Waterproofing is generally defined
as the treatment of a surface to prevent the passage of water
under hydrostatic pressure, either constant or intermittent.
Water exerts a pressure of 62-64 pounds of force per foot of
depth.
Functional waterproofing must
keep water from penetrating into the building interior or the
protected substrate.
Waterproofing is classified
as positive side and negative side waterproofing. All Barrett
systems are positive side waterproofing, installed on the exterior
side of the structural surface where the water pushes against
the membrane adhered to the wall.
Waterproofing is further defines
as horizontal or vertical application; above grade or below
grade.
Barrett has different specification
for horizontal and vertical applications.
Barrett specifications are
generally applicable to both above-grade and below-grade installations.
Detailing of waterproofing
should follow the general guideline of ASTM C 981 Standard Guide
for Design.
Adequate designs should include:
- Provide positive slope
- Depress drain sumps below
membrane elevation
- All flashings must rise
8 inches above the highest expected water level
- Locate multi-level drains
within a vented part of the building
- Flood test completed
membrane (ASTM D-5957)
- Concrete substrates should
be properly cured (water, paper or burlap). Test according
to ASTM D 4263
- Concrete substrates should
be properly prepared in accordance with ASTM D-5295
guide
- All cracks, cold joints,
control joints and expansion joints must be properly
detailed
- Raise or curb expansion joints
above membrane level
- Provide for Quality Control
Inspection
- Planters and water features
should be constructed on top of continuous waterproofing
membrane, if possible
- Provide adequate drainage
on vertical applications
- Provide dew point calculations
to prevent interior condensation
- Provide metal gutters
under expansion joints, if possible
- Lightweight insulating concrete
is an unacceptable substrate
- Light weight structural
concrete shall be at least 3000 PSI and preferably 4000
PSI strength
- Precast concrete decks
must be securely tied together. Provide 3 inch or thicker
concrete topping, reinforced with welded wire fabric
over precast units
- Contaminated concrete
decks should be conditioned by shot blast, sandblast
or scarification procedures
- Confirm the absence of
deleterious soil chemicals through laboratory analysis
of site soil
