Many thatched roof structures don’t have gutters. Some use dripline trenches to collect and infiltrate rainwater from the rooftop instead. A dripline trench controls erosive runoff water from the rooftop. These trenches store the rainwater until it soaks into the soil. They reduce back-splash and protect the house and prevent water from pooling near the foundation.
If you are going to install a dripline trench, you will want to check with your municipality or local governing agency to check permit requirements.
How To Install A Dripline Trench
To install a dripline trench, first dig the trench itself. The trench should be 18″ wide and 8″ deep. It should be located right along the dripline beneath the edge of the roof. You will want to slope the bottom of the trench away from the house. This will help the water drain away from the foundation. Fill the trench with 0.5″ to 1.5″ inch crushed stone. You can hold those stones in place more carefully by lining the sides and front of the trench with stone or pressure-treated lumber. In order to make the trench last longer, you should line the sides of it with non-woven geotextile fabric. Fill the trench within 3″ of ground level, then fold the fabric over the top of the trench. Add more crushed stone on top of that fabric to finish it off.
Dripline trenches shouldn’t be used near foundations that are improperly sealed. They will function best in soils that are sandy or gravelly. Maintenance is less involved than maintaining a flower bed. Simply remove weeds and debris from the surface of the trench. Over time, the dripline trench may clog. You can just remove the crush stones, wash the sediment off, make sure the trench is still at the proper depth and width and refill with the existing crushed stone.