Avoiding Exterior Envelope Failures with Code-Compliance Northern - - PDF document

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Northern Michigan Code Officials Association

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.”

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Northern Michigan Code Officials Association

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-

• n-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

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Northern Michigan Code Officials Association

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. . .”
• What is an “Envelope Consultant”?
• One who specializes in science regarding the

envelope, its structure, functions and problems to help keep the envelope healthy.

• “Dermatologist”

skin skin

Northern Michigan Code Officials Association

Overview Areas of Discussion

• Grade
• Below Grade Walls and Slabs
• Above Grade Walls
• Roofs

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Northern Michigan Code Officials Association

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

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Northern Michigan Code Officials Association

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

• f 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.

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Northern Michigan Code Officials Association

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. . .

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Northern Michigan Code Officials Association

Below Grade

• If Dampproofing Required:
• Section 1805.2.1 Floors: “Dampproofing materials for floors

shall be installed between the floor and the base course . . . “ (unless mud-slab provided)

• This is “code language” for under slab vapor retarder
• Since dampproofing is only required if you have below grade

interior spaces that retain earth, an under slab vapor retarder is not required by Chapter 18 beneath slab-on-grades for above grade structures; caution consult Section 1907 . . .

• Selected flooring may dictate providing one. . .

– No ‘easy’ or ‘economical’ fix if need to add after built . . .

• Section 1805.2.2 Walls: Apply to exterior and extend from

top of footing to above grade (pretty bare bones. . .)

Northern Michigan Code Officials Association

Below Grade

• Under-Slab Vapor Retarders:
• Excellent Industry Reference: ACI 302.2R-06 Guide for

Concrete Slabs that Receive Moisture-Sensitive Flooring Materials

• If vapor retarder necessary, do you place on top of sub-base,

under sub-base, or within sub-base?

• ACI recognizes challenges of either scenario:

– On top = increase potential for slab curling – Under/within = increase for water reservoir and floor problems

• Recognize these challenges and address accordingly in

design and installation procedures.

• A critical decision involves sequence of construction. . .

Northern Michigan Code Officials Association

Below Grade

• ACI Figure 7.1

– If moisture sensitive flooring present, when will watertight roof be installed relative to sub-base and concrete placement? – Question is not “do I need one” it is “where do I put it”. . .

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Northern Michigan Code Officials Association

Case Study #3 – Flooring Failure

• Facts and Findings

– Hospital operating room suite Michigan west side; built in 2005 – Resilient sheet flooring; supported slab – Occupied April 06; problems Nov 06 – Rutting and blistering – Appropriate MVER tests were done; appropriate results achieved (<3 lbs) – Flooring adhesive “fluid”; deteriorated hydrolysis reaction (alkalinity + moisture) – Over 90% RH in slab in Feb 08 – “Water-based” acrylic adhesive (green) . . .

Northern Michigan Code Officials Association

Below Grade

• If Waterproofing Provided:
• Section 1805.3.1 Floors: Must be concrete and

designed/constructed to withstand the hydrostatic pressure with waterproofing materials placed under the slab.

• Section 1805.3.2 Walls: Must be concrete or masonry and

designed/constructed to withstand the hydrostatic pressure.

– Only required from bottom of wall to minimum of 12 inches above maximum elevation of ground-water table (bare bones approach requiring a bit of “scientific guess-timation”) – Remainder of wall height can be dampproofed

• My recommendation – waterproof whenever the budget will

allow; if the budget will not allow . . . add to the budget or cut

• ut the granite countertops instead

Northern Michigan Code Officials Association

Below Grade

• Is a perimeter drain required?
• The code uses terms like “ground water control system”

(Section1805.1.3), “subsoil drainage system” (Section 1805.4), and “foundation drain” (Section 1805.4.2)

• In summary:

– Dampproofing required = perimeter drain required – Waterproofing provided = perimeter drain not required (However, providing a perimeter drain is relatively ‘cheap’ redundancy vs. water infiltration since you have to dig the hole and backfill it anyway . . .)

• The provided ‘perimeter drain’ does not have to be a

traditional ‘drain tile pipe’ system but could be an engineered assembly of permeable materials – left open for designer . . .

