AROUND THE HOUSE: Noisy heat ducts may take multiple attempts to quiet

Dear Ken: We moved into a new home a short while ago. The main heating ducts make a cracking and popping sound when the furnace comes on. Do we have to live with this?
Richard

You may have to live with some of it, but there are ways to minimize the noises. The source of all this irritation is metal ducting passing through or near to framing lumber, like floor joists and studs. As the duct work heats up, of course, it expands a little, and anywhere there is wood-to-metal contact there is rubbing and slipping going on.

Your HVAC contractor can help with this. They can slip pieces of foam rubber here and there between the wood and metal; they can screw metal stiffening straps on to the widest and longest portions of the trunk lines; and they can widen holes with a reciprocating saw.

This is all trial and error, so it may take a couple of visits. And they may never be able to get rid of all of it, so you may have to learn to live with of it in diminished form.


Dear Ken: You talked about condensation on window sills. But what about drops up in the corner where the ceiling and walls meet?
Rebecca

I’ll bet you live in an older home. We didn’t do as thorough a job insulating houses decades ago, because energy was sort of an afterthought then. Hard to believe, isn’t it?

Behind the drywall in that location are a collection of 2x4’s at the top of the wall, which conduct heat out of the house, and so produce condensation. In addition, the attic insulation may not extend out far enough toward the soffit overhang.

Have someone check in the attic space. Maybe they can poke some batt insulation out into this area to protect those wood framing members from extreme cold temperatures.


Dear Ken: I have a bathroom fan that leaks moisture when turned on. What could be causing this?
John

When you shower, the water vapor gets sucked up into the fan’s 3-inch metal ducting. The pipe is cold, so the water vapor condenses rather quickly and runs back down towards the bathroom. There’s a neat trick you can try, but it requires crawling into the attic. When you get up there, grab the event pipe and create a flat spot just above the fan (if you have enough slack, bend it downhill slightly to create a “trap” in the pipe). That will collect the water, which will slowly evaporate over the course of the day.


Dear Ken: When I leave in the winter, I always turn off the basement water valve. My question is how can I prevent pipes from freezing after that?
Steve

You need to eliminate the pressure in the system. Once you do that, there’s enough space in the pipes to allow expansion-without-breaking if there’s a freeze-up. After you turn the main valve (the one closest to the basement floor) off, open the hot and cold faucets in the lowest basement bathroom lavatory. Just walk away so they stay open while you’re gone on your trip.

In addition, open that drain faucet at the bottom of the water heater tank and run a couple gallons of water into the floor drain.  Make sure that the gas is totally off — including the pilot! If yours is an electric water heater, turn the 30 amp breaker off in the panel. Pour some mobile home-type anti freeze into the toilet bowls (after flushing) and into the sink traps. Finally, set your thermostat no lower then 55 degrees — and enjoy your trip!

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Former homebuilder Ken Moon is the owner of Colorado Home Inspectors and a member of the American Society of Home Inspectors. Hear him Saturdays at 9 a.m. on KRDO 1240 AM and 105.5 FM. Reach him at www.aroundthehouse.com.