The approach I employ when it comes to building design and evaluation is similar to the approach for doing the same with a living, breathing organism. Buildings must provide the requirements end-users need in order to have a good, enjoyable, and comfortable environment. Human beings require shelter from the elements, clean air, energy in the form of food, sleep, and of course a doctor’s visit to maintain our health at least once a year, if not more, as we age.
Keeping with this analogy, I see a building similarly to the human body. The building provides shelter with four walls and a roof. The HVAC system provides clean air. Electrical systems, gas and/or oil provide energy, and the building does not require sleep but does require a doctor’s visit or repair on an ever increasing scale as the building ages. As with any complex living organism with each system influencing the other, buildings require a holistic approach. I use this holistic approach when evaluating building enclosures since many components play a role in healthy performance from roof, walls, support systems, windows and doors, to the HVAC and electrical systems.
Just like a physician’s checkup where the doctor checks all vital signs to make sure they are functioning, Elevar looks at all basic functions of the building enclosure from the hair on top (the roof) to the feet (the foundation). We check the lungs (HVAC systems) to see if they are healthy and the skin (walls) to make sure they have been designed correctly and are protecting the end-users. Without properly designed and functioning roof, windows, doors and walls, the HVAC systems will not operate properly.
For example, in buildings with return plenums above the ceiling, if the walls are not properly sealed, the return plenum can draw moisture through the walls above the ceilings providing opportunities for organic growth to form on materials with high cellulose content. This can have an adverse effect on the people inside of the building. This also affects the machinery in the HVAC system by causing rust to form and premature component degradation, not to mention the negative effect it can have on the exterior walls. Constant moisture in the exterior walls can cause major problems; especially in areas where freezing and thawing are a regular yearly occurrence, like Indianapolis, Indiana where the winters are cold and wet and the summers are hot and humid. Human beings are not designed to be in a constantly wet state and neither are most buildings. Buildings go through wetting and drying cycles in most areas of the world. The key is to understand the cycles and to allow for drying of the building components when they do get wet. That is why concealed spaces are vented and rain screen walls circulate air.
It is also imperative to be familiar with the materials in a building, their properties, how they behave when wet, and how thermal changes affect them. One mistake I see often is that materials are expected to behave in ways they are not designed to do. For example, masonry and concrete are often used in situations where they are expected to be water proof. Left untreated, these materials are not water proof and, in fact, absorb significant amount of moisture. This misunderstanding of materials has led to many problems in the construction industry.
Too often, repairs to a building are made without understanding what caused the need for repairs in the first place. For example, roof replacements are often performed in response to roof leaks without understanding where the leaks originated. “The water is coming from over head so it must be the roof.” Not always. I had a client that asked me to evaluate issues in their building constructed in 1969. The building had reportedly leaked since it was first constructed. The building had three roofs installed during that period along with a later curtain wall replacement in an effort to stop the leaks. None had worked. The roof, of course, appeared to be in great condition with all tight seams and no visible openings.
My approach was simple. I followed the ASCE30-00, “Guideline for Condition Assessment of the Building Envelope”. I evaluated each system of the building, using the process of elimination when I had proven that system was not the root cause of the leaks. I looked at the electrical system. Sometimes conduits, which are not always water tight, can allow water to enter the building. I looked at the HVAC systems. Sometimes roof top mounted units have holes in the condensate pans. I looked at the curtain walls systems. If the flashing around the curtain walls are not installed correctly they can leak along with the gaskets in the glazing system itself. I looked at the balcony drains and the through wall flashing at the drains.
After removing some of the roof and wall systems, I discovered the answer when I saw that the areas around the balcony drains were wet. Balcony drains have a curved clamping ring that is supposed to seal the roof system to the drain. The bend in the clamping ring does not allow the ring to seal tightly against the drain bowl. There was an opening at the bend that allowed water to enter the roof system. This is an inherent flaw in this type of roof drain. The balcony drains are also called “side wall drains” and had to be replaced with conventional roof drains.
When the walls at the exterior columns were opened up, another point of entry into the building was exposed. The original through wall flashing at the columns was not terminated, leaving the top of the flashing completely open. This was allowing to water to drain down the air space behind the exterior cladding, and behind the flashing and into the roof system and the building.
Our solution for this client included replacing all of the roof drains and the original through wall flashing while keeping the exterior of the building looking like it had in 1969.
Since materials and construction methods have changed over time it is also important to know how materials today will interface with materials used when the building was built. For example, Cement-Lime Mortar, Masonry Cement mortar, and Mortar Cement are all slightly different. Knowing the difference and where they can be used is important when performing masonry restoration on historic buildings. Using the wrong mortar can cause more problems than what the repairs were attempting to fix by allowing more water to enter the wall or by increasing the strength of the mortar from the original design.
Building enclosure evaluations and design must include all building systems as well as an evaluation of the materials used in its original construction along with the forces that are exerted on it. My approach to building enclosure assessments is a holistic one because, like the human body, all building systems interact with one another. As we look at each system we take into account its influence on the other systems. Testing and forensic investigations can help in the evaluation process and should be used as a tool in determining the required repairs. Like living organisms, buildings get better with age, but only with attention and maintenance.