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant to exterior walls

– Fire-Resistance

• By far, code targets “interior” construction regarding fire-

resistance but some aspects apply to exterior walls:

– Primary Provisions: » Chapter 5 Heights and Areas (Dictates Construction Type) and Mixed Use Criteria (Separated vs. Non-separated mixed uses) » Chapter 6 Type of Construction (Table 601) and Separation Distance (Table 602) – Secondary Provisions: » Unique hazard conditions in Chapter 4 » Conditions due to building configuration in Chapters 7, 9 and 10 » Claddings comprised of combustible materials in Chapter 14 » Exterior wall covering utilizing plastics in Chapter 26

Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant for exterior walls

– Ventilation

• Chapter 12 Interior Environment

– Section 1203 Ventilation: “Buildings shall be provided with natural . . .

• r mechanical ventilation . . . .” But if dwelling unit air infiltration rate is

less than 5 ACH, must provide mechanical to dwelling unit per MMC. – If natural ventilation option provided, Section 1203.5 requires: » It be provided via windows, doors, louvers or other openings » Operating mechanisms be readily accessible and openable » Minimum openable area be 4 percent of floor area served – If mechanical ventilation option provided, comply with MMC – Depending on building configuration, may need to address ‘openings’ in envelope due to required ventilation of enclosed attic spaces or under- floor crawl spaces.

Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant for exterior walls

– Attics

• Section 1203.2: Traditional vented attic space

– Provide net free ventilating area not less than 1/150 of SF of attic – Maintain 1 inch airspace at pinchpoint of insulation and roof sheathing – Exception for 1/300 ratio if ALL the following: » 40%-50% of net free ventilating area is provided within 3 feet of highest point (i.e., ridge) with balance by eave or cornice vents. Exception to 3 foot rule if obstructions present. » If Climate Zone 6, 7 or 8, also need a Class I or II vapor retarder installed on warm-in-winter side of ceiling (attic floor).

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant for exterior walls

– Attics

• Section 1203.3: Unvented attics and rafter spaces

– Allowed provided all of the following are met: » Unvented space is completely within the thermal ‘bubble’ » No Class I vapor retarder on attic floor or ceiling rafter underside » If wood shingles/shakes, ¼ inch vented space provided under shingles/shakes » In Climate Zones 6 thru 8 (Michigan 5A, 6A & 7), air- impermeable insulation must be Class II vapor retarder or underside of insulation shall be treated with Class II vapor retarder coating or covering » Four possible solutions, must comply with option selected: 1) air- impermeable, 2) air-permeable, 3) combination air- impermeable + air-permeable, or 4) rigid board on sheathing

Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant for exterior walls

– Components and Cladding

• Chapter 14 Exterior Walls and Chapter 16 Structural Design
• Typical loads imposed on Exterior Walls

– Live and Dead Loads – Snow, Rain, Wind, and Seismic – Deflections: Short-term (wind) and Long-Term (creep) – Other Unique Loads due to Location or Use

Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant for exterior walls

– Components and Cladding

• ASCE 7-10 Minimum Design Loads for

Buildings and Other Structures

• Chapter 6 Wind Loads

– Three Design Methods available: » Method 1 – Simplified Procedure » Method 2 – Analytical Procedure » Method 3 – Wind Tunnel Procedure Use caution if selecting Method 1 (simplified) as it is limited to very specific criteria

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 1)

• Chapters relevant for exterior walls

– Components and Cladding

• Cladding Specific:

– Chapter 14 Exterior Walls specifically requires compliance with TMS 402/ACI 530/ASCE 5-2013 for “Anchored” and “Adhered” masonry veneers – Numerous other Cladding-Specific resources available, such as: » Indiana Limestone Institute (ILI) » Marble Institute of America (MIA) » Brick Industry Association (BIA) » Cast Stone Institute (CSI) » Glass Association of North America (GANA) » Sheet Metal and Air Conditioning Contractor’s National Association (SMACNA) – Other resources, such as these, help establish ‘standard of care’. . .

