What’s a reasonable qoute for ground works

The cost depends on the size of the extension, the depth of the foundations required by Building Control, soil conditions, access to the site, and whether any existing drains need to be diverted or upgraded. As a general guide, groundworks including excavation, foundations, concrete, drainage alterations and reconnecting a waste pipe to the main drain can range from £5,000 to £15,000+. If deeper foundations, clay soil, steelwork or manhole alterations are required, the cost may be higher. The best approach is to obtain a detailed quotation following a site visit and review of the drawings, so there are no unexpected costs later.