Remeidiating blocked soffit-to-ridge venting around skylights in a cathedral attic

A homeowner building a new house with a cathedral ceiling (a vaulted roof with no separate attic above it) ran into a common problem: skylights installed in the roof block the airflow path that's supposed to run from the soffit vents (under the roof eaves) up to the ridge vent (at the roof peak) inside each rafter or truss bay. This venting normally helps keep the roof deck dry and cool. With skylights in the way, four of the bays have no clear channel for air to pass through.

The homeowner considered drilling holes through the wood truss members near the skylights so air could shift sideways into open bays before the insulation goes in. But a building science expert responding to the question warned against this: you cannot drill holes in engineered truss chords without approval from the truss manufacturer, and manufacturers are unlikely to approve holes that large. Smaller holes might not even work well enough anyway. The suggested alternative is to treat those specific bays as "unvented" and fill them with spray foam insulation instead, which seals the space directly rather than relying on airflow.

For anyone planning a home with skylights set into a cathedral ceiling, this is a reminder that skylight placement can interfere with roof venting design, and that fixing it after trusses are built has real limits. It's a detail worth raising with a designer or builder before construction, not after installation, since the options narrow considerably once the roof structure is in place.