InspectAPedia.com InspectAPedia®
Google
InspectAPedia
 

Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair

Ask a Question or Search InspectAPedia

  • HOME
  • AIR CONDITIONING
  • DAMAGE ASSESSMENT
  • ELECTRICAL
  • EXTERIORS
  • HEATING
  • HOME INSPECTION
  • INTERIORS
  • PLUMBING
  • ROOFING
  • SEPTIC SYSTEMS
  • STRUCTURE
  • WATER SUPPLY
  • ENERGY SAVINGS
  • ENVIRONMENT
  • INDOOR AIR IAQ
  • INSULATION
  • MOLD INSPECT TEST REMOVE
  • NOISE
  • ODORS
  • SOLAR ENERGY
  • VENTILATION
  • EXPERTS DIRECTORY
  • CONTACT US



InspectAPedia ® Home

AIR CONDITIONING & HEAT PUMP SYSTEMS
ICE DAM PREVENTION
INSECT INFESTATION / DAMAGE
INSULATION IDENTIFICATION GUIDE
INSULATION INSPECTION & IMPROVEMENT

AIR BYPASS LEAKS
AIR CHANGE RATE ACH HEAT SAVINGS
AIR FILTERS for HVAC SYSTEMS
AIR LEAK DETECTION TOOLS
AIR LEAK MINIMIZATION
AIR LEAK SEALING PROCEDURE
AIR TEST FOR MOLD: ACCURACY
AIR TEST SAMPLING CASSETTE STUDY
ALLERGEN TESTS for buildings
ALLERGENS in BUILDINGS, RECOGNIZING
ALLERGY & MOLD IAQ PRODUCTS
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
ANIMAL ALLERGENS / PET DANDER
APPLIANCE EFFICIENCY RATINGS
ASBESTOS FLOORING HAZARD REDUCTION
ASBESTOS-FREE INSULATION MATERIALS
ASBESTOS IDENTIFICATION IN buildings
ATTIC LEAKS, CONDENSATION & MOLD
ATTIC VENTILATION

BACKDRAFTING HEATING EQUIPMENT
BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BASEMENT LEAKS, INSPECT FOR
BASEMENT WATERPROOFING
BATH & KITCHEN DESIGN GUIDE
BATHROOM VENTILATION
BIOGAS PRODUCTION & USE
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BLOWN-IN INSULATION
BRICK LINED WALLS
BRICK VENEER WALL AIR LEAKS
BRICK VENEER WALL Loose, Bulged
BRICK WALL DRAINAGE WEEP HOLES
BUCKLED FOUNDATIONS due to INSULATION?
BUILDING NOISE DIAGNOSIS & CURE

CATHEDRAL CEILING INSULATION
CATHEDRAL CEILING VENTILATION
CEILING FINISHES INTERIOR
CEILINGS, DROP or SUSPENDED PANEL
CEILINGS, PLASTER TYPES
CHIMNEY INSPECTION DIAGNOSIS & REPAIR
COOLING LOAD REDUCTION by ROOF VENTS
COMBUSTION AIR for TIGHT BUILDINGS
CONDENSING BOILERS/FURNACES DAMAGE
CONDENSATION or SWEATING PIPES, TANKS
COOLING LOAD REDUCTION by ROOF VENTS
CRAWL SPACES

DEFINITION of Heating & Cooling Terms
DEHUMIDIFICATION PROBLEMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DUCT SYSTEM & DUCT DEFECTS
REMOTE ELECTRIC POWER, PHOTOVOLTAIC

ELECTRIC HEAT
ELECTRIC POWER, PHOTOVOLTAIC, REMOTE SITE
ENERGY STAR PROGRAM
EVAPORATIVE COOLING SYSTEMS

FIBERGLASS INSULATION
FIBERGLASS HAZARDS
FIBERGLASS INSULATION MOLD
FLASHING MEMBRANES PEEL & STICK
FLAT ROOF MOISTURE & CONDENSATION
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN buildings-mold
FLOOR COVERING for OVER THERMAL MASS SLABS
FLOOR TYPES & DEFECTS
FLOOR TILE HISTORY & INGREDIENTS
FOUNDATION WATERPROOFING
FRENCH DRAINS
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRAMING METAL STUD PERFORMANCE
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB

GREEN BUILDING CONSTRUCTION CODES GUIDES
GREENHOUSE DESIGN for SOLAR HEATING

HEAT LOSS in BUILDINGS
HEAT LOSS DETECTION TOOLS
HEAT LOSS INDICATORS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION
HEAT LOSS RATE CALCULATIONS
HEAT TAPES & CABLES on Roofs for Ice Dams
HEATING COST SAVINGS METHODS
HOT ROOF DESIGNS: Un-Vented Roof Solutions
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSE DOCTOR, how-to be
HUMIDITY LEVEL TARGET

