The Sound Roof

Re-roofing is one of the most expensive building maintenance projects. It is also one of the most common areas of construction disputes.

Here you will find some practical information designed to help you: avoid common mistakes, save money and reduce the need for frequent roofing work.


  • Our eclectic building styles provide examples of most of the world's roofing materials and applications. Victoria's B.C.'s homes have thatch. Sod roofs can be found on some innovative, energy-efficient homes, slate is often found on the east coast, and even the yurt is making a comeback. Most people, though, would be satisfied with one of the more conventional long as the roof didn't cost a king's ransom, required no maintenance, and lasted forever.

    All of that may not be possible, but many good roofing choices are available. Cost alone will not determine quality, and that is good news, because roof replacement is one of the more expensive aspects of the typical home's construction and maintenance program. Yet, with careful selection of materials, qualified contractors, proper installation practices and modest maintenance, roof replacement can result in a properly functioning roof for 20 to 50 or more years.

  • The choices in the past were easier to make. There was shingle, there was shake, and then there was composition roofing. We rarely used metal roofs on residential construction, and relegated the use of ceramic tile roofs to Southern California. The dozens of roofing products on the market today make the choice a little more difficult.

    In addition to the far greater choice in roofing materials, homeowners today can benefit from a large variety of roofing materials and products. Many products are being developed in response to the shortcomings of older roofing materials, the demands of modern building techniques, and ever more stringent building codes.

    For example, most of today's building materials are tested for their fire resistance and flame spread, and are rated according to flame resistance standards. Similarly, most roofing materials are covered by a manufacturer's warranty, with typical warranties ranging from 20 to 40 years.

    See also Q&A #20: Roofs, Topics: Cedar Roofs

  • George's Roofing Material Ratings
    * * * = Great! * * = Very Good * = Good No star = Not Recommended

    Roofing Material Manufacturer's Warranty Life Expectancy Relative Cost (low=1 high=10) Special Maintenance Requirements Fire Rating Comments
    20-year composition 3 Tab shingles * 20 years 20+ years 1 None Class A - good Economic fiberglass product, but I would recommend the 25+ yr. versions.
    25-year composition* * 25 years 25+ years 2 None Class A - good Upgraded 20-year version, good choice for roofing over existing material.
    Architectural grade composition 30-40 Yr.* * * 30-40 years 30-45 years 2-4 None Class A - good The variety of styles and textures makes this product very popular.
    Cedar Shake (Medium and Heavy) Generally none 8-25 years 5-6 Repair, clean and treat with wood preservative every 3-5 years None - can be ordered with fire retardant Requires careful selection of materials and workmanship. High maintenance cost.
    Treated Cedar Shake (Medium and Heavy)* 30-50 years 30+ 6-7 None None If you must have cedar, this may be the best way to go. Treated with a preservative or a fire retardant.
    Standing Seam Metal* * * 20-40 years 20-50 years 5-7 None None - non-combustible Made out of steel and/or aluminum. Factory painted in various colors. Very good for heavy weather locations.
    Metal - Exposed fastener* 20 years 20+ years 4 None None - non-combustible Tends to hold debris and deteriorate at fasteners.
    Metal "Shake"* "Lifetime" ? 30 years 7 None Class A This is a new product with a limited "track record", installation requires special training
    Concrete shakes and Tile* * 50-60 years 50+ years 5-6 None Non-combustible Several styles are available.
    Hot tar* Generally none 10-20 years 3 Seal coat every 5 years None Best on low sloped roofs.
    Torch down* * 10-12 years 10-20 years 3 Re-coat every 5 years Generally none Best for flat or low sloped roofs.
    Natural slate* * * None 50-150 years 10 Leave it alone Non-combustible An excellent roofing product, but not all slate will stand up to wet climates.

  • While the selection of contractors and materials is very important, so is attention to some important related details. Before a new roof is installed the following items should be inspected and, if necessary repaired or replaced:

    • The chimney and chimney flashing

  • Skylights
  • Gutters, down spouts and drains
  • Roof vents including vents for various fans and kitchen hoods. See Roof Venting Systems under Topics.
  • The siding at dormers
  • Overhanging tree limbs (should be removed without damaging the trees!)
  • The electrical strike and wires
  • Insulation in roof structures without an attic access
  • Repair or replacement of these items is usually easier before or during the roofing process.

