2 SITEWORK, FOUNDATIONS, BASEMENTS, SLABS
2.1 BUILDING PERIMETER FOUNDATION DRAINAGE
2.1.1 ANALYSIS OF NEED
Subsoil (foundation) drainage provides a means of removing water that may
percolate to the footing level of a building foundation system. Establish the
need for a subsoil drainage system by an analysis of the climate, topography,
soil character, water table, geological factors and the judgment of the
designer. Where topographical or other factors exist which would lead to
uncertainty regarding the ability of natural drainage to function and avoid
damage by subsurface water, provide a subsoil drainage system and show on the
architectural basement floor plans. Sections must show relative elevations
compared to lowest floor level.
2.1.2 LOCATION
Provide subsoil drains, when judged advantageous and where individually
required, at building perimeter wall footings adjacent to basement, crawl
spaces, or pipe basements below grade.
2.1.3 PITCH
Subsoil drains shall maintain a pitch as uniform as possible and shall drain
to suitable outfall. Minimum pitch shall be 1/2 of 1 percent.
2.1.4 ROUTE TO OUTFALL
Unless site conditions otherwise dictate, no subsoil drainage piping shall
traverse a building area to reach an outfall. Where a condition makes this
imperative, use solid pipe with sealed joints to traverse a building area.
2.1.5 ELEVATION
Subsoil drains shall in no case be lower in elevation than the base of
adjacent footings. When an abrupt change in elevation of footings occurs,
drain tile shall lead away from building at the higher elevation of the
transition. The lower level shall be separately drained.
2.2 MEMBRANE WATERPROOFING AT INTERIOR FLOOR DRAINS
2.2.1 GENERAL
Provide membrane waterproofing under floor finishes surrounding floor drains
in areas subject to wet conditions to prevent water and moisture from
penetrating the underlying floor slabs and damaging the finishes and contents
of the rooms or spaces below. Attach the membrane waterproofing to the floor
drain by a clamp, and extend outward from the floor drain under the entire
area of the surrounding floor surface which slopes toward the floor drain or
which is subject to surface water, and carry up abutting vertical surfaces at
least 75 mm (3 inches).
2.2.2 EXCEPTIONS
Do not provide membrane waterproofing if:
A. The floor slab is placed on grade; or
B. The floor finish itself is latex mastic with waterproofing membrane.
ARCHITECTURAL DESIGN MANUAL
2-1
SITEWORK, FOUNDATIONS, BASEMENTS, SLABS
Previous Page
