The Roof

Safety Tip
Anatomy of a Roof
The Roof Deck
The Roof Surface
Flashing
Types of Roofing Materials
Inspecting Your Roof for Damage
Inspecting Your Roof from the Inside
Inspecting Your Roof from the Outside
Locating a Roof Leak
Where Roof Leaks Usually Begin
Temporary Repairs for a Leaky Roof

Safety Tip

Tile and slate roofs are extremely slippery, and the materials can break easily. Metal and plastic roofs also tend to be slippery. If your house has one of these out-of-the-ordinary roofs, it's best to leave inspection and repairs to a professional roofing contractor.

Anatomy of a Roof

A typical roof consists of a framework of rafters that supports a roof deck (or subroof). This roof deck consists of sheathing and underlayment and provides a nailing base for the roof surface material.

The Roof Deck

Most roof decks have both sheathing and underlayment.

• Sheathing is the material that provides the nailing base for the roof surface material. Sheathing can be constructed of various materials ranging from solid plywood to fiberboard to open sheathing (used with wood shelves).
• The underlayment is sandwiched between the sheathing and the surface material. Underlayment is usually roofing felt - a heavy, fibrous black paper saturated with asphalt.
• Roofing felt is thick enough to resist water penetration from the outside, yet thin enough to allow moisture from inside the attic to escape.

The Roof Surface

The material on the roof must be able to withstand wind, rain, snow, hail, and sun. A wide variety of roof surface materials are available.

Flashing

Flashing provides weatherproofing around the angles and protrusions of a roof. Made from malleable metal or plastic, flashing is used at the drip edge along the eaves and rake of a roof, the collars around ventilation and plumbing pipes, the valleys between two roof planes and the "steps" along a chimney or dormer. Less obvious flashing also protects other breaks in the roof, such as around some solar panels and skylights.

Types of Roofing Materials

• Traditional sloping roofs are usually covered with overlapping layers of asphalt shingles, wood shingles or shakes, or tile, though you can find such roofs covered with slate, aluminum, or galvanized steel.
• Flat or low-sloping roofs are most often surfaced with alternating layers of roofing felt and asphalt with a layer of gravel on top. These are known as built-up, or tar-and-gravel, roofs.
• Some flat roofs are covered with insulating polyurethane foam.

Inspecting Your Roof for Damage

It's a good idea to inspect and repair your roof in autumn, before the hard weather hits. Then examine the roof again in spring to assess whatever damage may have occurred during the winter.

Inspecting from the Inside

• Begin an inspection in the attic, using a strong flashlight, a thin screwdriver, a knife, and a piece of chalk to examine the ridge beam, rafters and sheathing.
• Look for water stains, dark-colored areas of wet wood, moisture, and soft spots that may indicate dry rot.
• Mark the wet spots with chalk so you can find them easily later on.
• Safety Tip If it's necessary to remove fiberglass insulation batts to examine the sheathing, be sure to wear loose clothing, gloves, goggles, and a respirator for protection.
• Turn off any lights.
• If you see any holes above you, drive nails or poke wire through them so they'll be visible from the roof's surface. (In a wood shingle roof, small shafts of light coming in at an angle indicate cracks that may swell shut when the shingles are wet).

Inspecting Your Roof from the Outside

• When you examine the roof from outdoors, evaluate the condition of the structure, surface material, flashings, eaves and gutters.
• Stand back from the house and look at the lines of the ridge and rafters.
• The ridgeline should be perfectly horizontal, and the line of the rafters, which you can assess by looking along the plane of each roof section, should be straight.
• If either sags, call a professional contractor - you may have a structural problem.
• Inspect the roof's surface.
• If you're at all nervous about going up on the roof, make the inspection from a ladder, using a pair of binoculars.
• Don't walk on the roof any more than is absolutely necessary. You can easily cause more damage.
• Inspect the flashings for rust spots and broken seals along the edges.
• If you have metal gutters and downspouts, look for rust spots and holes.
• Examine the roof surface for signs of wear, loose or broken nails, or curled, broken or missing shingles.
• Use a knife and screwdriver to test the boards along the eaves and rakes.
• Scrape out any damage caused by dry rot, treat with a wood preservative, and fill the holes with wood putty.
• If the damage is extensive, replace the boards and finish them to match the existing areas.

Locating a Roof Leak

Roof leaks usually appear during storms, when you can't make permanent repairs. But you can take some steps to temporarily divert or halt the flow of water.

• During a storm, trace the course of water from where it's dripping through the ceiling to where it's coming through the roof.
• Drive a nail or poke a wire through the hole so you can find the hole later when you get up on the roof.
• Once the roof is dry enough, check it thoroughly, looking for weak spots that indicate a source for the leak.
• Keep in mind that the point where a nail or wire is poking through may be below the actual source.
• Make permanent repairs or call a professional.

Where Roof Leaks Usually Begin

• Flashings
• Where shingles are damaged or missing
• In valleys
• At eaves

Helpful Hint

The puddle of water you see is often far from the point where the roof is leaking.

Temporary Repairs for a Leaky Roof

Water diverter - Drive a nail or poke wire up through the hole to direct some of the water into a bucket directly below. Position a second bucket to catch runoff.

Emergency patch - Using a putty knife or caulking gun, apply special roof patch liberally to the hole from inside. Work the compound in thoroughly so it adheres.

Temporary shingle - When the roof is dry, slide a 2-foot square of galvanized sheet metal under the row of shingles above the missing or damaged shingle.