats to this board it became clear that it would be a challenge to install this given its weight. It was doable, but riskier than if I had two smaller pieces, so I decided to cut it in half. By cutting in betwen the slats, this extra seam would hardly be notiable.

Test Installation

Final Slat Assembly

With all the slats installed on the backing boards, it was time to do a test installation. This would serve the double purpose of checking the fit and knowing exactly what we would be in for when we installed the finished panels. These panels weighed significantly more than when I was just test fitting the backing boards and that had implications on how to best assembly everything. This test installation step was also very satisfying because it was the first time we got a real view of what this would eventually look like. Helps to keep the motivation up for what was already a large body of work.

Slats Installed for Dry Fitting (north view)

Slats Installed for Dry Fitting (south view)

Slats Installed for Dry Fitting (close-up, south view)

Slats Installed for Dry Fitting (close-up, north view)

Sanding

Slats and Ribs Ready for Sanding

Though there was less surface area than for the main ceiling, there were a lot more individual pieces to sand (and finish). This means more surfaces and more edges, which tends to be more time consuming that just sanding a large flat area.

Stain and Polyurethane

As with the main ceiling, the backing boards got a red mahogany stain, while the mahogany wood slats got a couple coats of clear satin polyurethane.

Curved Slat Backing Board Stained

Wall and Ceiling Backing Boards Stained

Both Curved Slat Backing Boards Stained

Slats Prepared for Polyurethane

Slats after Polyurethane (close-up)

All Slats after Polyurethane

Covering the Gaps

Additional Blocks for Wallboard Support

One thing I had not worked out until this point in the project was how to cover the gap between the new curved ceiling and the existing straight walls. What was obvious was that I needed some form of curved piece to fill the gap, but what was less obvious was how to support this new piece of wall.

Since this new piece would curve and get thin at the ends, I chose to use 1/2'' plywood instead of sheetrock since it would be more stable and easier to work with. The tricky part of what this would bind to was solved by adding some support blocks to the curved slat assembly.

Final Board Assembly

Side Wall After Assembly (north wall)

Curved Slats After Assembly

Walls and Ceiling Slats After Assembly

All Pieces After Assembly

Extra Ceiling Support Structure

Extra Ceiling Support Layout (south)

The previous light fixtures and their wooden boxes were not that heavy and I was also not that impressed with how they chose to support it. Since it held up for decades, I guess it is hard to say they did it wrong, but it seemed a bit amateurish in some regards. What I was about to install was going to be much, much heavier than what was there previously. Thus, I needed to add a beefier support structure. This consisted of a new 2x4 across the back length, beefing up the support for the existing 2x4 across the front length, and installing a few cross beams so that The boards would be supported in the middle and not just the ends.

Extra Ceiling Support Layout (middle)

Extra Ceiling Support Layout (north)

Installed Ceiling Support Cross-beams

Installation

After Installation (north view)

The one design principle I had to violate for this phase of the project was the visible screws principle. For the main ceiling, I used some tricks to achieve this, but that was only possible because I get up into the attic on the other side of the panels. Since one of the sink area walls was an external wall, this would have required a major effort, especially since the house has stone veneer on it. This was beyond worth doing. I did the best I could by using very thin headed nails, located between the slats and whose heads were dark brown in color. You would have to look very hard to notice them.

The good part about all the test installations is that there should be no surprises when you finally put up the real thing (and there was not).

After Installation (close-up, north view)

After Installation (south view)

After Installation (wide view)

Light Installation

It was time for another trip into the attic to install and wire the recessed light fixtures. The center light would be controlled from a switch by the door whose wiring I had rerouted when I added the lights to the main ceiling. The other two lights would be controlled by the original switch located adjacent to the sink area.

Light Fixture Holes (attic view)

Light Fixtures Installed (not wired)

Light Fixture Installed and Wired (north)

Light Fixture After Installation from Below

All Lights Installed (north view)

All Lights Installed (close-up)

Adventures in Making Trim Pieces

Unless you were looking extra closely at the previous post-installation pictures, you would not have noticed the need for some trim around the mirror. The mirror is rectangular and its corners can now be seen tucked behind the curved sections. This also leaves an unsightly gap showing some wall board and the gap at the top is very different from the gap at the sides. What this needs is some trim to make the mirror look like it was part of the design and that hides the unsightly wall gaps.

Router Compass Positioning

Router Compass for Curved Trim

Making the curved trim pieces was a challenge and filled with problems. I had to throw away my first attempts, and even went through 2 other prototypes before I figured out how to do this. In all cases though, it required me to make and use a compass fixture for my router.

The key part to making this was to join two pieces of wood at the edges (glued) so that I had a wide enough board that the required circular arc could fit on. I had to do this more than once do to problems.

Router Compass Setup for Testing

Test Piece for Curved Trim

Positioning Trim for Curve Cutting

Broken Router Bit

A router rotates it bit at 25,000 rpm. It can do damage very, very quickly ... and it did. I tried to cut the piece in a single pass using the router. I should have known better. It is far better to rough cut the curve with a jigsaw and just use the router for cleaning up the curve without taking off so much material at one time. If you forget this, like I did, you wind up with a destroyed router bit as shown at right and a piece of scrap wood. I had to start over and re-glue new pieces to be routed.

Curved Trim After Cutting

Curved Trim After Cutting (close-up)

Curved Trim Tearing Problem

Staining Trim Mirror Spacers

Trim and Spacers Ready for Finishing

One of the other reasons I went through so many prototypes was my attempt to have the trim pieces also compensate for gap between the wall surface and the mirror surface. For the trim to sit flush, it needed to be at the wall surface in some places and the mirror surface at others. This was very, very tricky and I never succeeded. Instead, I just made some spacers the same thiuckness as the mirror and mounted them to the walls, then the trim pieces cound sit flush against the mirror and spacers.

I was not yet done with the complications for this trim. The curved parts of the trim would be over the corners of the mirror which meant that I could not nail them into anything. I decided that I would have them just be floating pieces held in place by the adjacent straight trim pieces. The curved pieces would have dowels in their ends, while the straight pieces would have slots that went around the dowels.

Dowel and Slat Jointing (close-up)

Dowel Hole Drilling for Curved Trim

Notches for Dowels in Trim Ends

Repaired Curved Trim Edge (close-up_

Fixing the Routing Rounding Mistake

To give the trim a finished look, I used a router bit to round off one of the edges. During this process, in a brief moment of lost concentration, one of the curved trim edges caught the router bit ever so briefly in the wrong direction. In less than 100 milliseconds, the router bit rotating at 25,000 rpms had 40 revolutions to be chomping away at the wood and that was plenty to do a lot of damage.

This was by far the most frustrating part of this project and all my own fault. The amount of labor and time it would take to fabricate another curved trim piece was significant. Instead, I tried to find the best wood repair/filler I could and try to mend it. The stuff I found did work well, but it did not come in a color matching the wood so I was left with something very disappointing. Functional, but a glaring reminder of past mistakes.

Trim Installation

Trim Mirror Spacers Installed (close-up)

Trim Pieces Prepared for Polyurethane

Installing the trim was relatively easy. First the spacers were screwed into the wall, then the trim pieces nailed into the spacers using small finished nails. I would set the nails and use some wood filler to cover them up.

Trim Mirror Spacers Installed

Trim Installed (south view)

Trim Installed (north view)

Before and After

Before

After