UNDER-FOUNDATION PREPARATION

Homebuilding doesn’t begin as a task to simply scrape off the ground, pour out some concrete, and put up a house. Whether the ground has a slab on it, a crawl space above it, or a basement in it, careful planning for structure, electrical, plumbing, ventilation, infiltration, moisture resistance, and under-the-house drainage, is an absolute necessity. Common points to address are:

• • Chase-ways for easy installation of fluid-transport tubing, wiring, and cabling such as heat distribution and collection for both standard heat pumps and geothermal systems, as well as solar energy absorption and convection.
  • Buried Conduit for Electric Power Delivery connects power to kitchen islands, floor plugs, detached outbuildings, remotely and distantly located lights for features of ambiance, such as pools, fountains, and lighting; security lighting and observation cameras; and control networks for communications, and gates.
  • Crawlspace Air Control is best accomplished by the elimination of holes and passages which wrongly encourage the movement of air into and out of a crawlspace. Even so, some regional codes prefer to enforce the installation of damper-controlled vents for the purpose of ventilating open space under a house.
  • Plumbing Piping typically travels underground before it enters a site and home. Then, at some point, both water-delivery pipes and sewer drains pass through the floor to enter or leave. The cost and practicality of installation depends on travel distances across the site, and up through the structure. Careful planning can minimize wasted material and money. Material selections range from traditional cast iron and copper to a variety of petroleum based, synthetic pipes. Synthetic types offer ease of installation, and some are resistant to freeze related bursting. However, not all pipe materials are safe for delivering drinking water. Carefully check that any pipes used in your project meet safety standards for human consumption and contact.
  • Radon & Soil-Gas Ventilation prevents the build up and drifting of certain gasses out of the ground beneath a foundation into the living space of a house. Soil Gas is caused by the breakdown of soil-carried organic material, such as plant matter and insect bodies. Soil Gas in primarily benign, but still may cause respiratory problems in susceptible individuals. Radon is a byproduct of the breakdown of naturally occurring radioactive elements, which are scattered all around the world. Long-term exposure to Radon is likely to cause serious health issues in most individuals.
  • Stub-outs for Garden Faucets and Irrigation Taps, at some point, leave the foundation to travel, either underground to isolated fixtures and faucets, or to pass through wall framing to reach wall mounted garden faucets. However, proper installation originating under and within the foundation is critical.
  • Termite Protection involves methods of poisoning as well a discouragement. Chemicals placed under and around a foundation offer termites fatality-inducing effects, which may last for several years. Such poisonous pre-treatments may be legally placed only by trained, certified, bonded, licensed professionals. Physical barriers such as steel plates, and stainless steel mesh screens are too tough for termites to chew through. Framing lumber, treated for termite resistance, offers another type of physical barrier. But because it’s attached to untreated framing lumber, the termites favorite food, it really only guides the insects home for dinner.
  • Under-Foundation Drainage Grading : ( applies to slab-on-grade, basement and crawlspace ) Even underneath a house, drainage is critical. For any under-foundation water collection and drainage system ( eg : footing drains under the slab and within the perimeter footings ), grade the earth beneath the slab, or across the ground of the crawl space, to achieve a downward slope to point(s) where the drain pipe(s) penetrates the perimeter footing, or curtain wall, and either joins with an exterior footing drainage system, or empties into a land-formed ditch, swale, or feature, which guides the water quickly away.          
  • Footing Drains are only effective when they’re positioned below the lowest point where water might collect and affect the foundation and house structure. From that lowest point, relative to the bottom-most point of the foundation, footing drains must lead further down and away to a point called an outfall, from which water can proceed by gravity into any natural drainage courses created by the terrain of the site.

• Waterproofing of Exposed Surfaces, such as basement walls, or partially ground-embedded walls, may be achieved by applying exterior liquid or viscous coatings, or by installing semi-rigid sheets adhered with special coatings. The most critical part of either method is that ALL involved wall parts are thoroughly covered. No part of any subject-wall may be left out. Water has the seemingly magical quality of finding a way where there seems to be no way, to penetrate inside a structure where it’s most unwelcome. Don’t take any shortcuts, and don’t stop until the job of waterproofing is totally finished.
• Granular Capillary Barrier  – A trait of physics called Capillary Attraction is when water is able to follow a smooth surface, even uphill. This action can be employed under a concrete slab, using smooth, rounded gravel or fine sand. Moisture from the ground is ‘captured’ by capillary action with, and attraction to, the gravel or sand, which holds moisture away from the bottom of the slab, keeping the floor above dry.

• Waterproof Membrane aka Water Resistant Capillary Ground Cover Barrier – It’s a long name for a sheet of plastic lying on the ground. This sheeting is placed over the granular barrier, as another layer of protection to resist the intrusion of moisture through the floor. Combined, the granular barrier, and the ground cover barrier achieve a high degree of success in keeping a home dry.

Dry, Safe, and Warm are the key words to describe the entire existence of human beings at home. Do everything possible to assure that what lies beneath will reinforce the meaning to those very special words, as you and those in your care live your lives in your very special home.

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