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WINTERIZE A BUILDING
Fiber cement board lap siding repair guide. This article describes repair procedures for cosmetic or functional siding issues that may arise such as loose siding, wind-damaged siding, siding paint or coating failures, and siding gaps, especially gaps at fiber cement siding butt joints where lap siding is installed. Our page top photo shows loose and improperly installed fiber cement siding on a New York home. We quote from the siding manufacturer's installation guides, contractor guides, and appropriate codes & standards and we debate the pros and cons of caulking vs. flashing for certain siding repairs. We include sources for building siding back flashing & H-flashing products.
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Adapted, expanded & excerpted from CertainTeed Corporation's "CertainTeed WeatherBoards™ Fiber Cement Siding Installation Manual" [5a], from "Fiber Cement Siding Best Practices for Effective Job Site Management"[5b] and from JamesHardie Corporation installation instructions and bulletins for JamesHardie HardiePlank lap siding. [12b] and finally also from applicable building codes & standards.
Here we tackle steps to stop ongoing leaks, damage, or to un-do damage from either a sloppy siding installation job or from more normal wear and tear as a building's exterior siding is exposed to weather, kick balls, peeing dogs, squirrels and raccoons, or to my grandsons and granddaughters, all six of whom (Chase, Tanner, Quinn, Sophie, Zoe, Chloe) could be hired as a home wear and tear test gang.
Separately at SIDING, FIBER CEMENT GAP CURES we describe solutions for buildings where owners complain of apparent shrinkage gaps in fiber cement siding - gaps sometimes larger than 1/4" between the butt jointed ends of laps siding boards. Other problems have included peeling paint, loose boards, and occasional building leaks are described and diagnosed at SIDING, FIBER CEMENT DEFECTS.
Separately at SIDING, FIBER CEMENT MAINTENANCE we describe steps that the installer or homeowner may take to protect fiber cement damage from undue weather wear & tear.
Our close-up photo of a butt joint gap in this fiber cement lap siding (above left) shows the width of the shrinkage gap. The installers failed to install the recommended backer flashing / weatherproofing at any of the butt joints that we examined and we think the siding was installed wet and possibly not properly end-butted.
Here as well as at page top are photos of loose fiber cement siding.
Considering that in our photo at left the siding should have been lapped (by the board above, typically 1 1/4"), for this end butt joint to be completely out of alignment with its neighbor we figure that the board above was also not properly nailed, possibly bulged as well.
Also notice that the boards are misaligned vertically as well. All of these clues suggest a super high-speed, sloppy siding installation by un-trained and un-supervised installers.
For more diagnosis we ask about the fiber cement siding's original installation & nailing: was the siding installed according to the product specifications for type of nail, nail spacing, overlap, back priming, butt joint and trim joint end priming & caulking? See the product's caulking, nailing, flashing, installation details provided by James Hardie and excerpted in our notes below.
Pin-Back Nailing repairs for loose fiber cement siding
In James Hardie's technical bulletin No. 17, the company provides a description of PinBack nailing for use at loose planks that were "high nailed" at original installation) or where there are problems with gaps, loose planks, or rattling noises.
At left we show a different loose siding problem: where the diagonal end-cut siding was installed against the home's sloping gable-end trim, the installer perhaps couldn't catch a stud, or perhaps s/he simply didn't want to move the ladder to nail the end of the siding board.
Now just a few years later the siding ends are curled away from the building. How can we fix this other than by a complete removal and replacement of this wall covering?
Cures for Buckled Fiber Cement Lap Siding
Buckled fiber cement siding is most likely to occur because the installer failed to give the recommended gap between the ends of the fiber cement boards and abutting vertical trim at corners, windows, doors, etc.
Buckling fiber cement siding may also occur if the product was not properly nailed.
It may be possible to cut an end gap clearance in place between the siding end and vertical trim, wearing proper protective gear to avoid silica dust hazards etc.
Also see Pin Back Nailing discussed above.
At JAMES HARDIE HardiePlank Siding we discuss the failure of this factory-coated fiber cement siding installation.
How to Decide on a Remedy for Paint Failure on Siding
Cosmetic issues: Building owners should also be made aware of possible future cosmetic issues, depending on the repair method used and workmanship;
For cosmetic concerns, if building condition permits a slower approach, consider trying more than one product and method for gap sealing, examining the durability and appearance of the repair after 12 months or longer of weather exposure on the most-challenged building sides.
Details about repair approaches to open butt joints in fiber cement lap siding are give at SIDING, FIBER CEMENT GAP CURES.
There we also discuss adding back flashing to seal open lap siding butt joints against leaks into the wall system.
Cures for Algae, Fungus, Moss, Lichens on Building Siding
Algae, fungus, moss or lichens on siding are usually due to a combination of moisture and shade on the building wall. Plants too close to the building wall, repeated wetting by sprinkler systems, or unnecessarily dense close shade tree growth are conditions that can usually be remedied. See TREES & SHRUBS, TRIM OFF BUILDING.
For more about algae, lichens, moss growth on buildings see ALGAE, FUNGUS, LICHENS, MOSS.
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Technical Reviewers & References
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