Grasscrete is a green system for walks, driveways and parking lots developed by Bomanite Corp. By using special 24-by-48-inch molds made of biodegradable paper pulp, the concrete is poured and formed into a pattern of open spaces. Grass, ground covers, sand or gravel are inserted into the voids, allowing water to penetrate to the soil beneath the paved area.
Remove the topsoil to a depth of 12 inches in the area where the Grasscrete will be installed. Rake the underlying soil smooth.
Pour a 6-inch layer of crushed gravel into the excavated area. Rake smooth. Compact with a plate compacter until firm.
Add a 1/2-inch layer of sand over the gravel base. Rake evenly, sprinkle lightly with water and compact.
Install the edge formwork around the outer perimeter of the Grasscrete pad according to the manufacturer's instructions.
Insert the Grasscrete forms onto the sand and gravel base. Allow a 4-inch space between the edge formwork and the molds. Trim the Grasscrete forms as needed to fit the space.
Lay concrete wire mesh over the Grasscrete forms, cutting the wires to fit over the forms.
Pour the concrete mix over the Grasscrete forms to a depth of 5 1/2 inches. Spread and smooth the concrete using a long, flat 2-by-4-inch board across the top of the forms. After smoothing the concrete, drag a stiff broom across the top to make a non-slip surface.
Wet the concrete every day by spraying gently with water. Keeping the concrete moist for a least a week allows it to dry slowly, preventing cracking.
Burn off the tops of the paper pulp form with a flame gun after the concrete is completely dry. Alternately, soak the forms with water until the paper pulp disintegrates.
Sweep soil or gravel into the voids. Sprinkle with water and repeat until the voids are completely full. If you are growing grass over the Grasscrete, scatter grass seed over the entire area and water daily until the grass is established.
Things You Will Need
- Crushed gravel
- Plate compacter
- Grasscrete molds
- Concrete wire mesh
- Concrete mix
- With larger areas, it's not practical to mix the concrete yourself. Instead, measure the area where the Grasscrete will be installed. For example, a two car driveway might be 20-by-20-feet square. Give the length, width and depth of 5 1/2 inches to a concrete supplier and arrange for delivery.
- Allow the Grasscrete to cure for a month before driving on it.
- If installing a light application such as a walk, compacting the soil and adding a layer of sand may be a sufficient base for the Grasscrete molds.
- Consult with the vendor before installing Grasscrete.
- Wear gloves and safety glasses.
- Wear a breathing mask when working with dry concrete mix.
- Do not use a flame gun if the area is very dry or in a medium to high fire danger zone.