Home & Garden Columns

A friend of mine has a bassist living upstairs who is still working out the chords to In a Gadda Da Vida after living there for about 12 years. My friend is a patient person but she’s begun to exhibit something of a tick and often looks dolefully into space for long periods of time, returning from her reverie only when the music has stopped for some short spell. 

I don’t thing that’s she’s given to thoughts of homicide normally but she’s recently begun asking a lot of unwholesome questions about firearms and those CIA poisoning tricks they used to talk about in the sixties (probably while “In a Gadda Da Vida” was playing in the background). 

I have begun to suggest that she might want to try some sound control techniques in the building before moving on to anything more rash. She has agreed and we’ll see how things work out. These problems can be complex and changes in buildings which are designed to reduce sound can be expensive, but if that cute little freckly kid from next door has grown into a 17-year-old drummer in a band called Trama, you might also benefit from some of these notions. So here goes. 

If your problem is between the floors of a building, one of the best techniques is to use what is called Resilient Channel (sometimes called sound channel). This requires replacement of the sheetrock ceilings or the addition of another layer to the ceiling. If you have plenty of ceiling height, it’s fine to leave the first layer of sheetrock, although testing by National Research Council Canada suggests that this is not a good technique. First let me explain resilient channel. 

This is a Z-shaped piece of metal that comes in 10’ lengths and is screwed onto the bare rafters of a ceiling before sheetrock is applied. The channel is run perpendicular to the floor joists so that it runs across the bottom edge of many joists. Once you’ve run them every 16” from one wall to the other, you hang your sheetrock ceiling to the channel, not to the joists. The shape of the channel is such that the sheetrock has a bit of bounce to it and rather than being firmly mounted to the floor above it sort of hangs and is, therefore, much less able to transmit sound through the floor.  

The resilient metal allows the sound to get lost between the floor framing and the sheetrock.  

You can also add some other things to this methodology if you like:  

• You can insulate the space between the joists, in the floor thickness using common insulation. You can also install Sound Board, which is essentially a fibrous cellulose matting that’s 1/2” thick.  

• You can also install this material across the bottom of the joists prior to installing the Rezi-channel but remember that you’ll need longer screws. It’s a good idea to use 5/8” sheetrock on the ceiling if you want to really kill those bad vibes. 

For the really serious isolationist, cement tile-backer can be used as a part of such an assembly, although this is probably better for high frequencies than for low ones. You’ll want to remember to bring the launch codes with you when you lock down for the night. 

For walls between living spaces you can use sound channel and insulation or additional layers of sheetrock but the best method in my opinion involves building one of two types of party walls: 

My favorite works like this and you’ll actually be rebuilding the wall between the two spaces (unless this is a new project): You build a wall with two sets of studs (upright 2x4’s) on a 2x6 bottom and top member. One set of 2x4’s is built to one edge of the 2x6 facing one room. The other set is built to the other edge facing the other room. 

They sort of stagger across the length of the wall. Each 2x4 occupies most of the wall space but none of them touch the sheetrock of both sides. Each one touches and attaches to just one. So when you hit the wall on one side (or strike a power chord), one set of 2x4’s will vibrate but none of the other 2x4’s or the other layer of sheetrock will. 

I used this technique in a duplex in Richmond many years ago and when we were done, we could holler on one side and hear virtually nothing on the other. Great for marital disputes or privacy during intimate moments. 

The second type of party wall is simply a second wall built almost against the first with one or two layers of sheetrock in between. This eats up another few inches of room space and seems less efficient than the staggered technique. Nonetheless, it is simple and can be added to an existing wall. 

I should also mention that carpeting with thick padding is a great sound absorber and requires no significant alteration to the building. 

For sounds next door (like Trama’s weekly band practice), there’s nothing quite like double-glazed windows. It’s impressive how well these advents of modern building science perform at sound inhibition. About 12 year ago, I was inspecting a small house built right beside the 580 freeway. 

It was up a small hill so that you looked right over onto the freeway and the hill acted like an amphitheater capturing and funneling the sound right toward the house. Outside, for our best efforts, we could not converse but when we walked into the house, recently fitted with these new-fangled windows, the sound was little more than a distant hum. It was striking. 

This works equally well for neighbors that fight, dogs that bark all night or whatever drives you to and beyond distraction. If you work nights and sleep days, it might just keep you sane. 

I’ll add one last measure for the band members. If you live at Mom’s house or the police have now been at your house more than 4 times, you might try the following technique. 

Drum kits can be placed on a floating floor or in a hanging room. You can build a floor that sits above the primary floor in the room and either place it on isolation bumpers or hung from the ceiling. bumpers can be found at Granger’s (or another industrial supply house).  

I suggested these bumpers when my osteopath-friend Catherine was being assaulted by the vibration created by a restaurant ventilation system in her building. They can be used on motors or anything that creates vibration or noise. You can also hang a floor from the ceiling by use of cables or threaded rod. 

The secondary floor need only hang a fraction of an inch above the floor to prevent transmission of the vibration from a drum kit. The hangers (rods or cables) can employ isolation devices like the one mentioned above where they connect to the ceiling above. 

If you build a room instead of just a floor and hang it from above, you can really isolate the sound. There are certainly more techniques and high tech materials one can buy if you want to take this further but hopefully, this will get you started on the road to serenity. 

So if the person you’re sharing the duplex with starts a Herman’s Hermits cover band, don’t get mad, don’t get even, just get resilient. 

Got a question about home repairs and inspections? Send them to Matt Cantor, in care of East Bay Real Estate, at realestate@berkeleydailyplanet.com.