Go to Forum Home Building Design Frost protected shallow foundations (FPSF)

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    • #31651
      Paul Buckingham
      Participant

      I'm working on a project at the moment and I'm looking for alternative foundations systems and I've come across FPSF and was wondering if anyone on here has any experience with this. The project is an existing garage that is to be demolished and rebuilt as a heated studio built as sustainably as the budget allows.

    • #38484
      Anonymous

      It seems to relate to the avoidance of excavating BELOW the frost line in US practice:
      See http://oikos.com/esb/43/foundations.html

      In these latitudes, the base of a strip footing needs to be below GROUND frost, typical depth of 750mm below ground/ 900 below FFL (unless you're using High Step passihaus DPC detailing…which is a' whole 'nother discussion)

    • #38485
      Tom Foster
      Participant

      One way to increase the path-length of insulating soil, between freezing outside air and the ground surface that the found sits on, so the latter never freezes, is to inset the found line back inboard of the building's perimeter.

      The slab or subfloor beams then cantilever outboard to support the walls – or else there are columns also inboard, with all floors and roof cantilevering out to suspended walls.

      Such inset found line can be as shallow as you like, without need for special FPSP insulation. This design allows completely seamless, bridge-free insulation continuity between wall and floor insulation.

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