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Maintenance of the Building Envelope

 
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The issues facing the condominium sector today with regard to maintaining their buildings are becoming increasingly complex. Even a relatively small multi-unit residential building can contain as many components as a jet aircraft and it’s not surprising that these systems need regular inspection, maintenance and repair.
 
Regular inspection and maintenance can also be an important factor in controlling costs and extending your buildings service life. This is of particular importance when you are able to identify performance problems in the early stages - before they become full-blown building failures.

Defining the Building Envelope

Building professionals in Canada have long recognized the importance of the building "envelope" which separates the indoor and outdoor environment and provides protection for the occupants and interior systems.

The system functions to “enclose space in such a manner that the interior environmental conditions can be regulated and controlled within acceptable limits"
 
The definition sounds reasonably simple - however because of the hundreds of products, components & systems, the extremity of our climate (as well as the number of trades involved) - the chance of construction deficiencies and premature failure is actually quite high. There is no doubt that it represents a maintenance challenge. 
 
The term “envelope”, when used to describe the wall systems evolved gradually over the years and in many ways the use of the term envelope reflects the ongoing changes in materials employed in its construction.
 
Construction Technology has Evolved

The technology has evolved to the point where unlike traditional masonry or stone construction employed in the past which could be as much as 3 feet thick, the modern building envelope has no major structural function except to adequately support itself and resist the various physical forces exerted on the assemblies by severe weather, pressure differentials, impact, vibration and other environmental conditions.

In addition to controlling weather factors such as temperature, air movement, humidity, rain, snow and radiation, the system must also be capable resisting the effects expansion & contraction, and the effects of foreign substances.
 
The building envelope also provides connections to the outdoors, security, controlled access and incorporates fenestration components. The envelope must also be economical, durable, maintainable and attractive.
 
It is indeed fortunate, considering the rather extensive list performance criteria involved, that the system is rarely called upon to serve all of its functions at the same time.
 
Of course we expect the building envelope to be durable, especially in Canadian climate conditions.  In most cases it does have a lengthy service life - however it will not last forever.
 
Maintenance of the Connection Details

Building scientists and engineers are well aware that it is often what we term the “connection details” that represent the true the maintenance challenge.  For example weatherstripping, caulking, expansion joints, weep holes and flashings are just a few typical examples.

We have also learned that in cold climates the chances of the sealing all the connection joints “perfectly” is remote or, according to some experts, impossible - as a result of continuous expansion and contraction. 

As a result we now design building envelope systems to allow any water that manages to get past the first line of defense to drain out of the wall. This utilizes what is called a “pressure equalized rainscreen wall system”.
 
Most people understand quite well that roofing systems require periodic maintenance, repair and/or replacement. However I often have to explain to building owners that in fact it is the building envelope and not the roof - that is the source most building performance problems.

We know from experience that the envelope is typically overlooked from a maintenance perspective. Over time this oversight can have expensive consequences.

When inspection and maintenance is overlooked there is a rather long list of problems that can develop. On the exterior of the building this can include:
• Spalling or efflorescence can form on brick & masonry surfaces.
• Rust can damage door/window frames and other appendices.
• Building sealants, weatherstripping, and caulking can be damaged.
• Seams can split on the roof or parking garage.
• Weep holes can become clogged with debris.
• Cracks can form on concrete or masonry and enlarge over time as a result of the effects of freeze thaw cycling.
• Water is able to infiltrate and remain in the wall system.
• Condensation can damage fenestration components and interior finishes
On the interior of the building we watch for any signs of:
• Staining of the interior wall surfaces.
• Water-damaged insulation above the ceiling tiles or ceiling finishes
• Damaged window soffits, jambs and sills
• Water stains on the floor finishes.
• Peeling of wallpaper or cracking of interior finishes
• Debris in window tracks
• Water stains around AC units
• Mold
When these problems go unnoticed for long periods of time, the result is building component deterioration.
 
By implementing a periodic maintenance program, the service life of the building envelope can be increased and in many cases the cost of future restoration/replacement projects can be decreased because you identified a problem before it mitigated. This proactive approach serves to minimize repairs that can disruptive to occupants.

Building Envelope Maintenance Program
 
A comprehensive building envelope maintenance program is a key factor in controlling and reducing building operation costs as well as extending service life.
A building envelope maintenance program should encompass the following elements:

• Preparation of an annual maintenance budget.
• Regular building condition assessments.
• Annual proactive maintenance.
• Routine inspection following severe weather.
 
Integrating maintenance funding into the yearly budget is essential for the property over the long term, and a regular review of the buildings condition allows a reliable to access the remaining life expectancies of the materials.
 
Detailed Inspections are a Necessity 

Inspection of these numerous components, by necessity, has to be very thorough and detailed. The building envelope inspection should evaluate and report on the condition of:
• Building envelope system &components including connection details.
• Drainage fittings and components (Weep holes/flashings, etc.)
• Exterior sealants, weatherstripping, caulking, flashings and copings to verify integrity.
• Windows, doors, soffits, jambs and sills and other fenestration components, including operable fixtures and hardware.
• Interior finishes.
Exterior signs to look for:
• Rust marks are present at imbedded steel locations.
• Spalling or efflorescence on brick.
• Cracks in concrete or masonry.
• Rusted door and window frames.
• Condensation on windows or glass.
• Compressed or incomplete building sealants at expansion joints.
• Seam splits on roof or parking garage.
• Weep holes are clogged with debris or caulked shut.

Brian Burton is a regular columnist for Glass Canada and a Business Development Consultant for Kleinfeldt Consultants Ltd. Brian was recently appointed to the Personnel Committee for the Canadian Standard Council’s new Fenestration Installation Technician Certification Program. He can be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it or visit www.kcl.ca