Roofing – FAQs
Roof Inspection Checklist
1. From outside:
- Are there any blistered, curled, or split shingles? A few can be repaired, but if the general appearance of the roof is poor, it may be time to re-roof.
- Are there loose or missing shingles or tiles? Simply re-nailing loose shingles may only mask a problem that will eventually get worse.
- Do you see any exposed nails? They can be a source of leaks.
- If your roof is covered with composition (asphalt) shingles, look for dark patches indicating the granular coating has worn away.
- Look for significant accumulation of granules in your rain gutters. Some granules are normal, but a lot, combined with dark patches on your shingles, is a sign of an aging roof.
- Check where ridges and hips meet. Shingles may break or work loose in these spots.
- Any rusty metal or displaced shingles along the valley are signs of roof weaknesses.
- Inspect the flashing around plumbing vents and chimneys. Loose shingles or rusty, loose flashing is another sign of trouble. Step flashing around chimneys must be well embedded in the mortar between bricks.
- Where a vertical side of the house meets the roof, such as along dormer walls, flashing should be firmly in place or it is a potential leak.
- Check the gutters closely for sagging and signs of leaks between sections. Are the downspouts firmly in place and directing water away from the house foundation?
- If you have a shake or shingle roof, inspect the flashing around chimneys and vertical walls carefully because acid in the wood can eat away at the flashing over the years. In consistently moist areas, prevent mildew by regularly removing wet leaves that collect in certain parts of the roof.
If you have a shake or shingle roof, inspect the flashing around chimneys and vertical walls carefully because acid in the wood can eat away at the flashing over the years. In consistently moist areas, prevent mildew by regularly removing wet leaves that collect in certain parts of the roof.
2. From inside:
- In the attic, look for signs of leaks. Dark stains on the rafters or the underside of the roof decking material generally indicate water trails. Look for water signs around plumbing vent pipes and along chimneys, skylights, and valleys.
- Lookup through the roof for any pinpoints of light.
- Look for sagging sheathing between rafters. This is one sign of an old roof in need of repair. Sagging or cracked rafters will certainly require repair or replacement as part of a new roof installation.
3. Flat roof:
- Look for any blisters on the roof. If not already broken, blisters eventually will break, which may allow water to enter the roof.
- Look for depressions around vent pipes where water can collect and begin leaking through cracks in the surface.
- Check all flashing for any separations by the parapet that surrounds the flat roof.
- Clean drains at the low end of the roof so water can run off without interruption.
What are Composition Shingles?
Also called asphalt shingles, these cover 70% of all roofs in this country. Composition shingles are divided into two types, organic or fiberglass. Organic composition roofs are manufactured with a cellulose fiber base made from recycled paper and wood fibers. This base is then saturated with asphalt and given a mineral coating on one side to resist weathering. Fiberglass shingles are made in a similar fashion but the central core is fiberglass, which is more flexible and stronger than the cellulose materials.
Composition shingles are manufactured in a wide variety of colors and are rated by their projected life expectancy, typically 20, 25, and 30 years. Most roofing manufacturers warranty their roofs for these periods, but only if certified roofers install them. Otherwise, the manufacturers disallow any guarantees.
What are Dimensional Shingles?
These are made from the same material as organic or fiberglass composition shingles but are much thicker. The additional layers may be sculpted to provide attractive shadow lines that give the roof a customized appearance. The extra thickness also increases their life expectancy, up to 40 years. As with composition shingles, the manufacturer’s warranty generally applies only if one of their certified roofers installs the material.
What is Roof Sheathing?
The skeleton of a roof is formed with rafters or trusses, generally spaced 16 inches or 24 inches on center (from the center of one rafter to the center of the next) apart. To stabilize the rafters and support the roofing material, rafters are covered with sheathing, or decking.
Common roof sheathing materials include the following:
Plywood: Plywood, which comes in standard 4-by-8 foot sheets, is strong, durable, and relatively light. It holds roofing nails well. The common grade of plywood for roof sheathing is CDX. As a quick primer in plywood, each side is rated from A to D. A is smooth and knot-free while D, the lowest quality, has missing knots and cracks. One side is usually better quality than the other – C in this case. It should be placed up on the roof. X stands for exterior use. For rafters spaced 16 inches on center, 1/2-inch plywood is standard. For rafters spaced 24 inches on center, 5/8-inch plywood is preferred to minimize sagging.
Tongue and groove 2-by-6: These boards are commonly used as roof sheathing where a ceiling will not be installed and they will be visible from inside the house, such as across beams in a vaulted ceiling. Wood is an excellent insulator and in moderate climates no additional rigid insulation on the roof is necessary. The boards can be painted, stained, or coated with polyurethane to retain their natural color.