Building Sustainable Roads
/“Southrise” is the name of Hillside’s newest building constructed with hempcrete. Residents will start moving into the multi-unit cottages in February.
As you may know, the nation has a stormwater runoff problem. The more impervious or paved surfaces there are in a given area, the more surface area that rainwater traverses, picking up oil, debris and animal waste along the way. The dirty rainwater then enters catch basins along roads or sidewalks and in our area is ultimately emptied into the Merrimac or Little Rivers.
In an effort to create a more permeable road surface that is especially inviting to pedestrians, we are swapping out asphalt and concrete for clamshells and wood planks along the 12-unit Southrise building. We hope to create a park-like setting that encourages people to slow down and enjoy the space. The wood portion of the road is eight feet wide. The clam shell and gravel road is 12 to 14 feet wide, all straddled by benches and plantings.
One may wonder how a boardwalk could survive delivery trucks, snow removal equipment, construction vehicles and fire apparatus traffic. Let us introduce you to construction mats made from cross-laminated timber, or CLT, which are commonly used for road construction in environmentally sensitive areas and access over soft soils.
CLT construction mats in action! Picture credit: GFI Solutions
We were fortunate to find a manufacturer of CLT mats that was liquidating thousands of newly constructed 8 ft by 14 ft by 6 inch thick hard pine wood mats. They are beautiful!
We liked them so much we decided to use them as the porch deck surfaces at Southrise as well.
CLT porches around a Southrise unit
An example of CLT boardwalk in front of a Cape Cod residence
Though these mats are often used for temporary road construction, the team will be installing them for permanent use in Fireman’s Drive. CLT, being made out of wood, is sequestering carbon, which is much more sustainable than concrete or asphalt (if you can keep it from rotting). Borate plugs are inserted and borate coatings are generously applied to all surfaces for rot and pest resistance. Borates are naturally-occurring salts or esters of boric acids. The mats will also be bedded in alkaline limestone sand from Vermont, which is inhospitable to the fungi that cause wood to rot.
Move-in to Southrise will begin in February!
Stay tuned! Soon after move-in, we will be hosting a multi-day open house. You are welcome to join! Details coming soon.
Next up on the Newsletter: The chickens are coming!