How deep should foundations be?
Foundations must reach firm, undisturbed ground below the zone affected by frost and moisture. For many domestic walls that means at least 450mm, and commonly around 1 metre, but the depth depends on soil, trees and Building Control.
Foundations need to bear on firm, undisturbed ground and sit below the level affected by frost heave and seasonal moisture. As a general minimum this is around 450mm, but on clay soils, near trees or on made ground it is often 1 metre or more.
The required depth is set by ground conditions and agreed with Building Control on site, so treat these figures as a starting point rather than a fixed rule.
Otis helps a customer estimate concrete volumes for a footing once the size is known, checks stock and prices the materials for the account.
General guidance for the trade. Always follow current Building Regulations, manufacturer instructions and the specifics of the job.
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Book a strategic call and we will model it against your own numbers.