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1988 bi-level building practices and energy retrofit

matt9923 | Posted in Energy Efficiency and Durability on

Have been reading on here for years, I did  search this topic and found a lot of good information but still have some questions. I am in the processes of buying my first home.
It is a 1988 split level in southern NY zone 5, block wall foundation. The basement is finished, there is no form of insulation on the floor, wall or ceiling. The attic has fiberglass bat insulation that needs to be fixed and there are no vent channels. There is a central air conditioning system in the attic and many unsealed penetrations. The house has plywood sheathing and  3/8″ xps  under the vinyl siding and the front has a brick wall in front of sheathing/ 3/8″ xps.
There is  fireplace in basement that appears to have wide open make up air channel. Id like to install wood stove insert but have a way to close the make up air when not in use.
With the basement finished I am unsure were to begin. maybe the attic. Part of me feel this house is a lost cause for energy efficiency and to just live with it for 5-10 years until I can build a proper house. NY offers a free home energy assessment/ blow door test that I plan on having done. Any advice is appreciated.

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  1. Expert Member
    Dana Dorsett | | #1

    With a sub- 10 year time window for "payback", unless it's heavily subsidized there isn't much more that will actually pay back other than air-sealing the attic floor/ceiling plane and the ducts.

    [edited to add]

    Air sealing the basement might still pay off too, depending on how much demolition might be needed to do it.

    Insulating cantilevered floors hanging exterior to the basement (common in "raised ranch" type buildings) will pay off in wintertime comfort, if not totally on a energy savings.

  2. GBA Editor
    Martin Holladay | | #2

    We need to know which "part of you" we are talking to. Are we talking to the part of you that wants to fix up this house and live in it to many years? Or are we talking to the part of you who wants to move out soon?

  3. matt9923 | | #3

    Thanks for the imput, I want to fix up the items that can be more easily remedied. A complete energy retrofit may be off the table. Starting with air sealing the attic and spending some time up there sounds like a good idea. How would you adress the cantilevered portion of the home.
    Do you think blown in insulation in the basement ceiling/ first floor would be worth while?

    1. Expert Member
      Dana Dorsett | | #5

      Specific to the cantilevered floor question, see this:

      If the air-barrier in the joist bays and the insulation in contact with the subfloor is foam board and well sealed you don't need foam board on the bottom.exterior sides of the cantilever cavity. Something like this:

      If there is any plumbing in side the cantilevered bays you're insulating, make sure to have at least 2/3 of the total R exterior to the pipe. That may require boxing in some slots between the plumbing & subfloor if the plumbing is nearer the bottom of the bay than up close to the subfloor.

      If the basement is conditioned living space &/or has the furnace/boiler in it, do NOT insulate the basement ceiling.

  4. GBA Editor
    Martin Holladay | | #4

    Q. "How would you address the cantilevered portion of the home?"

    A. Read this article for a few ideas: "How to Insulate a Cold Floor."

    Q. "Do you think blown-in insulation in the basement ceiling/ first floor would be worthwhile?"

    A. No -- that's somewhere way down the list, close to "never." Start by air sealing your basement -- to the extent that you have access to any of the leaky areas.

  5. matt9923 | | #6

    The deal ended up falling apart at the last minute. None the less great information.

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