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Community and Q&A

Exterior Foundation Insulation

ChicagoSuz | Posted in General Questions on

I am considering buying a newly renovated house in Chicago with a slab foundation. I found this pinkish stuff in two places between the ground and the foundation of the house. After some internet research, I am wondering if this is some sort of slab edge insulation. If so, should I be concerned about the fact that I don’t see it around the entire perimeter of the house and only in two spots? It doesn’t seem like something that would last – in fact, you can see the photo that the right edge has already chipped off.  Am I correct about what it is? Would you be concerned about buying a home with this. What would you ask the developer to ensure all is OK? Thank you!

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  1. creativedestruction | | #1

    Yes, that's extruded polystyrene (XPS) and it's not properly finished. It should not be left exposed to the elements.

    I can't speak to why it's only installed in a couple locations but it does need a finish covering, be it prefinished metal trim coil or a brush-on coating or it will degrade from UV and insects.

    1. Deleted | | #2


      1. capecodhaus | | #3

        I dislike older homes. The dank basements, uneven basement slabs, low ceilings, uneven floors. layers of parging, janky mix and matched utilities patched, modified and/or abandoned. Asbestos and lead paint.

        Everything is odd in a home that's more than 30 years old unless built well. It would show.

  2. onslow | | #4

    Chicago SuzyQ,

    I lived in your area for 30+ years, so my first question about the odd placement of the foam is "are they covering something up?" Have you building knowledgeable friends to look at more than the odd foam? If not, a home inspector might be a good expense to incur. Unfortunately, finding one that is good is a real problem. Plus the guarantees are often not easily enforced.

    As a general question - have you looked at flood plain mapping and verified where the home you are looking at is relative to rivers and creeks? Even if there is no apparent flooding risk, you need someone to inspect any floor ducting if the home has forced air. I have had some contact with slab homes out past O'Hare and would urge caution regarding the duct work. Plumbing lines are another thing to check closely. Rehabbing can be done well and with integrity or with the intent to gloss the surface up. The many TV shows about flipping should be cautionary tales not promotions.

    I can't say I am impressed with the brick work. Does it match the rest of the house or is the area next to the foam different - like a patch job?

    1. Deleted | | #5


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