durable building envelope ibs 2006 - builders' show€¦ · · 2006-01-04durable building...

Durable Building Envelope

January 14, 2005

11:00 – 12:00 PM

Glen SalasD&R [email protected]

(301) 588-9387

Dana BresHUD, PD&R

[email protected](202) 708-4370 x5919

IBS 2006

2Partnership for Advancing Technology in Housing

About the PATH Program

Partners: Advancing Technology in HousingU.S. Department of Housing and Urban DevelopmentBuilders and RemodelersHomeownersEducators, Researchers, and InsurersManufacturers, Designers, DistributorsTackling institutional barriers to innovationPromoting focused co-operative housing research Providing the latest information on innovative building materials, processes, and systems


The PATH Tech Sets

Resource Efficient

Plumbing

Forced Air System

Durable Building Envelope

Energy Efficient Lighting

Storm Resistant Roofing


Overview

1. What are Tech Sets2. Tech Set #2 - The Durable Building

Envelope3. Tech Set #5 – Storm Resistant Roofing4. Questions and Discussion


PATH TECH SETS Goals for Housing Improvement:

AffordableDurable

Safe to build and live inDisaster resistant.Longer intervals between maintenance work.

Energy EfficientEnvironmental Performance

Air quality and occupant comfortReduced use of natural resources


Why TECH SETS?

Integration of several technologies promotes a systems design approach

Benefits enhanced when certain technologies are used together

Tech Sets answer the what, how, so what, and who cares of technology deployment

Facilitates acceptance of the features rather than fear of the new product or process


DURABLE BUILDING ENVELOPE


Start with Good Design Details

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


Start with Design

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


Passive Solar Design

Thermal heating


What? Precast Concrete Foundation

Foundation is installed on 6” compacted bank-run gravel base

Sub-base continuity beneath slab and wall eliminates need for interior drain tile

Foundation installed by the manufacturer.

Walls cure in plant; foundation can be backfilled as soon as it is braced by basement slab and floor deck.



Foundation is installed by the manufacturer.

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


Courtesy: Superior Walls



How? Precast Concrete Foundation

Bond beam at bottom of wall disperses load –eliminating footingEngineered bond beams and greater cement/water ratio in mix provides strengthExtruded polystyrene foam (XPS) is cast in wall –X-1 wall will meet IRC Energy Efficiencyprovisions through Climate Zone 13 Vertical bond beams provide cavity for additional insulation/mechanicals, pre-drilled wire chases, and drywall attachment surface for simplified interior finishing


Precast Concrete Foundation So What?

Resource efficient - precast wall uses less concrete and more insulation than CMU or poured-in-place concrete

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

Site safety is enhancedExcavation is open for a shorter period Walls are set with a crane - fewer workers required in the excavation


Precast Concrete Foundation Who Cares?

IRC recognizes “approved” precastassemblies on gravel baseLocal approval on case-by-case basisFoundation plans can be certified by the manufacturer’s engineerCustomized product - Brickledges and porch haunches, openings for doors, windows, stairs and beam pockets must be specified at order placement


What? Redundant Barriers

Redundant BarriersUse building wrap or “weather resistant barrier” (WRB)Use mechanical flashings at all openings and plane abutments

Counter flashingHead flashingTrims and windows with integral “J”

Air seal inside and outCovered (roofed) door openings


How? Redundant Barriers

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


What? Advanced Framing Techniques

Minimize structural members without compromising load bearing capacity of the structureAlso referred to as Optimum Value Engineering - OVE


How? Advanced Framing Techniques

Design for modular layout 2’ modulesDoor and window openings at (24”) spacing distances from corners, each other

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


How? Advanced Framing Techniques

Right size headers by (wood) species and load, orInstall insulated or boxed headers on exterior bearing wallsEliminate headers at non-bearing openings.Install wood interior walls on 24”center spacing with single top plates.Ladder frame at perpendicular wall intersectionsMinimize wood in outside cornersDevelop framing plans to accompany architecturals and bill of materials so material is properly used. Order components and precuts where cost effective


Advanced Framing TechniquesSo What?

