If you are talking 'Z' flashing for where there is a vertical stack of
sheet siding (like on a gable end), the same place you got the siding
should have it. If not, any builders supply will- a very routine item.
Make sure to not deform the 'Z' shape to make a pocket of water that the
upper board sits in- best to hold it slightly off the metal 'shelf' with
shims as you nail it up. There should be no need for flashing on the
vertical joints, since there should be a lap joint on a factory edge.
If you are piecing in an area, either fake the lap edge, or nail the
joint tightly and caulk.
If this is horizontal plank siding, there should be no need for
flashing- use a mitered lap joint, or butt tightly and caulk. The Tyvek
or tarpaper behind provides the moisture seal, the siding is basically
porous to moisture due to the horizontal lap joints. (Need to make sure
the house wrap and/or metal stock flashing at bottom of wall extend
below rim joist/sill plate, and provides a drip edge, or that wood will
Standard cautions apply- always seal any cut edges before you put the
siding up. Especially true for sheet siding- that lower edge loves to
suck water, double-especially at foundation level. As you make each
joint, look at it like a drop of water would- make the outside of the
wall away from the house, the easiest path to follow. (I've replaced
plenty of fascia boards and fly rafters where this principle was NOT
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.