ICE DAM PREVENTION
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
INSULATION CHOICES
Insulation Air & Heat Leaks
INSULATION FACT SHEET- DOE
INSULATION for GREENHOUSE or SOLARIUM
INSULATION IDENTIFICATION GUIDE
INSULATION INSPECTION & IMPROVEMENT
  INSULATION R-Values & Properties
  Air Bypass Leaks, Thermal Tracking
  AIR LEAK DETECTION TOOLS
  AIR LEAK MINIMIZATION
  AIR SEAL STRATEGIES
  ATTIC CONDENSATION CAUSE & CURE
  BASEMENT CEILING VAPOR BARRIER
  BASEMENT De-Watering Systems
  BASEMENT HEAT LOSS
  Blocked Soffit Intake Vents
  BLOWER DOORS & AIR INFILTRATION
  BLOWN-IN INSULATION
  BRICK or BLOCK WALL CAVITY INSULATION
  BRICK VENEER WALL AIR LEAKS
  CATHEDRAL CEILING INSULATION
  CATHEDRAL CEILING VENTILATION
  HOT ROOF DESIGNS: Un-Vented Roof Solutions
  ENERGY SAVINGS in buildings
  ENERGY SAVINGS RETROFIT CASE STUDY
  ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
  ENERGY SAVINGS RETROFIT OPTIONS
  ENERGY STAR PROGRAM
  ENERGY USE MONITORING, SOLAR
  FIBERGLASS DUCT, RIGID CONSTRUCTION
  FIRE PROTECTION FOR FOAM BOARD INSULATION
  FOUNDATION INSULATION OPTIONS
  FRAMING DETAILS for BETTER INSULATION
  FRAMING DETAILS for DOUBLE WALL HOUSES
  FRAMING METAL STUD PERFORMANCE
  HEATING COST SAVINGS METHODS
  HIGH MASS TRADEOFFS, HEATING vs COOLING
  HOUSE DOCTOR, how-to be
  Inspect Attics for Moisture or Mold
  Inspect Attics for Blocked Soffit Intake Vents
  Inspect Basements for Moisture or Mold
  Inspect Building Exterior - Roof Venting
  Inspect the Ridge Vent System from the Attic
  Inspect the Soffit Vent System from the Attic
  INSECTS & FOAM INSULATION
  Insulation Air & Heat Leaks
  INSULATION for GREENHOUSE or SOLARIUM
  INSULATION CHOICES
  INSULATION FACT SHEET- DOE
  INSULATION PLACEMENT in buildings
  INSULATION R-Values & Properties
  LOG HOME ENERGY EFFICIENCY
  LOG HOME WALL INSULATION VALUES
  PHENOLIC FOAM INSULATION
  POLYCARBONATE GLAZING
  POLYISOCYANURATE FOAM INSULATION
  POLYISOCYANURATE FOAM BELOW SLABS
  POLYSTYRENE FOAM INSULATION
  RADIANT BARRIERS
  REFLECTIVE INSULATION
  RIGID FOAM USE INDOORS
  ROOF VENTING ENERGY SAVING DETAILS
  ROOF VENTING NEEDED?
  ROOF VENTILATION SPECIFICATIONS
  REMOTE ELECTRIC POWER, PHOTOVOLTAIC
  ROCK-BED SOLAR HEAT STORAGE DESIGN
  SLAB INSULATION, PASSIVE SOLAR
  SLATE THERMAL MASS for SOLAR HEAT STORAGE
  SOUND CONTROL in buildings
  STRESS SKIN INSULATED PANELS
  STUCCO OVER FOAM INSULATION
  SUPER HI-R INSULATION
  SUPERINSULATION RETROFIT
  Urea Formaldehyde Foam Insulation UFFI
  URETHANE FOAM Deterioration, Outgassing
  VAPOR BARRIERS & AIR SEALING at BAND JOISTS
  VAPOR BARRIERS & CONDENSATION in buildings
  VAPOR BARRIERS & HOUSEWRAP
  VAPOR BARRIERS, VINYL SIDING
  VAPOR CONDENSATION & BUILDING SHEATHING
  VERMICULITE INSULATION
INSULATION LOCATION - WHERE TO PUT IT
INSULATION MOLD
INSULATION R-Values & Properties

LEED GREEN BUILDING CERTIFICATION
LEED Building Designation & IAQ
LIGHT, GUIDE to FORENSIC USE
LIGHTING, EXTERIOR GUIDE
LIGHTING, INTERIOR GUIDE
LOG HOME ENERGY EFFICIENCY
LOG HOME GUIDE
LOG HOME WALL INSULATION VALUES

METHANE GAS SOURCES
MOBILE HOME INSPECTIONS
MOISTURE CONTROL in BUILDINGS
MOLD in FOAM INSULATION, RESISTANCE
MOLD INFORMATION CENTER

Nanomaterials Hazards
NOISE / SOUND DIAGNOSIS & CURE
NOISE CONTROL for HEATING SYSTEMS
NOISE CONTROL for FLOORS
NOISE CONTROL for PLUMBING
NOISE CONTROL for ROOFS

ODORS & SMELLS DIAGNOSIS & CURE

PAINT FALURE, DIAGNOSIS, CURE, PREVENTION
PASSIVE SOLAR DESIGN METHOD
PASSIVE SOLAR HEAT PERFORMANCE
PASSIVE SOLAR HOME, LOW COST
PHOTOVOLTAIC POWER SYSTEMS
PLASTER & BEAVERBOARD & DRYWALL
PASCAL CALCULATIONS

RADIANT BARRIERS
RADIANT HEAT
RADIANT HEAT Floor Mistakes to Avoid
RADIANT HEAT TEMPERATURES
RADIANT SLAB FLOORING CHOICES
RADIANT SLAB TUBING & FLUID CHOICES
ROOFING INSPECTION & REPAIR
ROOF VENTILATION SPECIFICATIONS
ROT RESISTANT LUMBER
ROT, TIMBER FRAME
ROT, TIMBER ASSESSMENT

SEARS KIT HOUSES
SHEATHING, FOIL FACED - VENTS
SOUND CONTROL in buildings
STAIN & BIODETERIORATION AGENT CATALOG
STAINS on & in BUILDINGS, CAUSES & CURES
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
STAINS on INDOOR SURFACES: PHOTO GUIDE

