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Top Signs of Façade Problems – How to See the Invisible “Vision is the art of seeing things invisible” – Jonathan Swift – NAREIM Home Page Carolyn L. Searls

Outline – How and Where to Look for the Invisible

• I. Top ten signs to look for to detect façade problems • II. The prepurchase survey (and NDT methods) • III. Current problems we’re seeing in building materials

and systems • IV. Current problems we’re seeing in the building

process

I. Top 10 Signs of Façade Problems Water Leaks

10. Deteriorating Sky-facing Surfaces

• Look for – Concrete or masonry parapets without metal copings – Horizontal ledges without waterproofing – Any horizontal surface with deteriorated joints,

waterproofing or paint

9. Efflorescence and Water Stains

• Look for…

8. Rust Stains

8. Rust Stains

• Look for – Orange rust stains – The source of the stains (the steel) – The source of the water

• Expansion of rust product can cause spalls

7. Cracks

• Look for these normal shrinkage cracks

7. Cracks

• Look for these cracks indicative of problems

Thermal and moisture expansion; lack of support

Marble expansion Corrosion

7. Cracks

• Look for these cracks indicative of problems

Corrosion of window lintels

7. Cracks

• Look for these cracks indicative of problems

Seismic

7. Cracks • Cause of the cracks

– The material wants to move but can’t – The material can’t take the stress – Moving or non-moving cracks?

6. Paint Failures

• Look for

5. Deteriorated Mortar Joints

• Look for – Missing mortar, holes in mortar joints – Cracks in mortar joints – Separations between mortar and masonry units – Underlying causes

4. Deteriorated Sealant Joints

• Look for

Cohesion Failure

Reversion

Adhesion Failure

3. Deterioration of Window Systems

• Look for – Gaps at gasket corners – Hardened or failed

sealants or gaskets – Water streaks down

interior vertical mullions – Wet finishes below

window sill – Wet finishes above

window (from floor above)

– Weep holes caulked over

2. Mold

• Look for – Red, black or green mold – Pink spots visible through vinyl wallpaper

1. Pieces Falling Off

• Look for subtle cracks can indicate delaminated pieces, ready to fall off

• Displaced elements • Out-of-plane elements

1. Pieces Falling Off

The Biggest Problems Occur…

• Where components of a building intersect

II. The Pre-purchase Survey Hoping to Uncover the Invisible

• Review drawings and specs, maintenance records, leak records

• Speak with building managers/engineers, occupants • Visual survey from ground • $$$ - Maintenance and repair costs • Close-up visual survey • NDT • Investigative openings • Water testing or other testing, as required

Pre-purchase survey – Interview

• People who are familiar with the everyday behavior of the building

• Gather data on leaks, cracks, previous repairs or alterations

• Are any drawings available? • Does the building leak every time it rains? Or only when

it is windy? • How long after the rain starts do leaks appear?

After the Visual Survey - Next Steps

• More detailed survey – Larger sample size – Close up inspection – Selective disassembly

• Field and laboratory testing – Appropriate water testing

• Analysis – structural, hygrothermal

• Repair design & budgeting

• Options analysis

Pre-purchase survey

• Benefits of close up inspection

Southwest Museum – Rope Access Condition Survey, Sounding, Petrographic Analysis of Plaster

Pre-purchase survey

• Benefits of inspection openings

Nondestructive Testing

• The value of inspection openings

– Open an area to visually or physically confirm the nondestructive test results (say, from GPR, pachometer, etc.)

• The value of a 2nd nondestructive test method

– If openings are not possible or not valuable, it’s good to have a 2nd method to confirm the results of the 1st

• Test results need to be interpreted (and may take some time)

– Data may be immediately available, but the significance may not

– With any test, understand what the test is really measuring

Your Most Important High Tech Tools

Borescope

Photo credit: Michael Schuller

Photo credit: Michael Schuller

Metal Detectors

• Eddy current induction • Run over surface of masonry to identify metal

reinforcement, anchors • Many versions: pachometer, Ferroscan, Profometer

Ground-Penetrating Radar (GPR)

• Next best thing to physically seeing • Produces a “virtual” picture through data on a screen • Data requires interpretation by a trained operator • Excellent for identifying:

– Location and depth of metal reinforcement – Voids in masonry construction – Presence of grout in CMU cells

Ground-Penetrating Radar

• Generally speaking, GPR can locate position and depth of objects within a medium

RILEM Tubes (or Karsten Tubes, or Stormdry Gauges)

• Compare absorption of different types of masonry or before/after treatment

• Correlation with wind-driven rain

RILEM Tubes

• RILEM Test Method II.4: – Affix tube to substrate with putty – Fill tube with water from top; ensure no leaks through putty – Read water level at regular time intervals (e.g. 5, 10, 15, 20, 30,

60 minutes, depending on material and absorption rate) – Report results on a graph of water volume absorbed vs. time

• How many tests? Where? – Up to the judgment of the design professional

• Test standard describes how to do the test, but not how to interpret the results

Infrared Thermography

• Shows differences in temperature not the location of water

• Requires experienced operator (certified thermographer) • Very fast, can cover large areas easily • Time of day can be important in effectiveness of testing

– Early morning – building surfaces relatively cool – Mid-day – building surfaces are warmest

• Useful for diagnosing: – Voids in masonry (including ungrouted cells) – Changes in construction (window infills, etc.) – Wet areas during water testing – Rising damp

