Exterior slab-edge insulation (retrofit)

Passive

The same cold path closed from outside on a house already standing. The perimeter is excavated to expose the slab edge, rigid insulation that does not mind moisture is fixed against it, and whatever is left above ground is capped and covered. Heavy work, but it does not need the house rebuilt.

One of 4 ways to meet Thermal bridging elimination. Build 2/4, Upkeep 4/4, Efficiency not rated. Cost, carbon and footprint below are rated against those 4, not in absolute terms.

Cost
Medium
Upkeep
Occasional
Skill to build
Intermediate
Lifespan
As long as the insulation itself; the above-grade cover protecting it from sun and impact is the part that gets renewed
Embodied carbon
Medium
Space / material use
Low
Output timing
None
Skill to repair
Basic

What your site needs

Room to dig around the perimeter, and ground that can be opened without undermining the foundation or cutting buried services

Inputs

none

Outputs

none

Ranking in its sub-function out of 4 alternatives

Every option in this sub-function, with the value on each axis and a note on what drives it (this solution highlighted):

SolutionBuild skillUpkeep burdenEfficiency
Continuous exterior insulation detailingBasic1N/A
Strapped straw external insulation (ITE paille sanglee)Intermediate2N/A
Insulated slab edge and slab-to-wall thermal breakIntermediate0N/A
Exterior slab-edge insulation (retrofit)Intermediate3N/A

Build skill and upkeep burden are proxies (lower burden = simpler to maintain); the efficiency column is this sub-function’s ranking, 1 = best. “N/A” where an axis isn’t rated here.

Sources

Tutorials

No build tutorial recorded yet.

What this page does not tell you

No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.