I am renovating an 1800s farmhouse after having built an addition. The house is old-style timber frame with 3″x4″ “studs” at oddball centers. I have re-sheathed the house with 1/2″ Zip and have installed “outie” window boxes. I’m now preparing to install 2 layers of 1’1/2″ exterior insulation, strapping and 26 ga. corrugated metal siding.

For the addition I spaced the strapping to land on studs at 24″ o.c. attached with Headlok screws, also spaced 24″ o.c. vertically. I feel that was overkill as the siding can easily span over 5 feet.

The various tables for hanging siding on strapping don’t deal with this situation. I’m thinking of installing strapping at not more than 48″ o.c. which saves a ton of labor. I imagine I’ll have to add screws and washers more often to hug the foam to the wall, but I can’t see any downside.

Any opinions?