Review the notations you made about the roof, chimney, and eaves. Now look for outdoor-indoor relationships such as missing flashing and stains on the underside of roof sheathing.
Structural condition is the first thing to consider. Are the rafters and ridge sagging? If so, you should hire a structural engineer to see how serious the damage is. This damage likely resulted from too many layers of roofing. Deformed framing may need replacing or additional support, as shown in "Reinforcing a Roof,” on p. 12.
And excessive layers of roofing may need to be stripped off to lighten the load. Caution: Truss — type floor or rafter systems will be weakened if cut into.
If the roof sheathing is bellying (sagging) between the rafters, it’s probably too thin and should be replaced with thicker plywood when you replace the roofing.
Water damage is one of the most common problems. Dark brown stains around the chimney that smell of creosote are probably caused by cracked flue tile, which allowed caustic creosote compounds to work their way through mortar joints. Such a chimney is unsafe to use and must be either relined or replaced.
Cracks in the chimney’s mortar joints may be caused by an undersize or shifting chimney footing—another major cause of flue failure.
Water stains around plumbing vents, dormers, and chimneys are more likely caused by failed or absent flashing. If the wood is damp after a rain, the leaks are active.
Ventilation and insulation are crucially important but often misunderstood. Attics that lack adequate ventilation are excessively hot in the summer. In winter in cold climates, unventilated attics allow rising water vapor from the living area to collect as frost on the underside of roof sheathing. The frost eventually melts, soaks the sheathing, drips onto the attic floor, and perhaps
soaks through top-floor ceilings. Also in winter, unventilated attics trap warm air from below, which warms the roof, causing snow to melt and run into unwarmed overhangs where it refreezes, resulting in ice dams that can damage roofing and leak behind the siding. Adding soffit, gable, and ridge vents sometimes alleviates these types of problems.
Discolored rafters along the roof-wall joint and delaminated roof sheathing, coupled with stains at the top of interior walls below, are caused by warm, moist air from living spaces. To mitigate the problem, add insulation to the attic floor, improve ventilation, and/or add bath and kitchen vent fans.
Types of attic insulation and standards for their installation are addressed in Chapter 14.
Attic floors and attic insulation may also show roof leaks clearly. And if moisture is migrating up from the living spaces, the insulation’s underside may be moldy. Pull up affected sections and see if water has collected there and caused damage.
Most home buyers repaint or repaper walls to suit their tastes anyway. So instead of concerning yourself with paint colors or wallpaper patterns themselves, focus on surfaces that suggest underlying problems that may require remedies. Also, after consulting the notes you recorded outside, study wall-ceiling joints, which also can tell stories.
Water stains on interior outside walls, especially above windows, may have multiple causes: missing outside flashing, gaps between siding and exterior trim, and leaks in the gutters or roof.
Crumbling drywall or plaster and extensive mold at the top of walls may be caused by exterior leaks or, just as likely, by excessive moisture in the living areas. If the problems are severe, rot- inducing mold may be growing on framing inside the walls. After correcting the sources of moisture, you may need to tear out drywall or plaster and replace studs and plates.
Large diagonal cracks in drywall or plaster at the corners of doors and windows may correspond with cracks on the house exterior. Such cracks suggest structural shifting and foundation distress.
Door and window trim that tilts toward a common low point suggests failure in the substructure (girder, post, or pad) or in the foundation itself.
