Exterior Siding and Paint

Some homeowners re-paint the exterior of their home every few years only to find that the new paint does not last, others find that their siding has failed and that they need a new sidings system.

Here you will find the information you need to help you select and maintain the siding at your home. The information here-in will can save you the $$$ and the time to enjoy you summer.

All siding systems require regular maintenance. While some siding systems require more maintenance than others, any promise that a particular product is maintenance-free or permanent should be viewed with skepticism.

Siding failure is one part of the epidemic exterior envelope problems that have plagued many condominiums in British Columbia, the Pacific Northwest and other wet or moist areas. Siding failures have also plagued many residences. These problems have been due in part to material failure (e.g. LP, EIFS and poor quality wood products) but an equally important part has resulted from poor quality designs and installation practices (e.g vinyl siding).

The importance of siding design, material selection, installation practices and maintenance practices can't be overstated. Siding must perform a number of vital functions, including the protection from sun, wind, rain and moisture. It must also cope with moisture that emanates from the interior of the house.

Siding related decisions have always been important. They have become even more important with the advent of energy efficient construction practices, new materials and modern designs. Here you will find information to help with exterior siding related decisions.


  • This type of siding consists of short panels with one or more rows of thin shingles that are factory laminated onto a plywood like base. "Shakertown" is one brand name for such a system. The idea here being that the shingles are factory fabricated and the panels can be quickly installed at the building site. The promise of such a product is in it's lower cost of: material, production and installation.

    Some of these products come with shingles that are about 1/4 of the thickness of premium side-wall shingle. In other words they are similar to a veneer that is used in furniture making or finish grade plywood. These panels come in various shingle configurations.

    My inspection work in Western Washington has allowed me to see numerous buildings with panelized siding with very thin shingles. Many of these buildings are multi-story apartment houses and condominiums. Many are flat roofed structures with limited roof overhangs and exposed deck structures or other features with exposed siding surfaces. These inspections have confirmed the limitations of these thin shingles:

    • The very thin shingle surfaces are more prone to weather damage.
    • The panels tend to expand and bulge.
    • Repairs are more difficult than with regular thickness shingle siding products.

    In addition, some of the older styles may be hard to find and thus hard to match.

    Most of the damage with this type of siding is usually found on the south sides of the buildings (the faces exposed to maximum sun wind and rain) and/or areas with other difficult conditions. Panelized shingle siding seems to perform quite well on exterior surfaces that are protected, properly installed, primed and painted. And the best kind of panelized siding use a thicker shingle (1/2" or so at the bottom edge) Based upon my experience the thinner products are very short lived and subject to siding damage.

  • Siding, manufactured from oriented strand board and other wood composites, have the advantage of being manufactured from relatively low cost wood and young trees, thus saving money and attempting at a more benign impact on the environment. Such siding products became more attractive as traditional wood siding decreased in quality and/or increases in cost. Unfortunately, most of the experience with such siding products have been poor. Most of these products have experienced moisture related problems.

    Louisiana Pacific Corp. came out with an Inner-Seal Lap Siding (LP Siding). Masonite developed OmniWood, and a number of other companies launched other similar products. Of all of these products, LP is the best known, but for the wrong reasons. LP has been involved in a highly publicized legal action and has agreed to pay for some siding damage.

    I actually don't think that LP siding is such a bad product, and I hope that one of these years, newer versions of these products will have fewer problems. However, as of now (fall of 2004) I have not seen the evidence that allows me to recommend such a product.

    The key issues relating to the longevity of LP and other manufactured wood siding products seem to be as follows:

    1. A better formulation of the materials and the manufacturing process.
    2. Good quality installation and careful attention to manufacturers installation and maintenance instructions.
    3. Low interior moisture levels, good venting systems, wide roof overhangs and the proper control of vegetation next to the house.

    One of the problems with this type of siding is the requirement that it must be installed with "hidden fasteners", and not "face nailed." Each piece of siding is nailed along the top edge of the board, the nails are then covered by the next layer of siding. This requirement is intended to prevent water entry into the core of the material. Failure to follow these instructions has contributed to many of the damaged siding installations.

