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Evaluating Re-use of Existing Exterior Envelope

Re-skin vs. Renovate

• is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program 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 program 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.•In October 2010, the AIA/CES system was updated with the new CES Discovery system, in that time we have transferred more than one million records. This new update has made it necessary to remind us of the AIA/CES policies and procedures, to introduce the “new” provider ethics, and to reintroduce the AIA/CES audits/quality assurance program. This presentation covers those areas giving providers the opportunity to give feedback and input.

Learning Objectives

At the end of this program, participants will be able to:

1) Will understand the typical service life of different cladding materials in the Texas Gulf Coast area.

2) Will be able to identify critical failures of different cladding materials that indicate replacement.

3) Will be able to calculate the life cycle implications of re-cladding vs. cladding repair.

4) Will be able to identify the potential energy impacts of replacing or maintaining a building’s envelope.

The greenest building is the one that is already built.

Evaluation of Existing Structures

• Structural failure of façade or cladding• Water intrusion• Master Plan for long term Ownership• New Ownership

Major Reasons to Review the Envelope

Step One - Investigation and Evaluation of Existing

• Owner• Architect• Building Envelope Consultant• Structural Engineer• MEP Engineer• Project Manager or Broker• Facilities Engineer

5 Key Items

Structural Integrity

Thermal Performance

Permeance

Significance

Life Cycle

Good Condition Poor Condition

Good Performance Low Performance

Low Permeance High Permeance

Existing Image vs New Design

Short Life vs Long Term

Program, Design and Client Input

User Inputbuilding envelope

M,C,R

Option 1• re-glaze only• conventional HVAC• bldg. envelope repairs

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Option 2• modify precast: raise header• new vertical strip curtainwall• underfloor HVAC

Option 3• remove all precast: new unitized curtainwall• underfloor HVAC

Option 1• re-glaze only• conventional HVAC• new arch. metal at monitors• new skylights

Option 3• remove all precast, new unitized curtainwall• underfloor HVAC• all new monitors & piping

Option 2• remove precast below brim, new curtainwall• underfloor HVAC @ 1st fl, conventional HVAC @ 2nd

• mods to monitors for daylight

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Program, Design and Client Input – Building Use

Significance of façadeHistoric

Tax credits or Federal $ - must comply with review(Professional recommendation is the same)

IconicRepresents Campus Identity or Owner History

Intangibles - Façade Value

•Change of Use•5% increase of Lateral Load•Improvements worth over 50% of Building Value

What triggers a code upgrade?

2012 IBC - Chapter 34 Existing Building Code

Energy Code Compliance

Code and standards

Code and standards

If the owner wants windstorm insurance through TWIA, evaluation and/or upgrades may be required

Physical/Structural Characteristics of the Building Envelope

Deficiencies in one or more of these areas can lead the decision matrix for recladding:

• Condition of Façade Materials• Condition of Vertical Support Systems• Performance of façade systems

Visual Inspection

• Document Review• Visual Assessment• Establish Monitoring

Investigative Techniques

Performance of façade systems• Differential Movement• Displacement• Cracking

Control of water• Plugged weepholes• Malfunctioning downspouts• Improper flashing

Visual Inspection

• Condition of Vertical Support SystemsShelf angleLintelsPanel support clips

Typical distress conditions• Corrosion• Cracking• Displacements

Visual Inspection -

(Natural Stone, Cast Stone, Brick, Terra Cotta)

Indefinite service life with proper design and maintenance

Typical Deterioration ConditionsCrackingSpallingDelaminationDisplacementEfflorescenceMortar conditionPrior remedial treatments

Envelope Exterior - Masonry

Envelope Exterior - Masonry

Condition of Façade Materials: Precast Panels

Indefinite service life with proper design and maintenance

Typical Deterioration Conditions• Cracking• Spalling• Prior remedial treatments

Envelope Exterior - Concrete

Condition of Façade Materials: Glazing Systems

10-20 year lifespan (sealants and gaskets )50+ year lifespan -CW structure and single pane glazing