  • Most roofing disputes begin with an unrealistically low bid, a poor quality contract, incomplete specifications, or all of the above. For example, installing a "30 year" roofing product on top of damaged barge rafters makes no sense, neither does re-using rusted or damaged flashing. As in so many other cases, the roofing will only last as long as the weakest sub-element.

    Good roofing specifications should include the following information:

    Standards of Work - All work must be done: to code, manufacturers specifications and at least to "standard practices of the trades".

    Licensing and Qualifications - All work must be done by a licensed contractor, and by a qualified and supervised staff.

    Pre-inspection - The contractor's work proposal must be based upon a thorough examination of the entire roof structure. The quality contractor is the one who will point out the need for some associated work such as: trim and siding repairs, chimney tuck-pointing or interior moisture issues. Much of this type of work must be performed before or during the roofing work.

    Care and Safety - The contractor must be responsible for the protection of the house, contents, inhabitants and property during the work. The contractor is furthermore responsible for the regular cleaning and removal of all construction debris - yes, this should include cleaning the gutters.

    Schedule - When will the work start? when will it be completed?

    A New Roof or Re-coating - Will the old roofing be removed? or will the new roofing be installed on top of the previous layer of roofing?

    Roof Deck Modifications - If the old roofing is removed, what modification will be made to the "roof deck"? (Remain as is? New plywood? New OSB?...)

    Hidden Damage - If damage is discovered under the old roofing, what "time and material" formula will be used for any repairs? Note: a good roofer should be able to tell in advance if damage is likely to exist under the old roofing.

    Change Orders - The contractor must inform you of any required changes to the work. The good contractor will look out for problems and defects that are discovered during the roofing work. All changes to the contract must be made in writing and in a timely manner. The property owner's responsibility is to evaluate and respond to these modifications in a timely manner and in writing.

    Associated Systems - Do the chimneys need repair? how about the flashing? Is the venting to code and to manufacturers specifications? do the old skylights need replacement? does the house need new gutters? does the electrical strike need repair? is this work included in the bid? (chimney repair should usually be done prior to the new roofing installation, new gutters installed after the roofing.)

    A reputable company will do it's best to identify such item "up front", and reduce the need for costly change orders.

    Special Requirements - Are there some conditions which require special methods? for example: short fasteners at open soffits? stainless fasteners at an ocean side house? foam board insulation in a "hot roof"?

    Material Selection - What kind of roofing material will be used? Color? what kind of felt? will the material be nailed or stapled? what style of roofing vents? does your roof need moss control "zinc strips"?

    Warranties - What is the length of the roofing material warranty? (20 yr. min. on sloped roofs, 10 yr. min. on flat roofs) labor warranty? (5 yr. min.).

    Price and Payment Schedule - What is the total price of the job? does this include sales tax? When are the payments due? (Some smaller roofing companies may require a small deposit at the start of work. Most of the contracted amount should only be due after all of the work is completed in a satisfactory manor).

    Remember: a roof is much more than the installed roofing material. It is an entire "system" of components. And, as is so often the case: "the devil is in the details".

    Please note: the above list of specifications is not a legal contract review. It is only a listing of some of the more common and important specifications which should be one part of a complete roofing contract.

  • There are some very good roofing products on the market. Some of the better ones should last 40+ years. But even the very best roofs will require some maintenance.

    Here are some basic roofing maintenance tips:

    As a general rule: when you have the urge to climb on the roof, have a cup of tea and wait until the urge passes.">

    • Many roofs are damaged by people who don't know how to "walk" on a roof.
    • Falling off a roof (or ladder) is not much fun.
    • "Flat" roofs need more frequent and regular inspections and cleaning than do sloped roofs.
    • Roofing materials are not designed to be used as decks - one "4th of July rooftop fireworks viewing party" can destroy most roofing surfaces.
    • Remove any tree limbs which overhang the roof and gutters.
    • Most roofing surfaces should not be pressure washed.
    • Start treating your roofing with a moss control agent as soon as the moss starts growing. In wet climates, and northern facing roof surfaces this moss can start to develop after one or two wet seasons.
    • Take a good look at your roof at least once a year. This can often be done with a set of binoculars from a safe/nearby location. Look for missing roofing material, loose flashing, debris and similar signs of damage.
    • Most roof leaks can be repaired and don't require the immediate replacement of the roof. If a new roof is required, take the time to get a good set of bids.

    See also: Moss On The Roof, Pressure Washing Roofs, and A Field Guide to Bad Home Repair and Remodeling Contracts.