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Community and Q&A

Best insulation upgrade choices?

GBA Editor | Posted in Energy Efficiency and Durability on

I am going to replace some siding on the outside wall of my kitchen, Laundry room, and Family room. This is old fiber board siding. The house was built in 1984 and is located in the Atlanta area. The house has an unfinished block wall basement. Since I am removing the siding I have an opportunity to reinsulate the walls. We get cold air when we open the kitchen cabinets which back up to this wall and have their own wood backing. The chooses include:

1) Install Micro E foil wrap over the existing two sided foil sheathing board once we remove the siding and do not go any further but install tyvek housewrap over the micro e wrap then add the cement board hardie plank

2) Take the wall down to the studs and remove the batt insulation (R11) then have the pockets spray foamed (expensive) Pay a professional to do this.

3) Take the wall to the stud removing all insulation cut pink rigid foam board 2 two inch pieces flush and tightly install between the studs. Board has R10 value for each 2″ piece. Then add new sheathing (foil coated on both sides) and finally tyvek housewrap and hardie plank cement siding.

I am concerned about moisture build up and mold but want to upgrade the wall insulation while I am doing the siding work. Which is the best option or do you suggest others.


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  1. GBA Editor
    Martin Holladay | | #1

    The worst of the options you mentioned is #1. Forget about foil wrap. Aluminum is a conductor, not an insulation.

    There is a fourth option: install thick rigid foam on top of your sheathing; then install vertical strapping to create a rainscreen gap, and install your new siding.

    You may want to read this article: "Roofing and Siding Jobs Are Energy Retrofit Opportunities."

  2. Scott | | #2


    Thanks for the information. I received a quote for closed cell foam spraying in the wall cavities. for about 700 square feet $1850. Is this on par with typical costs? Should I be concerned about spray foam next to the HVAC duct in the winter when the heat is warming the metal duct. Also, is there a concern about outgassing of chemicals from closed cell foam causing health issues?

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