Home repair: Insulation for a Chicago-area attic

Q. I live in the Chicago suburbs, and I have read your column in the Daily Herald for many years. Although you have covered the subject of insulation many times over the years, I hope you can help me with your most current thoughts regarding my specific situation.

Last spring my home was struck by lightning and set on fire. The roof has been replaced, but I am unsure how to proceed with my attic floor insulation. I would like to know what the most cost-effective and efficient insulation would be. I have been given conflicting information by contractors and would most appreciate your thoughts before the extreme weather sets in.

My home is brick, built in the 1920s, and the attic is planked with tongue-and-groove flooring. Under the deck are 8-inch-deep floor joists. The current insulation looks like sawdust covered with paper. This insulation rests over the second-floor lath and plaster ceilings. The attic space is unheated, and a window on each gable end is the only ventilation. The roof is quite steep, which creates a large open space.

The old decking insulation will be coming out, but before the new decking is installed, I would like to know my options for the space between the second-floor ceiling and attic floor.

A. I am sorry about the damage to your house from the lightning. I hope it has not been too extensive. Blown-in cellulose is your best choice. It meets the criteria you have set.

Q. Would using the Ecoflex/Enerflex/Reflectix type of insulation (aluminum-faced bubble rolls) on inside walls over wallboard help reduce heat loss and prevent drafts? I have a 100-year-old house with fiberglass wall insulation, but I still get drafts. The house has vinyl siding with no house wrap installed.

A. If you intend on covering the bubble-type insulation with new gyp board, there will be little gain because, to get the benefit of the reflective heat properties of the aluminum skin, the skin needs to have nothing in contact with it. It needs an airspace, and it needs to be kept clean.

A better insulation to use is XPS (extruded polystyrene), which comes in several thicknesses and needs to be covered with a fire-retardant material such as drywall.

If you tape the joints between the boards with compatible tape, the installation will act as an air barrier. But a considerable amount of infiltration is likely to take place around doors and windows unless they have been replaced with tight, efficient models and any joints between adjacent materials caulked.

Q. I have panels of T1-11 on the front of my split-entry house. They have been there for 34 years, facing west. I’ve used a lot of wood preservative, but never pigmented. Deterioration of the outer layer is now unsightly. Is there any product or technique that can refurbish the panels to make them look presentable? If not, as a second choice, can the panels remain and be covered with new panels or with siding of cedar, redwood or vinyl? Are there precautions to take if doing a cover-over?

A. It sounds as if the wood preservative you used didn’t protect the siding from the UV rays of the sun. There is no practical way to repair the deterioration, but you can cover it with any of the choices you mention. My bias is not to use redwood, as it is a shame to encourage the cutting of these beautiful giants that take so long to grow. Cedar, on the other hand, is plentiful, especially in Canada, which exports a lot of it. Clapboards or vertical boards would be beautiful, but you should apply a protective coating that contains UV protection, such as Amteco TWP (www.amteco.com), which comes in several varieties and hues.

Q. Our home is 40 years old and has an original masonry wood-burning fireplace. Last year we had it converted to a gas log fireplace. We also installed a spring-loaded flue closure to prevent heat from escaping when the fireplace is not in use.

During heavy rains, we noticed a slight dripping in the fireplace. So this summer we had the chimney tuck-pointed. Subsequently, the leak has gotten worse, and now water actually puddles in the fireplace and splashes on the hearth. We have to cover the logs with plastic and lay out towels in a heavy rain.

We walked onto the roof, which is a mansard roof less than seven years old, and checked all the caulking and surveyed the chimney. Everything looks perfect.

Where could the rain be coming from, and what can we do to stop the flooding of the fireplace box?

A. Since you do not mention noticing leakage before the top chimney damper was installed, I can only assume that it may be causing the leak.

There are so many different types of top chimney dampers that it is not possible for me to know if the one you had installed is responsible for the leakage.

You should have an experienced mason look at the chimney itself, the top cap and the flashing around the chimney. You may be perfectly competent to examine it and find everything in order, but another pair of eyes is often very helpful, as I have found out over many years.

Q. We own a 1940s Cape Cod-style home. We have a mold and mildew problem on the upstairs windows, and I would appreciate your advice. The windows are double pane, double hung and not the originals. Many are Pella. The upstairs windows all have “honeycomb” shades. When the weather gets colder, we get a lot of moisture on the windows in the morning that has led to a mold problem. It is unsightly, and I’m worried the windows will eventually be damaged. The mold is all along the painted trim and the glazing. I try to get all the shades up first thing in the morning, but I don’t think this has been enough to keep the problem from being progressive. I keep the house moderately cool — master bedroom not above 60 degrees and kids’ rooms only slightly warmer.

