Not being an architect or engineer, I have very little knowledge of what goes into building a house. When the architect said we would have to build the house on pilings I imagined the house up on stilts like you see at the beach on the east coast. (My grandfather, a home builder his entire life, would be aghast.) Our architect quickly disabused me of that notion, explaining that the pilings would been in the ground and that grade beams would connect them to create a very sturdy platform on which to build our house. Cool. what's a grade beam? Off to the internet for answers.
Grade beams serve two purposes: it acts as a beam that carries the foundation load while simultaneously bracing the foundation. Unlike a spread footing, which primarily supports the foundation via latitudinal reinforcement, grade beams utilize longitudinal reinforcement for the bulk of its weight-supporting bearing. The beams essentially act as connectors between footings and pile caps. (Thank you www.alignfoundationrepair.com for a definition a layman can almost understand.)
Based on that description, spread footings distribute the weight of the foundation and building horizontally across the ground, while grade beams connect the pilings and spread the weight vertically down the pilings as well as horizontally. Got it, I think. So here's the plan:
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| Foundation walls are gray, piling locations are the little circles and the grade beams are white with a black outline. |