Winthrop, Maine
Office (207) 377 9293
Mobile (207) 557 2844
Fax (207) 377 4444
A Contractor That Knew Better
A contractor built a new room above his garage and connected it to the second floor of the house over the mudroom. He sealed and insulated the knee walls and roof but left the top of the ceiling open so he could run some wiring before he closed it up. He also left the garage stairway open to bring more materials up and the floor un-insulated until he replaced the garage doors.
Obviously the heat loss was high around the new room doorway over the mud room and the garage was very drafty as the old doors and windows were very leaky. The air pouring out through the opening in the new room ceiling was pulling cold outside air in through the gaps in the doors and window in the garage and a little from the home.
One day he had some free time so he and his crew jumped back on the project, replaced the old garage doors with new insulated ones with good weather stripping and installed an insulated side door. That night after supper he replaced the old window with a new one.
Later as he was washing up and getting ready to go to bed he smelled furnace exhaust in the house.
He awoke his family and got them out of the house while calling 911. When the fire department folks arrived they found very high levels of carbon monoxide (CO) in the house. The levels would have been deadly in only a few hours ... and he did not have a single CO detector in the house!
The improvements to the garage had stopped the outside air from pouring into the garage, but not the interior air from leaving.
The make-up air for the air that was still going up through the open ceiling in the new room was now being pulled down the boiler flue and chimney!
The next day after everyone had been checked out at a medical clinic, and staying overnight at a motel while the fire department ventilated their home, the contractor ran the wiring and insulated and finished the new room ceiling, all while being extra diligent in air sealing the joints and the new hall over the mudroom to the garage. He then sealed and insulated the floor of the new room.
The lesson here is two-fold:
First, always have working Carbon Monoxide detectors in any occupied building that uses combustion appliances for heating or cooking.
Next, buildings are SYSTEMS and what you do in one area will affect other areas. Everything is interconnected and controlling the air flow in any building can be tricky. Sometimes something as simple as new windows, or finishing the basement without air sealing the attic, can cause terrible problems. Remember that if you don't stop or slow down the air leaving from above, the air entering from below may come from sources that are unhealthy, or worse. So seal from the Top Down.
You can see why we recommend combustion zone testing (CAZ) testing before you begin a project and CAZ testing along the way.
It really makes sense!
