Durable Building Envelope

Durable Building Envelope IBS 2006 11:00 – 12:00 PM January 14, 2005 Dana Bres HUD, PD&R [email protected] (202) 708-4370 x5919 Glen Salas D&R I...
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Durable Building Envelope IBS 2006 11:00 – 12:00 PM

January 14, 2005 Dana Bres HUD, PD&R [email protected] (202) 708-4370 x5919

Glen Salas D&R International [email protected] (301) 588-9387

About the PATH Program ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ

Partners: Advancing Technology in Housing U.S. Department of Housing and Urban Development Builders and Remodelers Homeowners Educators, Researchers, and Insurers Manufacturers, Designers, Distributors Tackling institutional barriers to innovation Promoting focused co-operative housing research Providing the latest information on innovative building materials, processes, and systems

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The PATH Tech Sets Storm Resistant Roofing

Durable Building Envelope

Forced Air System Energy Efficient Lighting

Partnership for Advancing Technology in Housing

Resource Efficient Plumbing

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Overview 1. What are Tech Sets 2. Tech Set #2 - The Durable Building Envelope 3. Tech Set #5 – Storm Resistant Roofing 4. Questions and Discussion

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PATH TECH SETS Goals for Housing Improvement: „ Affordable „ Durable ƒ Safe to build and live in ƒ Disaster resistant. ƒ Longer intervals between maintenance work.

„ Energy Efficient „ Environmental Performance ¾ Air quality and occupant comfort ¾ Reduced use of natural resources

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Why TECH SETS? ƒ Integration of several technologies promotes a systems design approach ¾Benefits enhanced when certain technologies are used together

ƒ Tech Sets answer the what, how, so what, and who cares of technology deployment ¾Facilitates acceptance of the features rather than fear of the new product or process Partnership for Advancing Technology in Housing

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DURABLE BUILDING ENVELOPE

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Start with Good Design Details ƒ Site house to benefit from passive solar exposure for winter warming and prevailing breezes for summer cooling ƒ Overhangs should be sized to provide summer shading ƒ Cover door openings with roofs and porches ƒ Detail building and material interfaces with redundant barriers

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Start with Design Take advantage of the sun (and keep the rain off your walls and windows)

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Passive Solar Design Thermal heating

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What? Precast Concrete Foundation ƒ Foundation is installed on 6” compacted bank-run gravel base ƒ Sub-base continuity beneath slab and wall eliminates need for interior drain tile ƒ Foundation installed by the manufacturer. ƒ Walls cure in plant; foundation can be backfilled as soon as it is braced by basement slab and floor deck.

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What? Precast Concrete Foundation Foundation is installed by the manufacturer.

Manufactured under qualitycontrolled factory conditions, and ready in a fraction of the time needed for a poured foundation

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What? Precast Concrete Foundation

Courtesy: Superior Walls

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How? Precast Concrete Foundation ƒ Bond beam at bottom of wall disperses load – eliminating footing ƒ Engineered bond beams and greater cement/water ratio in mix provides strength ƒ Extruded polystyrene foam (XPS) is cast in wall – X-1 wall will meet IRC Energy Efficiency provisions through Climate Zone 13 ƒ Vertical bond beams provide cavity for additional insulation/mechanicals, pre-drilled wire chases, and drywall attachment surface for simplified interior finishing

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Precast Concrete Foundation So What? ƒ Resource efficient - precast wall uses less concrete and more insulation than CMU or poured-in-place concrete ƒ Controlled factory environment eliminates variation in mix or conditions that can be found in the field – no cold joints, form tie voids, or grout joints to allow moisture seepage ƒ Site safety is enhanced ¾ Excavation is open for a shorter period ¾ Walls are set with a crane - fewer workers required in the excavation

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Precast Concrete Foundation Who Cares? ƒ IRC recognizes “approved” precast assemblies on gravel base ƒ Local approval on case-by-case basis ƒ Foundation plans can be certified by the manufacturer’s engineer ƒ Customized product - Brickledges and porch haunches, openings for doors, windows, stairs and beam pockets must be specified at order placement

