How To Soundproof A Sliding Glass Door

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If you go online and look at pictures of recording studios chances are you will see a lot of sliding glass doors. Glass doors are great because they allow bands to see one another when live tracking, however, sliding glass doors are expensive when they need to be soundproof. In this article I will go over the best soundproof sliding glass doors in the United States, Canada, Europe, Australia and New Zealand.

1) How Soundproof Glass Doors Work

Before I explain which doors I recommend, first, we must look at how a sliding glass door keeps sound from passing through it. Like all things soundproofing, a glass door must accomplish three things. First, it must have enough mass in the glass to reflect sound back into the room. Second, it must have an air gap that will act as a spring in a mass/spring/mass system. Third, it must be air tight. Any pinhole leaks in a door can ruin an otherwise soundproof room. 

Let's now look at each component individually. The mass of the glass and the type of glass used are the key components in a soundproof glass door system. The mass of the glass should equal or exceed the mass of your two layers of drywall. In this case that is 4.4lb/sq ft for two layers of 5/8" drywall. 

Now, you can have glass that weighs less if you use tempered or laminate glass. These two types of glass are superior sound isolators compared to normal float glass. In my studio windows I recommend 1/2" and 3/8" panes of laminate or tempered glass (or a combo of both). 

Notice, how I said the two panes of glass should be different thicknesses. This is due to the fact that isolation improves when you do not use the same thickness of glass due to a phenomenon known as the coincidence effect. 

The space between our two paned of glass is also very important. The bigger the space between your two panes of glass the better the isolation. It is not uncommon to have 4-8" between two panes of glass in a soundproofing system. So, our sliding glass door is no exception. It must have two panes of glass and a large air gap to get a high enough STC rating. 

Lastly, our door must be air tight, so every seam or crack and crevice must be sealed with acoustic sealant, or gasketing to ensure the door doesn't transmit any sound. This is not easy to do with a cheap sliding glass door that was poorly made. 

***This diagram shows the soundproof windows in my studio. A sliding glass door must follow many of the same principles. 

2) Can You Build Your Own Sliding Glass Doors

The short answer is no. I have not developed a system for building sliding glass doors and it honestly is probably most efficient to buy them pre made. However, if you follow the principles above you could potentially find two sliding glass doors made of super thick glass and install them with a large air gap between a double wall system. However, you still may have issues if the door is not completely airtight. For these reasons I only recommend buying sliding glass doors from reputable suppliers. 

3) Where To Buy Sliding Glass Doors 

I have found the Soundproof Window Inc. has affordable sliding glass doors that can either be bought as a pair or go over an existing sliding glass door to improve isolation. You can check out there doors at this link: https://www.soundproofwindows.com/soundproof-sliding-glass-doors/

In Canda there is a company called Arc Acoustics, which sells as sliding glass door that can achieve an STC rating of 50. You could buy two of these or one with another sliding glass door. https://arcacoustics.com/product/soundproof-sliding-glass-doors/

UK/Europe:

I have found over the years that the only soundproof suppliers in europe are mostly located in the UK. The best soundproof sliding glass door supplier I found was Hugo Carter. They do custom doors for clients, so I am sure this is not the cheapest option, but it would be a good one. 

https://www.silentwindows.co.uk/soundproof-windows/soundproof-doors/

Australia: 

Lotus Doors is a supplier based out of australia and provides sliding glass doors with acoustic capabilites. If I used them I would buy two of there acoustic doors to get a higher Rw rating. I would also request differing thicknesses of glass in each door. 

https://lotusdoors.com.au/product/acoustic-sliding-doors/

Another option is Sydney's Prestige Plus, who have a lift and slide door. Remember to request a quote for a high STC or Rw door that would meet the needs of your studio. Two doors will always be better than one. 

https://prestigeplus.sydney/lift-and-slide-doors/

A company based out of Melbourne called Soundproof Windows also offers soundproof sliding glass doors: 

https://www.soundproofglazing.com.au/soundproofing-products/double-glazed-doors/double-glazed-patio-doors/

New Zealand: 

New Zealanders can also buy Lotus sliding glass doors - https://lotusdoors.co.nz/product/acoustic-sliding-doors/

A more commercial approach would be to look at GLYDE Acoustic Sliders. As per usual the highest Rw value they offer is 39, which is not enough for a recording studio. We are looking for Rw or STC ratings in the 50-60 range at least. For this reason you would want to look at two sliding glass doors. 

https://glydearchitectural.com.au/products/operable-sliding-doors/

Conclusion 

Sliding glass doors by nature are not good at sound isolation. Glass in general will not isolate as well as a solid door. However, if you want to see into a drum booth or vocal booth you will likely want a sliding glass door. 

As you can see from this list, they are also not easy to find all over the world. Your best bet is to know that you are looking for a door system that can achieve an Rw or STC value of 55+. The best way to accomplish this is to have two doors on each side of a double wall system. The glass must be laminate or tempered and ideally in the 3/8" to 1/2" thickness range. Lastly, the gap between your two doors should be as large as possible and both doors need to be airtight. 

When you talk to the sales reps on the phone ask these questions and ensure they know what they are talking about. If they seem to guess or try to sell you something you don't want then move on to another supplier.