Construction Tolerance

Where codes or regulations establish minimum or maximum values and allow no tolerance outside the limit, industry standard construction tolerance should be incorporated into the design. For example, concrete ramps that must comply with "zero tolerance" maximum slope requirements for wheelchair accessibility should be designed at less than the maximum slope, such that allowable construction tolerance for concrete surfaces will not result in a slope that exceeds the maximum for wheelchair accessibility. If the maximum slope for wheelchair accessibility is 1:12, a design slope of 1:13 (or 0.95:12) may provide sufficient tolerance for construction to meet the slope regulations.

Masonry Design: Separate hung masonry from foundation-supported masonry

When drawing up elevations for masonry walls, in addition to locating control joints (arguably "expansion joints") to accommodate expansion and contraction related to temperature and moisture, it is important to consider how masonry supported on lintels hung directly from deflecting structural steel will move differently from masonry that is supported directly by the building foundation. While "loose" lintels supporting masonry over openings usually rest on foundation-supported masonry at the ends of the spanned opening, hung lintels should be isolated from foundation-supported masonry in a way that allows for independent vertical movement related to deflection of structural steel. If the hung lintel overlaps the foundation-supported masonry, a soft joint similar to that below a relieving angle may be appropriate below the end of the hung lintel. And the control joint above the lintel should also be located to allow for independent movement of the two masonry conditions. Determining the location of the ends of the hung lintel is important for construction that will properly respect the different needs of the two conditions. It gets more complicated for hung lintel assemblies suspended from beams that are interrupted by columns. In any case, careful consideration should be given to the locations of control joints within the wall area that is supported by the hung lintels.

In some cases the best control joint locations for wall performance will not be the best locations for aesthetic intent. But, then, cracks are not usually attractive in appearance.

Purposeful chaos (the 2-minute design offense)

While throwing staff at a project at the last minute is likely to be counterproductive (see Staffing a design project), an imminent project deadline can ignite productive and purposeful chaos that is otherwise hard to generate. Consider the possible accomplishments of the "2-minute offense" or "no huddle offense" that are so well known and widely used during the last minutes of a football game. A scripted sequence of plays may produce effective results in a short time. Deadlines and completion milestones are important for efficiency, because work tends to fill the time available, and it will likely take more hours (and therefore cost more for labor) to do a task without an imminent deadline. Interim or "partial completion" deadlines with well-defined scopes of work and timely, attentive reviews can be helpful in keeping a project on schedule and also on target in terms of design intent. Architecture is like other work when it comes to efficient production.

Mike offered another idea for managing labor costs on a design project. "If you know you are going to have to work overtime on a project," he said, "do it in the beginning. It costs less to do overtime when there are only one or two people working on a project."

Masonry Design: A subtle difference in brick sizes

It may come as no surprise that bricks are available in different shapes and sizes. But, in at least one situation, the difference in size may be too subtle to notice until you see an area of infill that does not match the rest in coursing or joint thickness.

"Hey! Look at that small area of bricks with the fat mortar joints. What happened?"

Many U.S. buildings that are decades old were constructed of "standard" brick, each unit with an actual length of 8 inches. Today's "standard modular" brick of similar height and depth typically has a nominal length of 8 inches including the mortar head joint and an actual length of 7.625 inches, allowing for a .375 inch mortar head joint. (An actual length of 7.5 inches may also be available to accommodate a .5 inch head joint.) If you are renovating or adding to an existing brick building, it's a good idea to measure the existing brick. And, if you can't get a matching size, you may want to consider that in designing areas of infill.

(Similar issues can apply to matching existing brick color and bond. It may take a close look to spot a Flemish bond, a possible indication of underlying construction that differs from today's typical cavity wall or brick veneer construction.)

Productive coordination meetings on the go

When an architect assembles a conference room full of consultants for a coordination meeting, power and status can sometimes interfere with productive coordination. Some of the consultants may have traveled for hours, may feel uncomfortable or out of their element, or they may be unnerved by having to make a presentation in the architect's office. They may not be at their best when attending such a meeting. And they may tune out much of the conversation, feeling like they are wasting time waiting for their turn to speak or to go home. Coordination points may be lost during the meeting or on a long drive home. "We talked about that," recalled the architect. "I'm sorry, but I don't remember that," replied the consultant.

Some of the most productive coordination meetings can take place when the architect goes to the consultants' offices. The consultants are on their own turf and may be more comfortable with the conversation. They may also have better access to coordination information and materials. Individual members of the consultant's team can be on call and participate only as needed, while continuing to be productive with other tasks in their office outside the meeting. A meeting in the consultant's office can be more economical for the consultant, and it can also be beneficial for the architect to see where and how the consultant's business is organized.

Building Thermal Movement: Everything in a building moves

We tend to think of buildings as static creations.

Sure, doors and windows may move, elevators and escalators go up and down, water runs through pipes, air through ducts, and fans turn on and off. But we tend to think of the structure, the walls, the floors, and the roof as fixed components that do not move. In fact, they all do move. They expand and contract at different rates in response to changes in temperature and/or humidity. Bricks and wood swell with moisture absorption; concrete shrinks as it cures; aluminum expands at a much higher rate than steel under the same temperature increase. Some movement is reversible; other movement is not. Much of this movement is imperceptible until the forces of expansion or contraction result in a visible scar like a crack in a wall or broken glass or water damage. Alas, the rewards for successfully accommodating building movement are not usually published.

Value Engineering can add value

Architects and engineers may be used to thinking of Value Engineering as a form of design torture, where value is stripped out of a project design in order to save money. But Value Engineering can also provide an opportunity to consider values that may enhance the performance of a building over time. It is a good time to consider or revisit questions of maintainability, access for maintenance, and flexibility for changing uses over time. One use change that is common but rarely considered is the conversion of non-storage spaces to storage use; this is often done informally by building users and without consideration for the capacity of the floor or other supporting structure that is being loaded. In some cases the structural capacity of a floor can be increased by including additional floor joists and reducing the spacing between them, and the initial additional cost may be minimal for a substantial gain in flexibility. (Storage uses may also bring other requirements that should be considered in making the decision.)