Our Forensic Wateproofing Expert Delivers a Successful Lunch and Learn Program for SOM Los Angeles

Terra-Petra’s Forensic Waterproofing Expert, Barry Taheri, presented his sixth lunch and learn program for global architecture, planning and design firm, Skidmore, Owings and Merrill (SOM), at their downtown Los Angeles offices on Grand Avenue, on August 29, 2018.

In his presentation, “The Principles of Building Enclosure Systems,” Taheri provided info on the importance of building waterproofing and the benefits of investing in mock-ups, along with a few live demonstrations. Our delicious lunch was catered by Mendocino Farms.

Terra-Petra’s presenter Barry Taheri was more than happy to stay after the presentation to field questions from many of the audience members. We want to thank SOM for their time as we were very impressed with this world-class firm and hope to be able to work with them on projects in the near future.

Contact Terra-Petra for more information on how to schedule a Lunch and Learn Program for your organization.

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The Principles of Building Enclosure Systems: Lunch and Learn Program

Terra-Petra’s Forensic Waterproofing Expert, Barry Taheri, recently presented a lunch and learn program for global architecture, planning and design firm, CallisonRTKL at their downtown Los Angeles offices on Hope Street on August 22, 2018.

In his presentation, “The Principles of Building Enclosure Systems,” Taheri provided info on the importance of building waterproofing, and the benefits of investing in mock-ups along with a few live demonstrations.  He plans to present more of lunch and learn presentations in the months to come.  Contact Terra-Petra for more information on how to schedule a Lunch and Learn Program for your organization.

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Observing bentonite waterproofing system installation for high rise development in DTLA.

Observing a Bentonite Waterproofing System Installation in DTLA

Building waterproofing systems should always be inspected by a certified professional. As a part of their waterproofing warranty program, most waterproofing systems manufacturers now require a certified independent inspection, but it is also important to provide assurances to the architects and developers that the systems will work properly. Terra-Petra’s Waterproofing Division has a team of highly trained inspectors on staff who hold certifications from several of the major waterproofing manufacturers in the market today.

Check out the process of a new Downtown Los Angeles bentonite waterproofing system installation and read more about Terra-Petra’s inspection and CQA/CQC monitoring services here.

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The Terra-Petra Waterproofing Division team will be exhibiting at the RCI Trade Show Exhibit in Houston

Terra-Petra Waterproofing Division Exhibits at RCI International Convention & Trade Show

The Terra-Petra Waterproofing Division team exhibited at the RCI International Convention & Trade Show at Houston’s George R. Brown Convention Center on March 24-27, 2018.

Our group of professionals provided information and further insight on our BUILDING ENVELOPE CONSULTING * ELECTRONIC LEAK DETECTION * CERTIFIED AIR & WATER TESTING  * INSPECTION & MONITORING services.


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The annual RCI, Inc. International Trade Show offers attendees the chance to meet and learn from representatives from over 130 manufacturers of roofing, waterproofing, and exterior wall products. 




ELD Technology vs. Traditional Flood Testing for All Waterproofing Membrane Installations

Terra-Petra employs state of the art Electronic Leak Detection (ELD) technology to detect leaks for waterproofing membranes installed at roofs, plaza decks, pools, water features, covered reservoirs and other waterproofing applications in accordance with ASTM D7877-14. The ELD testing can be used in lieu of, or in concert with traditional flood testing. Flood testing, historically speaking, is more expensive, time consuming and provides for less accuracy and assurance than the ELD system. Terra-Petra’s ELD technology uses a minimum of water and time and provides absolute confirmation that a membrane is watertight. This system can be used on horizontal and vertical surfaces and can also locate hard to find leaks in older membranes.

IntegriScan electronic testing ensures that the waterproof membrane on your roof, green roof or plaza deck is dry and water-tight. Watch the latest video from Detec Systems:

How ELD testing works (with Detec’s TrueGround Conductive Primer)

Stucco doesn’t crack spontaneously, it responds to significant external STRESSES!

Stucco Cracking and the Causations

By Robert R. Tellez

Stucco is widely used all over the world as an exterior cladding because of its aesthetic appeal, durability, fire resistance, design flexibility, low cost and ease of maintenance. Stucco is by nature hard and strong, but it is relatively thin and brittle and, will crack when subjected to stresses that exceed its tensile strength.

Assessing “causation” of plaster cracking is, at times, very complex, difficult and extremely limited when restricted to a visual inspection only. Contrary to belief, when evaluating the nature of Portland cement plaster cracking, one must consider other factors. Plaster cracks form when a stronger force exceeds the restraint capacity of the Portland cement.

It is important to remember that stucco is not structural, it is a finish. The International Building Code (IBC) and American Society for Testing and Materials (ASTM) do not require any specific flexural resistance, compression or tensile strength for Portland cement plaster because they do not value it structurally, unlike steel or concrete. Plaster cracks are stress-released energy. Although it contributes to and provides some form of shear value against wind or seismic forces, it carries no structural value.

