How to Reduce Traffic Noise in Your Backyard

‘Reduce’ is the operative word in our title. It is impossible to eliminate traffic noise coming into your backyard. But if you erect some kind of barrier between the traffic and the backyard, your life can be more peaceful. Also, keep in mind that noise pollution has been linked to increased stress, concentration problems, and hearing loss, not to mention sleep loss, which has its own set of issues. Here are 8 possibilities to make your backyard more enjoyable.

 

Reducing Traffic Noise – 2 Noise Reduction Strategies

Before you start building your noise reduction barrier (fence or something else), you will have to choose the strategy you are most comfortable with. Essentially, there are two options–sound deflection and sound attenuation.

 

Traffic Noise Sound Deflection

To achieve sound deflection, you will need to build a solid structure to bounce traffic noise over your backyard or deflect as much of it as possible back to where it came from. These barriers are usually more expensive than attenuation barriers.

 

Traffic Noise Sound Attenuation

Sound attenuation barriers absorb sound rather than deflect it, lowering the sound intensity. Generally, they are less effective than deflection barriers. But they are also less expensive.

 

8 Traffic Noise Reduction Barriers

To be truly effective, your barrier will have to address the following elements, which could be an issue in some highly-regulated jurisdictions. 

• Height. Higher is better to keep noise away. 6′ is a bare minimum. 7′ is better. (If you are sitting on a deck that is 4′ off the ground, your ears are pretty close to 7′.) In other words, your barrier needs to block the ‘line of sight.’
• Thick and Heavy. Ideally, your sound wall should weigh over 5 lb. per square foot. Sound is caused by the vibration of molecules–in the air or through a barrier. A thicker, heavier barrier vibrates less. 
• Porosity. Where air travels, sound travels. Eliminate as many gaps and cracks in your fence (or barrier) as possible. Make sure it touches the ground (below ground level is even better). Seal any gap or crack.
• Coverage. Make certain to build it as wide as your property allows. Because sound travels in all directions from its source, you might want to continue the fence on the sides–especially if your neighbors do not have noise-reducing fences across the rear of their property. (Quite likely, this will require some neighborly negotiation.)
• Placement. Install your barrier as close to the road as possible to have the best chance of deflecting noise. (I know this sounds dumb because you want to enclose your backyard, so it will likely go on the property line anyway. But let’s cover all of the bases.)

 

1) Solid Brick (or Concrete) Fence Deflects Traffic Noise

A brick fence is probably the best noise deflection option. It is also likely the most expensive. (A brick fence is not just built onto the ground. It will need a concrete foundation. It needs to be more than one brick thick.) A brick fence will reduce noise by up to 50% because of the huge amount of mass you are erecting between your backyard and traffic-caused noise. Unless you are a bricklayer or know someone who is, you will need to hire a crew to do the work.

Concrete fences (or walls) will also reduce noise by around 50%. Also expensive and time-consuming if you do not do this for a living. 

Both options can be very attractive (stucco on the concrete). Make certain you get all of the appropriate permits. Having to remove your fence, for whatever reason, is expensive, annoying, and you will still have to replace it with something.

 

2) Solid Wood Fence Deflects Traffic Noise

When building a wood fence to stop the noise, it needs to be solid. Any gaps or cracks defeats the purpose. Although the price of wood is somewhat insane as I write this, it is still way less expensive than brick or concrete. And building a wood fence is a relatively easy DIY project. For some wood fence design ideas, check out 70 Best Wooden Fence Designs. Keep in mind that your purpose is noise reduction. A few things to keep in mind:

• Shrinkage. Wood shrinks as it dries. Depending on the design, you could have issues with gaps opening up.
• Rotting. Even the best cared-for fence can rot over time. Make sure it is painted or stained soon after you build it. And regularly thereafter (every 3 -5 years). Any part of the fence that contacts the ground should be pressure-treated wood made for ground contact–not ACQ deck material. Pressure-treated is more expensive, but with a lifespan of up to 40 years, it is well worth the investment.
• Maintenance. As mentioned above, a wood fence requires painting, staining, and/or gap and crack filling. (Use high quality paintable exterior caulkingto seal gaps.) If the idea of cleaning, scraping, and painting your fence every few years is not appealing, you might want to consider some other barrier.

Another option is to purchase pre-built fencing. This usually comes in 8′ wide x 6′ high sections. Then all you need deal with is putting in posts the correct distance apart. Consider something like Fast 2K fence post setting foam. First time I used it was for 6 x 6 posts to anchor an aluminum patio cover. 75 mph winds later, all is good.

 

Add Mass Loaded Vinyl to Your Wood Fence

If your new fence, or existing fence, is smooth and flat, add Mass Loaded Vinyl (MLV) to the inside. MLV absorbs sound. You can cover it with plywood to add more mass, then paint the plywood. Another option is to just paint the MLV with latex paint.

Installation Note: If I planned to paint the MLV, I would staple it on top and bottom, then cover the staples with 1 x 4 cedar to hide the fasteners. Then paint the entire fence. 

 

3) Shrubs and/or Trees Absorb Incoming Traffic Noise

Planting trees and/or shrubbery is an excellent way of absorbing and diffusing traffic noise. Not sure anyone wants to wait 10 years for it all to grow tall enough and thick enough to do the job. So you are probably going to a tree supplier to buy trees or shrubs that are at least 3′ tall to give yourself a running start. Stick with an evergreen hedge-like Juniper, because deciduous trees lose their leaves in the fall and defeat your sound attenuation efforts for at least part of the year. (And you do not have to rake leaves.) For some ideas for fast-growing noise-absorbing hedges, check out <leafyplace.com>. 

