Are you tired of looking at that plain builder-grade bathroom mirror? These frameless mirrors are seen in many houses, condos, and apartments because they are a fairly inexpensive and easy installation option for the builder. Large bathroom framed mirrors can be pricey however in this post, how to build a DIY bathroom mirror frame (step-by-step instructions) we take you through upgrading your frameless mirror for a fraction of the cost of a brand new one.

About the Project

I mentioned that “we” will share how to upgrade your mirror because I decided to enlist Ray, my husband for this project. I needed his math mind and construction skills to pull this one off. Also, this mirror upgrade was done for my Mom at her condo. She was tired of looking at the plain large mirror in her master bathroom and felt a new look was in order!

Level of Difficulty for this Project

You will need a few power tools AND know how to use them! You will also need some understanding of measurement – both of these are not my strong suit so as mentioned above, I brought in the big guns (my husband) to help with this DIY mirror. While I don’t have a specific metric for the level of difficulty for this project, I would offer that on a scale of 1-10 – I’d give it a solid 6.

Time Requirement

In terms of time, this DIY mirror frame and installation took approximately 3 active hours (this does not include shopping for the supplies or waiting for paint to dry)

Supplies and Tools for Building a DIY Bathroom Mirror Frame

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Assessing the Current Mirror and Planning the Frame

On the first day, Ray and I went to my Mother’s home with a screwdriver and tape measure in hand. Our goal was to determine whether the builder used mirror adhesive to attach the mirror to the wall. While not a super popular practice anymore, some builders still use glue. We were encouraged when we saw the mirror clips and simply unscrewed one of the little clips in order to move the mirror just enough to determine that the mirror was not glued to the wall.

unscrewing the mirror clips to make sure the mirror was not glued to the wall.

Since we wanted to raise the mirror to accommodate a new frame, we also needed to check how much space existed between the top of the mirror and the light fixture. We were able to determine there were 4.5 inches, leaving plenty of space for raising the mirror and adding a frame.

measuring the sapce between the top of the mirror and the light fixture.

The mirror being attached with just mirror clips and with space above to allow for a frame made this project a lot easier! We then moved on to taking measurements.

Note: If you are working with a mirror that is glued to the wall you may want to consider covering the mirror with a frame (i.e. hang a frame on top of the mirror) or gluing trim directly on the mirror for a similar look.

Taking Measurements

The mirror measurements (without the frame) were as follows: 46 inches wide by 42 inches tall. As mentioned above, the light fixture was 4.5 inches above the top of the mirror. The vanity extended longer than the mirror at 49 inches long. This gave us just over 1.5 inches on each side to line the new frame up with the vanity countertop.

measuring the space between the mirror and the outside of the countertop.

With these measurements, we decided to make the frame 2.5 inches wide with roughly 3/4 of an inch covering the mirror. This size worked for both sides of the mirror and would line up with the length of the vanity countertop. We also knew it would fit under the light fixture even with raising the mirror. We wrote these measurements down and headed to Home Depot to pick out some decorative trim and supplies.

the plan written on a piece of paper.

Shopping for Stock

At Home Depot we shopped in the trim and chair rail aisle. I wanted something decorative that would compliment my mother’s home. We focused on the width of the trim as well as the thickness. The thickness was important since we planned to cut a groove (or shiplap joint) into the trim to work double duty by both covering and holding the mirror. We were also looking to stay with the 2.5-inch measurement. We decided on this trim which is listed as a chair rail. I liked the style, the thickness, and the width was right – it checked all the boxes! This trim came in 8-foot lengths at $20.58ea so we bought 2. While at Home Depot we picked up wood glue, painters putty and caulk.

trim piece from Home depot.

Prep Day

We decided to prep ahead of time by cutting all the trim and painting the pieces at our house. The first step on prep day was cutting these long 8-foot pieces to make working with them more manageable. Each piece had an inch to spare for our project so we measured and with a miter saw cut them into 2 – 50 inch pieces – leaving 2 at 46 inches (creating 4 boards).

measuring to cut the long 8 foot boards into smaller more manageable sizes.

Cutting the Mirror Grooves ( Shiplap Joints )

The mirror was 1/4 inch thick and we planned for the overhang (the part covering the mirror) to be 3/4 inches. We first marked the boards a little over 1/4 inch thick to allow some wiggle room for fitting the mirror. Using a table saw with the trim piece on its side we cut the first pass, the width of the overhang (3/4 inches).

