Home repair: Layer of plastic can minimize roofing mess

Q. We plan to have roof shingles replaced this spring. Last time, all the dirt and debris fell through the openings onto the pink insulation in the attic. Could I spread something to prevent such a mess? Plastic with newspapers on top, so we can roll up the newspapers? Anything I can leave there permanently? I won’t be able to get to all the corners, but I’d like to do something.

A. You must have an older home with plank sheathing over the rafters; this would not happen with plywood.

You certainly can spread plastic over the fiberglass insulation, but why bother with newspapers? The plastic can be tucked into the corners using a broomstick or garden rake. Once the roofing job is done, simply bundle the plastic and shake it outside.

You should not leave plastic on permanently as it would create a vapor retarder on top of the insulation, which you do not want. Condensation could occur on the underside of the plastic, caused by moisture-laden air from the heated living area convecting into the attic through the numerous little cracks found in almost every home. This could wet the insulation and greatly reduce its effectiveness, as well as damage the ceilings below.

Q. I have a prefab fireplace in the basement family room. It has no gas start or outside vents. Every time I start a fire, the family room fills with a little smoke until the chimney flue warms up. Is there a way to start the fire without the family room getting smoky? I had the fireplace cleaned professionally before the season began. I bought the house last year, and the inspectors said nothing was wrong with it.

A. One way to heat a chimney fast is to crumple several pieces of newspaper and light them to start a draft. Set up the firewood and place the crumpled newspapers on top of it, then light them as well as the paper below the logs and the kindling. You can also place several pieces of kindling (cedar shingles or strips of birch bark are great!) over the crumpled newspapers to make the chimney warm-up last longer. You should also crack a nearby window to encourage the draft until the fire is going.

Q. My ranch home with a basement is 2 years old. During the heating season only, as the ducts heat up and cool down, I have excessive duct banging. It occurs only in a 6-foot section of the ductwork. Any help is greatly appreciated. The noise is very embarrassing.

A. Your best bet is to call the builder and have him or her send the HVAC contractor who installed the system to take care of the constriction or lack of support that is probably causing the banging.

Q. As a recent transplant from Southern California to Vermont, I have encountered the dreaded winter heating bill. I have a 2,100-square-foot, two-story home with a basement. The house is heated by a Smith propane boiler and baseboard heating and a wood-burning fireplace. I have three programmable thermostats: one for the upstairs master bedroom and bath, the second for two bedrooms and a second bath, and the third for the downstairs. The basement is unheated. I believe I have made the house as tight as possible.

I would like your recommendation for the most cost-effective way of heating. Should I set the thermostats at a constant temperature (65 degrees seems to be bearable, with an occasional boost to 67 degrees when my wife demands it), or would lowering the temperature at night (down to 62 degrees) and then raising the temperature in the morning to 65 or 67 degrees make a difference?

A. Welcome to the beautiful Green Mountain State, where winters can be challenging.

The best thing anyone can do to reduce heating costs is to improve the envelope of the house, which you may have already done.

My suggestion for controlling the indoor temperature and managing your heating costs without loss of comfort is to keep the upstairs master bedroom and bath at a lower temperature at night and during most of the day when the rooms are not used much, if at all. You may want to consider 60 to 62 degrees for these periods. Program the thermostat to raise the temperature to 69 degrees one hour before you rise in the morning and before you usually go to bed. A down comforter is awfully nice in a cool bedroom at night.

If the other bedrooms and bath are used, you can do the same with them. Otherwise, keep the thermostat at 62 degrees 24/7 and close the doors.

The temperature in the main level can be lowered to 60 or 62 degrees at night (and during the day if no one is home), and the thermostat can be programmed to whatever temperature is acceptable to your wife while you are home.

Wool sweaters are very nice and allow you to keep the temperature a little lower than otherwise. Keeping the relative humidity in the 40 percent range will also make you feel more comfortable at a lower temperature. Hopefully, you have storm windows to prevent condensation on the windows.

Considerable savings on heating costs can be achieved by following this regimen.

Q. Appreciated your response regarding zinc strips. I, too, have the same problem. I have been attacking the moss by manually stripping it and then applying a product called Wet & Forget. For those areas I have attacked, it works very well. However, it is a time-consuming task, and at my age, it is tough on the body. The zinc strips sound good.

Question: Will the strips defeat the moss without first removing the moss?

A. There is no need to remove the moss manually. The blooms will die over several months, and snow, wind and rain eventually will knock them off.

Q. My house was built about 1915. I have worked on this house for many years, painting, patching plaster walls, replacing multiple layers of flooring, etc.

My attic is quite large and constructed with real 2-by-8 joists, rough cut and actually to size.

