Concerns about the roof systems on homes is probably one of the most talked about when buying, renovating or repairing. The rest of the house can be in excellent condition but if the roof leaks nothing else seems to matter. Roof structures on houses involve a myriad of components and knowing how they all work together is crucial.

Any type of roof can leak because there is really no one product that could be guaranteed leak free. Certainly the more expensive products seem to work better, such as metal roofing, but the appearance and design of roofing materials have a huge impact on how a home looks and the homeowner doesn't always have a choice. In this section we will highlight the different types of roofing, how they can fail, and what can be done to solve some of the problems. First we'll review some systems that apply to virtually every kind of roof, including:

  1. Flashing - Flashing exists on pretty much every roof, whether it be a sloped one or flat, shingled or sheeted. Flashing comes in a wide range of shapes, sizes and purposes but the main reason they exist is to divert or shed water away from entering the house structure.
  1. Sealants or caulking - Sealants and caulking work to bridge gaps between flashing, roofing materials and the house structure itself. They do not last forever and should be inspected and replaced from time to time. If the homeowner is aware of where these are and how to maintain them many eventual problems can be averted.
  1. Underlayment or sheathing - This is what it sounds like, the materials that exist under the roofing materials. Sheathing, ship lap, strapping and other materials are placed directly on the upper building structure and form the foundation for the whole roofing system.
  1. Vents, chimneys, skylights, electrical poles, etc. - Anything that protrudes through the roof from the building structure is a source for potential leaks and other problems. Any and all of these are crucial to a sealed and well-functioning roof system. Even one small vent or pole could be a source for a major leak, regardless of how new or well-maintained the rest of the roof is.
  1. The chosen roofing material - Although we will deal with this in more detail, the overall choice of what roofing system used on the house can impact on how everything else works. The wrong roof can be picked for a house and this can lead to devastating results.

A Leaking Roof

Leaking roofs will manifest themselves in a variety of ways. The source of the leak may not be immediately evident, in other words the inside spots like stained ceilings or damp drywall, are not always directly under the breach in the roof system. Water can find a path and travel great distances before arriving at an inside location. Don't always assume the source of the leak by inside evidence. Here are some tips and techniques to help:

Access the attic or roof crawl space if possible and, at first, turn off any light you have. Any obvious sources of light will indicate a place to inspect inside and out.

With the light on look for evidence of water penetration or staining. Be very careful to stay on materials that will support your weight, you don't want to fall through the ceiling below.

Tip - While you're up there in the attic or attic crawl space take note of any other issues like insulation or wiring that may need attention.

From the ground, determine the general area of the leak, in other words, if its in the living room look at the whole roof structure on that part of the house. Note any vents, skylights or other protrusions through the roof and note any and all flashing.

Once on the roof examine all of the things mentioned and note what needs to be done to fix the problem.

When the source of the leak can't be narrowed down to one or two spots but the general condition of the roof system is poor then make a list of all the things that need maintenance and attention. If the leak is causing major problems inside the home and a "trial and error" technique isn't going to work then you may need to call a roofing specialist for an inspection and a quote.

Remember that while you're examining the roof structure you can also be looking at chimneys, vents, gutters, and other things that are related to the roof and the rest of the house. Always keep your eyes and mind open for potential problems with other systems.


ASPHALT SHINGLES The most common type of roofing installed in most parts of the continent, they can come in a variety of styles and applications. The longer the warranty the heavier the shingles. Most are a blend of asphalt and fiberglass compounds with a granular surface.

ProblemsAsphalt shingles can curl, crack and warp for a variety of reasons. Unfortunately many new asphalt roofs are applied in the wrong way thus shortening their life expectancy. Simply looking at a brand new asphalt roof will not tell you if it has been installed correctly. With the correct sheathing, the right tar paper, proper flashing, ice dam for freezing, and proper nailing techniques an asphalt roof should outlast its stated warranty. Slope is another enemy of shingles depending on what shingle was used for what slope. Research this topic heavily if you aren't familiar with all of the ins and outs.

WOOD SHINGLES & SHAKESThese products are a thing of beauty when installed correctly and can last many decades with the right maintenance. Today these products are treated for longer lasting wear, and, in most cases for fire retarding qualities. There are restrictions on these products in many parts of North America, especially in fire prone areas. Wood shakes are not installed directly on sheathing as asphalt ones are, they are applied to narrow wood strapping.

ProblemsExpensive first of all. Wood shingles or shakes can be more than twice as much as comparable asphalt shingles. There are more and more new products on the market that mimic the look of shakes and it helps if you strive to learn about what's available in your part of the country. The other problem can be maintenance, especially in wet climates prone to moss and mildew. Shakes that are poorly maintained will deteriorate quicker.

SLATE, CONCRETE & CLAY TILESNatural slate, concrete or clay tiles have many wonderful characteristics but are again very expensive. They must be installed and maintained by specialists. They are usually found on higher end homes built in either a Spanish or other European style, or homes with rock or stone facades. They are also installed over strapping as a rule.

ProblemsExpense of materials, installation and maintenance. The added weight is also an issue when changing over from another type of roofing system. Roof structures must be reinforced or built with added framing and structural support.

METAL ROOFING Metal roofing is typically made from steel coated with many layers of a type of finish that will last many decades. A metal roof is usually referred to as a 50 year choice at the very least, but can last up to 100 years if maintained properly. Once again examining a metal roof system should probably be done by someone who is expert in that field but, because it has flashing and vents like any other roof, you will be able to look at it for obvious problems or breaches. Metal roofing is installed on strapping too and should never be placed over existing asphalt shingles no matter what anybody tells you.

Problems There won't be a lot of problems with a properly installed metal roof other than flashing failures or missing pieces. Cost will be an issue as will appearance. Many housing developments will restrict what type of roofing is installed on your customers' homes and, in many cases, metal roofing just doesn't suit the style of the house.

TAR & GRAVEL, ROLLED ROOFINGTypically these kinds of roofing systems are used for flat or very low slope roofs. You will see this on commercial buildings, car ports, extensions, and many other types of structures. They are easy to walk around on and examine but can be elusive when there are leaks. Close examination inside and out is needed and the flashing and venting is even more critical for this kind of system. The roof is built up layer by layer and should only be done by professionals.

ProblemsWater penetration will almost always show up in the home in the last place you would expect. A leak in a flat or low slope roof will travel great distances before showing up in a ceiling or wall. Sealants and caulking are very, very important for this type of roofing system as is flashing. Regular maintenance is more critical for this kind of roof than almost any other type. Another issue you'll encounter will be the homeowners who have installed a deck or some other kind of platform on top of a flat roof. This can be done but must be carried out using specific techniques and materials and a lot of care. Research this topic thoroughly.

Copyright Morgan Jensen 2010

OTHER KINDS OF ROOFINGEvery day it seems someone is marketing new products for roofing made of rubber, plastic or some kind of composite material. Many have come and gone leaving law suits and mayhem in their wake. Caution should be taken by people considering changing their roof system to something completely different.

Final commentsMany low slope and flat roofs will have built-in gutter systems. Others will have copper, vinyl, aluminum and even wood gutters. Hidden gutters especially are tied in directly to the roof structure used and can be a source for leaks into the home. The EPDM membrane used is specially formulated and has its own sealants and lap compounds. The homeowner cannot, and should not, use any other kind of sealant, especially tar-based ones meant for shingles and flashing. Make sure you are aware of EPDM and other hidden gutter systems.