Non-destructive Testing to Locate Internal Conditions

• Infrared Thermography

Infrared Thermography

Measuring Moisture in Building Materials

Impedance Measurement

Pin-type Resistance Meters

Temperature/RH Probes

Wood Condition Assessment - Shangri La

Common Signs of Wood Deterioration

• Signs of Decay – Fruiting bodies – Surface depressions – Staining – Insect Activity

– Checks and splits – Cubical checking – “Spongy” feeling

– Mycelium mats – Rhizomorphs

Wood Condition Assessment - Shangri La

• Signs of Insect Activity – Frass – Earthen tubes – Tunnels in wood – Swarming in spring/fall – Shed wings – Chewing or knocking

sounds

Wood Condition Assessment - Shangri La

Wood Condition Assessment - Shangri La

Species Identification: Shangri La

Wood Condition Assessment - Shangri La Resistograph

Water Testing - Shangri La

• Determine leak paths to diagnose problems and design repairs

Water Testing Spray Rack and Pressure Chamber

• We simulate rain with a calibrated spray rack • We simulate wind using a pressure chamber on interior

and sucking the air out

Water Testing Calibrated Nozzle

• Used to isolate leak paths • As a quick check during construction

III. Current Problems in Existing Building Systems or Where to Look for the Invisible

• Window leaks • Non-drainage EIFS • Cement plaster (stucco) • Thin brick and thin stone veneer • Hardipanel • Flooring failures • Balcony decks • Early 20th century buildings deteriorating

Common Causes of Window Leakage Not Following Manufacturer’s Installation Instructions

• Open head-jamb corner

Confidential material protected pursuant to Evidence Code Sections 1115 et. seq.

Common Causes of Window Leakage Sill/jamb Corners

• Sill/jamb corner is not watertight; jamb drains into wall cavity

• Reason for using sill pan flashing

Confidential material protected pursuant to Evidence Code Sections 1115 et. seq.

Common Causes of Window Leakage Missing or Torn Heel Bead or Inadequate Sill Height

• Leads to overtopping of sill

Common Causes of Window Leakage Gaskets Shrink Away From Window Corners

Common Causes of Window Leakage Discontinuous Gaskets and Sealant at Mulled Windows

• Mulled windows are often problematic

Common Causes of Window Leakage Lack of Flashing or Reverse-lapped Flashing

– Incomplete integration of Tyvek with window assemblies

Common Causes of Window Leakage Improper Perimeter Sealant Joints

Non-drainage EIFS

• Relies on 1/8” thick lamina and perfect sealant joints for waterproofing

• No secondary flashings to redirect incidental water to exterior

Non-drainage EIFS Problems

• Cracks, especially at re-entrant corners • EIFS finish coat wraps into sealant joint

(sealant should be bonded to base coat) • Open cell backer rod • No sealant joints at penetrations

Cement Plaster

• When installed properly, cement plaster works well

• All plaster cracks and absorbs moisture – there must be a complete WRB w/flashings to handle incidental water that penetrates the plaster

• Flashings at penetrations are critical

Cement plaster

• Window flashing is critical – see ASTM E 2112

Cement Plaster

• Tears and holes in the WRB caused by overdriven lath fasteners

• Water enters through lath fasteners not engaged with studs or other framing (i.e. “spinners”)

Thin Brick Veneer

• 3/8” to 3/4” thick bricks • Three basic installation systems:

– Embedded in precast concrete panels – Adhered to sheet metal or insulation

panels – Field-applied to exterior cement plaster

or concrete walls

Thin Brick Veneer Adhesion Failures

• Detection methods – Tapping – Prying

Thin Brick Veneer Panelized Wall Systems: Brick Adhered to Metal Panels

• Thin brick glued to aluminum panels

• Over rigid insulation • Nailed to plywood

sheathing • Bricks falling off

aluminum • Entire system

separating from building

Hardiplank

– Incomplete integration of Tyvek with window assemblies

– No flashing between Hardiplank and adjacent barrier EIFS or cornice ledger beam

Flooring Failures - Vinyl

• Newer low-VOC adhesives less tolerant of moisture in concrete slabs

• Shorter construction schedules lead to installing flooring before slabs are dry

• Lightweight concrete

Flooring Failures - Stone

• Use of thinner stones, low-quality stone, mortar bed shrinkage

Flooring Failures - Tile

• Shrinkage of underlying concrete slab

Balcony Deck Assemblies Observations – Cantilevered Balconies

How they fail and why you need saddle flashings

Membrane stops short of deck edge – no termination

Balcony Deck Assemblies

Building Wall (Plaster and WRB removed)

Wood Corbel

Balcony Deck (concrete and membrane removed)

Water runs off deck, remains behind plaster

Observations – Cantilevered Balconies

Balcony Deck Assemblies

Sealant joint between plaster and wood, but WRB unsealed

Water continues to run behind plaster, runs behind WRB edge

Observations – Cantilevered Balconies

Balcony Deck Assemblies

Unsealed WRB at bottom and side of wood corbel

Water bypasses WRB at edges

Observations – Cantilevered Balconies Water accesses and deteriorates OSB sheathing

Ageing of Early 20th Century Buildings

• Now being rehabilitated in urban areas

• Steel windows • Concrete or masonry

cladding

IV: Current Problems in the Building Process Why are there so many failures?

• New products being used without track record or testing

• Bidding with incomplete construction documents – usually schedule driven

• Low-bid contractors • Inadequate construction observation • Poor decisions during construction due to schedule

or budget

Thank you