HomeMy WebLinkAboutFOUNDATION DRAINAGE - 06-00168 - 601 Autumn Ct - New SFRho
FOUNDATION DR AMAGE
Section SOS of the 2Q03 International Residential Cade requires that drains sl�aii
be provided around foundations. The CITY OF REXBURG �ui�din DepartmentCity E��gineer have decide. not to enforce This rine, �ani. the
Almost all buildina lots �ocaied ofd of the hill and dO""m in tie va�ZeY- have a soil
structure, which consi�t� of toPsoll overgravel.
Section 4Q5 of code includes an
�xceptian for well -drained soils. Lots on the hi�� are another subj pct altogether. The are
almost entirely com�pnsed of silt over bedrock. Foundation drainage could be very�
beneficial for most of these lots. many houses on the h*11 have part of their foundatiolas
bearing directly on the bedrock, As wader seeps into the soil (especially zn sprin it tends
to drain downhill along the bedrock. Some foundations actzx�g as a dam divert the flow�c�vater around -them. This Rends the home to possYble ��ater lama e ii� the basement. of
Foundation drains as called for in the International Code be installed
properties that match the desLriptxans given above. We ��1l allow the co at
developers to make this judgment calf. TncIuded below is the'code cover�n�aciars and
g this issue? .
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SECTION R405
FOUNDATION DRAINAGE
R405.1 Concrete or masonry foundations. Drains shah be
provided around all concrete Or masonry foundations that re-
tain earth and encase habitable or usable spaces located below
grade. Drainage tiles, gravel. or crushed stony drains, perforated
pips or other approved systems or materials shall be installed at
or below the area to be protected and shall discharge by gravity
ormechanicai means into an approved drainage system. Gravel
flr crushed stone drains shall extend at least 1 foot (305 mrn)
beyond the outside edge of the footing and 5 inches (x.53 rnm)
aba�re the top of the footing and be covered with an approved
filter membrane material. The tip of open
joints of drain tiles
shall be protected with strips of buildiz�g pager, and tie drain-
geatiles or ge�rf'ora��d pipe shall be placed, on a minimum of
2 inches (51 mm) of washed gravel Or mashed rock at least one
sieve size larger than the tile joint'opening'or perforation and
covered with not less than 6 incites (I53 mm) of the same
materia.
Excep�ian: A drainage system is not required when the
foundation is installed an well -drained ground or sand-
grave1 mixture soils according to the Unified So2I Glassif ca-
tion System, Group I Soils, as detalled in Table R405. L
8405.2 Woad foun.dations. ooun ations enclosing hab-
itable or usable spaces located below grade shall be adequately
drained in accordance with Sections 8405 .2.7 ihrou�;h
8405.2.3.
R4,05,2.1 Base. A porous layer of graved, cnushed stone or
coarse sand shall be paced to a minimum thickri-ess of
4 inches (102 mm) under the bas-ementfloor. Pro
vision shad
be made for automatic draining of this layer and the graved or
crushed stone walk footings.
R405.2.2 Moisture barrier, A 6-mflAhick (0. 15 mm) poly_
ethylene moisture baiTier shall be applied over the porous
layer with the basement floor constructed over the poly-
ethylene.
R405.2-3 Drainage system. In other than group Z Sol s2 a
sump shall be provided to drain the porous layer and foot -
in as.
The sump shalt be at feast 24 inches (6i0 mm) in dia-
meter or 24 inches square (0.0 129 X2), shag expend at least
24 inches (61a mm) below the bottom of the bas'ement floor
and shaIl be capable of positive gravid or mechanical drain-
age to remove any accurnuiatcd water. Thi drainage system
shall discharge into an approved sewer system or to daylight.
2003 INTERNATIONAL RESIDENTIAL DE