Masonry crack monitor

Thermal movements are caused by the response of a given material to thermal fluctuations over time. When masonry is exposed to increasing temperatures — think about a south-facing wall getting warmer during the day — it expands. On the other hand, exposure to decreasing temperatures will result in contraction.

When exterior masonry is exposed to hot-cold temperature cycles over time, it expands and contracts. Construction materials can also move on their own due to their physical properties. Shrinkage, which in simple words is the contraction over time of cement-based products, affects concrete masonry blocks, mortar, and grout. On the other hand, clay brick expands irreversibly over time. Since thermal movements and shrinkage cannot be fully prevented from happening in masonry buildings, designers try to accommodate movements and control cracking by using control joints, expansion joints, and joint reinforcement.

When structural elements are subjected to more load than they can handle, they will crack due to overloading. These cracks should be taken very seriously as they can result in structural instability and collapse if the overloading issue is not addressed. Have an engineer evaluate your masonry crack to determine if it is caused by structural overload. Figure 2. Cracks in masonry parapet due to differential movement between clay brick, which expands over time, and concrete, which experiences shrinkage over time.

Corrosion of embedded metal in masonry, such as wall ties, joint reinforcement, structural steel, lintels, etc. As the metal is exposed to moisture, the oxidation process is activated, forcing the material to expand. When severe corrosion occurs, the oxidized metal can expand up to 7 to 10 times its original volume and produce intense bursting forces in the surrounding masonry, which will eventually crack and spall.

It is very difficult to tell the cause of a crack just by looking at it. Given the complexity of the problem and the lack of standardized guidelines, crack diagnostics may be a challenging task. At the very least, the investigation should consist of two phases: documentation and interpretation. A good rule of thumb is to gather as much information as you can to help identify the cause. At a minimum, crack location, pattern horizontal, vertical, diagonal, etc.

Although difficult in most cases, an attempt should be made to estimate the age of a crack. On the other hand, clean edges are an indication a more recent crack.

If you are lucky, a building owner has paid enough attention over the years to tell you about the some of the crack history. And if you are really lucky, he also recorded on the wall the exact date the crack appeared. Ransom, E. Day discusses the Avongard crack monitors and other foundation monitoring methods - p.

Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon. Quoting: A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome.

Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level. Cohen, P. This article in turn cites the Fine Homebuilding article noted below. See our book review of this publication. Harris, P. Quality Standards for the Professional Remodeler, N.

Tel: Email: info carsondunlop. Typically, one plate is white with a contrasting measurement grid, while the other is transparent with red cross-hair centered over the grid. With the CRACKMON in position across a crack, the cross-hair shifts vertically or horizontally over the grid when movement occurs, making it easy to see and track crack movement in the X and Y axes.

If anchors and screws are used, the CRACKMON can be taken down and reused, but we don't recommend this method of installation in areas easily accessible by the general public. When deciding whether to use anchors or epoxy, take into consideration the type of surface for example, brick, masonry, concrete , the location and the risks including cosmetic involved in drilling holes for anchors.

In some cases, epoxy putty is the best mounting medium as it can minimize surface damage, is more easily removed, and helps compensate for uneven or curved surfaces. Tusanee Tondee, GM. White Paper Earthquake!