Good design and implementation can save 3-5% in framing package cost and streamline labor inputsEliminating redundant structural materials on exterior surfaces also eliminates thermal bridges and provides greater surface area for insulationEliminating excess material saves natural resourcesWider floor spacing provides larger bays for mechanical system layoutEfficient take-off and use means less waste and lower disposal fees


Tin Can Siding

Rubber Tire Building Envelope

Building EnvelopeSure, there are alternatives….

Check PATHnet for the details


Tech Set #3HVAC: Forced Air System

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.


Energy-Efficient LightingA Personal Favorite: Tubular skylights

AKA – Solar Tubes


Storm Resistant Roofing1) Moderately pitched (4/12 to 6/12) hips rather than gables2) Baffled ridge and soffit vents minimize the number of roof penetrations3) Fascia Board extended below underside of soffit4) Grid-marked sheathing5) OVE structural members

6) Light-colored wind and impact resistant roof shingles7) Tape OSB seams with a self-adhering bitumen tape

8) Proper underlayment9) Valley, junction, and pipe penetration flashing

10) Proper fastener/nailing schedules11) Hurricane straps tied to load bearing components


Storm Resistant Roofing

Basis:The roof should act like a good umbrella

The worst of the weather stays beyond the drip line Does not fold when the wind gusts.

These recommendations will improve:Durability of the roof and building envelopeOccupant safety and disaster mitigationAffordability


What? Moderately pitched hips

Hips rather than gablesModerately pitched - 4/12 to 6/12 in areas where high winds are likely.

Flatter roofs withstand strong winds better than steep roofs.


What? Baffled ridge and soffit vents

Minimize the number of roof penetrationsBaffled ridge vents are preferred : they prevent airflow and wind driven rain from entering the attic through the ridge vent.

If added daylighting is desired, specify tubular skylights with polycarbonate domes.


Tubular skylights

AKA – Solar Tubes


What? Extended Fascia Boards

Minimize the number of roof penetrationsBaffled ridge vents are preferred : they prevent airflow and wind driven rain from entering the attic through the ridge vent.

If added daylighting is desired, specify tubular skylights with polycarbonate domes.


What? Grid-Marked Sheathing

4’x 8’ sheets installed like any other roof sheathingPerpendicular to the framing componentsGappedsupported with “H” clips at mid-span between trussesspaced at 24” on center

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


What? OVE Structural Members

Roof truss components and engineered wood girdersEngineered structural components save lumber resources because

typically spaced on 24” centerfabricated with small dimension lumber – 2x4 and 2x6

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


What? The Right Roofing

Light-colored wind and impact resistant shinglesConsider the solar reflectance of the roof cladding and select light colors n warm climates

The higher the reflectance factor, the less heat absorbed by theroof from the sun. Cladding products that carry ENERGY STAR® reflectance ratings can be researched at the website for reflective roof products.


What? Proper Underlayment

Tape OSB seams with a self-adhering bitumen tape

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

Proper underlayment installed per manufacturers’specifications with approved fasteners.

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. Underlayment rows should overlap at least 4”


What? Proper Flashing

Valley, junction, and pipe penetration flashing: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 schedulesPay specific attention to this detail - change with product and wind zoneEnsure 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.


What? Hurricane Straps

Transfer loads from the gable truss/frame wall to the end wall below.

Ensure complete load paths at these pointsInstall 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.


PATH is…

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

PATH works to add value to housingaffordabilityenergy efficiencyenvironmental impactqualitydurability and maintenancehazard mitigationsafety


PATH Partners

Federal AgenciesUniversities & ResearchersProduct

ManufacturersHomebuilders & DevelopersHousing

Institutions & Professionals Homeowners


Technology Pipeline

Research

Technology Development

Demonstration & Dissemination

Barrier Removal

Market Acceptance

Goal: Cut time-to-market for promising new technologies and procedures by half.


Partners in Innovation

PATH’s goal: making quality, affordable housing a reality

Energy EfficiencyEnvironmental PerformanceDurabilityDisaster ResistanceSafety

PATH acts as a catalyst for innovation in the homebuilding industry.

42

PATH ActivitiesTechnology Demonstrations

Barrier Removal Field

Evaluations

Research & Development

43

PATH Demonstration Sites


Separating the Wheat & the Chaff

Literature from product manufacturers may not provide the whole picture.


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

www.pathnet.org


First Stop: www.PATHnet.org


Questions?

durable building envelope ibs 2006 - builders' show€¦ · · 2006-01-04durable building...

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