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Trench wall foundation insulation

irishguy60 | Posted in General Questions on

We are currently putting an addition on our home. The concrete contractor messed up and simply used a trench foundation for part of the foundation wall, he has been thrown off the job. We found out the village code requires 2 inches of rigid insualtion 24 inches down from the top of the foundation wall.

Being that part of the foundation is trenched, no forms, it is rugged and ragged and now has to be made smoother in order to apply the insulation,,,, Any suggestions on how to best chip away at the concrete to smooth it or other ideas to insulate?

We are in the Chicago area, zone 5.


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  1. pwalshe | | #1

    I am not an expert but I recall that closed cell spray foam can be used on exterior foundation walls. Or maybe the inspector would be happy with a shallow frost protected system with a wing or shelf of foam horizontal all around the foundation (with dirt over) - and even foam on the interior of the wall if that is still possible and depending on what you have (basement, crawlspace, slab etc)

  2. GBA Editor
    Martin Holladay | | #2

    My first thought was the same as Patrick's: your best bet is closed-cell spray polyurethane foam. If I were you, I would take the concrete contractor to small claims court.

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