STAIRS, RAILINGS, LANDINGS, RAMPS
STONE CLEANING METHODS

STRUCTURAL INSPECTIONS & DEFECTS
STRAW BALE CONSTRUCTION
STRESS SKIN INSULATED PANELS
STUCCO WAll FAILURES DUE TO WEATHER
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
STUCCO PAINT FAILURES

STRUCTURAL INSPECTIONS & DEFECTS
SUMP PUMPS GUIDE
SWEATING (CONDENSATION) on PIPES, TANKS

Thermal Expansion Cracking of Brick
THERMAL EXPANSION of HOT WATER
THERMAL EXPANSION of MATERIALS
THERMAL IMAGING, THERMOGRAPHY
THERMAL IMAGING MOLD SCANS
THERMAL MASS in BUILDINGS
THERMAL TRACKING Indicates Heat Loss

VAPOR BARRIERS & AIR SEALING at BAND JOISTS
VAPOR BARRIERS & CONDENSATION in buildings
VAPOR BARRIERS & HOUSEWRAP
VAPOR CONDENSATION & BUILDING SHEATHING
VENTILATION in BUILDINGS

WALL FINISHES INTERIOR
WALL CONSTRUCTION BARRIER vs CAVITY
WATER ENTRY in buildings
WIND ENERGY SYSTEMS
WIND TURBINES & LIGHTNING
WIND WASHING INSULATION At EAVES
WINDOWS & DOORS
WINTERIZE A BUILDING
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY

ZONE DAMPERS
ZONE VALVES

More Information

Stress Skin Panel Construction  (C) S Bliss Daniel Friedman SIPs: Stress-Skin Structural Insulated Panels in Timber Frame, Modular, Panelized, & Cathedral Ceiling Construction
     

  • Stress skin panels (SIPs or structural insulated panels) star in timber-frame construction revival
    • Stress Skin Structural Panels, history, current use practices, Stress skin panels & structural panels (SIPs) used to build entire building shells
    • Definition of SIPs, Structural Insulated Panels or Stress-Skin Panels
    • Rivalry Among Styrene & Urethane Stress Skin Panel Manufacturers
    • Fire safety, R-value, & components of stress-skin structural panels
    • Life Expectancy / Durability of Stress-Skin Insulated Foam Core Panels
    • US FPL study on the durability of stressed skin panels or SIPs
    • Do-it-yourself Home Made Stress Skin Insulated Foam Core Building Panels?
    • Stress Skin Insulated Building Panel Construction Details
    • Stress-Skin Foam Core Building Panel Marketing Tactics
    • Using Stress Skin Insulated Foam Core Panels for Insulated Ceilings
    • List of Producers of Stress Skin Panels for Timber Frame & Structural Insulated Panel Homes
  • Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices
  • Questions & answers about stress skin panel construction: installation, troubleshooting, repairs
  • References

Click to Show or Hide Related Topics

  • ENERGY SAVINGS in buildings - home
  • AFUE DEFINITION, RATINGS
  • AIR BYPASS LEAKS
  • AIR CHANGE RATE ACH HEAT SAVINGS
  • AIR CONDITIONING HEAT PUMP SAVINGS
  • AIR LEAK DETECTION TOOLS - home
  • AIR SEALING STRATEGIES
  • BASEMENT HEAT LOSS
  • BTU USAGE MONITORS
  • CATHEDRAL CEILING INSULATION
  • COOLING LOAD REDUCTION by VENTS
  • DRYER VENTING
  • DUCT SYSTEM & DUCT DEFECTS
  • ENERGY AUDIT - How to Use a Free One
  • ENERGY SAVINGS MAXIMIZE RETURNS ON  
  • ENERGY SAVINGS PRIORITIES
  • ENERGY SAVINGS RETROFIT CASE STUDY
  • ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
  • ENERGY SAVINGS RETROFIT OPTIONS
  • ENERGY STAR PROGRAM
  • ENERGY USE MONITORING, SOLAR
  • EVAPORATIVE COOLING SYSTEMS
  • FRAMING DETAILS for BETTER INSULATION
  • GLASS vs HEAT MIRROR SOLAR GAIN/Loss
  • HEAT LOSS in BUILDINGS - home
  • HEAT LOSS DETECTION TOOLS
  • HEATING COST APPORTIONMENT, BTU MONITORS
  • HEATING COST SAVINGS METHODS
  • HIGH MASS TRADEOFFS, HEATING vs COOLING
  • HOUSE DOCTOR, how-to be
  • INDOOR AIR QUALITY & HOUSE TIGHTNESS
  • INSULATION INSPECTION & IMPROVEMENT
  • INSULATION LOCATION - WHERE TO PUT IT
  • INSULATION R-Values & Properties
  • LOG HOME ENERGY EFFICIENCY
  • RADIANT BARRIERS
  • RADIANT HEAT
  • REFLECTIVE INSULATION
  • RIGID FOAM USE INDOORS
  • ROOF COLOR RECOMMENDATIONS
  • SKYLIGHT ENERGY EFFICIENCY
  • SOLAR ENERGY SYSTEMS
  • THERMAL IMAGING, THERMOGRAPHY
  • THERMAL MASS in buildings
  • THERMAL TRACKING & HEAT LOSS
  • TIMERS for ELECTRIC WATER HEATERS
  • VENTILATION, BALANCED SAVINGS
  • WALL CONSTRUCTION BARRIER vs CAVITY
  • WIND ENERGY SYSTEMS
  • WINDOW EFFICIENCY Features & Ratings
  • WOOD, COAL STOVES & FIREPLACES
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Building with stress-skin insulated panels: this article discusses the use of stress skin insulated structural panels for timber frame and other construction. We describe the history and current uses of stress skin structural panels or SIPs, the properties of SIPs and their fire safety, R-value, and durability or life expectancy. We also give details of how SIPs are constructed, how they are sold, and we list the current manufacturers and sources of stress skin insulated panels (SIPs). Illustration at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.