Then with the trim laying flat on the table saw we cut the depth of the thickness of the mirror. Using a sample board that was the same thickness as the mirror we could see that it was going to be a perfect fit.

45 Degree Angle Cuts (Corner Cuts)

After the grooves were cut we set out to make the corners of the frame. To do this we used a miter saw and cut each corner at a 45-degree angle.

a miter saw cutting the the trim pieces at 45 degree angles for the corners

Once the corners were cut we placed them together to make sure we were on track. We then measured again to ensure a perfect fit for installation day.

Painting the Trim

Some of the cut edges were a little rough so the first thing we did before painting was to sand them with sandpaper. Then I moved on to painting them. My mother just had her whole condo painted and had some woodwork paint left over so I used that. I made sure to paint the top part of the grove so that when the mirror reflected on it – it would look finished. I then painted the top and the sides. After the first coat dried, I applied a second coat.

Note: I did not paint the back of the frame since that part would be sitting against the wall.

Installation Day

With the trim all cut and painted, installation day was a cinch! We headed to my Moms with the prepped pieces of wood, wood glue, screwdriver, nailing gun, Painter’s putty, Caulk and caulking gun, extra paint, and a paintbrush.

Removing the Mirror

The first step was removing the mirror. To do so we simply unscrewed the mirror clips and lifted the mirror off the vanity top.

Cleaning Up the Vanity Countertop

There was some leftover clear silicone on the countertop of the vanity so we simply took a screwdriver and carefully scraped it off. The space was then ready for the new frame.

Note: By extending the frame beyond the footprint of the original builder-grade mirror we did not have to worry about filling the mirror clip holes or painting. We knew the frame would cover the full space. As you can see in the photo below the original wall color sat behind the mirror.

Gluing the Prepainted and Precut Boards

Starting with the bottom piece of the wood frame we first added wood glue and then placed it on the wall right on the vanity counter.

Nailing the Trim

Once the board was in place we went in with the nail gun and nailed on the outside thick part of the trim (see photo below for nail placement). We choose this part of the trim to stay clear of the edge of the mirror. Then we did the same with the left side, making sure to line up the corners.

Note: You can do this project with a hammer and finish nails but you will run the risk of cracking the mirror if not careful. For this reason, a nailing gun is preferred for this project.

Sliding the Mirror in Place

Once the bottom and left pieces were glued and nailed in place, we slid the mirror along the shiplap-like grooves that we had precut with the table saw.

Installing the Remaining Boards

Next, we added the right side trim and the top trim using the same process.

Note: For a secure hold, it is wise to find a stud when nailing the top piece. You can do this by using a stud finder.

Filling the Nail Holes

Once all boards were in place and the corners connected we went in with painter’s putty and filled the nail holes. We simply made the putty into a ball, filled each hole, and wiped the excess off with our thumbs. This way we did not need to sand before touching up with paint.

Applying Caulk

To give a nice finished look and to blend the seams in the corners we then caulked around the edges and on the seams. We applied the caulk heavily and then used a wet towel to wipe off the excess.

Note: We did not caulk the inside edge (on the mirror), just the outer edge and seams.

Touch up Paint

With nail holes filled and caulking done the next step was to go in with some touch-up paint to complete the DIY bathroom mirror frame.

Completed Project

We’re so excited about how this turned out! It gives the bathroom a fresh new look and the mirror has gone from one of those basic builder-grade mirrors to a beautiful custom mirror frame.

Cost of this Project

Note: We had all the tools and used paint that was left over from another job.

Trim – $41.16

Wood Glue – $3.68

Painters putty – $9.48

Caulk – $3.58


Total: $57.90 (plus tax)

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Save this project for later!

I hope you enjoyed this blog post, How to Build a DIY Bathroom Mirror Frame (Step-by-step Instructions) as much as we did building it. This DIY mirror frame is an easy way to give you a fun bathroom makeover without spending a ton of money buying a whole new mirror. And I just know a lot of people are looking at the basic builder-grade mirrors the home builders installed and wishing for something more! For more project inspiration please visit my DIY page.

Keep creating friends!

my signature, a drawing of me holding a coffee cup that says Create.

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