What footings do
Footings spread the load of the structure into the soil and keep posts from sinking, tilting or lifting in wind.
They are the most important hidden part of a pergola.
Depth and width
Footings must go below frost depth and be wide enough for the soil. Size depends on post spacing, roof weight and wind.
Local code gives minimums.
Soil conditions
Clay, fill and soft soil behave differently. Clay swells when wet and shrinks when dry.
We check the soil before we dig.
Post bases and anchors
Metal bases lift wood off concrete and tie posts to footings. Stainless or galvanized is best.
Never bury untreated wood in the ground.
Existing slabs and decks
Many slabs are too thin to hold a pergola. We may cut out sections and pour new footings or use deck framing.
Check before you attach.
Curing and inspection
Concrete needs days to cure before load. Footings may need inspection before concrete is poured.
Do not rush this step.
Spend your effort underground: right-sized footings below frost depth make every other part last longer.
