I like to crank up the volume of my home theater. I love the sound of explosions and the vibrations of low-frequency bass.
But the neighbors weren’t happy. So I thought I should soundproof my home theater room rather than give up on quality of my home theater experience.
For the wall, I had three options – a room within a room, staggered stud wall and double wall for soundproofing. Since room within a room was ruled out because of space and cost considerations, it was between the staggered stud vs double wall.
The double stud wall is better for soundproofing but has its drawbacks. Read until the end of this post if you would like to know the advantages and disadvantages of each type.
Staggered Stud Wall Construction
A normal wall will have 2×4 lumber used for framing separated by 16 inches. The 2x4s will be attached to the bottom and top plates. The bottom and top plates are 4 inches wide as well.
In a staggered wall, the top and bottom plates are normally 6 inches wide. The vertical 2×4 studs are placed alternately on each side of the plate. The gap between two ‘staggered’ studs is 12 inches.
With a staggered stud construction, what you will be gaining is an extra air cavity of slow-moving air which is highly beneficial for sound isolation.
Air cavities make a huge difference. Even an inch of extra air cavity will make a lot of difference to soundproofing.
Why Not Only Have Six Inch Wide Single Studs?
That was my question initially. The answer is not too complex.
First of all, the air cavity of a staggered wall is significantly larger than a normal single stud wall. It is this cavity that is benefiting us in soundproofing.
Secondly, there is some decoupling taking place in construction. If you’ve heard of the term decoupling, you know it simply means reducing the points of contact between the existing wall and the new wall.
With decoupling taking place, the transfer of sound vibrations to the outer wall is reduced.
Double Stud Wall Construction
It’s a no-brainer that a double wall or a double stud wall is two standard wall frames joined together.
But instead of just nailing them together, we leave a small gap between each wall fame. We want as much decoupling to take place.
So, what we have is two frames of 2×4 studs each with a gap in between. The overall thickness of the wall with a two-inch gap, for example, would be 10 inches.
Staggered Stud Vs Double Wall – Performance Comparison
Having learned the basic design differences between the two, my next question was – Which is better for soundproofing?
I compared the STC values (a standard metric for sound isolation) on the Soundproofing Company website and this gave me an idea.
Why I trust the Soundproofing Company website?
The website is owned by Ted White, an authority in the field of soundproofing and acoustics. If you spend some time on the website, you will know what I mean.
STC Of A Staggered Stud Wall
As per the data, with one layer of 5/8 inch gypsum installed at either side of the staggered stud, an STC of 48 would be achieved.
To give you an idea what 48 STC achieves, as per Wikipedia, at STC 45 loud speech will not be audible. At 50 STC, loud music (mid and high frequencies) will be faintly heard. So, a staggered wall with 48 STC will isolate loud noises and a bit of loud music.
STC of Double Stud Wall
With one layer of 5/8 inch gypsum installed at either side of the double stud wall, as per data by Soundproofing Company, we get an STC of 60.
If you go back to the Wikipedia page, it says that 60 STC and beyond is considered superior soundproofing and that most sounds will not be audible.
So, the performance of a double stud wall is superior.
Adding Mass and Damping
By adding more drywall, that is mass, and a damping compound like Green Glue, higher STC values can be achieved.
For a staggered wall, if I were to add only drywall on each of the sides, I could achieve an STC of 58. And with Green Glue in between the layers of gypsum, it could be bumped up to 62 which is very good.
On the other hand, if I were to go for the double stud wall, with only the drywall, the STC that can be had is 69. And with Green Glue on both sides, it can go up to 73 which is excellent.
Which One Did I Go For
The double stud wall is superior, no doubts. But it does take up a lot of space. The double stud would eat into almost two feet for each wall. That amounts to four feet reduction in length and another four feet in breadth of the room.
A hell of a lot of space sacrificed there.
With the staggered wall, I would be losing about 10 inches on each wall. This amounts to a loss of less than two feet on each side.
In the end, I decided to go for staggered studs for my walls along with the extra layers of drywall and Green Glue.
I was very happy with the results after my new walls were put up. My experiences during the installation is best left for another post.
My sub could be heard through from the other side but not loud enough to trouble my neighbors.
Staggered Stud Vs Double Wall – Which One is Right For You
The best is a room within a room design which is not practical in most cases.
If you have space, then you should go for double stud walls. The difference in STC ratings is quite a bit.
A double stud wall with only one layer of drywall will have about the same STC as a staggered wall with two layers of drywall and Green Glue.
Like me, if you can’t afford to sacrifice that much space, a staggered stud wall is the only way to go.
I would like to give you some tips that I know of, which you need to keep in mind while installing a staggered or double stud wall.
- Do check with your local building code to see if you are permitted to have 24-inch framing for walls. In some areas, this is not allowed.
- Make sure that the lumber is pressure treated.
- Cavities should be filled with loose insulation and not tightly packed. The insulation will prevent walls from resonating and absorb sound.
- Use acoustical caulk to seal gaps where the drywall meets the floor and ceiling.
- Don’t ignore the floors and ceilings. If nothing is done about them, you will still have issues owing to flanking.
- Don’t forget the windows, doors and air vents. These are weak links as far as soundproofing is concerned.
- Identify the problem areas which are causing sound to leak the most. This is what you should attend to before undertaking any soundproofing project.
To summarize, a double stud wall performs better than a staggered wall owing to cavity thickness and more decoupling.
The double wall has a drawback of taking too much space which is an issue. This is one of the reasons people go for staggered stud walls.
Hopefully, I have helped you make a decision. So, go for it and watch your favorite movies without worries.
Here are my recommendations for insulation materials.