We are considering buying a house built in 1976 near Annapolis, MD. My only concern came when I looked under the aluminum siding and found what appears to be sheathing made out of a “homosote type” of substance with a foil outer layer instead of the expected plywood. Does anyone have any concerns about the long term durability of this material as a sheathing? Have any of you renovators seen problems with this stuff absorbing or holding moisture? As the aluminum is looking a little tired, we are considering residing in cedar (probably Skakertown type panels) – any concerns about siding over this type of sheathing? Any experience good or bad would be appreciated.
Replies
There have been several homosote/foam/gyp board sheathing products over the years, and they're all fine for providing a smooth surface outside of the studs. The key to any of them is installing shear bracing in the walls (let-in 1x4's, metal straps, etc) to replace the shear value of the plywood.
The problem you'll have is with nailing up the shingles. The aluminum siding works, since it can be nailed directly to the studs at 16" o.c. If the shingle panels can be installed the same, you're OK- but there'll inevitably be areas where you'll have a hard time finding anything to nail to and you'll wish you have plywood sheathing.
Bob
Thanks. I did cover the R-max foam type sheathing on my last house with the Shakertown panels and it worked well since the cedar panels came in 8' lengths.
I still have some concerns about the "homasote type" sheathing absorbing moisture or having already done so under the aluminum siding. Anyone found this?
My last home was built in 1968, and was sheated with the same stuff, witout the foil face. It had a brick venier, but water is stillan issue , even with brick. I lived in and remodeled that house several time over 32 years of occupancy. Never had any probelem with the black board soaking up water.
The stuff is impregnated with tire, and unless left exposed to directly to the ellaments for a long time, doe a good job of shedding water.
When I worked on a framing crew as a pup, we installed a lot of it on homes of that era. Energy cost and housing cost were low back then. If I were residing one today, I would upgrade everything in the wall assembly while I had the opportunity. I t is a good time to add insulation to the walls without interior damage, air seal, check for water damage, and even do some electric up grades...all from the outside of the house.
Dave
My house has it, it's ok but you must hit studs for the siding. Ours has older vinyl and will need replacing soon. When the time comes I will replace with real sheething. One of the problems I'm having is many many nail pops. I'm thinking the house sways a bit because of no cross bracing. Nail pops are the enemy. Homesote for sheething, hate it.
Men do not quit playing because they grow old; they grow old because they quit playing! Holmes Sr. Oliver Wendell
Take peek behind the siding at the corners. If memory serves me correctly, even 30+ years ago. solid sheating or let in braces was required at corners. Current code allows black board or rigid foam as sheating with the proper corner bracing and additional sheating or bracing every x number of feet of wall. Check your local code for specifics.
BTW vinyl siding is nailed loose to allow for expansion and contraction. Your "nail pops" may be the proper nailing, or maybe not.
Dave