David Schulz Website

A flat roof should not really be flat but pitched down in one or more areas for adequate drainage.
A gable roof has two covered planes with a center ridge. The planes may or may not be of the same pitch,
as with the "Saltbox" style of home.
A gambrel roof is somewhat like a standard gable roof, but each of the covered sides has two planes.
A hip roof has four planes and meets either at a point or (more typically) a short ridge beam.
A mansard roof has four pitched planes with steep sides, and either a flat or lower pitched upper most surface.
A shed roof has a single plane, and is the roof most commonly used for additions to existing structures.
A butterfly roof has two planes angled down to the center.

So what are the goals when inspecting the roofing systems ?

To report on the type of roof covering material.
To report on the visible condition of the roof covering.
To inspect and report on the visible flashings.
To evaluate the roof drainage & guttering system.
To report any overhanging tree branches that may have an
adverse effect on the roof covering.
To report on the chimney system.
To identify any obvious deficiencies with "through-the-roof"
components and their flashings.
To report on any visible deficiencies in the underlying structure, for example "swayback" ridge beams.
To report the methods used to inspect the roof, for example from the eaves with a ladder, or from ground with binoculars.
To inspect and report on roofing trim, such as rake boards,
soffits and fascia boards.
To report on any visible roofing problems that can be inspected from accessible areas of the attic, such as signs of sheathing problems, evidence of moisture intrusion or damaged structural components such as split rafters and damaged trusses.

It is also important the understand what you are NOT required to do.

Walk on every roof surface.
Report on the future life expectancy of roof coverings and systems.
Warranty the roof.
Inspect most connected components such as antennae, solar panels, etc.
Report on underground guttering terminations.
Inspect the roof framing system if not readily accessible.

There are many factors that can influence the life expectancy of the roof sheathing and coverings. The material, pitch, orientation, ventilation, and environment can determine the life span of the roof.

**Roof covering service life spans**

All of these figures can be significantly reduced by other factors
Material type	Projected life span
Asphalt shingle (standard)	15 to 25 years
Asphalt shingle (architectural)	20 to 40 years
Roll roofing	Less than 10 years
Built up roofing	10 to 20 years
Single ply membrane roofing	10 to 20 years
Wood shakes & shingles	20 to 30 years
Clay and cement tiles	25 to 50 years
Asbestos cement shingles	25 to 50 years
Slate roofs	50 to 100 years
Metal roofing (shingle and sheet)	25 to 50 years

All roof coverings, regardless of materials, are susceptible to outside influences such as:

Weather
Orientation
Ventilation & Insulation
Structural problems
Impact damage
Environmental issues
Installation defects

Weather issues. We have all seen pictures on the news of homes in "Tornado Alley" with their roofs blown off, but it is not unusual to see weather damage in all areas of the country. Sometimes this will manifest in ripped shingles or dislodged tiles affecting just one or two areas, but occasionally there can be more widespread damage that is easier to spot.

The direction that the roof faces can have a significant influence on the condition of the roof. For example, south-facing roof planes tend to show signs of overheating (particularly with asphalt shingles), and north-facing roofs or those in the shade tend to have more algae and moss induced problems, both of which will shorten the life of the roof covering.

Ventilation and insulation will also have an influence on the longevity of the roof covering. Poorly vented roofs (especially those over Cathedral ceilings which are hard to ventilate) will show signs of overheating and may also show signs of moisture damage. Badly insulated attics will also promote rapid failures of the roof covering due to issues like ice damming in colder climates. We will go into this area in much more detail in the upcoming ventilation and insulation course.

Structural problems with both the roof sheathing and framing can sometimes be seen on the roof surface. They may be as apparent as cracked shingles or tiles above a structural defect, but more commonly there will be a "wavy" look to the roof caused by thin roof sheathing that is over-spanned.

Impact damage is very common and most often caused by overhanging tree branches, but it is also common to see damage from falling masonry or cracked tiles and shingles from people being on the roof. In a development near me, indentations appeared on the roof covering from being too close to the 13th fairway!

Environmental damage. The rapid deterioration of the roof covering from either air born pollutants as you may find in may industrial areas or more simply from the acidity of pine needles breaking down on the roof surface.

Installation defects. All roofing systems are only as good as the installer, and it is not uncommon to see all types failing due to poor fastenings or other installer problems.

This is wind damage on a fiberglass asphalt shingle roof. The shingles become brittle and the wind can get under them and rip them off. Here you can see damage from tree branches rubbing across the roof covering. Impact damage on a clay tile roof. Here you can see broken and dislodged tiles. Asphalt shingle roof that shows evidence of overheating. This was probably caused both by the orientation of the roof and poor ventilation.

The inspector must report on the following when inspecting asphalt shingle roof coverings.

Shingle type.
Missing shingles.
Damaged shingles.
Number of layers of covering.
Signs of previous repairs.
Cupping or buckling shingles.
Moss or vegetation on the shingles.
Granular erosion.
Shrinkage of shingles.
Lack of a drip edge.
Nail pops.
Shingles incorrectly installed.

The inspector should always report on the following:

the method used to inspect the roof.
the material and style of the roof covering.
missing, damaged or slipped tiles.
missing or damaged flashings and bird stops.
any signs of moisture penetrating the roof covering.
any required repainting where applicable.