I want to put some Eco Tec (non-fiberglass) insulation up there in batts. There is about 4 inches of a poured-in insulation there now, soft and sort of like cotton.

A friend of mine said that in his house, he took out all of the old insulation and poured it down the outside walls to insulate them. He then put the new, thicker insulation in the attic.

Does this sound like a good thing to do? I have never taken any plaster walls down, so it would help to get any insulation in there.

I can’t get an answer from any company I call because they want to come out and give me an estimate. I want to do it myself because I can’t afford to hire a company to do it.

A. The existing insulation is probably rock wool, commonly used in those days. It would be difficult to get it down the uninsulated walls because rock wool does not go down easily, and there are likely to be a number of obstructions within the wall cavities. If rough lumber was used for the studs, the insulation is also likely to hang on it.

A better way to insulate the outside walls is to have cellulose blown in, which I gather can be done from the attic since your friend, who may have a similar house, was able to do so.

Houses built at that time were balloon-framed and the attic floor joists set on a 1-inch by 6-inch ribbon mortised into the studs, which also served as a ground for the plaster on the walls below. The studs were set on the mudsill on top of the foundation and went all the way to the roof.

This type of construction is also at great risk in case a fire starts in the basement, because the open stud cavities act as flues.

The open pockets in the basement or crawl space should be sealed before the cellulose is blown in. When this is done, simply add a layer of your chosen insulation on top of the rock wool.

Q. Our kitchen does not have a standard range hood vent. Instead, we have a Jenn-Air gas cooktop with a downdraft vent. The cooktop is installed in a quartz counter over a regular cabinet, with the exhaust venting through the cabinet to the outside. With the cold we get here in winter, and especially on windy days, the counter is like a block of ice, and when it is windy you can feel the draft coming in through the vent on the cooktop.

Is there a way to insulate the venting without rendering it inoperable that will allow the counter to be warmer and eliminate the draft? To redo the kitchen to accommodate an overhead vent would be cost prohibitive with the layout of the kitchen.

A. The first thing to check is the flap in the outside jack of the Jenn-Air. If it is missing, loosefitting or stuck, a lot of cold air will be sucked into the duct. It may need to be replaced.

To insulate the duct is easy if you have an open basement. Loosely wrap some fiberglass insulation with a kraft paper or aluminum vapor retarder around the duct and tie it with a string.

If the basement ceiling is finished with gyp board (as opposed to a drop ceiling with removable tiles), one solution is to have cellulose blown in the joist cavity that contains the duct. The insulators should be able to figure out how to do it. I had an identical installation in my previous house, and I insulated the duct during construction. The outside jack was performing well, and I had no problems with cold air infiltration or a cold countertop, in spite of living in a very windy area in the mountains in a cold climate.

Under-floor venting is superior to overhead venting because physics works for you. The natural stack effect in a house tends to seal the flap tightly if it is functioning properly, whereas an overhead installation robs the house of energy, similar to an open chimney.

Q. I have a roof leak that is coming from a wind turbine roof vent. It’s not much of a leak, but it has caused the plaster to puff up from the moisture. The vent sits about 20 inches off the roof. This is a flat roof with some pitch. It seems that the water is coming through the vent, and possibly a little condensation. On the inside of the sheet metal tube you can see some rust where the water has come in. The attic is insulated. Should we cover the vent in the winter? Get a different type of vent to place on top of the sheet metal? Or use a leak diverter tarp? Or do you have a different answer?

A. Considering how little water there seems to be, condensation is a strong possibility.

If you have access to the attic, have you noticed any signs of moisture over the entire roof sheathing or only on certain areas? It would indicate that warm, moist air is convecting into the attic and causing condensation inside the turbine’s duct. It also would indicate the existence of an unhealthy situation. In such a case, you should try to find all possible sources of convection and seal them. More may be needed, but without more details, I can’t do better.

Since a turbine vent was installed, I assume there is an air space above the insulation, but there may not be — stranger things are found in construction.

If there is no access to the attic, and if the rafters are also the ceiling joists, consider having an energy auditor check the attic ceiling-roof-sheathing assembly with an infrared camera and digital thermometer to make sure the insulation is still effective and not wet. If the testing shows a problem, you should consider a more thorough investigation before structural damage occurs.

Turbine vents are not very effective, and it is difficult to ventilate the attic space below a nearly flat roof. But I am reluctant to suggest you cover the turbine vent if there is a moisture problem in the attic, as it may aggravate the situation.

Changing from a turbine vent to a static cap is not going to improve the attic’s ventilation or stop any condensation, if that is the problem.

Ÿ Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him via email at henridemarne@gmavt.net. His book, “About the House,” is available at www.upperaccess.com and in bookstores.

© 2011, United Feature Syndicate Inc.