Beware moisture: Do you spot moisture in your house? That's the first clue that there's a breach in your roofing. You may notice a slightly discolored spot on the wall, a loose piece of wall covering, peeling paint on a ceiling, or a damp smell along a hallway. Your roof is your house's waterproofing system. If water is still standing after 48 hours, your roof needs repair.

Ice dams: Ice dams are formed when heat from the attic melts snow at the ridge or peak of the roof causing an "avalanche" of snow and ice to overflow the gutters. The melted water can then back up under the shingles and work its way into the house.

Common problems: Flashing seals the joints along the roof. Most flashing is made of metal, so it can rust or break. Any roofing material can be damaged over time. A common source of damage is impact (hail, tree branches, etc.). If the damage is small and localized, the area can be replaced. More extensive damage may require you to replace the entire roof.

Roof pitch and slope: Roof pitch can dramatically affect installation and repair. In fact, the slope or pitch of a roof can determine the kind of roofing material you use.

Slope and pitch are two terms often used interchangeably, but they actually mean different things. Slope is described in inches of vertical rise per foot of horizontal run. For example a gently sloped roof that rises 4 inches for every 12 inches of house covering is said to have a 4 in 12 slope. Pitch is expressed as a fraction - the ratio of rise to the total span of the entire roof. The same gentle 4 in 12 slope translates into a 1:6 pitch.

Dormers: Dormers create additional openings in your roof, which will affect your roof installation. One notable area is at the joints, which will need to be sealed with metal flashing. The style or dormer can also affect your roofing material. A shed dormer will decrease the slope of your roof over the opening. A gabled dormer often has higher pitches which will shed water more easily.

-- Tips courtesy of HomeAdvisor.com