Roofing

There are many different roof types.  Your inspector will generally evaluate the roof by walking on its surface.  Every roof will wear differently relative to its age, the number of layers, the quality of the roofing material, exposure to direct sunlight and prevalent weather conditions. 

Regular maintenance will certainly extend the life of any roof, and will usually avert most leaks that only become evident after they have caused other damage.  In addition, other factors can play a role in a roof's integrity including design elements such as valleys, skylights, flashing, and gutters. 

Regardless of design, every roof is only as good as the waterproof membrane beneath it. This membrane is concealed and cannot be directly examined without removing the roof material. 

Here’s information on the some of the specific roof types that we find in our area. 

Composition Shingle Roof

There are a wide variety of composition shingle roofs, which are comprised of asphalt or fiberglass materials impregnated with mineral granules that are designed to deflect the deteriorating ultra-violet rays of the sun.  Typically these roofs are warranted by manufacturers to last from 20 to 30 years, however, the installer may guarantee against leaks for three to five years. 

The first indication of significant wear is apparent when the granules begin to separate and leave pockmarks or dark spots.  This is referred to as primary decomposition, which means that the roof is in decline, and therefore susceptible to leakage.  This typically begins with the hip and ridge shingles and to the field shingles on the south facing side.  This does not mean that the roof needs to be replaced, but that it should be monitored more regularly and serviced when necessary. 

Flat Roof

Flat roofs are rarely flat, and generally slope toward drains, in or near surrounding parapet walls.  However, water ponds on many of these roofs only disappear through evaporation.  For this and related reasons, flat roofs have always been problematic and must be maintained. 

Flat roofs are generally covered with mineral surface roll roofing or a single membrane material.  Daily temperature fluctuates cause the roofing material to expand and contract, often causing roll roofing to buckle, split, or separate.  When this happens, the roof is susceptible to leaks.  The single membrane roofing material, although more expensive, will give better protection and a longer service life of 15 to 20 years versus five to ten years with roll roof. 

Regardless of the age or material use, a flat roof should be inspected seasonally, kept clean, and serviced frequently.  Although less expensive than other roofs, they can end up costing more if they are not maintained. 

Metal Roof

There are different types of metal roofs, but the most common ones consist of ribbed, interlocking panels, or tiles that have been coated with a mineral compound that are warranted for as long as fifty years. 

As with other pitched roofs, many metal roofs are dependant on the waterproof membrane that is concealed beneath them and cannot be directly examined by your home inspector. 

Slate Tile

Slate is a stone and as a roofing material can have a useful life varying between 50 and 150 years depending upon the geographic area where the slate was mined. 

Pennsylvania slate has the least longevity lasting approximately 50 to 80 years.  New York and Vermont slate have a useful life of about 100 to 125 years, and slate from Virginia has been known to last as long as 150 years. 

Wooden Roof

Wood shingles and shakes are among the oldest of roofing materials, but are no longer permitted in some jurisdictions.  They are comprised of uniformly thin shingles or thick shakes, installed on either spaced or solid sheathing. 

Wooden roofs have a life expectancy of 25 years, which is similar to many other roofs. However, they tend to weather more rapidly and must be carefully monitored and maintained.