Published on February 7th, 2018 | by Henri0
Re-siding house for energy efficiency
Q. Thanks for your work. It’s great. I have a 1960 frame house 20 miles west of Chicago. On the outside is steel siding with 5/8″ black cardboard underneath.
I would like to remove the siding and leave the black cardboard. Over the black cardboard I would like to install ½” plywood and 1 ½” XPS panels and then vinyl siding. Should the plywood be tongue and groove? Do I need housewrap? How do I install everything? Do I use screws or nails and what size? Thank you.
A. Consider a much better system. If you are going to the effort of replacing the siding and installing XPS to improve the energy efficiency of your home, look into the Huber Zip system, which has an excellent record.
The Zip system consists of various thicknesses of foam insulation from 1-inch to 2-1/2-inches integral to an OSB board. The panels are 4-feet by 8-feet.
You have probably seen buildings in your area sheathed with it; its green finish seems to be everywhere.
Consider removing the old Celotex and what must be 5/8th plywood at the house’s corners that provide structural rigidity to it. Since Zip panels are structural, do the removal in sequence so as not to cause problems.
Remove the plywood structural panels one at a time and replace each immediately with a Zip panel.
Apply the Zip system with the proper size nails. If you choose the 2-1/2-inch foam (as you are proposing), the nails will need to be 4-inches long (20 penny) and will need to be driven with pneumatic guns that can take 4-inch nails. You may be able to rent one or work with a contractor who has one. Hand-nailing following the manufacturer’s instructions would be very tedious.
Be careful that the nails penetrate close to the center of the studs, which will take some care, having to go through 3-inches of material before entering the studs.
Regardless of whether or not you decide to use the Zip-system or choose to proceed with your original plan, you will still have to deal with the windows. They are a large component of heat loss in a house and you should consider replacing them with top-of-the-line efficient windows. Why spend a considerable amount of money on the walls if you decide to keep the old 1960s vintage windows?
If you want to look into the Huber Zip system, go to www.huberwood.com, click on Products, then Wall Sheathing in the drop down menu, followed by clicking on Insulated R-sheathing. Scroll down to the illustrations of the wall thicknesses.
Be sure to follow installation instructions including taping of the joints. Your best bet is to hire a contractor experienced in the installation of the Zip system.
The vinyl siding is best installed with 1-1/2-inch large-headed nails. Be sure that you do not nail the siding tightly; stop short to allow the siding to move as it expands and shrinks following outdoor temperature swings.
If you insist on following your original plan, let me know and I’ll provide additional instructions.by