Making sure that the roof of your house is functioning well is very important. A poorly functioning roof can spell problems for everything underneath it and be quite expensive to repair if small problems aren't taken care of in a timely fashion. In Philadelphia, roof inspection is a preventative measure that will identify little problems caused by a hard winter, excess moisture, or simply old age before they become too large to be easily solved.
General Roof Inspection
Homeowners should get their roofs inspected before a problem occurs. An inspector will be able to examine the roof while it is still functioning well and identify areas where problems are likely. In this manner, many secondary issues can be avoided. If you already have a leak that is large enough to notice, it's time to hire a contractor.
Additionally, anyone looking to purchase a home should have the property's roof professionally inspected to make sure that there are no major issues present. In fact, many lenders will require that a certified professional be hired to inspect the roof as a condition of the loan.
What to Expect in a Philadelphia Roof Inspection
Since there are a few different types of roofs in Philadelphia, roof inspection can take a couple different forms. In the country in general, and in the northeast in particular, asphalt shingled roofs are the most common.
When inspecting an asphalt-shingled roof, inspectors will look for weak spots using specialty infrared tools that identify temperature differences. These temperature differences are often a good indicator of where a leak is likely to occur (or where a leak is already happening but is not yet noticeable to the naked eye). While this technology can identify problem areas without actually coming in contact with the roof, it is very likely that the inspector will require access to both the attic and the roof itself.
If you have a tile or slate roof, an inspector will probably not walk on it because the material is so brittle. This does not mean, however, that your inspection will not be thorough: The inspector can use information gathered from under the roof in the attic as well as the view from a ladder (or even from the ground with binoculars) to determine how the roof is holding up. Similar techniques might also be used when examining a metal roof.
Since snow and ice will hinder a proper roof inspection, Philadelphia residents should try and schedule the inspection when there is no threat of winter precipitation. In some cases, when the inspection needs to be done immediately and the snow cannot be avoided, roofs with a more gentle slope can actually be shoveled to allow visual access to the roof.
Prices for Roof Inspection in Philadelphia
Roof inspection is generally not a very expensive or intensive job. For a typical roof inspection, Philadelphia residents should expect a bill of around $300 and the job shouldn't take more than a few hours to complete. While you're getting your roof inspected, you might want to have your chimney cleaned and inspected (about another $300) to check for any common problems. 
Jon Nunan is a freelance writer who draws on his experience in construction, ranging from landscaping to log home building, for his articles on home improvement.