You may also want to give some consideration to a combination of fence and hedge to get both deflection and absorption.

Note: Additional plantings inside the backyard will also help diffuse the noise that does get into the yard.

Personal Note: I hate Juniper bushes, having fought my way through them while installing windows. But for this purpose, they are almost perfect. Thick. Evergreen. You can’t kill them. And are tougher to get through than a fence.

 

4) A Berm/Fence Combination Deflects Traffic Noise

Building a berm (hill of dirt) as part of your traffic noise reduction strategy is a good way of stopping noise. The problem with it is that you require a lot of dirt to get any amount of height, and the base tends to get pretty wide to support the berm. If you are considering re-landscaping the yard (especially by digging it down), a berm can work out very well. You can get increased noise reducing benefits of building up the berm and lowering your yard. You can also use decorative concrete block walls to reduce the width of the berm’s base.

The maximum berm slope is 2:1 (horizontal: vertical), meaning a 6′ high berm has a base footprint of 12′. A more gentle slope of 5:1 gives you a chance to plant something on it but makes the base 30′ wide. Most yards are not big enough to handle that, so building a smaller berm and incorporating a shorter fence on top of it is a good sound suppression option. Shorter fences will also save money.

Note: Studies show that a berm is approximately 2 decibels less effective than a sound wall.

 

5) Acoustic Fencing Absorbs Traffic Noise

An acoustic fence will deflect some of the traffic noise, but mostly it will absorb sounds. A good acoustic fence will not only reduce traffic noise but also most other noise, by about 50%.

 

Manufactured Acoustic Fence

Ordering pre-manufactured panels from a company such as Acoustiguard is a relatively simple solution. As with wood fencing panels, you will have to know the size of your panels before installing posts. Once the posts are in, it is a matter of fitting panels between them and sealing any gaps. Make sure the panels are tight to the ground.

Construction Note: If I were building this, I would want all of the material on-site and use Fast 2K Post Setting Foam. Put up the first post, attach a fence section, then put in the next post tight to the fence section, etc., until complete. Not that I am not a trusting person. Everything should come in the proper sizes, and the posts should be plumb. But Murphy’s Law (Anything that can go wrong, will go wrong.) works. Occasionally I think Murphy was overly optimistic. 

 

Do-It-Yourself Acoustic Fence

A DIY acoustic fence is essentially a sandwich panel consisting of wood, or metal, exteriors with sound-absorbing material between. (Note: I would build the sections on the ground, deck, or garage floor–then install them between the posts.) If the posts are already up, you can build them to size. If the posts are not up–you can use the ‘Construction Note’ system mentioned above. Build one side of the sandwich using 1 x 6 pickets or plywood. Turn it over, cover with 2″ Roxul 80 rockwool insulation or 2″ Styrofoam SM, then add the other side of the sandwich. You can also add Mass Loaded Vinyl to the inside of your sandwich to improve sound absorption. Install the MLV on the yard side of your panels.

Make sure you use plywood–not Oriented Strand Board (OSB). OSB will absorb moisture more readily than plywood. And that includes any exterior paint you try to apply.

Note: Rockwool is a better sound-absorbing product than foam, but it also absorbs water. So, if there is any chance of leakage, foam is a safer choice.

 

6) White Noise Machines

No, I am not talking about those small bedside units that block sound in your bedroom, but fountains or other outdoor peaceful sound-producing products. The sound of running water has a soothing effect on almost everyone (unless it is your toilet). There are hundreds–probably thousands–of backyard fountains available for purchase. If you are a DIY type, you might want to take a look at countryliving.com for ideas c/w tutorials on how to build them. And then modify the one you choose to suit your circumstances.

 

7) Sunrooms to Keep Out Traffic Noise (and Mosquitos)

Combining a sunroom with a sound barrier can give you the most peaceful backyard possible. Adding the room on your deck not only further reduces noise pollution, it provides a comfortable extension to your home away from the elements. Many styles and designs are available. Below is a picture of one I built c/w dual-glazed glass, insulated pony walls, insulated ceiling with skylights. And the customer added heavy curtains. Comfortable and quiet. (And real close to the hot tub.)

 

8) Build a Shed or Garage to Block Traffic Noise

Building a garage or shed on the property line to block noise really only works in the back yard because very few jurisdictions will let you build one in the front. But if the noise is coming from behind the house, and you need more storage anyway, build as near to the fence line as possible to help cut down traffic noise. For even better sound reduction, insulate and finish the interior with Roxul rockwool insulation and drywall or 3/4″ plywood.

 

End Notes

Hopefully, one of our suggestions will help make your yard more livable, but if you are living beside a freeway, moving maybe your best option.

Just a couple of final reminders.

• Make absolutely certain you get all of the permits you require to build your fence, plant your hedge, or construct your berm.
• If you are digging in posts, get a line locator to check your property. Cutting into a gas line or power line is depressing. Do not rely on old plot plans. They have been known to be wrong.
• Talk to your neighbors–especially if you are building on the property line. ‘Yeah, sure’ is not enough. Get a signed document detailing what you are doing and an agreement from the neighbor. (You might be best buds, but stuff happens–like them selling and moving.)