A reader who lives on a busy highway asked, "What makes for a good noise-barrier fence? I love my property, but because of its proximity to heavy traffic, I do not have the peace and quiet that I crave. What type of fencing is best for blocking road sounds?"
Yes, our privacy requirements often include relief from external sounds, as well as from sights. Here is how I answered this reader's email:
Noise-Barrier Fences: Factors to Consider
A fence intended to serve as a noise barrier or "sound barrier" will typically use thick tongue-and-groove boards, in order to form an impervious barrier. These boards are nailed to heavy rails, which in turn are supported by heavy posts. The operative word for noise barriers is obviously "heavy." That is because, as a rule of thumb, mass dampens sounds best -- so fencing serving the purpose of blocking road sounds needs to be heavier than most other fencing.
For the same reason, masonry walls are more effective at blocking road sounds than even the best wooden fences. Walls of earth (called "berms") also make for great noise barriers if you can build them so that they are high enough (which takes a lot of earth).
But if you are, in fact, committed to using wood, aim for a fence that is high and solid (that is, no gaps between the boards). Whichever material you use, first submit a detailed plan (with precise installation location on your property, exact measurements, etc.) to the powers that be to ensure that you will not be violating any city ordinances. A tall fence situated close to the road will often put you on City Hall's hit list, especially if it is on a street corner (where it could reduce drivers' visibility). This is unfortunate, since height is a key element in blocking road sounds (sound waves can travel right over a short fence, thereby defeating its purpose).
Mass-Loaded Vinyl: a Step Beyond the Typical Noise-Barrier Fence
One way to improve the effectiveness of a wooden noise-barrier fence is to add a soundproofing material called "mass-loaded vinyl" to it. The product is sold in rolls. Make sure it is listed as being for outdoor use.
It is easiest to apply mass-loaded vinyl when a fence is in the process of being built, rather than retroactively. The latter is certainly possible, but it means removing fence panels and then reattaching them later.
Installing mass-loaded vinyl is simple enough once you understand the basic components of a wooden fence. The posts and the rails form the frame of the structure. It is to this frame that you staple the mass-loaded vinyl. Overlap the sheets to compose as solid a barrier as possible, then caulk any seams with acoustical caulk. Lastly, attach the wooden panels to each side of the fence (the mass-loaded vinyl is sandwiched in-between).
Get by With a Little Help From Your Friends
Whichever material you construct it with, your noise-barrier fence will bear the brunt of the load in keeping your yard quieter. But it need not do all of the work. Enlist the support of whatever complementary features you can find. Two examples are:
- Plant material
- Water fountains
To complement the fence or wall that you build to block road sounds, make sure your property is well landscaped with plants, especially plants with substantial mass, such as trees and shrubs. On their own, plants will not be sufficient to solve the problem, but they do absorb enough sound to merit their use as complementary pieces in your noise-barrier project. The plants can be grown in front of the fence (as in my photo), in back of it, or both. Evergreen shrubs and evergreen trees are best, since they will aid in landscape noise reduction year-round.
Also of a complementary nature are what we might term "white noise" components. Think of them as "fighting noise with noise." They do not reduce the noise levels in your yard, but they do mask some of the less desirable noises (for example, from traffic or from the neighbor's kids yelling) by introducing more desirable sounds. The best example is the gurgling sound made by the cascading water of a fountain.