Use and Care Guide
550
450
350
250
150
50
Figure 2:
STYROFOAM
TM
Brand
PERIMATE
TM
Insulation
Withhstands Pressure
gal/hr/linear foot
2" STYROFOAM
TM
Brand
PERIMATE
TM
Insulation
2-3/8" Fiberglass Board
528
107
®™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
Stand Up Under Pressure
A typical basement wall is bombarded with pressure from non-
moving water, and this hydrostatic pressure increases at greater
depths. Without proper drainage, water can pool at the lowest point
on the wall. Pressure builds up, and the water seeks a path right
through cracks in the foundation.
Waterproofing can resist hydrostatic pressure, but waterproofing
and damp-proofing should be complemented with a means to drain
water away from the foundation, such as STYROFOAM
™
Brand
PERIMATE
™
Insulation. It has drainage grooves to direct water down
to the drainage tile and away from the foundation, which reduces
hydrostatic pressure against the wall (Figure 2).
STYROFOAM™ Brand PERIMATE™ Insulation effectively directs
water away from foundation walls toward the drainage tiles.
Figure 2: STYROFOAM
™
Brand PERIMATE
™
Insulation
Withstands Pressure
Third-Party Test Results at 600 lbs/ft
2
Soil Pressure
STS Consultants Ltd. located in
Vernon Hills, Ill., performed lateral
transmissivity tests (flow or drainage
rate testing) following ASTM D4716
on various foundation drainage
products. Each test used normal
stresses of 200-1,200 lb/ft
2
in 200
lb/ft
2
increments and a 1.0 gradient.
Gradient is the height of the water
divided by length of sample, which
produces a certain water pressure
that forces water through the
sample. Project report: Laboratory
Testing of Drainage Products –
STS Project No. 29280-C,
October 6, 2003.
4
Handle a
Heavy Load
Below grade, soil exerts a
great deal of pressure on a
basement foundation wall. As
the soil weight presses down-
ward, it also exerts a horizontal
(lateral) pressure. Insulation or
drainage material without
sufficient compressive strength
is unable to resist this pressure
and compresses, reducing
R-value and drainage capability.
STYROFOAM
™
Brand XPS
Foam Insulation has the
necessary compressive
strength to fully resist soil
pressures over the life of the
building.
At 8' below grade, lateral soil pressure
against the basement wall can be as
much as 1,000 lb/ft
2
.