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Exterior insulation system may be letting in wind, rain

Q: We have a 30-foot-wide dormer on the back of our two-story home. When it's raining and the wind blows into the house, there are leaks in the ceiling and over our kitchen window.

Can Dryvit (stucco over board) leak enough to cause this? Or is it caused by leakage around the windows that are not flashed on the top and sides (caulked only)? Can stucco be sealed? Are there any other solutions?The builder did not put a gutter on the dormer (non-gable). Is this a contributing factor? - B.M., Murfreesboro, Tenn.

A: Dryvit is one of many brands for the EIFS (exterior insulation finishing system). The building is covered with an insulating material that is then coated with a pigmented stucco cement.

According to Frank Lesh, a leading inspector of EIFS in the Chicago area, the system has been subject to moisture problems.

EIFS is a barrier system - that is, it is supposed to keep water and moisture out. If water does penetrate the covering, there has been in the past no means for draining off the water. When the wood beneath the covering gets wet it is subject to decay.

Lesh says the most common areas of concern are windows, doors, hose bibs, utility openings and roof-to-wall flashings.

"There is supposed to be a half-inch gap between the stucco and any penetration," he said. "A closed cell backer rod is then installed and the opening filled with a special silicone base caulking. Probably the worst area is where the roof meets a wall and there is improper flashing and no counter flashing."

Lesh inspects homes with EIFS by using a moisture meter to pinpoint areas of concern. If an area has high readings, a probe is used to reach the wood behind the insulation. If the moisture reading of the wood is greater than 20 percent, the EIFS has to be removed and repaired.

Lesh also photographs the home and checks inside the foundation for signs of moisture problems. A typical inspection and report costs between $300 and $500, but some larger homes may cost more. Contact the Exterior Design Institute at (757)491-6840 for an approved inspector in your area.

Q: We live in a ranch home on a slab. The home has cinder-block walls, but there are insulation and paneling on most of the walls inside the house. We have boiler hot water heat and duct work along all the outside walls - more than adequate, we are told. The outside of the house and the attic are well-insulated, but we seem to have a terrific amount of cold air sweeping across the floor. When the temperature drops into the low teens, we cannot keep the house warm.

I would like to have someone pinpoint places where we are losing heat and gaining cold air, but I have no idea whom to contact. We want to correct the problem before next winter. - V.B., Lemont, Ill.

A: According to home inspector Frank Lesh, a lot of homes in the Lemont area have metal-framed windows. Metal frames and single-pane windows allow a lot of cold air to enter the home. Because cold air is heavier than warm air, it tends to drop to the floor next to the windows and makes it feel as if a cold breeze is coming through the wall.

You stated that a lot of your walls are insulated, meaning some may not be. A cold wall is like a cold window. It feels like a cold breeze near the floor.Cracks in the slab floors also will let cold air in.

What you need is an energy audit. Contact Northern Illinois Gas, (708) 547-6400, for a list of contractors. If possible, have the gas company personnel perform a fan door audit to pinpoint exact areas of air infiltration. It would be best to have this done before winter sets in so that you'll have time to make repairs.