2802 HOYT AVE EVERETT ELKS Geotech Report 2018-01-02 MF Import

Geotechnical Engineering Evaluation Everett Elks Club November 2, 2006 NGA File No. 751106 Page 13 through the use of cut-off or "French" type drains. The need, extent, and actual design of such systems will depend on prevailing conditions. This can be evaluated at the time of construction. We recommend the use of footing drains around structures. Footing drains should be installed at least one foot below planned finished floor elevation. The drains should consist of a minimum four -inch -diameter, rigid, slotted or perforated, PVC pipe surrounded by free -draining material wrapped in a filter fabric. We recommend that the free -draining material consist of an 18-inch-wide zone of clean (less than threc- percent fines), granular material placed along the back of walls. Pea gravel is an acceptable drain material or drainage composite may also be used instead. Tire free -draining material should extend up the wall to one foot below the finished surface. The top foot of soil should consist of impermeable soil placed over plastic sheeting or building paper to minimize surface water or fines migration into the footing drain. Footing drains should discharge into tightlines leading to an appropriate coliection and discharge point with convenient cicanouts to prolong the useful life of the drains. Roof drains should not be connected to wall or footing drains. Footing drains as described above may not be feasible if a permanent shoring wall is utilized. In that case, water should be allowed to seep through the shoring wall face and then be collected in a drainage system installed in front of the shoring wall. Typically a concrete or a CMU wall is placed in front of the shoring wall and the drainage system is placed between the two walls. This drainage system could consist of a suitable drainage composite connected to a perforated drain pipe. The perforated pipe would transmit the collected water under gravity into the storm system, or the water can be routed to a sump where it can be pumped out. USE OF THIS REI'OR'C NGA b'ts prepared this report for Gary Parkinson Architects, and their agents, for use in the feasibility planning and budgeting of the development planned on this site only. The scope of our work does not include services related to construction safety precautions and our recommendations are not intended to direct the contractors' methods, techniques, sequences, or procedures, e; cept as specifically described in our report for consideration in design. There are possible variations in subsurface conditions between the explorations and also with time. Our report, conclusions, and interpretations should not be construed as a warranty of subsurface conditions. A contingency for unanticipated conditions should be included in the bu�get and schedule. NELSON GEOTECH.NICAL ASSOCIATES, INC.