    This "hidden fastener" requirement makes partial replacement of LP type siding very difficult. When replacing wood lap siding, a damaged piece is carefully removed and a new piece installed. The new piece is then face nailed into place. With LP siding repairs, such face nailing needs to be minimized and carefully caulked, or the siding needs to be glued into place.

    Methods to reduce additional de-lamination - Before doing anything, it is very important to find out what if any help is available from the siding manufacturer. Following all of the manufacturers maintenance guidelines may be required in order to keep any warrantee in force.If the siding shows some swelling or thin fissures at the bottom edge, it may be possible to reduce further damage by priming the siding with "Permenizer Plus" or a similar primer and then repainting. The primer and paint may be applied with a spray gun, but the bottom edge and any other areas of defects must be brushed.

    LP Siding Maintenance

    Some of the pre 1996 versions of the LP and similar siding products failed soon after installation. Later versions have lasted longer but as of the fall of 2004, I have yet to see such a product that stands up in our wet Pacific Northwest Climate. The most common conditions which seems to warrant some "preventative" maintenance and eventual replacement are: limited swelling and thin cracks along the bottom edge of the siding.

    LP (Louisiana Pacific Co.) does not seem to have any official recommendations about the maintenance of such siding. However, some of the LP staff and other suggest the following:

    • quality caulking of any dimpled nail heads and other holes etc.
    • priming with Parker "Flex Bind", Pittsburgh "Permenizer Plus", or similar primer material. Note: brushing the primer into the bottom edge of the siding is a critical element of this work.

  • keeping vegetation, soil, roof drainage and sprinkler water off the siding.

    This type of maintenance work is unlikely to solve all of the problems with this type of siding or help with severely deteriorated material but it should prolong the life of the product.

    How long can the damaged siding be made to last? Will this maintenance work help? I don't know, and no one else will know until the siding fails completely. But if I had some slightly damaged LP siding on my home, I would invest in this type of maintenance work.

  • So, we can't use cement asbestos board. LP and composite wood sidings are problematic. Wood is expensive and of lower quality. What now? There are no simple answers. One newer and promising product on the market is Hardi Board and Hardi Plank. These are concrete composite products and look like bevel or lap siding. The reports, so far, are very promising.

  • Premature paint deterioration is often the result of moisture and water vapor, which originates inside the home and penetrates through the wall and siding. For example, one of the most common ways to detect failing tub and shower walls is by the appearance of blistering and other paint deterioration at the outside of the wall in question. Such exterior paint damage cannot be corrected by any exterior painting process unless the cause of the moisture or water vapor is first eliminated and associated repairs are made. A careful inspection of the exterior and interior of the home should thus be performed before exterior siding and painting work begins. Poor quality painting is counter productive. A good exterior paint job should last 10-15 years. Good quality painting includes the following steps:

    • Removal of any unused miscellaneous fittings, hooks, old electrical equipment, etc.
    • Removal of tree limbs and other vegetation in contact with the house or overhanging the roof.
    • Re-grading of the yard in such a way as to eliminate the possibility of any soil touching the siding or any portion of the wood framing of the house.
    • Check that a proper drainage system exists and is functioning. Please see: Gutters, Downspouts, and Drains, and Downspout Drain Systems.
    • Replacement or repair of any damaged siding and trim.
    • Modification, or repair of the various venting systems in the house to assure low interior moisture.
    • Washing, scraping, and sanding as required. Caution: Older paint products often contain high levels of lead. Paint chips and sanding dust from such buildings are often ingested or inhaled by small children. It can also contaminate the soil. For more information, you may want to contact the Washington State Department of Labor and Industries, Office of Health and Safety, (1-800-423-7233).
    • Some siding products are best maintained with good quality stains. Check with a good painter, lumber yard, or full service paint store to decide on the best product for your home.
    • Prime as required, including all raw wood, and damaged areas.
    • Painting: use good quality paint and follow instructions on the can or manual.

    Note: Painting rags, tools, and debris covered with some painting products can start fires through spontaneous combustion - be careful. Dispose of leftover paints and other household products in accordance with the law - call the Household Waste Information Hotline: (206-296-4692).

    Note: Full service paint stores are usually available for technical assistance in preparation for good do-it-yourself exterior painting work, and/or referral to reliable painting contractors. As a rule of thumb, you should count on spending 80% of the total time required to paint your home in preparation, and only 20% of the time with the brush in hand.