What’s the best field joint detail for rainscreen clapboards?
slugboy6000
| Posted in Green Building Techniques on
I’m installing horizontal cedar clapboard rainscreen siding. I was intending to face screw each board just above the lower course into 1×3 pine furring strips, installing 3″ wide splines of aluminum behind the butted field joints. Unfortunately, the stainless screws at these joints will penetrate through the aluminum spline reducing it’s effectiveness, made worse over time by the galvanic action between the stainless and the aluminum. I’m looking for options. Would an un-splined scarf joint be a better detail?
Thanks for your help,
-Richard
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Replies
Richard,
You don't need screws -- just ring-shank SS siding nails. Keep your nails 1.5 or 2 inches back from the butt joint, and you won't hit the aluminum. Make the aluminum narrower if you want to nail closer to the butt joint.
How narrow can I safely go with the aluminum joint flashings? One source specified 2". I don't think I could go much wider and still hit the furring strip.
Richard,
Now I understand your dilemma. If it's not too late, switch to 1x4 furring strips.
Furring is installed.
I could blind nail the top edge of each board, but would prefer scarf joints if I can figure out how to cut them. I'll work on it.
Thanks Martin.
Richard, substitute a piece of Grace Ice and Water Shield for the aluminium splines.
Malcolm,
Good suggestion. Here's another suggestion for Richard: substitute strips of good old fashioned asphalt felt.