There are two fundamental types of stresses that cause stucco cracks.

Internal and External Stress Cracks.

    Internal stresses are due to the natural curing and drying hydration process of stucco application, which usually occurs within 1 to 2 days. This is why the California Building Code and ASTM C 926 call for 48 hours of moisture curing for the hydration of the stucco application. This 48-hour period is when most stucco “shrinkage cracks” occur. This shrinkage, when controlled, may still create hairline cracks in different directions and patterns depending on temperature and wind speed. All internal stress cracks will appear within 14 days. Once the 14-day period is reached, “external stress cracks” will begin to develop.
    External stresses are due to the transfer of outside forces into the stucco membrane. Common examples are at the corners of windows and doors. These stresses can cause movement within the stucco, which can result in wider cracks than internally generated cracks. The following are common, but not exclusive, sources of external stresses that are associated with stucco cracking.

Plaster crack development is caused by underlying lateral and perpendicular forces. These forces are influenced by building structural components’ behavior beneath the plaster system. Plaster walls become an illustrative canvas, charting out graphic diagrams and outlines of stress relief-type cracking. Plaster cracks are visual indicators of building structural movements behind the 7/8” stucco wall membrane. The ability of Portland cement plaster to flex or resist perpendicular forces (flexural) is commonly overlooked and overestimated.

Essentially, Portland cement plaster can be extremely hard, solid, durable, and weather-efficient. However, it can at the same time be rigid and inflexible when flexurally-challenged. The repercussion of a plaster wall’s inability to flex or bend is to crack. A plaster crack is the symptom of movement, not the primary movement.

  1. Soil movement: Seismic events, settlement, and expansion of soil under the building can cause the foundation to move slightly.
  2. Loads on building: Live loads (i.e., traffic, furniture, and occupants) and dead loads (i.e., roof tile and equipment vibration).
  3. Wind and solar energy: Wind loads can place pressure on stucco wall panels, due to the kinetic energy force. Solar energy is the primary cause for external stress on the building and can create stucco cracks.

All building materials expand and contract with changes in temperature, but each material expands at its own rate depending on the thermal coefficient rating. An aluminum and vinyl window frame in a stucco opening is usually separated due to movement from the stucco panel by temperature. In most cases, the movement being considered is perpendicular to the joint, but in fact, the greatest movement is parallel to the joint because of the difference in expansion of the aluminum and vinyl window systems and the stucco wall thermal coefficient rating.

The parallel movements of a window frame can cause diagonal stucco cracks at the window frame joint corners where the window frame’s (corners) perpendicular intersections meet. This diagonal cracking pattern is ignored by some experts who do not know the different coefficient ratings and blame the stucco mix or the application. When making a decision about building design and material selection, this different coefficient rate of expansion must be considered. J-Trim and backer rod systems around window frames are the most important factors. Including two pieced expansion joints and control joints is helpful, but there is no guarantee it will stop underlying movement.

The parallel movement between window frames and stucco terminations breaks the stucco bond and can allow water to travel directly onto the weather-resistant barrier/paper products, which cannot perform as a waterproofing membrane.

Weather-resistant barriers were never designed as waterproofing material for many good reasons. If a waterproofing material is installed in place of a weather-resistant barrier, it could lead to mold and other issues.

In addition, weather-resistant barriers have hundreds of linear feet of dry, unsealed laps that can leak vertically and horizontally. There are also thousands of staples, nails or screw fasteners that do not self-seal once they penetrate the weather-resistant barrier. This is the main reason why we need to seal window frame perimeters to the stucco and all other first lines of defense building components that come into contact with the termination of the stucco membrane.

Contact Terra-Petra Waterproofing Division for further information regarding the use of proper waterproofing measures to prevent or mitigate stucco cracking.

Arcadia Group Manufacturing Plant Tour

2301 East Vernon, Vernon, CA 90058

The Terra-Petra Waterproofing Division would like to thank James Fitzsimmons and the Arcadia Group for their time and generosity in leading us on a very informative tour and presentation of their store front, curtain wall and window manufacturing plant in Vernon CA. James was a very courteous host and allowed Terra-Petra’s Waterproofing Division team an opportunity to see firsthand what goes into the manufacturing of these systems.  Terra-Petra was well represented as members of our consulting, design and field testing teams all participated in the tour.


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Arcadia Group advertises themselves as being a leading single source supplier of architectural building products, curtain wall, storefront, entrance, window and interior framing. Arcadia also offers a considerable source of expertise in architectural glazing systems, and can design custom solutions that will help builders to realize their most challenging concepts. Mr. Fitsimmons explained that he typically communicates and works directly with architects and contractors in detailing and specifying the appropriate system for a given project.

