Avoiding Exterior Envelope Failures with Code-Compliance Northern Michigan Code Officials Association (NMCOA) Winter Training Event Alpine Lodge - Gaylord, Michigan February 23, 2018 Presenter and Class Information: Instructor Name: Brian J. Tognetti, RA, CCCA PA 407 State Instructor Identification Number: #1730 PA 407 State Program Approval Number: #18380 Northern Michigan Code Officials Association Welcome and Introduction • Class Objectives • Identify specific code provisions that apply to exterior envelopes, from below-grade to roof • Explore the technical requirements of these provisions • Discuss and correlate these provisions with applicable design and installation standards • Understand the potential problems of non-compliance by reviewing failure case studies Does code “compliance” mean the exterior envelope will not fail?? Northern Michigan Code Officials Association Exterior Envelope • What is it? • ASTM E 2018: “The enclosure of the building that protects the building’s interior from outside elements, namely the exterior walls, roof and soffit areas.” • 2015 Michigan Building Code: “A system or assembly of exterior wall components…that provides protection of the building structural members, including framing and sheathing materials, and conditioned interior space, from the detrimental effects of the exterior environment.” • 2015 International Energy Conservation Code: “The basement walls, exterior walls, floor, roof, and any other building elements that enclose conditioned space or provide a boundary between conditioned space and exempt or unconditioned space.” Northern Michigan Code Officials Association 1
Exterior Envelope • What is it? • Construction Code Act PA 230: “. . . The elements of a building which enclose conditioned spaces through which thermal energy may be transferred to or from the exterior.” • ANSI/ASHRAE/IESNA 90.1: “The elements of a building that separate conditioned spaces from the exterior.” • NIBS Guideline No. 3: “The exterior enclosure of a building includes all systems separating the interior environment from the exterior, including exterior walls, fenestration, and roofing and roof openings, below grade perimeter walls and the slab- on- grade or crawlspace.” Northern Michigan Code Officials Association Exterior Envelope • What is it? Northern Michigan Code Officials Association Exterior Envelope • Why is it Important? • Envelope as a “Filter” • Controls occupant flow • Allows vision flow • Keeps in: – Vapor, air, heat, cold • Keeps out: – Water, dirt, fire, noise, intruders, insects, air, heat, cold Northern Michigan Code Officials Association 2
Exterior Envelope • Why is it Important? – $$$ Risk, Exposure, Dollars Paid – According to the Insurance Information Institute’s review of U.S. Catastrophe Losses from 1989-2008 (20 yr period): • 81.5% of losses were caused by hurricanes, tropical storms, tornadoes, severe thunderstorms, and winter storms • In 2009, severe thunderstorms and winter storms resulted in over $10 billion in losses • Common Theme = Water related damage Northern Michigan Code Officials Association Exterior Envelope • Specialized Consultants Now. . . • “Facade Consultants, Exterior Consultants, Exterior Envelope Consultants, Exterior Enclosure Consultants, Waterproofing Consultants, Exterior Commissioning Consultants. . .” “Dermatologist” • What is an “Envelope Consultant”? • One who specializes in science regarding the envelope, its structure, functions and problems to skin help keep the envelope healthy. skin Northern Michigan Code Officials Association • Overview Areas of Discussion • Grade • Below Grade Walls and Slabs • Above Grade Walls • Roofs Northern Michigan Code Officials Association 3
Grade • Chapter 18 Soils & Foundations – Relevant portions to mitigate water infiltration: • Section 1803 Geotechnical Investigations • Section 1804 Excavation, Grading, and Fill • Section 1805 Dampproofing and Waterproofing • Section 1809 Shallow Foundations Northern Michigan Code Officials Association Grade • Chapter 18 Soils & Foundations • Section 1803.5.4 Ground-water table : • “ A subsurface soil investigation shall be performed to determine whether the existing ground-water table is above or within 5 feet . . . below the elevation of the lowest floor level where such floor is located below the finished ground level adjacent to the foundation.” • Exception: Not required if waterproofing provided in accordance with Section 1805 ( . . . not dampproofing ) Northern Michigan Code Officials Association Grade • Chapter 18 Soils & Foundations • Section 1804.4 Site grading: • Non-impervious Surfaces. . . • “ The ground immediately adjacent to the foundation shall be sloped away from the building at a slope of not less than one unit vertical in 20 units horizontal (5-percent slope) for a minimum distance of 10 feet . . .” (also a swale alternative) • About 5/8 inch per foot or 6 inch drop after 10 feet • Quick Check: 4 foot level + width of typical cell phone Northern Michigan Code Officials Association 4
Grade • Chapter 18 Soils & Foundations • Section 1804.4 Site grading: • Impervious surfaces (i.e., hardscape) • “Impervious surfaces within 10 feet . . . of the building foundation shall be sloped a minimum of 2 percent away from the building.” • 1/4 inch per foot or 2.5 inch drop after 10 feet • “The procedure used to establish the final ground level adjacent to the foundation shall account for additional settlement of the backfill.” Northern Michigan Code Officials Association Case Study #1 - Flood • Facts and Findings – School; constructed 2006 – Contractor led design-build – September 2008 rain; flooding – Origin; internal courtyards – Civil engineer and contractor intentionally slope to building – Arch detail opposite – Hop-scotching pipe size. . . – Grading sheet “missing”. . . – Portions closed; $200,000+ “Corrective” costs unknown Northern Michigan Code Officials Association Below Grade • Chapter 18 Soils & Foundations • Section 1809.4 Depth & width of footings: • 12 inch minimum depth below undisturbed ground surface • Unless protected from frost, then also ( Section 1809.5 ): – Extend minimum 42 inches below finish grade – Construct per ASCE-32 (Design/Construction of Frost Protected Shallow Foundations) – Build on solid rock Main Exception: Free-standing buildings meeting ALL of the following: Risk category I building (i.e., agriculture, temp buildings, minor storage), 600 SF or less light- frame or 400 SF or less other, Eave height 10 feet or less. Northern Michigan Code Officials Association 5
Below Grade • Chapter 18 Soils & Foundations • Section 1805 Dampproofing and Waterproofing: • Where required: “Walls or portions . . . that retain earth and enclose interior spaces . . . below grade . . . .” (few exceptions) • If no below grade (i.e., slab-on-grade); no requirement • If below grade, need to dampproof or waterproof • Dampproofing vs. Waterproofing – What is the difference? – Examples provided but not defined in code . . . Northern Michigan Code Officials Association Below Grade • NRCA Manual • Dampproofing: “. . . the treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.” • Waterproofing: “. . . the treatment of a surface or structure to prevent the passage of water under hydrostatic pressure .” – Hydrostatic Pressure (62.4 lbs/SF per foot of depth) – Same force is present whether 1/2 inch thick drainage board or swimming pool next to your wall . . . Northern Michigan Code Officials Association Case Study #2 – Soil Pressure • Facts and Findings – 2001 large excavation; new parking structure downtown Detroit – 12 in thick x 250 ft long x 40 ft tall – Winter 2002; concrete wall collapse during construction – Portions displaced 1 foot inboard at top – Flowable backfill in lifts; occurred during third lift (about 20 feet tall) – ½ in thick drainage board on wall back – Analysis: unbraced length of 15 feet max before displacement. . . Northern Michigan Code Officials Association 6
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