HomeMy WebLinkAboutFOUNDATION DRAINAGE - 05-00333 - 1198 Pleasant View - New SFRFOiJNDATION DRAINAGE
Section 40.'r4) of the 2d03 Intemationai Residential Code requires that drains shall
be Provided around foundations. The CITY CSF RF-rtrn�G Buzid�ng Department and �.ae
City Engineer have deczded not t4 enforce this ru1e.
AIIIJOStL all building lots located off of the Iffli and down in alley have a soil
structure, which consists of topsoil over gravel. Section 4d5 of the code includes an
exception for well -drained soils. Lots an the hill are another subject altogether. They are
almost entirely comprised of silt over bedrock. Foundation drainage could be very
beneficial for most of these dots. Many houses on the hi11 have part of their foundations
bearing dl*rectly on the bedrock. As water seeps into the soil (especially in spring) it lends
to drain downhill along the bedrock. Some foundations acing as a dam divert the flow of
wader mound them. This lends th P homp. tri n Q c; hi A ----
�„ry7Ut V1L YY GL4L.E L..LG.11lQ.u�+ Ali i,l�,C [�G],�VLt1V.L.L�.
Foundafton drains as called fi
�r in the Intemational Code should
be installed at
P-LOyIC CIS LIldmaen ane aescriptions given above. We will allow the contractors and
developers to make this judment call. Included bel
ow is the code covering this issue ?
SECTION 8405
FOUNDATION DRAINAGE
R405.1 Concrete or masonry foundations. Drams shall be
provided around all concrete or masanry foundations that re-
tain earth and enclose habitable or usable spaces located below
grade. Drainage tiles, grave 4r crushed stone drains, pe�'orated
pipe or other approved systems or materials shall be installed at
or below the area to be protected and shall disc-
harge by gravity
ormechanical means into an approved drainage system. Gravel
or gushed stage drains shall extend at leash 1 feat (3a5 mm)beyond the outside edge of the footing and 6 inches (x.53 rnrn)
above the top of the footing and be covered with an approved
filter membrane material. "Ihe top of open joints of drain files
shall be protected with strips of building paper, and the drain-
age tzles'or perforated pips shaH be' placed- on a minimum of
2 inches (51 rnm) of washed gravel or crushed rock at least One
neve size larger than the tile joint opening or perforation and
covered with not less than 5 inches (153 mm) of the same
materia.
Exception: A drainage system is not required when the
foundation is installed on well -drained ground or sand -
gravel mixture sons according to the Unified Soil Classificd-
tion System, Group I Soils, as detailed in Table 84{35.1.
0
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2
R405-2 Wood foundations. Wood foundations enclosing hab-
itable or usable spaces located below grade shall be adequately
drained in accordance with Sections R405.2.1 though
R405.2.3.
R405.2.1 Base. A porous laver of gravel, crashed stone or
coarse sand shall he placed to a minimum thickness of
4 inches G 02, mm) under the basement. floor. Provision shall
be mate dor automatic draining of this layer and the gravel or
crushed stone wall footings.,
R405.2.2 Moisture barrier. A 6-maI-hick (0.. 15 Mm) poly-
ethylene
moisture barritAr shag be' applied over the porous
layer with the basementfloor cnnsfz-ucted over the poly-
ethylene.
8445.2.3 drainage system. In other than Group I sons, a
pump shall be provided to drain the porous Layer and foot_
ings.
The sump shall boat least 24 inches (6 10 mm} in dia-
meter or 20 inches square (0.0 129 rn2), shall extend at feast
24 inches (SIO mm) beIow the bottom of the basement floor
and shall be capable of positive gravity or mechanical drain-
age to remove any accumulated water. The drainage system
shall discharge into an approved sewer system or to dayh' ght.
2003 INTERNATIONAL RESIDENTIAL CODE@