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Here we discuss How to recognize, diagnose, & evaluate thermal expansion cracks in brick walls &: brick foundations and how to distinguish between this type of cracking failures and other cracks and movement in masonry foundations or walls, such as concrete, masonry block, brick, stone foundation damage due to impact, settlement, frost or water damage, and other causes.

Types of foundation cracks, crack patterns, differences in the meaning of cracks in different foundation materials, site conditions, building history, and other evidence of building movement and damage are described to assist in recognizing foundation defects and to help the inspector separate cosmetic or low-risk conditions from those likely to be important and potentially costly to repair.

Also see this close companion article: FOUNDATION CRACK EVALUATION which discusses in detail the process of evaluating foundation cracks and signs of foundation damage by examining the crack size, shape, pattern, and location. See THERMAL EXPANSION of MATERIALS for a table of the coefficient of expansion of common building materials including brick, concrete, mortar, and stone.

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How to Identify, Diagnose, & Evaluate Thermal Expansion Damage to Brick Walls

Thermal expansion failures in structural or veneer brick walls: is a topic misunderstood by many builders, masons, engineers, architects, and inspectors. As Dave Wickersheimer, R.A. P.E. and masonry failure expert has pointed out, brick "grows" in size indefinitely [though probably most of its size increase is early after it's manufacture.]

But a separate factor that can cause very large movements and extensive damage to brick structures or brick veneer walls is the thermal expansion which occurs across a long or tall brick wall when that wall is heated by sun exposure. The photographs here show significant thermal expansion damage in a long brick structure when we first photographed it in 1989. We visited this site again for an update in June 2007.

This brick veneer wall was built over a concrete block building. The brick veneer was attached using normal steel strap methods and the brick veneer was also reinforced at intervals using a horizontal steel wire. But the wall, more than 100' long, was built without a single expansion joint.

As the south-facing wall of this building heated in summer sun the wall grew in length until it pushed out the East and West building corners at their tops for a total of nearly 3" measured by dropping a plumb line from each building corner. The veneer movement produced a variety of damage, including:

• Cracks in the interior concrete block structural wall were observed in the building interior
• Leaks and water entry and some frost damage and related loosening of the brick veneer at various locations around the building but were most severe in areas exposed to thermal expansion of long brick veneer walls.

We were surprised that there was not more extensive damage to the structural walls themselves, and we urged the building management to consult an experienced mason for further inspection and repair. We expected the mason to cut vertical expansion joints in the wall and to seal these joints with an appropriate flexible filler material or gasket. No repairs were made, the cracks had grown slightly, and leaks had increased at the time of an informal site inspection and visit we made again in June 2007, as shown in the photographs below.

Here are some factors which determine the extent of thermal expansion damage to a brick wall or structure

• Proper installation of thermal expansion joints is the critical design factor to avoid thermal expansion damage to brick.
• Selection and application of connectors between the brick veneer and the structure is an important factor - some connectors permit more movement between the brick veneer and the structure. However even if a large brick veneer wall is properly fastened, if lacks expansion joints damage is likely, especially on the sun-exposed walls
• Sun exposure: simply walking around a large structure such as the building complex shown in these photographs, it becomes quite apparent that thermal expansion damage occurs worst on long brick walls which are facing South and/or those which receive the most sun exposure.
• Means of brick veneer attachment: A second factor in the probability of damage to a brick veneer wall is the means of attachment of the veneer to the building structure. Brick veneer walls were traditionally secured to the underlying wood or masonry structure using corrugated steel strips which were fastened at one end to the structure and at the other end laid in the brick veneer wall at mortar joints.
  