Stress Skin Panel Construction & SIP Properties

The text below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.

Stress Skin Structural Panels, history, current use practices

Structural Insulated Panel Home - US FPL 1935While stressed-skin insulated panels, currently referred to as SIPs or structural insulated panels have been in use in the U.S. since the 1930's, builders continuously call for more pre-manufactured components.

Home buyers and regulators demand greater energy efficiency in new homes. This was true in 1964 when the U.S. FPS studied the durability of stressed skin panels, it was still true in the 1980's when we looked at the use of stress-skin panels in Solar Age Magazine [September 1986] and it remains true today, more than eighty years since the US FPL began studying SIPs.

Photo (above-left) U.S. Forest Products Laboratory Structural Insulated Panel based prefab houses developed in 1937, built for study and evaluation.

Stress-skin panels are used to wrap around structural timber frames, to sheathe the roofs of cathedral ceilings, and even to build the entire building shell. All of the stress-skin panels for residential construction use similar components. They have polystyrene or polyurethane foam cores and are faced on either side with a "skin" - generally plywood, composition board, OSB, or drywall. But standardization ends there. Beyond the basic material options, stress skin panel products take off in a variety of directions that affect cost, performance, and durability.

Definition of SIPs, Structural Insulated Panels or Stress-Skin Panels

What is an SIP or stressed skin panel or structural insulated panel?

Cross section sketch of SIP wall panel, U.S. FPL

Quoting from the 1960's US FPL study cited later in this article:

Fundamentally, the [stressed skin insulated panel or SIP] system uses panels made of framing members to which plywood sheets or other facing materials are bonded either by glue-nailing or gluing by other types of pressure.

The gluing of these skins causes them and the framing members to act as an integral unit: therefore, under loading, the skins are stressed.

The use of the skins, structurally, allows a reduction in size of the framing material, and the elimination of sheathing and interior finishing materials reduces the weight of the construction considerably.

If it is desirable, the panels may be used only as a structural unit and any type of' exterior or interior finish may be applied.

The sketch of a structural insulated wall panel in cross section shown at left is from the above US FPL study. [Click any image to see an enlarged, detailed version.]

Roof panel SIPs used for roof covering on the 1936 US FPL study homes were nominal 6-Inch thickness units incorporating an air space between the top of the insulation and the underside of the roof deck.

Rivalry Among Styrene & Urethane Stress Skin Panel Manufacturers

Wrapping house with stress-skin panels - Tedd Benson (C) S Bliss D FriedmanBack in 1986 foam panel user and virtuoso timber-framer Tedd Benson characterized the competition between styrene and urethane foam based stress skin insulated panels: "It's a war out there between the styrene and urethane panel manufacturers!" Not quite a war, but the rivalry was and remains hot. The conflicts between competing types of insulating foam in building products in general have focused mostly on

  • fire safety of various foam insulating products
  • aged R-value of different foam insulations
  • long term durability of foam insulation products

The vast majority of the stress-skin insulated panels use polystyrene - commonly called beadboard - for the simple reason that it is much cheaper than urethane foam.

William Porter of W.H. Porter Company, Holland MI, a producer of both types of panels indicated that in the 1980's beadboard-filled stress skin insulated panels were selling 10 to one over urethane foam based panels. Those who want the urethane, said Porter, are looking for higher R-values, "... but don't want to go to a foot-thick stress-skin panel."

Our photo (above, left) from the original Solar Age stress skin panel article illustrates wrapping the house with stress-skin panels with drywall on the interior and OSB on the exterior. If heavy siding is used or the exterior is shingled, the OSB has to be strapped. [Click any image for an enlarged, detailed view.]

Inch for inch, a urethane foam core stress skin panel may cost twice as much as a beadboard panel. But compared by R-value the differences are small, said Amos Winter of the urethane-panel manufacturing firm Winter Panel Corp. in Brattleboro, Vermont.

An average 5 1/2-inch foam core stress skin panel filled with beadboard cost [1980's prices] from $1.75 to $2.20 per square foot, said Winter, compared with $2.20 for a 3 1/2-inch urethane stress skin foam core panel with comparable R-value. Urethane foam offers R-6 to R-7 per inch (according to most sources) compared with beadboard's R-3.8 per inch. How well either product holds its R-value over time is another bone of contention. [See INSULATION R-Values & Properties and POLYSTYRENE FOAM INSULATION and URETHANE FOAM Deterioration, Outgassing for current details.]

Fire Safety of Types of Stress Skin Insulated Structural Panels

Stress skin panel joint voids are filled with urethane foam (C) S Bliss D FriedmanUrethane foam insulated panel loyalists are skeptical of the performance of beadboard insulation in a fire. Said one builder, "I just wouldn't feel safe in a house that would melt in a fire."

The problem, says Amos Winter, "... is that beadboard panels will fail structurally when the foam starts to melt at around 200 degF, whether the panels burn or not." He says that the melted styrene (it flows at around 250 degF) will feed a fire like molten wax from a candle.

