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Deep energy retrofit planning

user-1150882 | Posted in Green Building Techniques on

Hello all,

First off just joined the site and am very grateful for all the info you’ve accumulated here!!

I’m working on plans for a deep energy retrofit of my house. It is a semi detached brick house built in 1875. The basement is local stone parged inside, pointed outside to 24″ above grade. The first and second floor are two course brick plastered inside on furring strips, stuccoed exterior. The third floor is framed with 2X4’s for the wall sections and 2X6’s for the rafters. There is a flat roof in some sections off the back of the house. The primary roof is a gambrel with two ridges.

The rear wall of the house was poorly constructed. The second story portion of the brick sits on top of wooden framing which is supported in the basement by a double 2×8 over a 14′ span. There is also a double or triple 2×8 directly under the brick. Long story short I plan on removing the rear wall and rebuilding so that the exterior second story wall sits above the existing foundation instead of the current situation which is seriously sagging.

I basically want to do a chainsaw retrofit of the house. I would love to use a Riversong Truss and blow in cellulose on the exterior. However my driveway is already narrow and saving a few inches could mean the difference of township approval(Already working with the zoning hearing board to permit expanding into the required setbacks). So I’m pretty sure foam boards are going to be it. I would go Spray Foam but I can’t do it myself and am trying to be as thrifty as possible on this.

In the spirit of thrift I’m hoping there are some detail drawings with fastener specifications for attaching 6-8″ of foam board to a masonry structure that are available to the public. I am also curious about ways to build a truss for blown in onto a masonry structure. I plan to side over it with hardie cement siding unless the additional weight is an issue for the structure in which case I’d be willing to go with vinyl. For the basement portion I’ll have to parge the exterior walls first to make a flat surface for the foam boards (they could probably use it any way). I would like to come to the original height of the foundation with a stucco covering in keeping with the aeshetics of the house. My thinking was concrete board on furring strips or some such thing stuccoed over.

For the roof I want to blow in cellulose and use foam boards on top.

Is it worth doing a Riversong truss on the replacement wall and third floor, or should I just frame it with 2×4’s flush to the brick and foam it as I do the brick? I really don’t like the Idea of foam on wood.

Also, is there a good detail for a termite barrier in this case? I’m thinking of cutting flashing into the brick where I transition to siding from stucco, and lapping it an inch over the face of the stucco for inspection at least. Any other Ideas?

I’ve worked as a contractor for the past five years doing all manner of construction, am a Master electrician, have my entry level NABCEP photovoltaics certification, am BPI certified as a home energy auditor, and have been studying this stuff frantically since I bought the house in 2009 so I could make it as efficient as possible.

Thanks everyone in advance.

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  1. user-1150882 | | #1

    Wow, that's a long post...

    Thanks again!!

  2. user-757117 | | #2

    Interesting sounding project you have there...
    What climate are you in?

  3. user-1150882 | | #3

    Lucas, sorry for the delay... thought I'd get an email if anyone posted back. I'm just outside of Philadelphia.

  4. user-1150882 | | #4

    AJ, definitely a Huge Project! I'm not familiar with verses studying. I googled it and all I got was some Biblical sites...?

    I am a paid member, I can't find any details with fastener specs for that much foam, especially over masonry. Am I looking in the right place?

    I'll check those other sites out too.


  5. wjrobinson | | #5

    Micah, Huge project. Am editing my post, see you may have an interest other than ROI for saving energy. If so, you will really start to educate yourself by doing some studying. I am thinking you will greatly enjoy the work. There is lots here to read. Also pay to become a paid member for much more information and hundreds of detail sheets.

    Also BSC, and JLC And Finehomebuilding sites.

  6. wjrobinson | | #6

    Use the search function Micah. Termites, foam. And foam fastening etc. All has been discussed. Martin is on vaca giving his fingers a rest. He will help you when he is back. Buy into the other two magazine archives. Enough to read for a lifetime including ideas I frown on like HPHW heaters.

  7. user-1150882 | | #7


  8. user-757117 | | #8
  9. user-1150882 | | #9

    Alright so I looked through all those things and tried to contact some fastener suppliers. Still can't find a detail for attaching 6- 8 inches of foam over a masonry exterior that could then be covered in siding... any body have any info on this? I've found plenty on installing exterior foam just no fastener specifications for installing more than 4 inches over masonry.

    Thanks for all the help so far! Learning tons!

  10. GBA Editor
    Martin Holladay | | #10

    Tapcon screws are available up to 6 inches long:

    Tapcons are used to fasten into masonry, and 6-inch screws (with washers) should work for foam up to 4.5 inches thick.

    If you want to install 8 inches of foam, you probably want 10-inch screws. That might be tough. Contact the manufacturer for more information -- maybe they make longer screws.

    Tapcons are manufactured by:

    ITW Buildex
    1349 West Bryn Mawr Ave.
    Itasca, IL 60143
    Technical department: 800-328-4539, ext 3259
    Fax: 630-595-3549

  11. user-1150882 | | #11

    Thanks Martin,

    Just talked to tony at ITW He gave me the OMG Roofing products(formerly owned by ITW) tech support number. They make screws for installing ridgid foam board on structural concrete decks. The screws come up to 16 inches long!!!!! Calling my ocal supplier for pricing right now.


  12. user-1150882 | | #12

    Scratch that up to 22" long!

  13. GBA Editor
    Martin Holladay | | #14

    Thanks for the link. I didn't know that masonry fasteners came that long. I suspected that there were available in longer lengths, which is why I suggested that you contact the manufacturer, but I wasn't sure.

    Good information to know.

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