The Terra-Petra Waterproofing Division routinely performs Quality Control/Quality Assurance Testing for numerous window, store front and curtain walls once they are assembled in the field. As such, the tour and presentation gave us a great opportunity to see everything that goes into the engineering, design, manufacturing, assembly and transportation of these systems prior to reaching the job site. The knowledge we gained can only serve to improve our testing capabilities in the field.

Learn more about the Terra-Petra Waterproofing Division. Contact us today.

What is a Passive House? Terra-Petra Waterproofing Division

What is a Passive House?

The Passive House concept represents today’s highest energy standard with the promise of slashing the heating energy consumption of buildings by an amazing 90%. Widespread application of the Passive House design would have a dramatic impact on energy conservation. Data from the U.S. Energy Information Administration shows that buildings are responsible for 48% of greenhouse gas emissions annually and 76% of all electricity generated by U.S. power plants goes to supply the Building Sector [Architecture 2030]. It has been abundantly clear for some time that the building sector is a primary contributor of climate-changing pollutants, and the question is asked: How do we best square our building energy needs with those of our environment and of our pocketbook? In the realm of super energy efficiency, the Passive House presents an intriguing option for new and retrofit construction; in residential, commercial, and institutional projects.

A Passive House is a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 90% of space heating costs, but also provides a uniquely terrific indoor air quality.

A Passive House is a comprehensive system. “Passive” describes well this system’s underlying receptivity and retention capacity. Working with natural resources, free solar energy is captured and applied efficiently, instead of relying predominantly on ‘active’ systems to bring a building to ‘zero’ energy. High performance triple-glazed windows, super-insulation, an airtight building shell, limitation of thermal bridging and balanced energy recovery ventilation make possible extraordinary reductions in energy use and carbon emission.

Today, many in the building sector have applied this concept to design, and build towards a carbon-neutral future. Over the last 10 years more than 15,000 buildings in Europe – from single and multifamily residences, to schools, factories and office buildings – have been designed and built or remodeled to the passive house standard. A great many of these have been extensively monitored by the Passive House Institute in Darmstadt, analyzing and verifying their performance. Even governmental agencies have adopted passive house standards in their policy-making (read more about the EU Commission’s intent to implement the Passive House Standard.).

Performance Characteristics

  • Airtight building shell ≤ 0.6 ACH @ 50 pascal pressure, measured by blower-door test.
  • Annual heat requirement ≤ 15 kWh/m2/year (4.75 kBtu/sf/yr)
  • Primary Energy ≤ 120 kWh/m2/year (38.1 kBtu/sf/yr)

In addition, the following are recommendations, varying with climate:

  • Window u-value ≤ 0.8 W/m2/K
  • Ventilation system with heat recovery with ≥ 75% efficiency with low electric consumption @ 0.45 Wh/m3
  • Thermal Bridge Free Construction ≤ 0.01 W/mK

What is a Passive House? Terra-Petra Waterproofing Division

The building science research culminated in the development of the Passive House Planning Package (PHPP) which projects detailed heat load, heat loss, and primary energy usage for individual building parameters. The latest version of the PHPP also projects cooling, cooling loads, and latent cooling. Based on feedback from many detailed data logged buildings, the software is constantly refined and incorporates updated calculations for various climates around the world.

Terra-Petra Waterproofing Division is available for you water management and consulting services.

Contact us for further information.

Bottom Line on Mold

Contributed by
Barry Taheri

According to the EPA, molds can be found almost anywhere -they can grow on virtually any organic substance, as long as moisture and oxygen are present. There are molds that can grow on wood, paper, carpet and insulation. When excessive moisture accumulates in buildings or on building materials, mold growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed.

Molds produce allergens (substances that can cause allergic reactions), irritants, and in some cases, potentially toxic substances (mycotoxins). Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis).

Allergic reactions to mold are common. They can be immediate or delayed. Molds can also cause asthma attacks in people with asthma who are allergic to mold. In addition, mold exposure can irritate the eyes, skin, nose, throat, and lungs of both mold-allergic and non-allergic people.

Since mold requires water to grow, it is important to prevent moisture problems in buildings. Moisture problems can have many causes, including uncontrolled humidity. Some moisture problems in buildings have been linked to changes in building construction practices during the 1970s, 80s, and 90s.

In order to test the levels of mold in a particular structure, an air sample is taken of the entire structure area. The doors and windows must remain closed 24 hours prior to the test. Depending on the size, air samples are taken in three to four locations and on each floor. Tape samples are taken as well to determine surface contamination. An air sample is then taken outside the building and the two are compared. The results are then interpreted and repair and remediation protocols are developed.

Need to find concealed moisture before it’s a problem? Contact Terra-Petra to schedule a consultation.


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