Northern Michigan Code Officials Association

Case Study #4 – Cladding Replacement

• Facts and Findings

– High-rise built in 1972; was tallest marble-clad building – 44,000 +/- white Carrara marble panels – Mid-1980s; cracking/bowing; WJE extensive investigation . . . – 40%+/- loss of strength; 16 years – Accelerated weathering testing; 70% loss after 26 years – Completely re-clad in new granite; tallest granite-clad bldg in world – Over 6 years and $100 million . . .

Northern Michigan Code Officials Association

• Short Break -

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Water Management
• Relative to claims, liability, and litigation, this is the . . .

“800 pound Gorilla in the room”

• Think of it this way: People aren’t suing because their

conference room is too small, or they feel their building is aesthetically “sub-par”, or their space adjacencies are not ideal . . .

• 80:20 Rule – 80% of your liability as a designer/constructor

comes from 20% (typically less) of the cost of the building; the exterior envelope

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Effective infiltration resistance

addresses:

• Kinetic Energy: dynamic action (i.e., wind)

– “Blow in”

• Gravity: direction of natural water flow; head of pressure

– “Flow in”

• Capillary Action: Surface tension of fluid to solid

– “Climb in”

• Differential Pressure: Suction; lower interior pressure

– “Suck in”

• Diffusion: migration through materials

– “Hocus-Pocus in”

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Methods of water infiltration?
• Flow as liquid bulk water
• Transport via air leakage
• Migrate via vapor diffusion
• Prior codes really only addressed “bulk” water flow with the

exception of limited verbiage for under-slab vapor retarders (addressing vapor diffusion beneath slabs)

What about vapor diffusion elsewhere??? What about air leakage???

“Bulk Water”

“Air Leakage”

“Vapor Diffusion”

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Vapor/Air Leakage Management
• Vapor management addressed in 2006 residential and

international energy codes (definitions + placement) – Residential: Section R318 in MRC – Commercial: Until 2009 code adopted. . .no req in Mich; now Section 1405.3 Vapor retarders (classes, etc.)

• Limited air leakage info in 2006 energy code and ASHRAE

– Residential: Section N1102.1.10 Air leakage in MUEC – Commercial: Section 5.4.3 Air Leakage in ASHRAE » “The following areas of the building envelope shall be sealed, caulked, gasketed, or weather-stripped to minimize air leakage. . .” – Emphasis changing in later IECCs; all about ‘air’ now

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1405.3 Vapor retarders
• In Climate Zones 5 thru 8 (Michigan), Class I (perm < 0.1) or

II (perm > 0.1 < 1.0) shall be provided on the interior side of frame walls, except: – Basement walls or below grade postions of any wall. – Any walls where moisture or its freezing will not damage the materials (i.e., concrete or masonry – no finishes???)

• Can use Class III for certain ‘vented cladding’ or ‘insulated

sheathing’ as prescribed in Table 1405.3.2 – Class III (perm >1.0 < 10) ok when insulating sheathing

• f Class I or II present (i.e., sheathing meeting ASHRAE

‘ci’ req or sheathing with 2.0 lb/pcf SPF meeting ‘ci’ R- value and applied to interior side of sheathing)

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Bulk Water Management
• Chapter 14 Exterior Walls

– Section 1403.2 Weather protection (general req’s) – Section 1404.2 Water-resistive barrier – Section 1405.2 Weather protection (material types & min thicknesses) – Section 1405.4 Flashing – Section 1405.11.2 Weather protection (specific to metal veneers) – Section 1405.12.7 Flashing (specific to glass veneer)

• Other relevant Cladding-Specific provisions:

– Chapter 19 Concrete (i.e., durability and vapor retarder req’s) – Chapter 21 Masonry (i.e., lots of info, material, corrosion, const req’s) – Chapter 23 Wood (i.e., protection against decay and termites) – Chapter 24 Glass and Glazing (i.e., loads, deflection, sloped, safety) – Chapter 25 Gypsum Board and Plaster (i.e., exterior plaster req’s) – Chapter 26 Plastic (i.e., use, height, location, extent limitations)

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1403.2 Weather Protection
• “Exterior walls shall provide the building with a weather-

resistant exterior wall envelope.”

• “The exterior wall envelope shall include flashing, as

described in Section 1405.4.”

• “The exterior wall envelope shall be designed and

constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1404.2, and a means for draining water that enters the assembly to the exterior.”