  These connectors permit some vertical movement between the structures but resists lateral movement. Some newer brick veneer connectors are designed to permit horizontal as well as some vertical movement differences between the brick veneer wall and the structure. And of course, where proper expansion joints are provided in the expanse of a brick wall and at windows and doors which penetrate that wall, we should not see thermal expansion damage to the bricks nor to the structure.
• Brick veneer bottom support: on some residential properties we've found loose brick veneer walls that lacked adequate support to carry their weight. Typical brick veneer support on a residential building uses either a steel angle iron fastened to the foundation wall to carry the bricks from their first course, or if the brick veneer was in the original plans for the building the architect or builder may have specified that the building foundation wall project approximately 4" (one brick width) out from the building structural wall to carry the load of the bricks.
• Combined effects of weather & thermal cracking may increase cracking and movement in a brick structure or brick veneer structure. It's possible that the wall-corner cracks in the photograph at the top of this page were aggravated by leaks at the roof or roof parapet since this building is located in a freezing climate.
• Distinguishing between brick thermal cracking and frost cracking: How can we distinguish between brick cracking due to roof or parapet wall leaks and brick cracking due to thermal movement: a leak and frost related crack on a masonry building tends to be horizontal near the top of the building wall at about the location of the roof surface behind the parapet wall, or just below that point - describing where water is entering the structure. Thermal cracking in the same brick wall will generate stair-step cracks or vertical cracks near the wall ends (or building corners) and will be independent of high-on-wall horizontal cracks that map the surface of the roof itself.
• Brick veneer vs. structural brick: OPINION: we suspect that at least in some cases, a brick veneer wall might suffer worse damage from thermal expansion than a brick structural wall, based on the hypothesis that a brick veneer wall, being a single brick in thickness, has less thermal mass and so will heat up more quickly across its surface than a structural brick wall which will be two or more wythes of bricks in thickness, joined by bond courses.

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

FOUNDATION CRACKS & DAMAGE GUIDE - how to inspect and diagnose foundation problems, in-depth diagnosis, and evaluation of all types of structural and non-structural cracks in residential foundations [Brick, Concrete, Masonry Block, Stone]
EARTHQUAKE DAMAGED FOUNDATIONS - examples of earthquake-damaged building foundations
FOUNDATION CONSTRUCTION TYPES - identify different foundation types, construction materials, effects of sequence of construction
FOUNDATION INSPECTION METHODS - what to look for when inspecting any building foundation
FAILURES by FOUNDATION TYPE & MATERIAL- unique failure characteristics of each foundation material
  Block Foundation & Wall Defects
  Brick Foundation & Wall Defects
  Brick Thermal Expansion Cracking
  Concrete Poured Foundation Wall & Slab Defects
  Concrete Pre-cast Foundation Defects
  Stone Foundation Defects
  Wood Foundation Defects
FAILURES by FOUNDATION MOVEMENT TYPE -recognize & diagnose types of foundation damage by the nature of foundation movement
  BULGED vs. LEANING FOUNDATIONS - distinction of foundation bulging from foundation leaning has important implications for stability
  COMBINATIONS OF FOUNDATION MOVEMENT - the real world of foundation cracks and movement: often more than one force is at work
    Bulge & step cracks
    Earthquake Damage to Foundations
    Flood Damage to Foundations
    Foundation Movement During Collapse
    Other Foundation Step cracks
  HORIZONTAL MOVEMENT IN FOUNDATIONS - detection, causes, effects, evaluation of horizontal or lateral foundation movement; hillsides
    Bulging, Leaning & Sliding Wall
    Horizontal Foundation Creep
    Horizontal Movement & step cracks in brick
    Impact Damage to Foundations
    Thermal Expansion Cracking in Brick
  VERTICAL MOVEMENT IN FOUNDATIONS - detection, causes, effects, evaluation of vertical foundation movement, differential settlement
    Diagonal Cracks in Concrete Foundations
    Diagonal Step Cracking in Masonry
    Differential vs. Uniform Settlement Cracks
    Leaning or Tipping Buildings
    Uniform Width vs. Tapered Foundation Cracks
    Vertical Cracks
FLOOD DAMAGE TO FOUNDATIONS - examples of flood damaged foundations, flood damage case analysis: were these cracks due to flooding?
FOUNDATION DEFECTS OF OMISSION - recognize things that were left out, like footings, reinforcement, soil compaction, during foundation construction
FOUNDATION CRACK EVALUATION- recognize & diagnose types of foundation cracks, movement, damage, by the size, shape, location, pattern of cracks
  DIAGONAL FOUNDATION CRACKS - causes and significance of diagonal foundation cracks, varies by foundation type & material
  HORIZONTAL FOUNDATION CRACKS - causes and significance of horizontal foundation cracks, varies by foundation type & material
  SHRINKAGE vs EXPANSION vs SETTLEMENT - which foundation materials shrink, which expand, & their characteristic crack patterns
  Sinkholes & Building Damage - sinkhole recognition, significance, cause, underlying geology, areas where sinkholes are worst
  VERTICAL FOUNDATION CRACKS - - causes and significance of vertical foundation cracks, varies by foundation type & material
FOUNDATION BULGE or LEAN MEASUREMENTS - procedure for documenting the amount of lean or bulge in a foundation or other building wall
FOUNDATION DAMAGE SEVERITY - rules of thumb for deciding how much foundation movement requires further action
FOUNDATION DAMAGE REPORTS - how to report foundation inspection results and damage
FOUNDATION INSPECTION STANDARDS - definition of scope of what a foundation inspector
FOUNDATION MOVEMENT ACTIVE vs. STATIC - determine if foundation movement was a one-time event or an ongoing problem
FOUNDATION REPAIR METHODS - catalog of methods used to repair damaged foundations and masonry building walls
  Bulged foundation Repairs
  Crack Repair Methods
  Horizontal Movement Repairs
  Shrinkage Crack Repairs
  Vertical Movement Repairs
SITE FACTORS AFFECTING FOUNDATIONS - drainage, rock, soil compaction, slope or grading, bedrock, sloping bedrock, proximity to roads
SLAB CRACK EVALUATION - recognize and diagnose different types of slab or concrete floor cracks and movement
  Control Joint Cracks in Concrete - what are control joints, why they are needed, what happens when they're omitted; are they structural?
  Freezing & Water Damage - recognize frost and water damage to concrete slabs, distinguish from other crack types
  Frost Heave/Expansive Soil Cracks in Slabs - distinguish between frost damage and expansive clay soil damage to slabs
  Seal Cracks by Polyurethane Foam Injection - stop basement or crawl space leakage
  Seal Cracks in Concrete, How To - products and methods used to seal or repair cracks in poured concrete walls, foundations, floors, & slabs.
  Settlement Cracks in Slabs - recognize slab settlement, assess risk, assess potential impact on structure
  Settlement Cracks vs. Frost Heaves - how to tell the difference between frost heaves and foundation settlement; does it matter?
  Settlement Cracks vs. Shrinkage Cracks - critical identification of shrinkage cracks (non-structural) compared with foundation movement
  Shrinkage Cracks in Slabs - causes, prevention, assessment of concrete slab shrinkage cracks
  Shrinkage Cracks Along Foundation Walls - why do we see a gap between a poured concrete slab and its abutting foundation wall?
  Standards for Repair of Cracks in Floors - when does a floor or slab crack need to be repaired? why?
WATER ENTRY in BUILDINGS
  SUMP PUMPS GUIDE - how a sump pump can avoid foundation damage and reduce building water entry
ADDITIONAL READING

