
Aluminum/Vinyl Inspection Guide
STANDARDS OF PRACTICE
The International Standards of Practice for inspecting the Exterior is located at www.nachi.org/sop.
Aluminum & Vinyl Siding

ALUMINUM WALL CLADDING DEFECTS
Observation

Missing corner backing.
The photos shows corner backing installed to keep siding tight at the inside corners. It is missing along the
length of most of the inside corner.
No window head flashing.
Siding cut short above window.
Observation

Poor installation at soffit.
The installation leaves gaps at the soffit.
Observation

No kickout flashing.
This will allow runoff to enter the space behind the siding.
Observation

Window installed sideways.
This is a sliding window installed as a single-hung. The weep holes on the right side should be at the window bottom.

Inadequate gap
Nailing hems should have a ¼” gap where they meet to allow for expansion.
Observation

Over-tightened fasteners.
Fasteners should be loose enough to allow siding to expand and contact freely.
Observation

Nailing hem not fastened
Observation

Missing Nail hem.
Observation

Inadequate clearance from shingles.
Standards call for a minimum ½” clearance from roofing materials.