A masonry inspection opening.

By definition, "envelope" is an encapsulating covering such as an outer shell or membrane. In simple building terms, it consists of the roof, above-grade wall system and the below-grade wall system. An envelope's purpose is to provide protection from external elements, which, in building construction means protection from moisture, air and temperature ingress and egress.

The definition sounds simple enough, but in reality-because of the thousands of complex products and systems specified and the multiple trades involved-the chance of error is high. As complex and intricate as the building envelope seems to be, how can one determine if a building envelope is going to have or is already having problems?

Proactive Investigations

In a perfect world, owners would engage a professional with building envelope knowledge before purchasing a structure to inspect it and determine the potential building envelope investment that may be required. Owners typically look at the roof, but rarely examine the remaining elements of the building. With good information from an investigation, a client can make a prudent business decision prior to purchasing a structure. Armed with this information, the price can be negotiated, or the client can decide to accept the risk while being aware of the financial needs, or walk away from the deal.

Unfortunately, proactive investigations are still rare, especially when the economy and real estate markets are booming and deal-making is fast and furious. A large majority of calls are from owners who have recently acquired structures, new property managers, new condominium board members, new church business managers or new building engineers - each of whom has just taken over a property and found that something is leaking or falling off the building.

Regardless of when and whom the call comes from, what is a good way to tell if the building envelope is having or will have problems?

Obviously, a building must be seen in person, and that brings up the question: How closely does one need to look? A good starting point is covered by ASTM E2270 Standard Practice for Periodic Inspections of Building Facades for Unsafe Conditions, which defines the levels of façade inspections to apply to a building. Before the creation of this standard term, definitions and methods were inconsistent throughout the industry. This standard is intended to establish a consistent minimum requirement for conducting periodic inspections of building facades to identify unsafe conditions that could cause harm to persons and property. One of the most inconsistent items was the level of proximity required to determine the access for an inspection. This standard establishes two options and defines them at the very beginning in the section 3.2.9 "levels of facade inspections." Option 1 - general inspection - involves visual observation of facade components from distances equal to or greater than 6 feet with or without magnification or remote optical devices, while Option 2 - detailed inspection- is the visual observation from less than 6 feet and tactile evaluation of facade components, including probing and non-destructive testing to observe concealed conditions of wall construction. Typically, the decision for a general inspection has been made because the detailed inspection is too expensive, would take too long, or a report is needed in a short amount of time.

A building envelope investigator's tool kit should consist of the following: a good carry bag (i.e., a hiker's waist pack), tape measure, rolling wheel, camera, notebook, several color pens, markers, duct tape, voice recorder and, most important, personal protection equipment including a hard hat, safety glasses and a pair of gloves.

The general inspection can be broken down into four basic steps:

• Initial Walk About
• Knowledge Gathering
• Interior Symptoms
• Exterior Signs

Exterior signs of brick spalling.

Initial Walk About

A basic tour of the structure and cursory visual examination should be performed as the first step in the process. Next, title three pages of notebook paper-one for the wall system, one for the roof and one for the wall system below grade. Use these pages for initial notes to start the documentation process (the camera generally is not needed until Steps 3 and 4). This step is used to get familiar with the structure so that the inspector will have a mental picture of the building, if and when they get to see the drawings.

Beginning with the wall system, it is vital to walk around the structure to get an understanding of the shape and makeup of the structure, materials used, as well as any features like balconies, cornices or ornamentation. Also, check to see how the building is terminated at-grade. Next, continue to the roof to see the layout-if it has a parapet, how the roof is terminated to the parapet, how the roof is accessed, and the roof system type. Finally, continue to the below-grade area of the structure to look for sump pumps, smell for dampness and determine the foundation wall construction. Once the brief walk about is complete, it is important to meet with the building manager, property manager, business manager and others to start the next step: Knowledge Gathering.

Knowledge Gathering

Start this step by asking for a set of drawings. Sometimes this is a challenge. It is best to inform the owner that drawings are going to be needed before arriving so they can find and organize them. Hopefully, they have drawings to review, but with older structures, they may not be available. In this case, in order to access some of the history of the structure, interview management, maintenance staff and tenants, in addition to reviewing the maintenance and project file. Also, ask for any warranties - there is typically one for the roof, but also ask for manufacturer warranties for the window systems and the below-grade waterproofing system.

Flip to sections with details on the wall systems. First and foremost, try to identify the wall system as a barrier wall or a water-managed wall. (See ASTM 2128 Standard Guide for Evaluating Water Leakage of Building Walls). Barrier Walls are defined as the mechanism intended to prevent leakage in this type of wall is blocking or interrupting the movement of water to the interior. Water Managed Walls are the mechanism intended to prevent leakage in this type of wall is the control and discharge of anticipated and accepted amounts of water that penetrates the exterior surfaces. If it is unclear or if it seems to be questionable, become suspicious of the design details. Next, check the details. If insufficient details are pulled out of the wall sections to show how to create terminations, penetrations and changes of plane for all of the particular wall system building materials, it immediately throws up a flag.