Urethane foam burns more like wood, he says. It stays intact until it burns through. Winter believes that a styrene foam insulated panel system is more acceptable if it has fire-stops throughout and full structural supports - for example, a system with full 2-by splines at all panel joints and edges.

Our photo (above, left) from the original Solar Age stress skin panel article illustrates the installer improving the thermal performance of the stress skin panels by filling joints with one-part urethane foam.

Either type of insulated foam panel can be made to comply with the 15-minute thermal-barrier requirement. But the codes were not written [prior to 1986] "... for a system that melts." says Winter.

William Porter, who makes both beadboard and urethane foam core stress skin panels, points out that both will burn at higher temperatures. He feels that the code requirement for 1/2-inch drywall on studs and 1/2-inch wood on ceiling panels is adequate. Using just drywall on a ceiling stress-skin panel is unwise, anyway, says Porter, because the panel could sag if the drywall ever got wet.

Styrene stress-skin foam core panel supporters counter by arguing that melting temperatures [of the foam insulating core] don't occur in walls or roofs under normal conditions or even during small fires. One manufacturer, Enercept in Watertown SD, says that its panel with drywall and waferboard on the interior surface passed the UL "corner test" intact. In that Underwriters Laboratories fire test, a 35-pound wood pile is ignited in a full-scale mock-up building corner. This type of test is challenged by Winter. He says it isn't representative of condition in a real fire because the space is not enclosed.

Longevity / Durability of Stress-Skin Insulated Foam Core Panels

Atlas Industries (Aywer MA, has been making stress skin panels since 1976. (C) S Bliss D FriedmanDiscussions about long-term performance of stress skin panels are equally contentious. Under moist conditions, says Porter, urethane expands slightly as it ages and styrene beadboard contracts. "Too much of either is not desirable," he says.

In a batch of urethane panels produced early on in the 1980's, the foam shrunk and warped the panels, said Winter, who removed and replaced them.

The foam core panel shrinkage problem was solved, he says, by improving the chemistry of the foam insulation. The message is clear: Urethane foam "needs a good cook" to insure good performance.

Our photo (above, left) from the original Solar Age stress skin panel article shows an employee of Atlas Industries, Ayer MA, preparing stress skin foam insulated panels by routing out space to allow spline inserts where panel edges meet. The company has produced stress skin insulated foam core building panels since the mid 1970's.

More important to the durability of stress skin panels is the longevity of the foam core itself and the bond of the foam insulating core to the facing materials of the panel. Many distrust the life expectancy of 1-pound density styrene beadboard, which has a soft, breakable consistency. To get a good bond, the adhesive must penetrate into the beadboard, says Winter. He prefers urethane adhesive with beadboard cores. Urethane, on the other hand, is difficult to bond to because the cells on the surface are cut open "like cracked egg shells".

US FPL study on the durability of stressed skin panels or SIPs

See Stressed Skin Panel Performance After Twenty-Five Years of Service. Quoting from that document's summary, and recognizing that panels, foam insulation, and adhesives have surely improved since the original 1962 study:

Wall panels used in construction of a prefabricated house, built in 1937, were removed in 1962 to determine their performance characteristics after 25 years’ service. The panels were evaluated for stiffness and bending strength, and the glue joints in the plywood and between the plywood and the framing members were evaluated for shear strength. Replacement panels. placed in the prefabricated house in 1962, were evaluated to equivalent design loads of 20 pounds per square foot prior to being placed in the house. Panels of a construction similar to the replacement panels were evaluated to failure.

The panel stiffness evaluations showed that span deflection ratios at design load, both for panels removed after 25 years’ service and for recently fabricated panels, exceeded by several times the normal allowable design values for walls. Failing load also exceeded design values by factors of more than 10.

Evaluations of plywood in shear, after the conventional exterior-type boil-dry cycle test, indicated relatively little change in quality of the glue joints after 25 years’ service. Results of dry shear tests of the casein-glued joints between plywood and the framing members showed little evidence of deterioration.

The panels were designed and maintained to control moisture effects and the entry of water during the 25 years’ service.

Stress Skin Panel Facings & Bonding

Stress skin panels by Northern Energy Homes, pre-cut house packages using polystyrene panels and timber frame (C) S Bliss D FriedmanThere are as many ways to fashion stress-skin foam core building panels as there are manufacturers. With some foam core panels, the urethane is best foamed in place between the sheets, providing its own integral bond between the cured foam insulation and the panel surfaces. More commonly, the plastic foam insulation core is laminated to the sheets of the panel with a contact adhesive or a pressure-set adhesive.

Our photo (left) from the original Solar Age article shows stress skin panels and timber frame components for a completely pre-cut kit house using polystyrene panels and a simplified timber frame system sold by Northern Energy Homes.

"Laminating [foam core insulated building panels] is tricky", says Porter. "If you haven't made a mistake you haven't been in the business long." At one point, he says, his company used an adhesive with a plasticizer that dried up over time and eroded the bond to the stress skin panel. Most glues are sensitive to air temperature and moisture content. They require industrial-type clamping to get good performance.

If laminating is difficult, foaming stress skin panels in place is even more so, says Winter, a veteran urethane foamer. The process is technically complex, chemically volatile, and as much art as science.

Do-it-yourself Home Made Stress Skin Insulated Foam Core Building Panels?

The manufacturers do seem to agree that it's best to avoid home-grown stress-skin insulated building panels - particularly if the panels will bear structural loads. The bond of foam to facing is what transfers the loads to the panel skin and gives the panels their strength.

