Effective Envelope Design Mitigating Risk with High Performance Panels and Acrylic Flashing Systems

Transcription

1 Effective Envelope Design Mitigating Risk with High Performance Panels and Acrylic Flashing Systems Presented by: Cale Kids & Sean Smith Huber Engineered Woods Disclaimer: This presentation was developed by a third party and is not funded by WoodWorks or the Softwood Lumber Board Huber Engineered Woods LLC. All rights reserved.

2 COPYRIGHT MATERIALS This presentation is protected by U.S. and International copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited HUBER ENGINEERED WOODS, LLC.

3 COPYRIGHT MATERIALS The Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES), Provider #G516. Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This course is registered with AIA CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

4 Course Description This course will explore the importance of effective envelope design to the success of large scale wood-frame projects. Four control layers critical to building envelope performance will be evaluated including structural integrity, bulk water management, air/vapor management and thermal performance in the context of high-performance panel solutions. Discussion will also include challenges with penetrations and how they can be addressed with acrylic flashing systems.

5 Learning Objectives 1.Identify the primary risks and causes of bulk water intrusion. 2.Evaluate the performance of single function/multiple application building envelope solutions Vs. multiple functions/single application building envelope solution. 3.Discuss proper installation techniques and best practices associated with common building envelope solutions. 4.Define potential failure modes of various building envelope solutions.

6 4 Control Layers 1 Structural Integrity Moisture Management Airflow/Vapor Control Thermal Efficiency

7 Order of Importance Moisture Management Airflow Control Thermal Efficiency Highest Importance Lowest Structure and safety are always the top priority. Moisture is the most immediate threat to a structure. Air movement must be controlled for insulation to work properly. Energy efficiency is enhanced with added insulation.

8 Control Layer 1 Design Parameter: Structural Integrity 1 Structural Integrity Moisture Management Airflow Control Thermal Efficiency

9 Requirement IBC code reference for Engineered design for wood shear walls IBC References AWC Special Design Provisions for Wind and Seismic Design Considerations: Panel thickness and length (combine design for shear and uplift) Panel strength Panel orientation (vertical vs horizontal)

10 Design Differentiator: Strength Structural I Grade: Who has heard of it? What is it? Who has designed with it? Why use it? Characteristics: Struc I panels have increased out of plane loading for vertical sidewall applications supporting adhered stone or stucco. Less deflection between studs means less cracking, minimizing water intrusion. Allows vertical application: preferred for top plate uplift resistance

11 Design Differentiator: Strength Applications 1. Where higher lateral resistance is required- Struc I has higher lateral PLF capacity Vs. commodity PS 1 And PS Where increased weak axis bending is required? Weak axis bending? What is it and why does it matter?

12 Design Differentiator: Strength Application 2: Increased weak axis bending capacity Strong axis application: traditional application where panels are installed perpendicular to supports. Weak axis application: non-traditional application where panels are installed parallel to framing members. Commonly found in vertical sheathing applications on tall walls. Increased weak axis bending an advantage when resisting wind loading perpendicular to the face of the panel.

13 Design Differentiator: Strength Which panel shows weak axis installation? In what application does this make a difference? Directly adhered brittle finished that rely on the stiffness of the substrate to resist movement and cracking that create leak paths into the cavity?

14 Control Layer 1: Envelope Design Risk Cracks in brittle finished claddings create paths for water intrusion.

15 Control Layer 1: Performance verification and testing All testing and inspection agencies test to the same performance standards Equivalent 3 rd party quality assurance testing Timber Engineering Company (TECO) and Engineered Wood Association (APA) both perform quality assurance testing

16 Control Layer 2 Design Parameter: Weather Resistive Barrier 1 Structural Integrity Moisture Management Airflow Control Thermal Efficiency

17 Requirement IBC code reference Only product in the code: asphalt felt How did all the others get qualified for use? Approved alternatives? Building wraps Combination structural panel with laminated WRB facer Evaluation Reports proving code equivalence» ICC-ES Evaluation Service Report (logo)» IAPMO Building Product Evaluations (logo)

18 Design Differentiator Performance characteristics Ease of application Durability in long construction cycles Inspect-ability (do you know what s going on behind the WRB. What you can see might hurt you.

