Leaky Housewraps

Results from the most recent Building Materials Laboratory study show some housewraps may do little to block rain intrusion.

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Liquid water is without question the most destructive force acting on light frame structures. As builders, we are mesmerized by vapor diffusion and vapor barriers. But it is still good old fashion water leakage that rots walls, sills and other building elements. There is no shortage of pathways leading water inward. Any discontinuity in a wall surface will do nicely: seams, windows, butt joints, knots, and siding overlaps are thirsty conduits. The trick is to build energy-tight walls that drain water leakage outward. Installation of high-tech housewraps is the most common attempt to have it all.

Housewraps, Felt Paper and Weather Penetration Barriers

Siding isn't weather-proof. A second line of defense is a critical component in smart weather-protecting wall designs.

The shell of a house serves as the first line of defense between the occupants and the outdoor environment. Walls function as a weather barrier, nail base for finish materials and an energy conserving boundary. A sensible wall system is durable. And this requires all components in a wall assembly to be compatible for the long haul. Siding, siding finishes, housewraps, insulation and wall frames must work together while achieving distinctive goals. So it is in this light that we should view a primary, but often overlooked, component in residential wall systems: weather-resisting wall wraps.

Wood, brick, masonry, vinyl, and other sidings do not function as barriers to driving rain. Siding is porous. There are a multitude of joints, laps, and connections making it discontinuous. Water and air are driven through these leakage points by wind, gravity and capillary forces. Also, we generally use water-sensitive materials for siding and structural elements. Leaking water rots wood, grows mold, corrodes steel and lowers insulating R-values. Another concern is that leaking air strips heat from homes and dollars from energy budgets. So air-tight construction is desirable.

Details That Keep Walls Watertight

Careful detailing of house wrap and flashing connections will reduce maintenance and lengthen the working life of structural components in wood-frame structures.

I vividly remember the job where I learned that even properly installed siding isn't waterproof. It was an expensive home I had contracted during the early days of my career: A large Gambrel on the peak of the highest hill in town. Start-to-finish the job was a plum. The clients were overjoyed with the finished product and moved in ahead of the scheduled closing date. But 6 months after they moved in, a wind-driven rain converted my plum into a prune. A late-night phone call explained in detail how many drips-per-minute were falling from the head jamb of the east-facing double-mullion window. A next-day fix was promised…..

Insulating On the Outside

Wrapping a home with insulating sheathing saves energy and can be cost effective, but the design must consider a host of structural concerns including moisture, shear loads, insects and fire.

The use of insulating sheathing is becoming popular as consumers and energy codes demand energy-smart details. Obviously, wrapping a home with foam insulation saves energy, but it affects overall performance and cost. Foam-sheathed walls are more complicated to build and most insulating sheathings are non-structural. Extra building components must be added to take up the slack. Also, the exterior skin of a house protects the structure and its inhabitants from the environmental influence of moisture, fire, and insects. Wrapping a home with insulating sheathing may be a great idea, but this plan requires a holistic sensitivity………..
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Reroofing and Residing To Save Energy

When it's time to replace worn siding and roof coverings, you can recognize this as an opportunity to upgrade your home's energy performance. Here are several options that can help you meet your goals for some roofs and wood siding rehabs.

The adage that says: within every problem lies an opportunity, is certainly valid when it comes to residing and reroofing a home. Roofing and siding a home is expensive. So, the decision to replace siding and roofing usually takes time to develop. Often a catastrophic event like water dripping from the ceiling launches the project into motion. But there is much to be gained beyond fixing leaks and worn out siding. A well-designed exterior retrofit will lower energy bills, improve comfort and redefine a home's level of performance….

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