Waterproofing is generally defined as the treatment of a surface to prevent the passage of liquid water under hydrostatic pressure, either constant or intermittent. Water exerts a pressure of approximately 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 that is adhered to the wall.
Waterproofing applications are further defined as horizontal or vertical application; above grade or below grade.
Barrett has different specifications, for horizontal and vertical applications, 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 waterproofing designs should include:
- Provide positive slope
- Depress drain sumps below membrane elevations
- All flashings must rise 8 inches above the highest expected water level
- All vertical flashings should be counter-flashed
- Locate multi-level drains within a conditioned air part of the building
- Electric field vector mapping tests completed (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 Observer and Quality Control Inspections
- 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 minimum 3,000 PSI and preferably 4,000 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 before project bidding