Negative pressure within the home can force smoke from the top of one chimney flue to be sucked down an adjacent, unused flue. This is a common occurrence and may result in multiple problems…from smoky smells in the house to actual poisoning of the residents! To prevent this, the Masonry Institute of America, which is the #1 source for published information on masonry, states that adjacent flues should have a vertical height difference of between 4 to 12 inches. The reason of course is to avoid smoke from exiting one flue and then being drawn down into the living area by an unused flue which is down-drafting. Yet most chimneys do not meet this standard. To make matters worse, the installation of a chimney cap, whether two single caps or one multi-flue cap, can make the situation much worse.
Our patented stainless steel Boost-A-Cap is an easy and cost effective way to bring your chimney up to spec and prevent down-drafting and smoke crossover problems. It also allows for the proper installation of two standard caps next to each other. It uses our unique, adjustable expansion system to tightly fit inside your flue and increases the overall height by 12 inches.
The Boost-a-Cap can be used with your current chimney cap, or you can now purchase a chimney cap from us! The Boost-a-Cap can also be used to extend most top mounted dampers and can can also be used to extend your chimney liner and cap.
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