• “Protection against condensation in the exterior wall

assembly shall be provided in accordance with Section 1405.3 (vapor retarders).”

#1 #2 #3 #4

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1403.2 Weather Protection
• Currently only Three Exceptions to the Rule . . .

– Exception No. 1: “A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls. . .” » This exception ‘permits’ the use of single-wythe masonry walls and concrete walls. » This exception can be interpreted to misconstrue the water management effectiveness of single-wythe masonry walls (i.e., not equivalent to solid concrete) » Single-wythe masonry walls are notorious for poor water management & resulting water infiltration

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1403.2 Weather Protection
• Exception No. 1 - IBC Commentary stated reasoning for

allowing this [single-wythe walls] . . . – “This is because the penetration of moisture behind the exterior wall finish is not detrimental to concrete and masonry substrates” – The above statement is true until you apply an interior finish to the single-wythe masonry wall (i.e., paint, furring with gypsum board or paneling, etc. . .) Basically, if you’re ok with periods of dampness and water flowing down the interior surface of your exterior wall – then go ahead . . . the code allows it.

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Northern Michigan Code Officials Association

Case Study #5 – Water Infiltration

• Facts and Findings

– 1881 barn; relocated and renovated to residence in 2006 – First contractor dismissed; second contractor troubles. . . – Lots of issues; one related to single-wythe CMU silo (stair) – No WRB req’d by code over CMU – Water test leaking extensive and immediate through CMU – Don’t solely rely on single-wythe masonry water infiltration resistance . . .

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1403.2 Weather Protection
• Currently only Three Exceptions to the Rule . . .

– Exception No. 2: Applies to any other wall assembly besides masonry or concrete » “Compliance with the requirements for a means of drainage, and the requirements of Sections 1404.2 [water-resistive barrier] and 1405.4 [flashing], shall not be required for an exterior wall envelope that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E 331 under the following conditions . . .”

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1403.2 Weather Protection
• Exception No. 2 Test Conditions (ASTM E 331)

– Test must include at least one opening, control joint, wall/eave interface (???), and wall sill – Test area shall be at least 4 feet by 8 feet in size – Test pressure differential of 6.24 psf » Equivalent to lifting water 1.2 inches or » Hydrostatic head resulting from 1.2 inch water depth – Test duration of 2 hours per test

• If ‘Pass’ no drainage, flashing, or WRB req’d.
• Exception No. 3: If wall cladding is ‘EIFS with drainage’ per

Section 1408.4.1

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• ASTM E 331

– Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference – This is NOT the appropriate test!!! – IBC Commentary states: “The test is not necessarily intended to test the performance of the penetrating item.”

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• If not ASTM E 331,

then what???

• ASTM E 1105

– Standard Test Method for Field Determination of Water Penetration

• f Installed Exterior Windows,

Skylights, Doors, and Curtain Walls, by Uniform or Cyclic Static Air Pressure Difference

Northern Michigan Code Officials Association

Case Study #6 – Forgot WRB?

• Facts and Findings

– Two-story commercial office bldg – 95% brick complete; project stopped due to lack of WRB over sheathing – Sheathing manufacturer stating: “No WRB necessary, just treat joints” – Jurisdiction stating: “WRB req’d unless ICC ES or testing provided” – Concern: Pull brick off and redo??? – Section 1403.2, Exception No. 2 water testing performed; passed – Only limited joint repairs; no brick removal

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1404.2 Water-resistive barrier
• “Not fewer than one layer of No. 15 asphalt felt, complying

with ASTM D 226 for Type 1 felt or other approved materials, shall be attached to the studs or sheathing, with flashing as described in Section 1405.4, in such a manner as to provide a continuous water-resistive barrier behind the exterior wall veneer.”

• “Attached to studs. . .” indicates that some ‘sheathing

products’ can provide this WRB requirement. Caution: If so, be sure sheathing product manufacturer can provide test back-up in support of its use (i.e., equal or better than one layer of 15 felt) and comply with manufacturer req’s (i.e., sealing or taping of board joints).

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1404.2 Water-resistive barrier
• WRBs: What “other materials” are “approved”???
• Any materials that have appropriate test data (according to

the building official) in support of their use as a WRB in lieu

• f one layer of No. 15 asphalt felt.
• ICC Evaluation Service (Acceptance Criteria and Reports)

– Searchable database for industries and/or systems that have been tested for, and are acceptable for use as, WRB functions.