19 Control Layer 2 Envelope Design Risk Hidden Risk of unseen water intrusion between wrap and structural panel Installation Risk of overcomplicated installation

20 Control Layer 2 Envelope Design Risk

21 Control Layer 2 Envelope Design Risk Inspectability The condition of an assembly such that any observer may assess proper installation without the necessity of inspecting multiple layers to determine installation risk.* *A.K.A. WYSIWYG

22 Control Layer 2: Performance verification and testing ESR 1474 Evaluation Report verifying code compliance Tested in accordance with ASTM E96: Standard Test Methods for Water Vapor Transmission of Materials

23 Control Layer 2: Performance verification and testing Code Conformance ICC Evaluation Services Acceptance Criteria 310 ESR 1474 ESR 2227 (Flashing Tape) Above & Beyond TAS 100 (A) -95 (Modified) Hurricane wind driven rain test Live Test huts Pool table test ASTM E1105 spray rack field test

24 Control Layer 2: Performance verification and testing ASTM E331 spray rack testing for water penetration: roof application

25 Control Layer 2: Performance verification and testing Above and beyond testing: pool table testing on overdriven fasteners

26 Control Layer 3 Design Parameter: Air/Vapor Control 1 Structural Integrity Moisture Management Airflow/Vapor Control Thermal Efficiency

27 Requirement The 2015 IBC/IRC provides methods to prevent condensation by controlling temperature and humidity in primarily two ways: Interior Vapor Retarders Exterior Insulation

28 Requirement 2015 IECC - Air Leakage Commercial Testing Option Blower door testing in accordance with ASTM E 779 at a pressure differential of 75 Pa Air leakage rate no greater than 0.40 cfm/ft 2 Regardless of Climate Zone

29 Requirement

30 Control Layer 3 Design Parameter: Air/Vapor Management Warm Moist Interior Cold Dry Exterior

31 Control Layer 3 Design Parameter: Air/Vapor Management Air Management Vs. Vapor Diffusion Interior at 70 F and 40% RH In one year, 100 times more moisture is transported by air leakage compared to diffusion and gypsum is 50 perms! Solid 4x8 sheet of gypsum 4x8 sheet of gypsum with a 1 in 2 hole

32 Design Differentiator: Material vs Assembly. Air Barrier Material vs. Air Barrier Assembly ASTM E2178 (Material Test) No seam No Penetrations ASTM E2357 (Assembly Test) Seams and penetrations

33 Control Layer 3: Envelope Design Risk

34 Control Layer 3: Envelope Design Risk How do you create an air barrier in a wrap system? Per manufacturer: Seal wrap at bottom of wall.? What happens to water that penetrates behind the wrap? How does it drain?

35 Control Layer 3: Performance verification and testing

36 Control Layer 3: Performance verification and testing Air Barrier Material Testing ASTM E2178 Air Permeance of Building Materials 1.0 m x 1.0 m specimen with no seams or transitions Must achieve less than 0.02 L/(s m 2 75 Pa

37 Control Layer 3: Solution Alternative Structural Panel with Integrated Air/Vapor Barrier

38 Control Layer 3: Solution Alternative Structural Panel with Integrated Air/Vapor Barrier Factory bonded water resistive barrier, bonded to wood bases structural sheathing. ESR Report 1474: evaluated as a combination wall sheathing, air barrier and water-resistive barrier. Specification Division 7, Section Air Barriers.

39 Control Layer 3: Performance verification and testing Air Barrier Assembly Testing ASTM E2357 Air Leakage of Air Barrier Assemblies 8.0 ft x 8.0 ft wall with penetrations/transistions Includes wind cycling Measures infiltration and exfiltration Must achieve less than 0.2 L/(s m 2 75 Pa

40 Control Layer 4 Design Parameter: Thermal Efficiency 1 Structural Integrity Moisture Management Airflow Control Thermal Efficiency

41 Air Leakage and Thermal Performance Testing for Air Leaks Thermography, or infrared scanning, detects thermal defects and air leakage in building envelopes in conjunction with a blower door test.

