How can highway noise be reduced?
The best way to reduce the amount of highway noise making its way to the cottage is to put mass in its path. A berm, a strategically placed man-made hill that will stop a truck’s roar in its tracks would do this. A berm has the advantage of looking natural and can be designed to avoid interfering with septic systems that may be in the way. To be most effective, a berm would wrap around the sides as well as the back of the cottage, deflecting noise from the point at which you first hear the trucks until their sound disappears. You can roughly calculate where to place your berm by standing inside your cottage on the side closest to the road and watching the trucks go by. Note the location of a truck when you start hearing the noise and when it stops being annoying. Your berm should block the view of the truck’s wheels for this entire time. The wheels generate the noise, so if you see the wheels, you’ll hear the wheels. If you imagine the berm as a shield stopping the sounds from getting to the cottage, you’ll be able to picture its appropriate shape and see that the closer to the cottage you build it, the smaller the radius you’ll need. The slope of your land will also affect the berm’s height. If your property is higher than the highway, you’re in luck, but if your property is lower than the highway, it may be difficult to construct a berm high enough to be effective.
A typical berm is about two metres high with side slopes of about 30 degrees and a width of about 7 metres. Berms will block out most of the noise but not all of it, and building a berm is a big project that requires bringing in lots of earth and then planting on top (conifer trees or ornamental native grasses are good choices). But a berm is cheaper than the alternative, which would be a stone or concrete wall.
Another project to consider is building a second, sound-deadening interior wall on the highway side of the cottage. This is an additional row of studs filled with sound insulation and surfaced in special sound-absorbing drywall. You could also replace your windows with triple-glazed fixed ones—but not being able to open the windows at the cottage defeats the purpose of being there, doesn’t it?