Northern Michigan Code Officials Association

Case Study #7 – Composite Panels

• Facts and Findings

– Large military project; multiple barrack buildings – Constructed in 2008; exterior walls of metal sandwich panels (2 inch thick) – Leaking prior to occupancy; No WRB; water testing performed – Panel joinery leaking at 6.24 psf (Section 1403.2, Exception No. 2) – Panel manufacturer complaining of test pressure “too high” – ICC in agreement with test pressure; panel industry playing “catch-up” . . .

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Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1405.4 Flashing
• Only applicable if you have an “Exterior Wall Covering”
• “Flashing shall be installed . . . to prevent moisture from

entering…or to redirect that moisture to the exterior.”

• “Flashing shall be installed at the perimeters of exterior

door and window assemblies, penetrations and terminations

• f exterior wall assemblies, exterior wall intersections with

roofs, chimneys, porches, decks, balconies and similar projections and at built-in gutters and similar locations where moisture could enter the wall.”

• “Flashing with projecting flanges shall be

installed on both sides and the ends of copings, under sills and continuously above projecting trim.”

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1405.4 Flashing
• Section 1405.4.1 Exterior wall pockets: “. . . wall pockets
• r crevices in which moisture can accumulate shall be

avoided or protected with caps or drips, or other approved means shall be provided to prevent water damage” (i.e., mortar washes on recessed masonry features or ledges)

• Section 1405.4.2 Masonry: “Flashing and weep holes shall

be located in the first course of masonry above finished ground level above the foundation wall or slab; at the heads

• f windows, doors and other wall openings; at window sills

and at other points of support including structural floors, shelf angles, and lintels where anchored veneers are designed in accordance with section 1405.6. Flashing shall extend to, or beyond, the finished face of the wall.

Northern Michigan Code Officials Association

Above Grade: Walls (Part 2)

• Section 1405.4 Flashing
• Relative to “flashings”, remember that the code only

requires flashings: 1) be present 2) at certain locations . . . nothing more.

• The code offers no further technical guidance as to 3) ‘how’

they should be implemented . . .

• Refer to cladding-specific manufacturer requirements (i.e.

brick, stone, metal panel, glazing system, etc.), industry- related guidelines (i.e., BIA, ILI, CSI, etc.), or an experienced exterior envelope professional for the necessary design, integration, and installation information In other words, regarding flashings the code is pretty “bare bones”. . . just recognize this . . .

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Northern Michigan Code Officials Association

Case Study #8 – Water Infiltration

• Facts and Findings

– Substantial children’s hospital; upper floor addition in 1994; surgery top floor – EIFS barrier cladding; leaking in 2010;

• perating room “out of service”

– Fly in for site visit and water testing – EIFS penetration detailing; failure of “barrier” sealants (plus poor detailing and maintenance) – Develop repairs and methodology – Reviewed by FM, Hospital Risk, etc . . . – Repairs resolved problems

Northern Michigan Code Officials Association

Roofs

• Chapter 15 - Roof Assemblies and

Rooftop Structures

• Fire-Resistance

– Exposure from ‘within’ building – Exposure from ‘outside’ of building

• Water Management

– Storm water drainage

Northern Michigan Code Officials Association

Roofs

• Fire-Resistance
• Exposure from ‘within’ building

– Risk managed by Chapter 6 Types of Construction – Table 601 – Second part of footnote ‘b’ only applies to Type I and II ...

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Northern Michigan Code Officials Association

Roofs

• Fire-Resistance
• Exposure from ‘outside’ building

– Risk managed by Section 1505 Fire Classification – Table 1505.1 – Tests UL 790 or ASTM E108 – Class A, B, or C rating » Simulates exposure from outside fire sources » 3 Tests: Spread-of-Flame (1400 deg F), Intermittent- Flame, Burning-Brand (Class A = 4.4 lbs ignited wood)

Northern Michigan Code Officials Association

Roofs

• Fire-Resistance
• Use of Combustible Material (i.e., wood) as a component
• f a Roof Covering in non-comb construction???

