Replace siding and add 4 inches of foam board and cement board?
I am looking on replacing my old wood siding with cement board sine I have had problems with woodpeckers previously so I would like to make it more bug proof. I would like to increase my insulation while I do this since we live in Minnesota . I have considered replacing what looks like newspaper insulation in my 2×4 walls by removing the sheathing. I am not sure if I should I would like to do spray foam for the air barrier, but torn by the cost. I am not sure if I should leave this as is and go with adding 4 inches of foam board on the exterior.
Our house is a simple rectangle house 43 ft by 26 with 8 feet walls
I have a couple questions about the process
I would also like to replace my single pane windows that also have storms with a good double pane window. If I have all that insulation outside what is the best way to mount the new windows. I have watched the following video and like their box idea but wonder how they mount the window.
https://www.greenbuildingadvisor.com/video-how-install-rigid-foam-insulation-outside-house
Another question was if I got 6 inch screws to put strapping on the outside of the foam would cement board weight hold on the strapping and screws to the wall or is that too much weight.
How do I mount the corner boards on my siding if I have 4 inches of insulation under, would the end strapping have to be 6 inches wide to have the screws go into the studs.
Thank you for any help you could give on this.
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Replies
Check out the "Builder’s Guide to Continuous Insulation" by Joseph Lstiburek (for Dow). Also, "Remote, A Manual" produced by the Cold Climate Housing Research Center. Also: http://www.solaripedia.com/files/1004.pdf
Exterior rigid foam is the way to go if you are doing siding. No thermal bridging and it keeps your sheathing warm.
Windows are tricky, but I would put them in the same plane as your WRB. So "innies" if using wrap over the sheathing but under the foam - similar to a "normal" install. I would also look into a "draining" house wrap like Tyvek Commercial or Kimberly-Clark BLOCK-IT. This will help water drain from under the foam.
Technically you can tape your foam boards to make a WRB, but the foam is known to shrink over time...
Definitely need to hit a stud with your strapping screws. FastenMaster HeadLok is great stuff. And you need longer than 6" if you need 1.5" into the stud... See here:
http://www.jameshardie.com/d2w/technical-bulletins/19-jh-over-advanced-framing-or-continuous-insulation.pdf
Thank you for the great answer and help.
Where would you get tyvek commercial also heard commercial d was good.
So I would have my sheathing, tyvek wrap, foam board, strapping then siding. So you recommend the windows where the tyvek wrap would be?
For the screws would you say 8 inches is a good length?
Do you think the cement board would be too heavy?
Trevor,
Are you sure you mean Tyvek Commercial? That's what I usually use. It's just a more robust version of regular Tyvek with a lower perm ring. it isn't a "draining" house wrap.
Tyler,
There are lots of resources here on the GBA site to help you. Here are links to several relevant articles. Have you read them?
How to Install Rigid Foam Sheathing
Fastening Furring Strips to a Foam-Sheathed Wall
Installing Windows In a Foam-Sheathed Wall