Stress Skin Insulated Building Panel Construction Details

Best Skin Material for Stress Skin Panels

As for the best skin material for stress-skin foam core panels, there is little agreement. Timber-framer Benson experimented with plywood on the exterior. He says he had problems with the plies delaminating. By the early 1980's he had switched from waferboard panels to Oriented Strand Board (OSB) because it is stronger and holds nails better than the waferboard.

Stress Skin Panel Strapping for Siding

All panel facing materials have to be strapped, he says, to receive heavy sidings, because there are no studs.

Another timber-framing company, Northern Energy Homes [photo above] tried waferboard panels before switching back to plywood skinned panels. The waferboard had a "negative appeal to clients" and the savings in cost over plywood were marginal.

Interior Facings for Stress Skin Foam Core Panels

On the interior face, Northern Energy Homes uses either 3/4-inch T&G Pine or 1/2-inch drywall. The 1/2-inch drywall is backed by 1/4-inch waferboard - there to keep the panels a uniform thickness and to provide a nailbase for interior trim. With just a drywall skin, hanging finish materials such as kitchen cabinets can present a problem. Tedd Benson has 2x4's custom fitted into the kitchen stress-skin wall panels where wall and base cabinets will attach. For lightweight items, he says, molly bolts into the foam work just fine.

Joints, Grooves & Slots in Stress Skin Building Panels

Stress skin foam core panel used to construct a bowed-roof cape: Winter Panel Corp. (C) S Bliss D FriedmanLike most building products, "an insulated stress-skin building panel is only as good as its installation," says Benson. The key is having a good system to attach one panel to another. Most stress-skin panels use some spline system to get continuity between panels.

Our photo (left) from the original Solar Age article illustrates a bowed-roof cape design using structural panels on a home from Winter Panel Corp.

How finicky one must be at the stress skin panel joint is a matter of judgment. A full wood spline - for example, a 2x6 for a nominal 6-inch foam core panel - is the most common treatment at a joint. A full spline nailed through from both faces, and sometimes glued, provides good structural continuity.

But the stress-skin panel joint is a weak link thermally. This will often result in "melt lines" or "frost lines" showing on the roof. Full splines can also lead to cracked drywall joints on the building interior if the wood spline swells during the first winter.

To beef up the stress skin panel joint thermally, many have switched to a double-spline system. This improvement is still vulnerable to thermal, air, and moisture leaks. To bridge the gap thermally, Benson intentionally leaves a 3/8-inch gap in the foam between the splines. The gap is foamed through 1/4-inch holes drilled about every 10 inches from the outside. Northern Energy Homes uses a 1 1/2 x 2-inch foam spline to get thermal continuity. Its panels are slightly beveled, leaving a gap on the outside to be foamed for an airseal.

Special Considerations for Stress-Skin Insulated Panel Roofs

Stress-skin roofs face another nuisance. Sometimes roof shingles refuse to lie flat over the stress-skin panel joints. The cause is attributed to expansion of the waferboard, which buckles the shingles. This problem has also been reported on conventional roofs with waferboard roof sheathing.

One solution, reports Winter, is to seal the waferboard edges with roofing cement and then wet down the roof to "condition" it to its normal moisture content. Some waferboard manufacturers are said to be responding to the problem by preconditioning their panels. Tedd Benson says that his solid foam-to-foam joint seems to prevent this problem, which he blames in part on moisture that escapes and condenses under the shingles.

Stress-Skin Foam Core Building Panel Market Tactics

Stress-skin building panels can't beat the cost of conventional building systems. But they are carving out a niche in the market for low-energy houses. Stress skin should be come more competitive since the costs of labor and materials for conventional buildings are increasing faster. Most would agree that stress-skin panels are used to their best advantage in manufactured and pre-cut panelized housing, where the increased material costs are offset by labor savings and quicker scheduling.

Enercept pre-cuts homes to the customer's plans. The company supplies a complete system through a dealer/contractor network. Enercept's building construction system is frameless with patented wood and metal connectors for wall and roof stress-skin panels. Vertical loads are picked up by thermally broken studs placed in the panels 4-feet on center. Once the foundation is in, an average house shell can be completed in two or three days, says Enercept's Ken Norberg.

Using Stress Skin Insulated Foam Core Panels for Insulated Ceilings

The W.H. Porter Company markets some insulated foam core stress skin panels with a tubular-steel octagonal frame. It's aimed at the recreational and vacation-home market. Most of Porter's panels are sold for roofs of conventional houses, and some for site-built panelized homes. Porter sees great promise for OSB-faced roof stress-skin panels that can san up to 24 feet. "There's no better product," he says, "for cathedral ceiling applications."

Northern Energy Homes supplies completely pre-cut house packages - using styrene core foam panels and a simplified timber frame. "Each piece is pre-engineered and pre-cut for each house," says Northern Energy's Richard Clancy. "This way," he says, "we don't leave our technology up to the contractor." The standard package includes such energy amenities as Heat-Mirror windows, integrated night insulation, and ground water heat pumps.

Other companies garget specialty markets for stress skin insulated building panels. Several pre-fab sunspaces use foam-core stress-skin panels for end-walls and roof sections. Energy Saving Products, a company that specializes in indoor swimming pool equipment, markets stress-skin insulated panels for swimming pool enclosures. The company's Rita Welebob says urethane panels are viewed as a one-step solution to problems caused by rusty nail heads and soggy insulation.

While no figures were available in the 1980's, manufacturers reported rapid growth over the middle of that decade. Enercept's Ken Norberg forecasted growth from 50 to 100 percent per year in stress skin panel use in the mid 1980's.