Unless the project had a high level of quality field craftsmen or really good inspectors, there may be some challenges in the way field decisions were made in order to make these details work. Also, shop drawings should be part of the requested drawings, especially for the windows if there is a curtain wall. From the window shop drawings, try to determine how the window system is managing water. A lack of wall details or the lack of shop drawings at any time makes Step 3, Interior Symptoms, more intense.

For the roof, always look at the system type and check if the construction drawings of the roofing system match the existing conditions. If they don't, has there been any modification or repair? Also if there has been a modification, what, if anything, has been done to the parapet wall? Because parapets are exposed to weather on three sides, there is a greater chance of them having problems, especially if the modifications did not take into consideration the original design intent. Identify the number of drains and whether there is an appropriate roof slope to drain. How the through-wall scuppers are detailed always should be reviewed, especially if the scupper outlet is directly at the vertical expansion joint. Last, locate the system specified for the below-grade waterproofing and see if any details were made on termination, penetration, and changes in plane.

Interior damage at the jamb of a   window.

Interior Symptoms

At this point, if the building management has any knowledge of interior water infiltration, severe cracking of interior finishes or both, now is the time to take the observations gathered in Step 1 and Step 2 to identify symptoms in the interior. Look for the following list of symptoms:

• Staining of the interior wall surfaces, the wall system above the ceiling tiles or both
• Water-damaged insulation above the ceiling tiles
• Stained ceiling finishes
• Water-damaged window soffits, jambs and sills
• Water stains on the floor finishes, including rust stains from excessively wet steel stud baseplates
• Peeling of wallpaper
• Cracking of interior finishes
• Stains/dirt in operable window tracks
• Water stains at the perimeter of the AC units
• Mold
• Odors

Document the location of these interior symptoms so that during Step 4, Exterior Signs, a determination can be made to see if there is a direct correlation. With regard to water infiltration, remember that water does travel. As such, symptoms are often not simply on the exterior of the building. Here is where ASTM  2128 Standard Guide for Evaluating Water Leakage of Building Walls is a tremendous resource.

Exterior Signs  

Roof run up the back of a parapet wall  that created damage to the terra cotta  cornice.

Once information has been gathered from the previous three steps, the inspector will have a better understanding of what to focus on during the review of the exterior signs. For walls, the obvious big three are bulging, spalling and cracking. Following is a brief list of other exterior signs to consider:

• When the wall system has a cavity wall but the flashing cannot be seen. Note, even if drawings and inspection drawings indicate a flashing, if the flashing cannot be seen to the naked eye in the field, the installation and or functionality is suspect.
• Weep holes are caulked shut
• Weep tubes or weep wicks were used
• The roof runs up the back of the parapet wall
• Rust marks are present at embedded steel locations
• Railing posts are set in concrete pockets
• Cracks go through the masonry and the mortar
• Capstones have craze cracking
• Capstones have inside and outside bed joints and the cross joints caulked shut
• Spalling brick
• Glazed brick shattered with efflorescence stains
• Cracking through EIFS lamina
• Post-tensioning ends with rust bleed out
• A white haze on a brick cavity wall
• Efflorescence from cracks in concrete or masonry
• Grade is sloped toward the building
• Rain water conductors cut off and run out on grade
• Horizontal rust lines in mortar joints
• Discolored stone or masonry
• Racked windows and doors
• Rotted or rusted door and window frames
• Signs of condensation on glass
• Excessive mortar joint popping
• Smeared caulking on mortar joints
• Step cracking off of steel lintels
• Glued down carpets on exterior horizontal concrete surfaces
• Painted and/or caulked terra cotta
• Glass-to-metal glazing has turned into gum or has shrunk from the window frame
• Compressed building sealant at expansion joints
• Face-sealed curtain walls or window systems
• Surface alligatoring of the roof membrane
• Roof seam splits
• Roof surface applied termination bar to a cavity wall
• Overall roof drainage
• Incomplete expansion joints

If any of these signs match with any symptoms identified in the previous steps, there is a very good chance that the building envelope faces some challenges. The exterior signs without interior symptoms do not mean there is not a challenge, but it's just a matter of time. In most cases, the interior symptom will occur at some point in the life of the structure, so it is important to continue to monitor these conditions.

In most cases, obvious building envelope problems are easy to identify. In order to identify the not-so-obvious signs, especially if the interior symptoms have not occurred or have not been identified, experience in the restoration of building envelope deficiencies is priceless. Combine this with the knowledge of architectural details, engineering basics, good waterproofing practices, as well as an inspection plan as outlined above, and the owner will have the best possible information about the building envelope. This information can be used as a tool to purchase a building, create capital projects or develop a maintenance plan.