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ARCHITECTURE & BUILDING COMPONENT ID
ASBESTOS IDENTIFICATION IN buildings
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BARK SIDE UP on DECKS & STEPS
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BEST CONSTRUCTION PRACTICES GUIDE
BRICK VENEER WALL Loose, Bulged
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BOOKSTORE - EXTERIORS
BUILDING SAFETY HAZARDS GUIDE
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CHIMNEY INSPECTION DIAGNOSIS REPAIR
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DECK & PORCH CONSTRUCTION
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DECK COLLAPSE Case Study
DECK FINISHES COATINGS PRESERVATIVES
DECK FLASHING LEAKS, ROT Case Study
DEFINITIONS of ENGINEERED WOOD OSB LVL etc
DRYWELLS, FRENCH DRAINS for FLAT SITES
EARTHQUAKE DAMAGED FOUNDATIONS
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EXTERIOR WALL SIDING TRIM & FINISHES
EXTRACTIVE BLEEDING STAINS
FLASHING MEMBRANES PEEL & STICK
FLASHING for METAL ROOFS
FLASHING ROOF WALL DETAILS
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FLASHING WOOD ROOF DETAILS
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FROST HEAVES, FOUNDATION, SLAB
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GLUES ADHESIVES, EXTERIOR CONSTRUCTION
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HEAT TAPES & CABLES on Roofs for Ice Dams
HOUSE PARTS, DEFINITIONS
HOUSEWRAP / SHEATHING WRAP
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HOUSEWRAP PRODUCT CHOICES
HOUSEWRAP at SILLS, SOLES, TOP PLATES
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSECT INFESTATION / DAMAGE
KIT HOMES, Aladdin, Sears, Wards, Others
LEAD POISONING HAZARDS GUIDE
LEAD TEST KIT for HOME USE
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LOG HOME GUIDE
METAL LATH, PLASTER & STUCCO
MOISTURE CONTROL in BUILDINGS
MOLD DETECTION & INSPECTION GUIDE
MVOCs & MOLDY MUSTY ODORS
ODORS & SMELLS DIAGNOSIS & CURE
PAINT & STAIN GUIDE, EXTERIOR
PAINT FALURE, DIAGNOSIS, CURE, PREVENTION
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PORCHES & Sunrooms
PORCH CONSTRUCTION & SCREENING
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RETAINING WALL DESIGNS, TYPES, DAMAGE
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ROOF ARCHITECTURAL STYLES - PHOTO GUIDE
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ROT, TIMBER FRAME
ROT, TIMBER ASSESSMENT
SEARS KIT HOUSES
SHEATHING, Gypsum board
Sheathing Celotex Homasote & Other
SHEATHING, FOIL FACED - VENTS
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STAIRS, RAILINGS, LANDINGS, RAMPS
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STONE VENEER WALLS
STRAW BALE CONSTRUCTION
STUCCO WAll FAILURES DUE TO WEATHER
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
STUCCO PAINT FAILURES
SURFACE GRADING, SITE DRAINAGE
TEST KITS for DUST, MOLD, PARTICLE TESTS
Thermal Expansion Cracking of Brick
THERMAL EXPANSION of MATERIALS
THERMAL IMAGING, THERMOGRAPHY
THERMAL IMAGING MOLD SCANS
THERMAL MASS in BUILDINGS
TREES & SHRUBS, TRIM OFF BUILDING
TRIM, EXTERIOR CHOICES, INSTALLATION
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
VINYL CHLORIDE HEALTH INFO
VINYL Siding or PLASTIC Window ODORS
Volatile Organic Compounds VOCs
WALL CONSTRUCTION BARRIER vs CAVITY
WATER BARRIERS, EXTERIOR BUILDING
WATER ENTRY in buildings
WIND ENERGY SYSTEMS
WIND TURBINES & LIGHTNING
WINTERIZE A BUILDING
This article discusses the causes and cure of wood siding failures including when siding is installed over rigid foam insulation - how to prevent siding cupping, siding nail pops, siding splitting, & siding separation or misalignment at butt joints and other wood clapboard and hardboard siding failures. Sketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
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"Nails A Poppin: how to keep wood siding from wriggling over foam sheathing" - links to the original article in PDF form immediately below are followed by an expanded/updated online version of this article.
