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When dust coats old bricks

4 min read
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Q. My son bought a condo in a home built in 1890. There is an entire original brick wall that is in his living area as well as in his bedroom and along a flight of stairs in a hallway. Unfortunately, some of the bricks are breaking apart, and there is a powdery residue that is falling on the baseboards. This just seems to happen without touching it. Please note that moisture has been discovered in ceiling areas above some of the bricks. The water has run down along some of the bricks on different sides. We would like to know how to preserve what is there and also to repair the bricks where chunks have fallen off. Is there something that can be used to prevent the powdery substance from happening?

A. The powdery substance could be efflorescence. The powder you’re describing could also be the mortar between the bricks disintegrating from age or efflorescence. Efflorescence is the formation of salt deposits on masonry.

Have a mason evaluate this for you and make sure there is no water getting in behind or inside these walls via a roof leak or siding or flashing failure.

Q. We have a modest ranch in an older neighborhood of Sudbury. We utilize the attic for storage and the basement for storage and hobby space. Our roof is about four years old and has approximately nine feet of ice and water shield. There is not sufficient overhang to add soffit venting.

One of the recommendations for the space is to add six or more inches of cellulose insulation, which would raise the floor height and make the space less useful for storage. It would, however, retain the ridge and gable venting that we currently have. This option would minimize the heat loss into the attic.

The other recommendation for the same attic is to spray foam on the underside of the roof and over the gable and ridge vents. This option is supposed to make the attic space essentially part of the rest of the house and prevent heat from getting through the roof to the bottom of the shingles.

As these options are significantly different in both installation and cost, we would appreciate an objective opinion regarding the relative merits of each, given that the overall goal is to minimize ice dams and roof raking.

DGARIEPY

A. The most likely causes of ice dams are heat loss, air leakage, and the general warming of the house structure due to conduction from the heated building. There was no mention of sealing air leaks and how you access this space (another possible source of heat loss and air leakage). The contractor would essentially have to peel back the existing insulation and look for wire penetrations, plumbing vent pipes, electrical light boxes, and recessed lighting. The contractor should install expanding foam to seal all of these leaks. Other sites of air leaks:

â- Â Openings at partition walls

â- Â Openings around chimneys

â- Â Spaces around ductwork and fans

I’m not sold on the cellulose option. It may help, but you will still have heat loss. Sealing off the attic is one idea, and by doing that you are creating an unvented space. That will be costly, but if done correctly, will probably work.

Check out the International Residential Code for One- and Two-Family Dwellings. It has information on unvented attics. Make sure to use only closed-cell foam, which is a vapor retarder.

Dear Rob

In a recent column I mentioned that “Banks or other lending institutions require home inspections before they lend money.” Liz Bolton, a realtor, was kind enough to explain that most banks require only an appraisal. Thanks, Liz.

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