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Insulation in modified monopoly roof

tg_johnson | Posted in General Questions on

We have built our roof as a modified monopoly roof design. See the video below. This brings the eaves of the house into the building envelope after you seal the joints with tape. Our attic/roof is then unvented and conditioned.

From the video they then insulate this space in the eaves along with the remainder of the roof. My insulation contractor thinks it’s a waste of money to insulate the eaves. He wants to spray closed cell foam in line with the interior wall to close off the eaves. I think this is a bad idea to not have air movement or insulation in unvented eaves. What are your thoughts?

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  1. Tim_O | | #1

    I thought the purpose of the modified monopoly roof was to avoid costly and not always reliable air sealing methods such as spray foam. How are you insulating the rest of the roof deck?

  2. tg_johnson | | #2

    We wanted to use exterior foam like we are doing on the walls but it was too expensive. We are using the appropriate thickness required for our climate zone of closed cell foam on the underside and then dense packed cellulose. I’m wondering what the negatives are to having eaves that are air sealed but not insulated.

    1. Expert Member
      MALCOLM TAYLOR | | #3


      If you are worried about possible condensation in the eaves, I would consider adding ventilation to the soffits, rather than insulating them.

      I've never head of moisture problems in the eaves of un-vented roofs, but it may be something that is climate dependent.

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