This article explains the causes of wood siding failures and continues with advice on how to prevent siding cupping, siding nail pops, siding splitting, & siding separation or misalignment at butt joints when wood siding is installed over rigid foam building insulation. As early as in 1979 failures of wood siding were reported when that material was installed over foam sheathing. By 1982 the problem was under study by the National Forest Products Laboratory and the Society of the Plastics Industry (representing insulating foam building sheathing manufacturers) and a 1983 report by that group made suggestions to avoid siding failures but did not identify the underlying causes.
In addition to the wood (clapboard-type) siding failures listed just above, wood product siding failures in the hardboard siding family were reported: siding waviness, hardboard siding dimpling (caused by over-nailing), or hardboard siding buckling lengthwise when hardboard siding gets wet on its back or building-side face. Other hardboard siding failures are discussed at SIDING HARDBOARD, and still more serious building damage including rot and mold where leaks occur between synthetic stucco are discussed at SIDING EIFS & STUCCO.
Text below excerpts from and paraphrases the original wood siding failure over foam insulation article shown in the links above.
Improper nailing of wood siding: Among wood clapboard siding failures when that material is installed over insulating foam building sheathing, the articles above report that improper nailing is the most frequently cited cause.
To avoid these problems it is important that the installer use nails of sufficient length to penetrate both the foam sheathing and the wood framing beneath, and also the siding should not be nailed so hard that it is cupped (lengthwise) by having compressed the foam sheathing. Contractors who installed siding using 7d or 8d siding nails were using fasteners that were too short - the nails barely made it through the foam and siding easily came loose later.
Moisture damage to wood siding: Cupped wood clapboards (across the width of the board) are caused primarily by water or moisture penetrating the wall and becoming absorbed into the clapboard through its back surface. Flat-sawn clapboard stock will cup more than vertical-sawn. The moisture problem in a clapboard wall may come from the building exterior (such as due to wind-driven rain, installation and flashing errors), from the building interior (indoor moisture problems, missing or defective vapor barriers), or from the wall cavity if ice dam leaks, roof leaks, or plumbing leaks wet the wall cavity.
Siding quality affects siding failures: poor wood siding stock is more prone to failures. Lower quality wood clapboard siding qualities that affect its failure rate include:
However the impact of these characteristics on siding failures varies by wood species. For example, redwood siding is reported to perform well even at thinner thicknesses and when not primed or coated.
Foam sheathing contribution to siding failures: Contributing to moisture damage in wood clapboards nailed over foam is the observation that because the foam provides no support for the nails passing through it, any movement in the wood (such as due to thermal or moisture changes) can cause the wood to loosen and drop out of alignment.
Hardboard siding installed over insulating foam sheathing may also suffer from lateral waviness or "cupping" due to over-nailing that compresses the foam sheathing behind the nail. Observing hardboard siding under proper lighting conditions can make this defect easier to see if you sight along the siding rather than observing it head-on.
Also see see SIDING, WOOD PRODUCT CHOICES and see SHEATHING, FOIL FACED - VENTS - do we need to vent building walls with siding installed over foam board insulating sheathing?Readers researching wood siding problems should also see PAINT FALURE, DIAGNOSIS, CURE, PREVENTION as well as the other siding types listed at page top or at Related Topics . Readers should also see SIDING TYPES, INSTALLATION, DEFECTS. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
Nailing Advice for Wood Siding
Finishing Advice for Wood Siding
Using Strapping or Furring Strips to Install Exterior Wood Siding
Wood Siding Moisture Leaks, Traps, & Dryout
Earlier in this article we cited several possible sources of moisture penetrating wood siding materials, especially from the siding back, leading to a variety of types of siding damage. Best practice to avoid moisture damage to wood siding will include proper siding installation - that we have discussed just above. But in addition to properly selected, installed, nailed, and finished wood siding, here are some other steps to avoid moisture or water damage to wood building siding products:
Siding wedges used to prevent paint failure and siding damage
Wood siding wedges (small wooden wedges, or small plastic wedges) are designed to create a gap between the bottom edge of clapboard siding and the surface of the board below, allowing wall moisture to escape. Especially on older buildings sheathed with wood clapboards that have been painted several times, the paint can seal the bottom edge of each clapboard against the board below, making it more difficult for moisture to escape the wall. Wedges sold for this purpose can be driven up below the clapboards to create a vent opening as a building retrofit. We're uncertain about the effectiveness of this solution to paint and siding failures:
Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
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