More Information

• "Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
• "Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
• Sal Alfano - Editor, Journal of Light Construction*
• Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles
• Terry Carson - ASHI
• Mark Cramer - ASHI
• JD Grewell, ASHI
• Duncan Hannay - ASHI, P.E. *
• Bob Klewitz, M.S.C.E., P.E. - ASHI
• Ken Kruger, P.E., AIA - ASHI
• Aaron Kuertz aaronk@appliedtechnologies.com, with Applied Technologies regarding polyurethane foam sealant as other foundation crack repair product - 05/30/2007
• Bob Peterson, Magnum Piering - 800-771-7437 - FL*
• Arlene Puentes, ASHI, October Home Inspections - (845) 216-7833 - Kingston NY
• Greg Robi, Magnum Piering - 800-822-7437 - National*
• Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
• Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
• Dave Wickersheimer, P.E. R.A. - IL, professor, school of structures division, UIUC - University of Illinois at Urbana-Champaign School of Architecture. Professor Wickersheimer specializes in structural failure investigation and repair for wood and masonry construction. *
• *These reviewers have not returned comment 6/95

More Information on Building Diagnostic Inspections and Repairs

FOUNDATION CRACK EVALUATION discusses detail the process of evaluating foundation cracks and signs of foundation damage by examining the crack size, shape, pattern, and location.
FOUNDATION BULGE or LEAN MEASUREMENTS explains a simple method for determining how much bulge or lean is present in a foundation or wall,
FOUNDATION MOVEMENT ACTIVE vs. STATIC helps determine if the foundation movement is ongoing,
FOUNDATION DAMAGE SEVERITY discusses how we decide the severity of foundation damage and the urgency of further action.
FAILURES by FOUNDATION TYPE & MATERIAL describes the types of foundation damage, cracks, leaks, or other defects associated with each type of foundation material (concrete, brick, stone, concrete block, etc.).

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