Instructions / Assembly

The Python™ Rolled Ridge Vent Installation
Instructions
Quick Pre-Install Checklist
 Contact your local code official before installing Python™ Rolled Ridge Vent for
compliance with local requirements.
 Please see online Python™ Vent Calculator App at
https://marcoindustries.com/ventilation/steep-slope/calculator to determine how
much ventilation is required.
Install only one type of exhaust vent and remove and plug existing vents including
turbines, gable vents, roof louvers and static vents unless you are installing into existing
penetrations per the instructions.
The NFVA (Net Free Venting Area) of the eave/intake vents should never be less
than the NFVA of the Python Rolled Ridge Vents being installed. Improper balancing of
the system could result in weather infiltration and inadequate attic ventilation.
The Python™ Rolled Ridge Vent is engineered for use on roof pitches from 3/12 to
20/12.
Installation Instructions
1. Use on a minimum 3/8" (10 mm) plywood or OSB decking.
2. Cut a 2" (51 mm) slot along the ridge, 1" (25.4 mm) on each side. Leave uncut (closed)
sheathing area of 6" (152 mm) at each end of the ridge. Cut through sheathing only,
avoiding roof trusses. (In houses with a ridge board, cut 3 " (89 mm) slot, one on each
side.
3. Where short ridges (dormers, ridge intersections) are used, mark and cut the slot and
make sure that the end of the opening stops at least 12” (305 mm) from the ridge
intersection.
4. Uncoil Python Weather-Tite Rolled Ridge Vent along the entire length of the ridge,
covering uncut 6" (152mm) sheathing area on both ends. Shorter lengths can be joined
by caulking and butting the end.
5. Install cap shingles directly over Python Weather-Tite Rolled Ridge Vent. Use included 1
¾” (44.4mm) coil nails. Python Weather-Tite Rolled Ridge Vent has a ¾” (19.1mm)
nominal thickness. Be sure not to crush or compress the vent during installation.