Drying out after a flood can cause additional issues

Q. I need some advice. Last October I had a drainpipe back up, which caused flooding in my finished basement and some of my first floor. I called my insurance company and it had a restoration company come out. That company removed sections of carpeting, drywall and insulation. Then workers brought in dehumidifiers and ran them for 11 days.

Repair work has not yet begun (partially due to our decisions). However, my wife and I have noticed that cracks and gaps (some are quite large - ⅛ inch) have appeared throughout the joints of molding on most of the first floor. We have extensive crown molding and trim work. Could this be from excessive dehumidification? Also, if need be, who would I need to call for an expert opinion?

A. It does sound as if dehumidification caused the separations. The excessive humidity may have raised the moisture content of the molding, which stressed the wood as it tried to expand. This was followed by rapid dehumidification of compressed fibers.

These cracks may be repaired by an experienced painting contractor, which should be a lot less costly than replacement. But it is best to wait until the relative humidity (RH) in your house returns to normal before attempting any repairs, as the fluctuation in seasonal changes in the RH may cause the repairs to fail.

A professional engineer would be the person to call if you need some type of expert report for your insurance company.

Q. I live in the Northwest suburbs of Chicago and enjoy reading your column in the Daily Herald. This has been such a horrible Chicago winter that I decided to ask your opinion about an ongoing problem in our home.

We own a split-level home and have always had problems keeping it warm in the winter and cool in the summer. We attempted to have an energy audit done to see what might be causing our problems keeping the home comfortable. The audit was unable to be completed because mold was located in the attic and they couldn't do the blower door test. That is another story altogether!

We have since corrected the problem and intend on having the audit completed. We became aware of a new problem today when my daughter took a stuffed animal out of her toy box and it was wet. The toy box was pushed directly up against an exterior wall. When the toy box was pulled away from the wall, there was a thin layer of frost on the baseboard. My daughter's room has always been the biggest challenge because both attic access doors are in her closet.

I have also considered calling a couple of companies in our area that drill holes in the exterior walls of the home and insert expanding foam into the wall cavity. This is done by either removing the siding and then drilling holes into the exterior or drilling directly into the brick. The expanding spray foam is then injected into the walls. They claim this will make the home more energy efficient. I wanted to know your opinion about injecting expanding foam into the walls.

Also, do you have any other recommendations other than having Nicor come out and finish the energy audit?

A. By all means have the audit completed. It will show you what needs to be done to make your house more comfortable.

From what you mention, I assume that your split-level house has brick siding on the ground level and wood elsewhere.

On the brick portion, you need to know if it is a brick veneer over a wood frame wall or a brick/block backup construction. In the latter case, it may not be worthwhile spending the money to inject foam in the small space between the exterior bricks and the masonry backup units. And foaming the space is not recommended because it is a drain space to allow bricks to breathe and dry. An alternative is to have rigid foam insulation installed inside and cover it with drywall.

If the construction is brick veneer, it would be easier to have the foam injected from inside. This would require minor repairs.

On the parts of the house with wood siding, it is common to do the foaming from the outside.

The access doors to the attic in your daughter's bedroom should be weatherstripped and insulated with rigid insulation attached to the attic side.

Q. I'm an avid reader of your column and appreciate your common-sense solutions. My current difficulty involves attic ventilation problems/solutions, which you have addressed several times. My 50-year-old, framed, hardboard-sided home was built with soffits and a gable venting system.

Roughly 35 years ago, a prior owner added more bat insulation in the attic. However, I believe insufficient care was taken to keep all soffits functioning properly. The bathroom fan vents directly into the attic. I do get significant ice dams on the roof flashing all the way around, but heaviest in the vicinity of the bath vent.

When my roof was reshingled 10 years ago, the contractor installed a ridge vent as well. I'm not sure how effective a ridge vent is in the winter when the roof is well covered with snow, and I subsequently learned from reading your column that I shouldn't have three venting systems anyway.

I would like to add more insulation to the attic, but shouldn't do that until I know which one of the three venting systems should be sealed off and how best to dissipate the hot, moist air currently being vented into the attic. The bath fan is located about 3 feet from an exterior wall, but roughly 30 feet from a gable. Because of the 3/12 pitch of the roof, it is extremely hard to get out to the soffits to do anything with them. Do you have any suggestions on how to proceed?

A. As you know, bathroom fans - and kitchen fans - should never be vented into an attic. Their discharge not only adds unwanted and damaging moisture to this enclosed cold space, but also heats the space, causing the snow to melt and ice dams to form.

These fans should not be vented through roofs or ridge vents, vented and unvented soffits, or gable vents. They should be vented through an exterior wall between two stories or a gable wall, preferably on the side most exposed to winter sun. In your case, either will do, but the better way is the closest.

If you have not seen my recommendations for venting bathroom fans in earlier columns, and would like to know how to best do it, please let me know.

The most effective attic venting system is a combination of full-length soffit and externally baffled ridge vents with an uninterrupted space between them. It is essential that soffit vents be unobstructed. This should be looked into and corrected if needed.

Gable vents in combination with soffit and ridge vents adversely affect their proper functioning because they will cause a short-circuit and interfere with the air wash that bathes every inch of the roof sheathing as the air flows from the soffits (the intake) to the ridge (the outlet).

In the winter, when the ridge vent is covered with snow, it is still effective because not only is snow porous, but the airflow from the soffit vents causes the snow in the ridge vent openings to sublimate.

I suggest you first make sure the soffit vents are clear. Then seal the gable vents with pieces of exterior grade plywood painted matte black on the side that will be exposed to the elements. When this is done, add insulation in the attic.

Q. I am a longtime reader of your column in the Pittsburgh Tribune-Review, and you have answered my questions via email in the past. I even consulted your book, which I have found very handy. My question concerns a very old icebox that I am going to have refinished (stains and strippers really freak out my sinuses).

The one thing I need to address is the interior portion where the ice blocks were stored, since the refinisher really does not do that stuff. So this is really a multiple series of questions.

The portion where ice blocks were stored is metal and possibly some sort of galvanized bare metal. The end objective is to paint that portion and clean up the porcelain part. Not being sure how that metal was protected, I really want to avoid sanding.

• Do you have any good suggestions to clean years of residue at bottom of that section? It is almost like calcium deposits.

• After cleaning, would it better to prime that metal first with Rust-Oleum Rusty Metal High Performance Primer (oil base) even though it is not rusty (I have this product), or would you suggest something better?

• For the final coat, I was going to use the standard white Rust-Oleum metal paint and use a good paintbrush. I do not need a perfect, car-quality smooth finish, or do you have different suggestion for paint?

A. To remove the calcium-like deposit, try Lime-A-Way or make a solution of one part white vinegar to three parts water, and apply it liberally to the affected areas by laying a white cloth saturated with it on them. Cover the cloth with plastic wrap to delay evaporation. You can also try CLR if the previous recommendations do not work.

Once the calcium has been removed, paint the surface as you outline above.

• 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.

© 2014, United Feature Syndicate Inc.