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What? Redundant Barriers Redundant Barriers ¾ Use building wrap or “weather resistant barrier” (WRB) ¾ Use mechanical flashings at all openings and plane abutments ¾ Counter flashing ¾ Head flashing ¾ Trims and windows with integral “J”

¾ Air seal inside and out ¾ Covered (roofed) door openings

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How? Redundant Barriers ƒ Sill seal at platform irregularities; air seal platform junctions ƒ Install housewrap or weather resistant barrier (WRB) over wall sheathing from bottom up, overlapped and taped ƒ Flashings at windows, doors, corners, and building/material interfaces ƒ “J” trim provides drainage channel at junction of dissimilar cladding materials ƒ Protect roof eave and overhang edges from ice dams and wind-driven rain with an adhesive membrane and drip edge trim

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What? Advanced Framing Techniques ƒ Minimize structural members without compromising load bearing capacity of the structure ƒ Also referred to as Optimum Value Engineering - OVE

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How? Advanced Framing Techniques ƒ Design for modular layout ƒ 2’ modules ƒ Door and window openings at (24”) spacing distances from corners, each other

ƒ Install exterior wall studs on 24” center spacing. ƒ Install floor and roof components on 24” center spacing.

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How? Advanced Framing Techniques ƒ ƒ ƒ ƒ ƒ ƒ ƒ

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Right size headers by (wood) species and load, or Install insulated or boxed headers on exterior bearing walls Eliminate headers at nonbearing openings. Install wood interior walls on 24” center spacing with single top plates. Ladder frame at perpendicular wall intersections Minimize wood in outside corners Develop framing plans to accompany architecturals and bill of materials so material is properly used. Order components and precuts where cost effective Partnership for Advancing Technology in Housing

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Advanced Framing Techniques So What? ƒ Good design and implementation can save 3-5% in framing package cost and streamline labor inputs ƒ Eliminating redundant structural materials on exterior surfaces also eliminates thermal bridges and provides greater surface area for insulation ƒ Eliminating excess material saves natural resources ƒ Wider floor spacing provides larger bays for mechanical system layout ƒ Efficient take-off and use means less waste and lower disposal fees Partnership for Advancing Technology in Housing

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Building Envelope Sure, there are alternatives…. Rubber Tire Building Envelope

Tin Can Siding

Check PATHnet for the details Partnership for Advancing Technology in Housing

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Tech Set #3 HVAC: Forced Air System ƒ To decrease the cost of construction, maintenance and energy efficiency of housing by promoting effective systems integration of the conditioned air delivery network into the structural framework.

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Energy-Efficient Lighting A Personal Favorite: Tubular skylights ƒ AKA – Solar Tubes

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Storm Resistant Roofing 1) Moderately pitched (4/12 to 6/12) hips rather than gables 2) Baffled ridge and soffit vents minimize the number of roof penetrations 3) Fascia Board extended below underside of soffit 4) Grid-marked sheathing 5) OVE structural members 6) Light-colored wind and impact resistant roof shingles 7) Tape OSB seams with a self-adhering bitumen tape

10) Proper fastener/nailing schedules 8) Proper underlayment 11) Hurricane straps tied to load bearing 9) Valley, junction, and pipe components penetration flashing Partnership for Advancing Technology in Housing

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Storm Resistant Roofing Basis: ƒ The roof should act like a good umbrella ƒ The worst of the weather stays beyond the drip line ƒ Does not fold when the wind gusts.

ƒ These recommendations will improve: ƒ Durability of the roof and building envelope ƒ Occupant safety and disaster mitigation ƒ Affordability

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What? Moderately pitched hips Hips rather than gables ƒ Moderately pitched - 4/12 to 6/12 in areas where high winds are likely. Flatter roofs withstand strong winds better than steep roofs.

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What? Baffled ridge and soffit vents Minimize the number of roof penetrations ƒ Baffled ridge vents are preferred : they prevent airflow and wind driven rain from entering the attic through the ridge vent. ƒ If added daylighting is desired, specify tubular skylights with polycarbonate domes.

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Tubular skylights ƒ AKA – Solar Tubes

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What? Extended Fascia Boards Minimize the number of roof penetrations ƒ Baffled ridge vents are preferred : they prevent airflow and wind driven rain from entering the attic through the ridge vent. ƒ If added daylighting is desired, specify tubular skylights with polycarbonate domes.