Is the problem the honeycomb shades? They clearly help with insulation but may be the source of the problem. Can you suggest anything that I can do to remedy the problem? I would like to have the windows repainted (and maybe reglazed?), but I am afraid this would just happen again.

A. Any shades that are lowered over windows on cold nights will result in condensation on the glass. The amount of condensation depends on the relative humidity (RH) in the house and the outside temperature. It can look like dew that does not run or it can be enough to puddle on the sills. This has nothing to do with the glazing, so there should be no need to contemplate replacing it.

You can lower the relative humidity in the house at the expense of comfort, assuming that it is now at a reasonable 30 percent to 40 percent level. You can wipe the windows as soon as you raise the shades in the morning. You can have storm windows installed to achieve the triple glazing that is desirable in cold regions.

If you keep a good paint seal where the wood and the glass meet, and wipe off the moisture, this should lessen the chance of damage.

If you choose to install storm windows, you can have triple-track ones installed outside, which will allow for quick changes as the temperatures fluctuate, or you can have Magnetite storms installed inside.

Q. I am a homeowner who considers himself to be of slightly above average competence. I have started many projects around my house and even managed to complete a few, some even to my wife’s satisfaction. However, I feel that in this case, if I begin dismantling walls without a clear strategy, particularly when those walls are in our bedroom, I may be taking up permanent residency on the couch with the dogs. Or worse.

I have enclosed some lackluster pictures addressing the problem. Water damage is occurring in the upper outside corner of our bedroom. This is the corner that frames the chimney, which has two flues. The nearer of the two is for the furnace and is lined with aluminum and capped. The other is for an obsolete fireplace and is sealed on top.

Here is what I can tell you: The flashing around the chimney appears sound. The chimney has been pointed not two years ago. The brick was sealed at the same time. The roof is seven years new. I have been in the attic numerous times, including during storms, and can find no direct seepage. Any cavities I have located in the vicinity of the problem area have been sealed with foam on the attic side. The wall is always cold and moist, even on warm, dry summer days. My walls are plaster. I first noticed water markings long ago. Then they were so minor I paid no attention. Every day the damage seems to get worse at an even quicker rate.

Can you please offer any advice?

A. From what I see in some of the photos you have sent, I think you have a problem with the flashing on the upper side of the chimney. If the flashing consists of a piece of metal following the plane of the roof and bent up the chimney wall, it may not be high enough or properly counter-flashed, or it may not be properly bent around the sides of the chimney, and not adequately covering the step flashing. There could also be a small hole that has gotten larger over time.

When a chimney is within the plane of a roof, as opposed to at its top, the joint of the roof and the upper part of the chimney should have what is called a cricket. If the chimney is in the field of the roof, a cricket is an A-shaped construction that diverts water around the chimney and prevents snow accumulation against the vulnerable upper chimney wall.

In your case, the chimney is at the side of the roof. If there is a rake overhang and the roof surrounds the chimney, a cricket can be installed. But if the chimney is at the edge of the roof, a cricket would be more in the shape of a slope that would have its highest point on the chimney wall and connect with the roof a foot or so above the chimney projection. This slope should be covered with metal and counter-flashed against the chimney bricks.

The step-flashing and counter-flashing should also be carefully checked. The furnace chimney should also be checked; there may be a problem there, too, since the bedroom wall does not dry and feels cold in the summer.

Any insulation between its aluminum flue and the original bricks may have become soaked.

I also see suspicious water stains and peeling wallpaper on the gable wall, as well as signs that the ceiling plaster has been subjected to moisture. If there is a gable vent at the peak of this wall, driving rain or snow could have entered the vent. If there is no rake overhang over this wall, and if the metal drip edge was mistakenly installed under the roof underlayment, wind can drive water between the two and lead to leakage into the structure.

As you can see, a number of things can be causing the serious damage the photos show. They should all be checked by a very experienced roofer. This is not meant as disparagement of your extensive skills, but only to point out that it takes a long experience to have “seen it all.”

Ÿ Henri de Marne 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 email at henridemarne@gmavt.net. His book, “About the House,” is available at www.upperaccess.com and in bookstores.

© 2011, United Feature Syndicate Inc.