Flue Symptoms
Rick Yeager searches a home to find the source of a mysterious scratching behind the walls.
Home inspector Rick Yerger traces the noises in the wall of Steve and Christy Karsten’s home to a gas combustion furnace and the water heater. Something in the flue system is causing a backdraft and allowing deadly carbon monoxide to flow into the Karstens’ home. Combustion gas is remaining in the flue in the wall; the backup is causing condensation and rain inside the space. Repairs, made from the garage through the upstairs to the roof, include removing drywall and flue ducts.
Steve and Christy also learn how to install vent duct from the gas furnace and water heater to ensure proper drafting and prevent carbon monoxide poisoning and the possibility of fire. Proper strapping, hanging flue duct and drywall repairs are also demonstrated.
Something’s scratching behind the walls of this house that has homeowners Christy and Steve Karsten scratching their heads. Series host and home inspector Rick Yerger finds it’s not alive as they all thought, but the walls are hot–above 90 degrees. He traces the trouble to a gas-combustion furnace and a water heater. Something in the flue system is causing a backdraft and allowing deadly carbon monoxide to flow into the Karstens’ home! The repairs include removing and reinstalling the flue system from the appliances up to the roof to ensure proper drafting and prevent fire. Proper strapping and hanging of the flue duct is also included. Fellow home inspectors Wally Conway and Tim Hockenberry join Rick Yerger to offer more safety advice on combustion appliances and proper flue systems in your home.
.Remove and Replace Flue:
Materials:
drywall or electric saw
safety glasses
gloves
face mask
flat bar
screwdriver and/or cordless drill
screws
metal strap
1. Unplug the furnace and turn the water heater down to the “vacation” setting to contain the CO gas (figure A).
Fig-A
2. To remove the flues, unscrew every connection at each of the joints and dismantle (figure B).
Fig-B
3. Cut through the drywall with a drywall or electric saw, adjusting the blade to ensure it cuts only through the depth of the drywall; this will avoid the risk of cutting through any electrical wiring or the flue itself. Be sure to wear protective gear such as safety glasses, gloves and a mask (figure C).
Fig-C
4. As soon as the dysfunctional pipes are exposed, they can be removed. A flat bar is used to help dismantle the connected pieces (figure D).
Fig-D
5. Remove the flue and any additional frame boards that will obstruct the necessary clearance needed to avoid a fire hazard. A minimum clearance of 1″ is required around the flue (figure E).
Fig-E
6. With the old flue out of the way, the new flue, which has been cut to size, is put in place. The first piece slides in place, going up through the roof (figure F).Note: Make sure the directional arrow is pointing up.
Fig-F
7. As one person holds the first section up, slide the second section of the flue down into the floor and connect the two pieces together, again making sure the directional arrows are pointing up.
8. To keep the flue securely in place and ensure clearance from the wall, install tightened metal straps. Cinch the screws in at an angle to pull the strap taut and remove any slack (figure G).
Fig-G
Up on the RoofMaterials:
roofing mastic
storm collar
rain cap
1. Once the flue is in place, head up to the roof. Apply a layer of roofing mastic around the flue piece to seal the joint between the new flue and the shingles (figure H).
Fig-H
2. Add a storm collar, again sealing with roofing mastic. Also, to keep moisture out, a rain cap is added, completing the exterior part of the fix (figure I) (figure J) (figure K).
Fig-I
Fig-J
Fig-K
Most of the aboveground work has been completed; now the crew heads down into the basement to install a fire stop. Then the drywall will be replaced and painted, and the repairs will be finished.
In the Basement
Materials:
fire stop
flue pipes (twist lock fitting, double wall insulation)
flue pipe Y connector
metal straps
cordless drill
1. In the basement, a fire stop is required at the ceiling and floor lines. In case of fire, the stop will prevent the fire from spreading into the wall cavity. Install fire stop sheet metal to close off the opening around the flue completely (figure L).
Fig-L
2. To vent the water heater and furnace properly, a directional, or Y, connection is needed. The new pipes and connectors should have double-wall insulation (figure M).
Note: Use twist-lock pipe fittings to make the job easier.
)  Figure L |
) Figure M |
3. The connection from the water heater to the new flue should have a 12″ rise from the water heater and connect at a 90-degree angle to ensure proper ventilation (figure N).
Fig-N
4. To relieve some of the weight from the pipes, install metal straps at the elbows for support (figure O) (figure P).
Fig-O
Fig-P
Replacing DrywallMaterials:
tape measure
utility knife
cordless drill
screws
drywall sheets
drywall mud
drywall tape
fine-grit sandpaper
paint and paintbrush
1. Measure the narrowest section between the two drywall sides. This will be the reference point for cutting the drywall (figure Q).
Note: When cutting drywall, cut a little bit wider than the measurement; you can always shave it down.
2. Use a utility knife to score the paper carefully. Apply pressure by hitting in the middle of the score; the drywall should easily break in half. Finish the cut by running a knife down the paper to separate the pieces (figure R) (figure S).
Fig-R
Fig-S
3. Position the drywall in place and secure with screws (figure T).
Fig-T
4. With the drywall patch in place, apply an ample amount of drywall mud, making sure to fill in the creases (figure U).
Fig-U
5. Apply drywall tape over the seams and cover with another layer of mud. Allow this layer to dry (figure V).
Fig-V
6. Once the mud is dry, sand down the first layer, add another coat of mud and allow to dry. Repeat this step as needed (figure W).
Fig-W
7. Paint the patch to match the wall color.
Source:Finders Fixers