Don't close home's only air return
Q. I have a question about a recent answer you gave. You told the reader to close off the heating registers in unused rooms and close the cold-air returns, also. I had wanted to do that in a second home I own and was advised not to do it by my heating contractor. He said the airflow across the plenum of the furnace could be reduced to the point that the furnace will "overheat" and go into high temperature limit. He told me not to close off any returns. What is your opinion of the advice given to me by my contractor?
A. So glad you have found some answers helpful. If the return or returns are centrally located - as opposed to being in each room - they should not be closed off. But if there is a return in each room and you shut off the supply register, then you should also close off the return to isolate the rooms that you don't want to heat. The potential problem your heating contractor mentioned can be dealt with by having a bypass installed between the heat and cold-air plenums, or with a two-stage blower fan.
Q. Is there a difference between using blown-in insulation compared to the rolls of fiberglass? Also, there was a hole in the fascia that allowed squirrels to infest that attic for a while before the house was purchased. The old and very thin insulation smells of urine, and you can see feces all over the place. Should this be removed before putting the new insulation in? You can't smell anything in the house. If it should be removed, would I have to take special precautions?
A. Cellulose is a very good and eco-friendly insulation, since it is made of shredded newspapers. It has the advantage of making it easy to fill any spaces, sometimes hard to do with batts if the roof is built with trusses, for example. Do-it-yourselfers can rent a machine to blow cellulose, but it is easier for them to use fiberglass batts. Cellulose is also healthier to handle; fiberglass fibers are not healthy to breathe. So if you choose to do the job yourself with fiberglass, be sure that you wear a good dust mask, gloves, tight sleeves, goggles, etc. Duckbill dust masks are the best in my experience; they are made by Kimberly-Clark and are available at Home Depot. You can also find them on Kimberly-Clark's Web site: www.kcdiy.com. You may also want to look at their Grip gloves, simply the best work gloves I have ever used for gardening and other projects.
You may choose to have an insulating contractor blow in cellulose. There should be no need to remove the old, thin insulation; just cover it up with the new. But if you do the job yourself, make sure you do not stir things up. Be aware that adding substantial amounts of insulation in an attic increases its relative humidity, since colder air cannot hold as much moisture as warmer air. If you choose to work with fiberglass, select batts with an integral Kraft-paper vapor retarder. You can use it over the existing thin insulation as long as the new insulation you add has at least twice the R-factor of the old you are covering up. Fiberglass has an R-factor of slightly above 3 per inch, cellulose R-3.5. So it should be easy for you to calculate what you have and need to add. You haven't told me where you live, but you should think in terms of obtaining a total R-38 factor.
Q. I read about a reader inquiring about musty basement odor improvement. He had mentioned a system called the Musty Basement Solution. You were skeptical. We had a Humidex (same concept) installed in our basement. It was one of the best investments we made. The air from the floor of the basement is removed and sent up the wall of the and out of the house via an enclosed tubing and a small exhaust fan. The air at the bottom of a basement is the smelliest, dampest and least refreshed air in the home. By removing this air, you are also removing the bulk of the humidity in the home. This disgusting air is also the most energy consuming to cool or heat because of the humidity.
The most efficient dehumidifier, constantly running (typically in the summer), uses well over $100 of electricity to run per month. We got rid of our 1-year-old top-of-the-line "Energy Star" dehumidifier after realizing this. Our electricity bills went down. We also found savings beyond this. After the Humidex was installed, our energy usage for this summer was less than last year's. I believe it to be that the air that is most energy consumptive on temperature regulation is removed via the Humidex. On top of this, the basement has no smell like before. You are absolutely correct about adequate ventilation preventing the back flow of furnace or water-heater exhaust. A competent installer will check this and put a louver panel or air-exchange vent in the door to your basement that is large enough to prevent this. I have no personal or financial interest in any of these venting companies, just an interest in spreading information that helps people be more "green." This is a very simple technology, yet a great improvement over an electrically expensive dehumidifier.
