Cold air coming through fireplace

Q. We live in an end unit condo, which is about 22 years old. We have a lot of cold air coming into our living room through our fireplace even with the flue closed. When we've had our chimney cleaned over the years, no chimney cleaner has mentioned any problem to us.

What is going on with this fireplace? Any suggestions would be most welcome.

A. Because you are in an end unit, your chimney is exposed to the weather and can get quite cold. It may also be that your damper is not closing as well as it should. Consider having a maintenance person knowledgeable in these matters check to see if your damper is askew.

But part or most of the problem may be cold air coming in through the chimney when warm air is lost from other areas of the house. If you only experience these cold drafts when your heating appliance is running (if it does not have its own fresh air supply), or the clothes dryer is used and bathrooms or kitchen fans are on, then those appliances are creating a negative pressure in your condo. With the need for make up air, the chimney is the easiest path to provide it.

It could also be that the amount of cold air you are experiencing is make up air compensating for a considerable loss of warmed air from the living area to the outside through windows and cracks. Consider having an energy audit performed to locate any possible source of exfiltration on the second floor.

Q. I have a strange septic situation that no one has been able to answer. I have a small two-bedroom, one-bath home. When using the bathroom (shower, sink or toilet) I have no problems with smell coming from the septic tank, which I have pumped out on a regular basis.

However, when emptying the kitchen sink (five to seven gallons, I would guess), an awful smell is emitted. In talking to several people, I have heard theories that it could be a blocked vent or a blocked or damaged clay tile in the leach field, which is 60 years old. But there has never been obvious leaks or standing water in the yard. The soil we're on here is black dirt at least 4 feet deep before it turns to clay.

I am guessing that perhaps the rate of water going in and out of the septic tank may be the cause of the problem as the kitchen sink drains very quickly, while the bathroom drains more slowly.

Any ideas as to why this is happening and what can be done to remedy the problem? I have been looking at a product called Aero-Stream. Have you had any experience with this product? Its product claims seem to be incredible, so I am wondering if this might be the answer?

A. The Aero-Stream is one of the many systems that transform the anaerobic environment of regular septic systems into an aerobic one. Aerobic systems are alive and eliminate some of the problems common with anaerobic systems. Their benefit is for the health of the leaching systems by promoting the absorption of the effluent into the soil and eliminating the clog mat that results from partially untreated anaerobic effluent. It's good for the soil, but I don't think that is what is causing your problem because you are not seeing any seepage in your yard.

From your description and the age of your house, I wonder if the drainpipe from your kitchen sink is of the old-fashioned siphon type (looking like an S instead of a U leading into the back wall - the latter known as a P-trap).

Because siphon traps are not properly vented, when a full sink is drained through these traps, it does so at high speed that ends with a sucking, gurgling sound, which often completely empties the drainpipe. As a result, sewer gases can now enter the house until the siphon trap has enough water in it again to seal the gases from doing so.

If this is the case, the easy fix is to run enough tap water slowly into the sink until the seal is restored after the main drainage has stopped. It's a lot less expensive than having a licensed plumber change the siphon trap to a P-trap, but your local code may require the upgrading when you are ready to sell your house and a competent inspector finds the problem and has to report it. However, there are other less expensive venting options available when the time comes.

Follow up from a Vermont reader: The following is in response to my comments on glass shower doors in a recent column. I responded to a reader who saw them as a danger to aging people. On the contrary, I find them to be a safety feature for several reasons.

This reader had a terrible and frightening experience that could have ended tragically while visiting Peru. She writes: "I agree 100 percent about the safety of a glass door rather than a shower curtain. You may find of interest, however, there is a type of shower door to stay away from. I will send you a photo.

"In Cuzco, Peru, recently, I was in this shower stall in a hotel and the door would not open, locking me in. After a terrifying hour, when I had not shown up downstairs to join our group, our tour leader came looking for me. Fortunately, I was rescued, but had the incident happened late at night, the outcome would not have been good! There had been a malfunction of the door hardware and you can bet once I recovered from the trauma, I made plenty of noise and complaints to the hotel."

She did send me a photo of a hinged shower door in a small shower stall that trapped her in the shower. My earlier comments were about sliding shower doors installed either on a tub or in a shower the size of a tub. I had never heard of, or experienced, this problem on any narrow, hinged shower doors in the U.S. or Europe. I was curious as to the brand of shower door with this very serious problem in order to warm readers.

Following my request for more information, she replied:

"I do not know the name or where available, perhaps used only in Peru. Our hotel was called the XIMA hotel, and I have warned the management in Peru to stay away from rooms with this style shower. I have even posted a warning on Trip Advisor."

The lesson I got from her frightening experience is that if I ever find a hinged door in a hotel, I would try the door with someone else in the room to make sure. A warning to all.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.