Soundproofing the office wall

My home office had hit a snag. I now have meetings in the early afternoon hours when my 2 year old daughter is trying to sleep in the room next door. She's an extremely light sleeper - meaning that most any noise and light will wake her up. She sleeps with a white noise machine and blackout curtains (for a while, we even had to tape blackout fabric to the windows so that absolutely zero light entered).

It should come as no surprise that my calls would rise above the sound level of the white noise machine. Add to that the fact that we wanted to have an accent wall in the office. So we decided to rip down part of the wall, sound-proof it, and put the wall back up again with shiplap.

Before

Look at this wall, all innocent, and not knowing what is ahead of it.

Materials

Here is the materials list for this project:

1. 17 6" Shiplap planks (Buy at Home Depot) - $200 - this is what is showing in the end
2. Rockwool Insulation (Buy at Home Depot) - $51 - this is slightly better than normal insulation for soundproofing. It's also better at climate control. Bonus points for the science of Rockwool being pretty neat.
3. Mass-loaded Vinyl (1lb) (Buy at SoundAway) - $132 - if you can find this locally, it will save you a lot of shipping costs. This is great for isolating sound without adding much thickness to your walls.
4. Vinyl Tape (Buy at SoundAway) - $10 - this helps cover the seams in the vinyl.
5. Acoustic Caulk (Buy at SoundAway) - $11 a tube - acoustic caulk helps soundproof in the cracks around the vinyl
6. Roofing nails - these are great for hanging the vinyl while having the nails flush with the wall
7. 1 3/4" brad nails - for hanging the shiplap planks
8. Paint of your choice. I used White Pepper by Behr
9. Brad nailer - I use a DeWalt brad nailer, nothing special.
10. Spackling paste - for filling the holes from the nailer
11. Network and power cables with 1 gang boxes
12. White caulk - for around the edges at the end

Step 1: Paint the shiplap

First, we pained the shiplap out on sawhorses on our front lawn. Although we're going to put a ton of holes in these, it's easier to paint outside than inside, and the sun and breeze will cure the paint pretty quickly.

Step 2: Demo the old wall

I took a hammer and destroyed the old wall. It was just drywall, so this did not take long.

Step 3: Electric, internet, and insulation

This wall is funny. It would appear that the wall was not always there, and was put up at one point to divide one room into two. (I think that the original floor plan had two rooms because there were two closets and two doors). The wall was set up as a non-load bearing wall, but had no eletrical outlets. (Code asks for an outlet within 6 ft of any wall place, with some exceptions.) I put an electrical outlet on both sides of the wall. I also added a gigabit ethernet jack as well, since my desk is to go in the corner under the window.

Next, I installed the Rockwool insulation. It fits very nicely. I had to cut out sections for the outlets, and I had an easy time stapling parts to the sides, in case it attempts to sag over time. I ran out of Rockwool, so I used normal fiberglass insulation for the remaining areas.

Step 4: Mass Loaded Vinyl (MLV), Caulk and Tape

These sheets are very heavy! They are 1/8" thick, but 1 lb per square foot. This means that a section that goes from floor to ceiling is about 32 lbs. I cut them outside with a normal utility knife. My spouse held them up and I nailed them in until they stuck. We then nailed them with the spacing of drywall. Every 12-18 inches there is a nail into the studs.

One thing I noticed with the vinyl is that it's very difficult to get flat, without ripples. I didn't stress much about this. When the wall gets installed in the next step, it's easy to push the ripples into the space between the studs.

After install the vinyl, I caulked around the sides, and taped the inner seams.

Step 5: Install Shiplap

This was fairly straightforward. First, we measured the width of the wall. Then we cut the shiplap. Then we installed with the brad nailer. Due to the weight and the amount of stuff in the wall, we nailed onto every stud in the wall. We started at the top and finished at the bottom. This was so that we could see a whole piece on the top. There is a partial piece on the bottom, but you cannot tell because it is behind the baseboard.

After the shiplap was up, we patched the tiny holes with spackling paste, sanded the extra off, and caulked around the sides. We added the baseboards and patched up paint, and we were done!

Results of soundproofing

The part I was most excited for, did this actually make a difference?. I ran a few tests.

1. Baseline - the sound level with nothing happening in the office
2. Planet Money - I played this podcast off of a speaker in the office
3. Maroon 5 - Sugar - I swear, I don't listen to Maroon 5 a lot. However, this song does have highs and lows, and I saw it in a YouTube video.

Also, I tested at different decibel levels. A normal conversation is about 60 dB and would reflect me taking a call.

All of these tests were done with a simple decibel meter app on my phone.

Test	Before	After
Baseline	30 dB	30 dB
Planet Money @ 65 dB	32 dB avg / 41 dB max	28 dB avg / 34 dB max
Planet Money @ 50 dB	32 dB avg / 36 dB max	28 dB avg / 30 dB max
Maroon 5 @ 70 dB	35 dB avg / 44 dB max	28 dB avg / 34 dB max
Maroon 5 @ 55 dB	30 dB avg / 40 dB max	28 dB avg / 35 dB max

Subjectively, 30 dB is pretty quiet. The ambient noise of my street and the room cause that amount of noise. It would appear that we have about a 5-10 dB reduction across the board. That equates to about a 30-50% reduction in noise. That's pretty good! Notably, the really loud music is still audible. The conversation is just a rumble now, and the quieter music and conversations are inaudible. When you pair this with the white noise machine, my daughter can now not hear me, even when on a call. That's a success!

There's one last thing I can note - this is just one wall that I've handled. I could obviously do more for the ceiling, and for the outer walls of the two rooms. That's a project for another day.