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What? Grid-Marked Sheathing 4’x 8’ sheets installed like any other roof sheathing ƒ ƒ ƒ ƒ

Perpendicular to the framing components Gapped supported with “H” clips at mid-span between trusses spaced at 24” on center

Grid marks facilitate cutting the sheets, using the correct fastening schedule, and the layout of shingle underlayment.

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What? OVE Structural Members Roof truss components and engineered wood girders ƒ Engineered structural components save lumber resources because ƒ typically spaced on 24” center ƒ fabricated with small dimension lumber – 2x4 and 2x6

ƒ Shape usually more conducive than solid sawn lumber rafters to accept continuous insulation for building envelope energy efficiency .

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What? The Right Roofing Light-colored wind and impact resistant shingles ƒ Consider the solar reflectance of the roof cladding and select light colors n warm climates ƒ The higher the reflectance factor, the less heat absorbed by the roof from the sun. ƒ Cladding products that carry ENERGY STAR® reflectance ratings can be researched at the website for reflective roof products.

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What? Proper Underlayment Tape OSB seams with a self-adhering bitumen tape ƒ Roof coverings and underlayment can blow off in high winds: sheathing can act as a water and wind barrier if the seams have been taped with a self-adhering bitumen tape ƒ Proper underlayment installed per manufacturers’ specifications with approved fasteners. ƒ Roofs with a slope of less than 4/12 require two layers of approved 15# felt underlayment or a continuous ice and water barrier underlayment. ƒ Underlayment rows should overlap at least 4”

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What? Proper Flashing Valley, junction, and pipe penetration flashing: ƒ ƒ ƒ ƒ ƒ ƒ

Installed wherever there is a change in surface plane or cladding material. Serves dual purpose of channeling water runoff during storm events and providing a second level of water intrusion protection. Roof edges should be flashed with a shingle starter strip or a self-adhering ice and water barrier. Apply a drip edge to all roof edges (including rake). Asphalt and fiberglass shingles should overlap the drip edge strip by at least ½” to ¾”. Meticulously follow building code and roof cladding manufacturers instructions.

Proper fastener/nailing schedules ƒ ƒ ƒ

Pay specific attention to this detail - change with product and wind zone Ensure that fasteners are installed to the proper embedment depth into framing members or sheathing - be aware of the depth that you set your automatic tools. Follow manufacturers specifications. Increasing the frequency of fasteners from four to six per shingle increases wind rating. Partnership for Advancing Technology in Housing

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What? Hurricane Straps

Transfer loads from the gable truss/frame wall to the end wall below. Ensure complete load paths at these points Install metal straps rated for a minimum tensile load of 770 pounds at each lateral brace. Install wall sheathing so that it overlaps the connection between the end wall and gable truss/frame by at least 12 inches.

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PATH is… …a public-private partnership that works to speed the development and adoption of advanced building technologies.

PATH works to add value to housing ƒ ƒ ƒ ƒ ƒ ƒ ƒ

affordability energy efficiency environmental impact quality durability and maintenance hazard mitigation safety Partnership for Advancing Technology in Housing

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PATH Partners Federal Agencies Universities & Researchers

Product Manufacturers Housing Institutions & Professionals

Homebuilders & Developers Homeowners

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Technology Pipeline Research Technology Development Demonstration & Dissemination Barrier Removal Market Acceptance Goal: Cut time-to-market for promising new technologies and procedures by half. Partnership for Advancing Technology in Housing

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Partners in Innovation ƒ PATH’s goal: making quality, affordable housing a reality ƒ ƒ ƒ ƒ ƒ

Energy Efficiency Environmental Performance Durability Disaster Resistance Safety

ƒ PATH acts as a catalyst for innovation in the homebuilding industry. Partnership for Advancing Technology in Housing

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PATH Activities Technology Demonstrations

Research & Development Barrier Removal

Field Evaluations

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PATH Demonstration Sites

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Separating the Wheat & the Chaff

Literature from product manufacturers may not provide the whole picture.

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To learn more about the Tech Sets and other PATH resources, please visit our Web site: www.pathnet.org

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First Stop: www.PATHnet.org

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Questions?

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