I’m looking for advice on how to replace the exterior of a 1962 manufactured home in Maryland. It is currently 2×4 walls with fiberglass insulation, metal diagonal strapping, and aluminum siding. There is no sheathing.
I’d like to remove the old siding, sheath the house, install foam board insulation and new siding. I’m tempted to use the ZIP-R sheathing which will put the foam inside the sheathing, making the new windows and doors easy to install. I imagine it might be cheaper to install OSB and foam board insulation.
What would you do? I’d like to maximize R-value and keep costs reasonable.
Replies
A lot of "depends on" here. I was taught to believe putting foam under the sheathing decreased the shear the sheathing creates. Maybe that no longer is considered accurate, for sure the zip with foam is getting lots of consideration. Hopefully someone knowledgeable on current standards will chime in.
Of course the wind loads in your area play in as well but even foam under osb would be stronger than your current set up probably.
It would be cheaper to put foam over generic osb and hardly any more labor if the foam was 1" or less. Thicker foam would require strapping and a little more work around the openings. That extra work is no biggie if you have the skills but also adds a bit of material cost.
If you haven't already it would be easy to figure the cost of material differences . I'd be interested in hearing that as well as the opinion of others about zip sheathing with foam and shear strength.
An update on this project. I've been seeking estimates for this work. One contractor wondered if the original aluminum siding could be left on, and then just add 1" of foam and vinyl siding. The house has survived for 60 years without sheathing.
Without thinking about the vapor issue the leave the aluminum on grates my teeth. It would be hard to tell if your vinyl nails would be hitting anything.
But this is an interesting case and your point about it lasting 60 years already is very relevant.
i'd love to hear about your estimates but of course how well the job is completed is the biggie...
I hope you keep us posted.
I'd love to hear your estimates.
Leaving the aluminum on and nailing through it sounds like a poor idea to me.
At the end of the day it may depend on how much the structure means to you and what makes sense to spend.
The fact it has existed 60 years is notable, could be an exceptional fix could make it go more decades.
I hope you keep us posted.