No one speaks as if stress-skin building panels are panaceas. But arguments and rivalry aside, everyone predicts a bright future for the foam core panel system that can provide structural integrity, exceptional energy performance, and freedom from moisture concerns.

This article is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

In this energy savings article series 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.

List of Producers of Stress Skin Panels for Timber Frame & Structural Insulated Panel Homes

CONTACT us to add stress skin and structural insulated panel SIP producers and experts to this list - no fees.

  • Eagle Panel Systems, Inc., Structural Insulation, Stress Skin Panels, Eagle Panel Systems, Inc. / P.O. Box 247 / Mulberry Grove, IL 62262-0247 sales@eaglepanelsystems.com / Phone: (800) 643-3786
  • Foam Laminates of Vermont, Structural Insulated Panel (SIP) Manufacturer, (800) 545-6290 info@foamlaminates.com
  • Foam-Tech Superinsulation Products, Building Envelope Services, Inc./ FOAM-TECH, PO Box 87, N. Thetford, VT 05054, Tel: 802-333-4333
  • Habitat Post & Beam Wall Systems, Habitat Post & Beam, Inc.• 21 Elm Street, South Deerfield, MA 01373 800.992.0121• www.postandbeam.com • info@postandbeam.com
  • Murus Structural Insulating Panels, The Murus Company, Inc. PO Box 220 3234 Route 549 Mansfield, PA 16933 Tel: 800-626-8787, email: info@murus.com
  • R-Tight Stress Skin Panels, PO Box 700 Jeffersonville, VT 05464-0700, Tel: 802-644-2500, email info@rtight.com
  • Vermont Timber Works, 36 Fairbanks Road N. Springfield, VT 05150 (802) 886-1917

Original article

The link to the original Q&A article in PDF form immediately below is preceded by an expanded/updated online version of this article.

  • Stress Skin Panel Construction part 1 - PDF version, use your browser's back button to return to this page. Original article, Solar Age Magazine, September, 1986, adapted and updated for InspectAPedia.com XXX 2010.
  • Stress Skin Panel - PDF form, part 2, use your browser's back button to return to this page.
  • Stress Skin Panel - PDF form, part 3, use your browser's back button to return to this page.
  • Stress Skin Panel - PDF form, part 4, use your browser's back button to return to this page.

Frequently Asked Questions (FAQs) about Stress Skin Panel construction, troubleshooting, repairs

Question: how is foam inserted into the stress skin box to fill it completely?

I understand that urethane foams are made from a two part process. How are they inserted into a stress skin "box" to get to all areas of the box? - wallspalomar@aol.com 2/27/12

Reply:

Walls: there are other approaches, but most often the plastic foam insulation core is laminated to the sheets of the panel with a contact adhesive or a pressure-set adhesive. Using that approach there are no air voids.

Question: how best to repair damaged stress skin panels

Own a 22 year old home with the stress panels that have T1-11. Our home is three stories and the horizontal decorative board to cover the panel joints was not caulked properly by the painters. Naturally water got behind the board and released water down the T1-11 an we have rot.

Only on one end of the home that gets the brunt of the elements, especially winter in Western NC. How do we fix this rot. Do we cut out the T1-11 if it isn't a large area, do we just cover with all new T1-11 and how to do that.

Winter is fast approaching and we just discovered the damage. It is a post and beam type construction with the SIP panels with T1-11 as the outside covering.

We need help and look forward to hearing from anyone that has had this problem. Is rot common with T1-11 as it ages? The rest of the house is fine. - Richard 9/22/12

Reply:

Richard, I've asked our expert Steve Bliss for comment on the subject of damaged SIPs.

From my own experience, which is more with T-111 type plywood exterior siding than its use on SIPs, if the siding is not kept weatherproofed by a coating (I prefer pigmented stains to paints) and if trim is not properly sealed to keep out water, we can expect to find spots of delamination of the plywood as well as rot behind and around poorly-sealed horizontal trim. Delamination and buckling of the outer skin of the plywood siding seems to occur first where there was already a small flaw, crack, or opening in the outermost ply. Those problems are not unique to plywood siding however.

Steps in exploring for hidden damage in an SIP building

Without having seen the extent of damage on your building, a detailed repair prescription amounts to pretty much wild arm-waving. I think the first order of business is a thorough damage assessment. While there is less of a water path and space within a SIP than a cavity type wood framed wall, water behind the outer ply of T111 invites rot and also insect activity. I'd want to

  • pull off the horizontal trim board on the damaged side of the house
  • explore the damage behind for the extent of water passage and rot
  • If water has penetrated the structure to the interior further inspection and repairs are probably needed
  • If the water leaks have invited carpenter ants into the structure, also further inspection and repairs are probably needed

Repair Ideas for limited-damage SIP stress skin panels on a building wall

If you find very extensive water, insect damage, etc. in the wall you may have to remove and rebuild it. I'm guessing you are going to find this extreme approach is not necessary.

If you do not find evidence of any significant water entry or deeper damage to the structure then you have two plausible approaches, depending on the degree of adhesion of the remaining plywood outer skin to the foam core:

  1. If it is relatively easy to separate the plywood skin from the foam core of the SIP then with a circular saw set to the depth of just the plywood outer skin,
    • Cut a horizontal line across the damaged siding at a point above the highest water or rot damage to the wall, and cut a second line lower on the wall, below the extent of damaged plywood there.
    • Peel away the damaged plywood;
    • insert Z-flashing appropriately positioned up under the bottom lip of the upper remaining plywood as well as over the upper lip of the lower remaining plywood and then piece in replacement plywood in that horizontal band you've cut and peeled away. If you match the color of z-flashing to the stain of the siding it won't be too ugly and this approach is enormously less troublesome than tearing off and rebuilding the wall.
    • Before replacing the horizontal trim, be sure the new trim boards are back primed, sealed on all sides, and sealed well especially along the top edge.

