Subscribe to Fine Homebuilding magazine now and save up to 52%
Thermal bypass yes... but more importantly a fire hazard as all chimneys should be fireblocked at every floor level...:)
© 2017 The Taunton Press, Inc. All rights reserved.
Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.
Start your subscription today and save up to 52%