42 Requirement

43 Requirement Prescriptive vs. Performance Performance Path relies on computer software to show overall compliance. Some trade-offs are allowed Non-compliant prescriptive portions can be offset by over complying portions.

44 Design Differentiator: R value of cavity insulation Today, the most commonly used insulation is still fiberglass batts, which offers a relatively low cost for the function it performs. What do all cavity insulations have in common? They do not address thermal bridging..

45 Design Differentiator: Foam types Most Common Types of CI Polyisocyanurate Expanded Polystyrene (EPS) Continuous insulation differs in: R-value Moisture Resistance Extruded Polystyrene (XPS) Mechanical Properties (rigidity, compressive, etc.) Environmental Impact (blowing agents, ODP, GWP) Fire Resistance Mineral Wool

46 Continuous Insulation in Codes and Standards Vapor Retarder Classification Class I -perm rating of less than or equal to 0.1 -sheet polyethylene, non-perforated aluminum foil, some plastic foam insulation Class II - perm rating greater than 0.1, less than or equal to 1.0 -kraft paper faced fiberglass batts or certain vapor retarder tested paints Class III - perm rating of greater than 1.0, less than or equal to most latex or enamel paint.

47 Continuous Insulation in Codes and Standards Vapor Retarder Requirements Climate Zone 2015 IRC R Not Required Marine 4 Class I or II 5 Class I or II 6 Class I or II 7 Class I or II 8 Class I or II

48 Control Layer 4: Envelope Design Risk Thermal Bridging Cavity Insulation Framing

49 Control Layer 4: Envelope Design Risk Condensation

50 Control Layer: Flashing Systems ASPHALT: Good BUTYL: Better ACRYLIC: Best ASPHALT messy installation poor temp range poor durability BUTYL expanded temp range greater durability adhesion degrades ACRYLIC synthetic greatest temp range superior durability

51 Design Differentiator: Acrylic composition Acrylic adhesive is known for its high cohesive strength. The high cohesive strength of the acrylic is due to the entanglement of strong polymer chains Acrylic adhesive has a higher internal strength than other construction tapes.

52 Design Differentiator: Acrylic composition Pressure activated adhesive is formulated for proper flow and superior lifetime bonding. Initial application 24 Hours 72 Hours As the adhesive flows into the peaks & valleys of the substrate it increase the amount of contact area between the tape and the panel and continues to improve in strength.

53 Design Differentiator: Acrylic composition Acrylic tape designed on purpose and for a purpose. Each layer engineered to perform a specific function. Top layer Thick inner layer, backing is 4 mils thick Thin bottom layer formulated to bond with adhesive layer. Specially formulated acrylic adhesive layer, 8 mils thick

54 Design Differentiator: Liquid Applied Flashing Liquid Applied Flashing What is it? Silyl terminated polyether (STPE) Available in 29 oz. cartridge and 20 oz. sausage Tested to adhere to masonry, PVC, wood.. Applied at 35 Deg F and higher

55 Penetrations: Envelope Design Risk Or.

56 ASTM E 331 Water penetration test for flashing tape Testing has been done with various flashing tapes. This photo is of an ASTM E331 Water Penetration Test with a competitive flashing tape. Competitive 3 rd party testing has shown Zip Tape to have considerably better adhesion properties than commonly used flashings on the market today.

57 Flashing tape: Performance verification and testing Field Testing:UV exposure

58 A New Approach Combination Sheathing Single product with both structural sheathing panel and an integrated layer of continuous insulation. Eliminates a labor step by installing both continuous insulation and a structural, nailable, sheathing all at once. Available in R-3 to R-12 using Polyiso insulation

59 A New Approach Combination Sheathing Best option is to rely on a product that has been tested. One manufacturer has obtained third-party documentation through the International Code Council s Evaluation Services to be used as an acceptable structural panel. See Evaluation Service Report ESR-3373

60 Questions? This concludes The American Institute of Architects Continuing Education Systems Course Cale Kids Huber Engineered Woods ZIPSystem.com AdvanTechPerforms.com