A. I am glad to hear that you have found the switch from a dehumidifier worthwhile. But the problem remains the same. To replace the basement air that is exhausted by either the Humidex or the Musty Basement Solution, air is drawn from other parts of the house or from the outside. So, yes, a competent installer may install a louver in the door to the basement if the house was not built tightly. But this air needs to be replaced with outside air through cracks in the building envelope, and this adds to the cost of air-conditioning in the summer when the Humidex or equivalent is most needed. In a tightly built house, makeup air must be provided from the outside by means of an air-to-air heat exchanger, and that air also needs to be cooled. So this technology is not as green as it sounds. It's a question of choices.
Q. I would like to redo my bathtub/shower area, which also has a window. The rest of the bathroom is just fine. I wanted to know your thoughts on companies like Bath Fitter that place fitted tubs and walls over the existing tub and walls. Is this a feasible way to redo the area without spending a ton of money? I'm also wondering if mold and mildew would be growing under these new walls.
A. It is indeed a feasible way to improve a bathroom. As to the cost, you will have to get some estimates, but having a tub and wall liner installed can cost a lot less than replacing the existing tub and tiled walls. If the installation is done properly over thoroughly dry walls and tub, there should not be moisture intrusion behind the new liners and no problem with developing mold.
Q. I read with interest and anticipation your column in the Daily Herald regarding the man with soil grading and drainage problem in the front of his house. I have a similar problem in the back of my house and have been dealing with various solutions and consultations for the past three to four years. It's frustrating, and I still haven't solved the problem. For some odd reason, the soil and grade up against my foundation hasn't necessarily dropped or sunk, but the rest of the lawn and gardens have somehow heaved up or raised themselves to a point where I can stand 20 feet out from my foundation wall and be a good 6 inches to a foot higher than the wall. An engineer from our village engineering department's suggestion was to build a retaining wall along the 30-foot span on the back of our house - sort of like a window well running 3 feet from the foundation and about 30 feet running parallel to the wall of the house. It's OK and a little better than before, but it doesn't really work.
In a recent deluge of rain, I again had a 6-inch-deep swimming pool between the inside of the retaining wall and the foundation wall. I've solved a lot of the potential for water leakage into my basement, but I still don't want 6 inches of water sitting up against my foundation wall.
I must say that in reading your reply I almost laughed out loud and choked on my coffee when you told the man to "- maintain a slope away from the foundation of 2 inches per horizontal foot." You've got to be kidding! Or perhaps you simply miss-typed your reply. Like me and my situation, the basic inability to achieve such a grade is the primary source of the problem in the first place. I realize that in a perfect world and situation, the starting point of 6 inches below siding and then grading away from there is ideal. Excuse my simplistic math, but trying to grade at 2 inches per horizontal foot would leave him, or me, with a drop of 12 inches at 6 feet out - and a 2-foot grade drop at 12 feet out. You're only 12 feet out from the foundation, and you're already 2 feet down. I'd have to build - and he would too - a retaining wall at that point.
A. You must have giant moles raising your back yard! Quite a feat! The village engineer's suggestion would have been OK if he had mentioned building the retaining wall closer to the house. Building it 3 feet away obviously creates the undesirable situation you are left with: water pooling between the retaining wall and the foundation. I have recommended and used this system with clients when there was no room to raise the grade against the foundation and there was a wide enough overhang to protect the area between the retaining wall and the foundation. The retaining wall was built with pressure-treated logs placed just 4 to 6 inches from the foundation. Soil was banked against the logs to create the slope I recommend: 2 inches per horizontal foot - you read right. However, what was missing from what you read, for whatever reason, was that it needs to be only 3 to 31/2 feet from the foundation - enough to keep water from running toward or pooling against it where the weak point is. Anything less allows water to stand there, as there is no way to ensure that the slope you suggest remains a slope. Once water has been allowed to flow a few feet away from the foundation, it will percolate in the soil and be stored harmlessly. If it is allowed to stand against the foundation, it seeps down at the interface of earth and masonry and finds the weak point. But I am glad it gave you a good laugh.
• Henri de Marne's column appears Sundays. He was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.