Looking Out for Window Replacement Trouble

Four tips for avoiding surprises that can turn a window replacement project into a catastrophe.

By Robin Suttell  

Any major capital improvement project comes with its fair share of possible roadblocks. Yet the surprise factor on window replacement projects often packs a greater punch than that on a routine painting job or flooring replacement.

Given that windows stay in place for decades, facility executives might only encounter a total replacement project once during their careers. Noise, dust, work crews and general disruption are to be expected in any building undergoing a window replacement project. And while complications occur, they don’t have to derail a project if the surprises are anticipated before demolition begins.

“It’s much easier, obviously, to do a window installation in an unoccupied building than in an occupied one,” says Theresa Shephard, an associate at Klein & Hoffman Inc. and manager of the firm’s Buildings Group. “It’s a terrible inconvenience for those who live or work in the building. Disruption can’t be avoided, but it can be minimized.”

Inevitably, complications will happen during the course of the job. Some of the most common events, however, can be mitigated, if not avoided entirely, with careful planning, preparation, attention to detail and ongoing communication, not just with the design and construction team, but also with the building occupants.
There are four items that should be on the don’t-do list of every facility executive planning a window replacement.

1. Complete a preliminary mockup.

No one would expect two buildings to have the same construction details. But it’s also rare to find a single building that is built exactly the same throughout. A building can have multiple construction variations in window openings, even if they all look the same once the window is installed.

“There can be slight variations from window to window,” says Pete Power, associate principal at Klein & Hoffman. “The windows may be the same size, but the openings aren’t. In a lot of buildings, the windows went in first and the interiors went in second. Plaster can hide a lot of things. Windows can be crooked. They might not be plumb. You have to expect some variations.”

That’s why a preliminary mockup — a trial run of the window installation on selected openings — is such an important step in eliminating surprises at demolition time. While some facility executives feel mockups add unnecessary time and cost to the bid package, many more swear by them as an effective way to avoid problems down the road.

“Mockups are invaluable to work out all the kinks before you start making a lot of openings in a building,” says Richard A. Weber, consultant with Wiss, Janey, Elstner Associates. “The process allows you to review the aesthetics and can allow testing to make sure the window system meets the proper performance criteria.” If the schedule permits the mockup to sit through the winter, it can also be used to review condensation issues.

Shephard agrees. “From a technical aspect, we always recommend a mockup installation to eliminate surprises that can directly affect the construction schedule and inconvenience the tenants,” she says. “Mockups give everyone a better understanding of what’s really involved in the installation.”

If the building has different types of windows throughout, such as areas of strip windows, punch windows or different types of configurations, Shephard advises a mockup installation and testing of each unique installation, for three reasons:

  • It allows the contractor to see how long it takes to physically remove the existing window and install the new one.
  • It weeds out window manufacturing errors or improperly specified windows before multiple windows are installed.
  • It allows the contractor and engineer to assess the condition of the substrate material.

“The substrate could be more deteriorated than it originally appeared once you remove the old window,” Shephard says. “You can make the assumption from a mockup, based on the damage seen to adjacent substrates if a previous detailed inspection was done, that the same damage will also be found with a percentage of other similar windows. This way you can lock the contractor into a unit cost to perform that kind of repair early on rather than at the end of a job.”

The cost for mockups is built into the bid package, although some facility executives opt not to include them, citing expense as a reason to avoid the practice. However, in many cases, a mockup can save money in the long run if it reveals the need for expensive repairs before a job starts rather than once it is underway.

“What you learn in a mockup can resolve a lot of details,” Weber says. “A mockup goes a long way to revealing what the construction sequence should be. It takes at least some of the headache out of doing the rest of the project. You learn what you’re in for. It really is effective.”

David Kriegel, partner at Gran Associates, stresses the importance of this step. “Insist on a mockup,” he says. “It’s helpful for everyone involved.”

2. Don’t ignore the risk of hidden hazards.

Environmental hazards such as lead paint and mold can throw even the most finely tuned window replacement plan off schedule for weeks — even months — if discovered in the middle of a job.

In most cases, the presence of lead paint can be determined and addressed before demolition work starts. Unless, of course, substrates topped off with lead-containing coatings aren’t visible or have been covered at some point with other coatings.

“Assume that the paint on steel casements probably has lead in it and that grinding paint off those windows will contaminate everything,” Kriegel says.

While lead paint issues often are obvious, the hidden danger comes from mold.

“One major problem in removing leaking windows from a building is finding out if the drywall or finishes contain mold,” Weber says. “Remediation can be expensive and can completely shut down a project if not anticipated.”

Weber tells facility executives to work on this rule of thumb: If you’re having water leakage problems, mold may be present behind interior finishes. An industrial hygienist can perform an inspection to find out if mold is a major issue before the contractor starts demolition work. An industrial hygienist can also determine what kind of safety precautions will be needed to remove the contaminated drywall and prevent mold from being released into the air.