      Note: I've found that it is difficult to seal horizontal trim along grooved exterior siding like T-111 unless you work meticulously to seal every single vertical groove along the top of the tim board; Even the smallest opening in the sealant (caulk) eventually leads to rot or insect damage.
  2. If you find that you cannot remove enough damaged plywood skin from the foam inside the panel, or if the foam itself has become damaged, then set your circular saw deep enough to cut through the panel to just inside the interior skin (building interior side) and
    • remove a horizontal band wide enough to excise all of the damaged material;
    • replace the removed band with solid foam or foamed-in-place foam and a new plywood skin and
    • continue to flash, seal, and trim as I outlined above.

Send us some photos of the conditions you currently face as well as what you find, and we may be able to offer more detailed suggestions.

...

Ask a Question or Search InspectApedia

Use the search box below to ask a question or to search the InspectApedia.com website.

Ask a Question or Enter Search Terms in the InspectApedia search box just below.

Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

  • Solar Age Magazine was the official publication of the American Solar Energy Society. The contemporary solar energy magazine associated with the Society is Solar Today. "Established in 1954, the nonprofit American Solar Energy Society (ASES) is the nation's leading association of solar professionals & advocates. Our mission is to inspire an era of energy innovation and speed the transition to a sustainable energy economy. We advance education, research and policy. Leading for more than 50 years. ASES leads national efforts to increase the use of solar energy, energy efficiency and other sustainable technologies in the U.S. We publish the award-winning SOLAR TODAY magazine, organize and present the ASES National Solar Conference and lead the ASES National Solar Tour – the largest grassroots solar event in the world."
  • Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: info@buildingadvisor.com
    Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
  • CSI Section 06 12 16: Stressed Skin Panels
  • Stressed Skin Panel Performance After Twenty-Five Years of Service, U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison WI, web search 01/22/2011, original source: http://www.fpl.fs.fed.us/documnts/fplrp/fplrp18.pdf
  • Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v1.pdf
  • Passive Solar Design Handbook Volume II, the Passive Solar Handbook Comprehensive Planning Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v2.pdf [This is a large PDF file that can take a while to load]
  • Passive Solar Handbook Volume III, the Passive Solar Handbook Programming Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v3.pdf
  • The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the InspectAPedia Bookstore
  • "Passive Solar Home Design", U.S. Department of Energy, describes using a home's windows, walls, and floors to collect and store solar energy for winter heating and also rejecting solar heat in warm weather.
  • "Solar Water Heaters", U.S. Department of Energy article on solar domestic water heaters to generate domestic hot water in buildings, explains how solar water heaters work. Solar heat for swimming pools is also discussed.
  • "Heat Exchangers for Solar Water Heating Systems", U.S. DOE describes the types of solar water heater heat exchange methods between the sun and the building's hot water supply
  • "Heat-Transfer Fluids for Solar Water Heating Systems", U.S. DOE, describes the types of fluids selected to transfer heat between the solar collector and the hot water in storage tanks in a building. These include air, water, water with glycol antifreeze mixtures (needed when using solar hot water systems in freezing climates), hydrocarbon oils, and refrigerants or silicones for heat transfer.
  • "Solar Water Heating System Maintenance and Repair", U.S. DOE
  • "Solar Water Heating System Freeze Protection", U.S. DOE,using antifreeze mixture in solar water heaters (or other freeze-resistant heat transfer fluids), as well as piping to permit draining the solar collector and piping system.
  • "Scaling and Corrosion in Solar Water Heating Systems", U.S. DOE
  • www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850 is the base U.S. DOE website for these articles
  • "Active Solar Heating Systems", U.S. Department of Energy, including
  • "Radiant Heating Systems" U.S. DOE
  • "Absorption Heat Pumps & Coolers", U.S. DOE
  • "Solar Air Heating" U.S. DOE also referred to as "Ventilation Preheating" in which solar systems use air for absorbing and transferring solar energy or heat to a building
  • "Solar Liquid Heating" U.S. DOE, systems using liquid (typically water) in flat plate solar collectors to collect solar energy in the form of heat for transfer into a building for space heating or hot water heating. The term "solar liquid" is used for accuracy, rather than "solar water" because the water may contain an antifreeze or other chemicals.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

  • Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
  • Home Reference Book - Carson DunlopThe Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

    Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

  • GO TO Carson Dunlop's Home Study Course Information - How to Become a Home Inspector: Carson Dunlop's nationally recognized Home Study Course, selected by ASHI the American Society of Home Inspectors and other professionals and associations. This website author is a contributor to this course.
  • GO TO Carson Dunlop's Home Study Course Information - How to Become a Home Inspector: Carson Dunlop's nationally recognized Home Study Course, selected by ASHI the American Society of Home Inspectors and other professionals and associations. This website author is a contributor to this course.
  • GO TO Carson Dunlop's Home Study Course Information - How to Become a Home Inspector: Carson Dunlop's nationally recognized Home Study Course, selected by ASHI the American Society of Home Inspectors and other professionals and associations. This website author is a contributor to this course.
    Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd
  • Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
    Special Offer
    : Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.

  • Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
  • ...

HOME ABOUT CONTACT COPYING DESCRIPTION POLICIES PRINTING PRIVACY © 2013 Copyright InspectAPedia.com