Differential Creep, A Case Study

By: Dominic L. Pusateri

Clay bricks are as small as they are ever going to be the day they come out of the kiln.   Concrete is placed wet and air cured.  Over time, the concrete shrinks, while the bricks swell from exposure to water.  Cast-in-place concrete and wood framed construction clad in brick masonry cavity walls must allow for the different movement of these components.  

In the masonry cavity wall example shown, floor line relieving angles were not installed in sufficient frequency and the angles that were installed did not adequately allow for the differential movement.  The windows are attached to the CMU infill on the concrete superstructure and have a nosing that bridges onto the clad side of the wall.  The brick swelling/concrete shrinking dynamic has opened the sealant joints at the head and portions of the sill, while shearing the sealant at the jambs. 

Considering the age of the building, the average amount of annual movement per brick is about 0.0002".  The actual movement is on a curve, the additional differential will be less extreme than the initial swell/shrinkage scenario.

A more robust sealant profile and material can be used that will accommodate more movement than the original sealant.  Other concerns may be more pertinent, such as evaluating the degree of damage that has resulted to the window frames as a result of the movement.

The video shows a schematic of the movement and examples from the case study.  The case study illustrates the need for the building envelope inspector to give consideration to long term building movement in the analysis of the water management performance of installed systems. 
 

Calculating Composite Production Values – Forensic Use

By:  Charles B. Antone   

As a follow up to previous brief indicating the underlining governing equation for calculating composite production values for multi-item assemblies, I will show how to use the equation forensically, specifically to solve for an unknown individual production value.

Placement of Thermal Break

By:  Todd Watson     

Thermally improved fenestration products offer the benefit of separating the interior portion of the window or door frame from the portion exposed to the exterior.  The benefits of such a configuration include decreased energy loss and enhanced resistance to the formation of condensation. For optimal performance, the portion of the frame containing the low conductive material that separates the interior and exterior portions of the frame must be placed in line with, or perhaps behind, the wall insulation or; better still, the full edge of the window should be insulated.  Oftentimes neither of these measures is executed.

Diagnostic Water Testing

By: Dominic L. Pusateri   

In order to evaluate wall components, various tests can be utilized. Methods for the evaluation of these components are outlined in ASTM E 2128, Evaluating Water Leakage of Building Walls. One of the methods described in this standard involves directing water in a targeted fashion by building a dam around suspect areas and applying water. Hydrostatic head pressure comes into play only if the water is retained at some level in the dam. However, when water exits the dam as fast as it is poured into the dam, then hydrostatic pressure is not necessary for water to enter the components, mere capillary conduction is all that is necessary and the dam acts then more as a funnel, isolating water to specific areas. The benefit of the approach is that it is more precise as to the locations where the defect lies. This helps with the inference of the results when comparing the test locations to section details. 

Rilem Tube Extended

By:  Gil Castonquay    

In this segment we'll focus on the "Rilem Tube" test method.  If this were a full length article, we certainly would get into a more detailed background as to how the test came to be, such as how RILEM originated in France and is actually an acronym for Réunion Internationale des Laboratoires et Experts des Matériaux, and is conducted per the RILEM Commission 25, PEM, Test Method 1154, but, for the purpose of this blog, for brevity sake, we'll just cover some of the high points to provide a brief overview as to how and why this test method, this tool, should be a part of your diagnostic approach tool bag when evaluating building enclosure performance.

AAMA 501.2 Testing as an Instrument of Effective New Construction Quality Control Programs

By: Craig Andrade

AAMA 501.2 Testing, sometimes referred to as “Monarch Testing” or “Hose Testing”, is a practical and cost efficient method of assuring the watertight installation of fenestration and cladding systems, for new construction as a quality control measure and for existing construction as a diagnostic tool.  For brevity sake, this blog pertains to the benefits that can be employed during a new construction project.   

Calculating Composite Production Values for Multi-Item Assemblies

By:  Charles B. Antone

In the following brief, I will show the underlining governing equation for calculating composite production values for multi-item assemblies.  A multi-item assembly can be represented in a multitude of forms, but in this discussion I will focus primarily on calculating production based construction cost estimates. Once understood, the composite production value underlining equation can be used forensically, as well as as a means to track the real-time labor usage on an active construction site.