– Section 603, Item 4 states “Roof coverings that have an A, B or C classification.” – Section 202 defines Roof Covering as “The covering applied to the roof deck for weather resistance, fire classification or appearance.” – As long as the component of the “Roof Covering” is not a structural element of the building per Table 601 and you provide a Class A, B, or C covering, you are protected from below and above and wood can be a layer within the covering (also no FRT req’d) – Can even have a ‘Roof Assembly’ qualify

Northern Michigan Code Officials Association

Roofs

• Water Management
• Two Most Critical Items:

– Slope – Rainfall rate

• Many other items for consideration

– Specific material requirements – Flashing design and terminations – Drainage capacity and overflow provisions – Coordination of penetrating items relative to roof slopes – Etc. . .

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Northern Michigan Code Officials Association

Roofs

• Water Management
• Slope: Steep-slope vs. Low-slope roofing system

» Per MBC, Steep-slope = greater than 2:12 » Per NRCA, Steep-slope = greater than 3:12 – Therefore, MBC will allow you to install asphalt shingles

• n slopes not recommended by NRCA – watch out
• Back-slopes (i.e., crickets and saddles between drains)

– Don’t provide slopes less than primary slope (i.e., don’t provide 1/8 inch back-slopes with 1/4 inch primary) » Simple geometry: resulting slope in valley will be less than 3/16 inch (<1.5% in lieu of 2%) » You want to provide slope as close or better to primary in valley.

Northern Michigan Code Officials Association

Examples of “Food for thought”. . .

Northern Michigan Code Officials Association

Roofs

• Water Management
• Rainfall Rate: Again, code vs. industry guidelines. . .

– MPC Figure 1106.1/Table 1106.2/MPC Appendix B – SMACNA Table 1-2 (Rainfall Data & Drainage Factors) – MBMA Section IX (Climatological Data by County)

• Recognize that each of the above available resources tell a

designer to base drainage capacity on different values (i.e., Detroit, Michigan 25 year or greater recurrence) – 2.7 in/hr (MPC Appendix B – 100yr) – 3.0 in/hr (MPC Figure 1106.1 with Table 1106.2 – 100yr) – 7.0 in/hr (MBMA – 25yr) – 8.9 in/hr (SMACNA – 100yr)

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Northern Michigan Code Officials Association

Roofs

• Water Management
• Rainfall Rate Comparison Summary:
• Code (MPC) is minimum; if only designing to meet minimum,

there will be periods of accumulated water on the roof (even with overflows during intense rain bursts) – plan for it.

• Carefully consider risk involved (i.e., roof area, flow direction,
• verflow design) and utilize an appropriate rainfall rate

relative to risk

• If you chose to use something less than industry

recommendations, may be good to get client sign-off after educating client as to risk involved

• No 2 inch diameter drains!!! (even though code allows)

Northern Michigan Code Officials Association

References and Helpful Online Resources

• “2015 Michigan Building Code” (MBC), Michigan Dept. of Labor & Economic Growth, Bureau of

Construction Codes, Effective date April 20, 2017.

• “2015 Michigan Plumbing Code” (MPC), Michigan Dept. of Labor & Economic Growth, Bureau
• f Construction Codes, Effective date April 20, 2017.
• “2015 International Building Code, Code and Commentary” (IBC), International Code Council,

Inc., May 2014.

• “NRCA Roofing and Waterproofing Manuals” (NRCA), National Roofing Contractors

Association, www.nrca.net

• “AIA Detroit, Building Codes & Regulations Committee” (BC&RC), www.aiadetroit.com
• “AIA Detroit, Building Enclosure Council – Greater Detroit” (BEC), www.aiadetroit.com
• “American Concrete Institute” (ACI), www.concrete.org
• “American Society of Civil Engineers” (ASCE), www.asce.org
• “American Society for Testing and Materials” (ASTM), www.astm.org
• “Brick Industry Association” (BIA), www.gobrick.com
• “Cast Stone Institute” (CSI), www.caststone.org
• “Indiana Limestone Institute” (ILI), www.iliai.com
• “National Institute of Building Sciences” (NIBS), www.nibs.org
• “The Masonry Society” (TMS), www.masonrysociety.org