Scope of Work
We will construct a drainage system along the entire left, rear, right, and a 16 feet portion of the front side of the residence. The system will be comprised of 2 legs, each discharging into a sump located near the right rear corner, from where the water will be pumped into the existing downspout drain that leads to the street.
The drainage system consists of two pipes in a rock filled trench.Â One is perforated, to collect sub-surface water and the other is non-perforated, to collect water from the roof downspouts.Â At the upper end or start of both lines, as well as at the major corners, a clean-out will be provided so that both lines can be tested or cleaned as necessary.
The minimum depth for the perforated pipe will be below the grade of the soil under the house and both the perforated and non-perforated pipe will fall at least 1/8 inch per foot for the total length of the system to the point of discharge.
The perforated pipe will be installed on top of a bed of gravel, two inches deep, with the perforations pointed down.Â The trench will then be then backfilled with drain rock.Â The rock we recommend is Class I, Permeable Type A drain rock per the California State Specifications.Â The drain rock is clean gravel that varies in size from 1/4 to 1/2 inch.
The trench will be a minimum of 12 inches wide.Â This permits a four inch blanket of rock on each side of the four inch perforated pipe.
We will carefully remove and replace the existing deck boards as necessary. If new lumber is needed, there will be additional costs for materials only.
We will construct a sub-drain approximately 80 feet long and 12 inches deep along the entire right side and a portion of the rear of your rear lawn up to the birdbath.