Perimeter insulation strategy for a slab on grade with conditioned and unconditioned spaces

[Julio Fernández Amodia]

Hi,

I am working on the thermal envelope design of a train maintenance workshop and would appreciate some advice regarding slab perimeter insulation.

The building includes both conditioned and unconditioned spaces at ground floor level. The unconditioned areas are mainly storage spaces located within the overall building footprint. I am trying to determine the most appropriate location for perimeter insulation in order to properly define the thermal boundary and minimize heat losses to the ground.

I have identified three possible approaches:

• Option 1 (Green): Insulate the perimeter of the entire building footprint.
• Option 2 (Blue): Insulate the perimeter between conditioned and unconditioned spaces.
• Option 3 (Red): Insulate only the perimeter of the conditioned spaces.

My understanding is that heat loss through slabs is highly influenced by the exposed perimeter length, but I am unsure which approach best represents the thermal boundary in a situation where conditioned and unconditioned spaces coexist under the same roof.

Has anyone dealt with a similar industrial or commercial building configuration? Which option would you consider most appropriate and why?

Thank you in advance for your insights.