Foundation Basics: Water Management

Posted by : Unknown Monday, September 8, 2014

When it comes to controlling water at the foundation level, your goals are:

1. Keep the groundwater out

2. Support the building above

3. Support your HVAC design

Water moves through foundations many ways, via water vapor, hydrostatic pressure, etc. Your first priority is to design systems to keep the water moving away from your foundation in the first place, the management of water. No structural system by itself is water tight.

If utilizing a basement:

a. Perforated drain tile surrounded by coarse gravel

b. Coarse gravel under the slab and polyethylene type vapor barrier

c. Damproofing on the exterior side

d. Roof precipitation flowing away from the foundation wall

If utilizing a “slab on grade design”:

a. Roof water is directed away from the foundation

b. Vapor barrier on the bottom of the slab

c. Drainage gravel under the slab

Coating an exterior foundation with bituminous materials creating damproofing. Damproofing resists the capillary forces of water, but not the hydrostatic forces. “Waterproofing” resists the hydrostatic pressure forces of water. Keep water flowing away from your building and foundation and therefore create no a hydrostatic environment.