R311.7.5.2.1 Winder treads
Winder treads shall have a tread depth of not less [...]
Winder treads shall have a tread depth of not less [...]
The tread depth shall be not less than 10 inches [...]
Winder treads shall have a tread depth of not less [...]
The tread depth shall be not less than 10 inches [...]
Winder treads shall have a tread depth of not less [...]
The tread depth shall be not less than 10 inches [...]