Traditional Windows• Flanged• Punch

Systems• Curtainwall / Unitized• Stick/Storefront

Sealants/Gaskets• Polyurethane• Silicone• Compressed gaskets• Zipper gasket• Structural silicone

Envelope Exterior – Curtainwall & Windows

Insulated panelsMetal building typeAluminum composite panelsCopper or Stainless Flashing

20-40 year service life with proper design and maintenance

Typical Deterioration Conditions• Oil-canning• Corrosion

Envelope Exterior – Metal

Step Two - Present Options & Constructability Review

• Design Alternatives• Impact of Codes and Standards• Hidden Conditions• Constructability• Budget

Physical/Structural Characteristics of the Building Envelope

Deficiencies in one or more of these areas can lead the decision matrix for recladding:

• Condition of Lateral Support Systems• Condition of Substrate/Weatherbarrier• Condition of Structure (At perimeter)

Hidden Conditions

• Arms-length investigation• In-situ testing• Non-destructive Evaluation

Investigative Techniques

• Condition of Substrate/Weatherbarrier

• Does system permit remedial repair of lateral systems?

• Does a weather barrier exist? • Water• Air• Vapor• Insulation

• What is condition of existing materials?• Antiquated systems• Asbestos Containing Materials• Water Damage

Substrate Analysis

Systems are typically concealedFailure represents significant risk to public safety

Typical warning signs• Outward displacement of masonry• Spalling• Localized failure

Current wind load requirementsVSBuilding Code in effectat time of construction

Condition of Lateral Support Systems

Condition of Structure (At perimeter)

• Façade elements may restrict access to superstructure

Condition of Structural Frame & Foundation

Thermal performance of existing wallWufi Model to evaluate existingWufi Model to evaluate proposed renovationAffect of hot-humid climateAffect HVAC assumptions/systems and operation - Existing and Future

Review of Water Vapor Permeance

Air and Water permeance of existing wallAir/Water vapor barrier location and integrityVapor drive - new 2013 materials vs Historic or late 20th century alternates

Tar paperTyvekPeel & stickMass wall

Intrusion from leaks – any opening in envelope

Review of Water Vapor Permeance

Tools for review of Insulation & Vapor Barrier

Sample WUFI OutputAir Temperature

Dew PointRelative Humidity

Water Content

Exterior Interior

BRICKCAVITY

AIR BARRIER & EXT. GYP

INSULATION INT. GYP. & VINYL

WALLPAPER

3 Year Cycle

Shaded Area = 3 Year Cycle

Tools for review of Water Vapor Dewpoint

THERM's heat-transfer analysis allows you to evaluate a system energy efficiency and local temperature patterns, which may relate directly to problems with condensation, moisture damage, and structural integrity.

Tools for review of Thermal Performance

Step Three - Cost Benefit Analysis

Building Life-Cycle Cost (BLCC) Program—Economic analysis tool developed by the National Institute of Standards and Technology for the U.S. Department of Energy Federal Energy Management Program (FEMP). http://www1.eere.energy.gov/femp/information/download_blcc.html#blcc

http://www.wbdg.org/tools/athena_eie.php

LCCA can be performed at various levels of complexity. Its scope might vary from a "back-of-the-envelope" study to a detailed analysis with thoroughly researched input data, supplementary measures of economic evaluation, complex uncertainty assessment, and extensive documentation. The extensiveness of the effort should be tailored to the needs of the project.

Owner’s long term plans : calculate the life cycle implications of recladding vs. cladding repair.

Government - LifetimeDeveloper - 100% Lease and SellOwner/Operator - Lifetime with Exit strategyHigh Maintenance cost – deferred maintenance problem

Life Cycle Cost Analysis

At what point does the cost of remediation approach the cost of recladding?

Repair vs Reclad

Low cost Repair

High Cost Removal

Repair Scope Extents of façade material removal

Improve Performance of façade systems Typically local

Repair of Vertical Support Systems Typically local (10%)

Repair of Structure Typically local (20%)

Repair of Façade materials Varies greatly - Local to Global

Repair of Lateral Support SystemsMinimal with appropriate substrate, Global with poor substrate

Repair of Substrate Typically global

Extents of façade removal required for various repairs

Park Towers - 2000

YEAR BUILT: 1972ENVELOPE REVIEW ISSUE: New OwnerPROJECT START DATE: 1998COST: $27M Core & Shell + GarageDESIGN SUMMARY – Vacant 13 years; purchase price allowed consideration of re-branding for new Class-A image. 24” floor extension was added to perimeter for NRA of 24,000 SF

Case Study – Park Towers RECLAD

Restore for Historic Significance and PerformanceCase Study – U of H Roy G Cullen RESTORE

YEAR BUILT: 1938ENVELOPE REVIEW ISSUE: Campus Master Plan, Water Intrusion of Historic First Building on U of H CampusPROJECT START DATE: Not StartedPROJECT COST: Est. $3.2 MDESIGN SUMMARY: Detailed review of documents and Broroscope investigation revealed that water intrusion was impacting limestone anchors. Previous re-windowing was not draining correctly. Limestone panels spalling.

Case Study – Sylvan Beach Pavilion RECLAD + RESTORE

YEAR BUILT: 1956 with 1962 & 1980 additionsENVELOPE REVIEW ISSUE: Hurricane Ike Damage to Curtainwall – Building abandoned since damagePROJECT START DATE: 2012PROJECT COST: $3.2 MillionDESIGN SUMMARY: Historic Restoration of 1950’s Mod Building for Harris County.

YEAR BUILT: 1973ENVELOPE REVIEW ISSUE: Campus precast buildings had some repairs and exposed rebar and spalls, but iconic imagery in a build to suit campus. PROJECT START DATE: 2009PROJECT COST: $300 MillionDESIGN SUMMARY: Restoration of Campus Lab Building with interior and glass element update for new office use

Case Study – Shell Technology Center RESTORE

Pros• New head height at window openings (9’-0”) allows more daylight and use of underfloor air on both floors. • Replacing glass w/ high performance low-e glass allows more visible light, less solar heat gain • Improved waterproofing at windows and overall exterior with new installation • New window mullion spacing will be closer to 5’-0” OC• Replacement of monitor allows upgrade of 30 year old pipe infrastructure. It allows phased replacement

during construction by having pipes at base roof level installed prior to demo. Future maintenance of piping at roof level is safer. Re-using structural slab (previous monitor floor) below pipe rack improves waterproofing below pipes.

• Replacement of monitor improves campus appearance by lowering overall height of secondary roof structure.

• New skylight at center allows double loaded office with perimeter circulation on glass and along skylight

• Additional demo will require construction waste recycling • Construction sequence will expose interior to weather; requires full building shut down to optimize

contractor’s work time

Cons

If 30% - 50% of exterior cladding must be removed for remediation, replacement may be a more cost effective alternate, depending on cost of cladding materials.

Integrity of Façade Assembly

Other factors – what is the business decision?!• Will new façade lead to increase in rent?• Can it lower energy usage?• Project staging - is building occupied?

Re-skin vs Rehabilitate Existing

Typically ReactiveImplementation

Mandates Periodic Inspections

Future – Façade Ordinances

Questions?

This concludes The American Institute of Architects Continuing Education Systems Course

Sustainable DesignThe BIM model allows for early staged energy calculations using DOE-2 compatible energy modeling software. This helps with glazing selection and adds valuable cost/payback calculations for the owner.

BIM @ Kirksey

• EVALUATION Structural Air / Water /Heat infiltration Market position Site and Context

• COST Project cost life cycle cost improved energy performance.

• APPEARANCE Historic importance of the façade Market position Site and Context

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