3. Don’t develop a schedule that is too tight or too ambitious.

While ill-fitting windows, deteriorating substrates and mold can impede a smooth window installation plan, so can poor scheduling, especially if the replacement occurs in an occupied building, such as a commercial office or a health care facility. Plan in great detail, from the start, what the job is going to entail and how long it will take.

“You need military precision to go through some of these occupied spaces,” Power says. “It’s not new construction where carpenters can come in and make a mess and no one cares. When you take windows out, it becomes windy. You have to run on a pre-determined schedule and let people know where you are going to be working on what day and maintain that.”

Power suggests insisting that the contractor follow a cardinal rule in scheduling: Only remove a window if a replacement window is on site and can be installed that day.

“Windows taken out in the morning must be replaced by the end of the day in any given unit in a building,” Power says. “Finish work might follow, but we don’t want to put that tenant out for more than a day.”

On average, most contractors can do about 20 to 30 individual window installations per day on a large job. The more difficult the installation, the fewer installations can be completed in a day.

“The trick is to keep it in some sort of logical order,” Power says. “Occupants will want to know when work will affect them. They want to know what’s next.”

Mockups can play a big role in developing a workable installation schedule, Shephard says.

A contractor might presume that it can remove and install 20 windows in a day, then do a mockup and find out it can only do 17 windows a day.

“If you’re talking about a project that might have 1,000 or 2,000 window openings to fill, that can have a serious impact on the schedule,” Shephard says.

It’s also important to avoid situations that require the contractor to board up window openings at night.

“It leaves you susceptible to water infiltration,” Power says, adding that sometimes an installation glitch can require the contractor to board up an opening so that repairs can be made the next day. But boards should be an exception, not the rule.

Of course, weather can derail even the best-laid plans. When working to develop a feasible replacement schedule, Shephard says it is advisable to build in a buffer for weather delays. She bases this recommendation on weather patterns over the past few years.

“If last year at this same time we had 14 days where work was cancelled because of inclement weather — rain, temperature or wind — we want to make sure we account for at least that many days in the current project,” Shephard says. “You can’t predict the weather, but you want to make sure you have weather days in the schedule.”

In the event that weather derails a schedule, careful planning will allow contractors to pick up where they left off before the delay. The schedule will just move back a day or two, depending on the length of the delay.

4. Don’t forget the human factor.

Scheduling ties directly into issues related to occupants. Facility executives not only have to oversee the construction crews and the success of their installations, they also have to maintain occupant comfort and happiness during a tumultuous time.

“Communication is crucial,” Shephard says. “You need to communicate what the schedules will be and how the occupants will be affected.”

Most window replacement experts suggest that facility executives have an informational meeting with occupants before the project starts to inform them how to prepare their spaces for the installation.

Some rules of thumb to offer occupants include the following:

  • Clear a 5-foot path from the door to the window. Contractors will need to walk through the space with materials to reach the window openings.
  • Clear adequate space around the window so installers have room to work.
  • Take things off walls and cover or remove items for protection. The space will be windy when windows are removed.

Make sure that contractor bids include materials to protect carpeting, flooring, furniture and fixtures, experts advise.

A community bulletin board in a well-traveled lobby or by an elevator bank serves as an ideal location to maintain an ongoing project status update for tenants. There they can check the daily construction schedule, which can be color coded to show completed units, those in progress and those next in line.

“We’ve learned that if you hand out a schedule, people don’t look at it,” Power says. “They’re more apt to look at a sign or bulletin board.”

Also consider putting some sort of security plan in place. Office units will be open during installations. Work with the contractor to ensure only approved personnel are on the worksite.

“Outside of product manufacturing or delivery problems, there really shouldn’t be surprises if everything is planned carefully,” Shephard says. “Window replacement projects end up being disasters when they are engineered and executed by a team that doesn’t have extensive experience in that area. Experience allows all involved to understand the technical issues that can affect not only the physical installation but also the human element.”

Robin Suttell is a freelance writer who has written extensively about building design, construction and operations issues.

Understanding Performance Metrics

Surprise mitigation starts at specification. Because window replacement projects don’t occur too often, many facility executives don’t understand window performance ratings and other factors that affect the long-term success of a system in any given building.

Architects and engineers can provide detailed information on performance ratings and what best suits the building during the early planning and design phases. This rating criterion takes air infiltration and water penetration into account.

Facility executives need to understand how performance ratings can affect the end results and that many times the best-rated window for a building won’t be the cheapest.

The least restrictive of the performance class ratings is residential, followed by light commercial, heavy commercial and architectural. The better the performance class, the better the performance in terms of water and air penetration. Architectural class windows meet the highest performance criterion and also undergo stringent life-cycle testing on operability, hardware, finishes and more.

The key is selecting the right rating for the building and not over- or under-specifying. Over-specify, and the costs run up needlessly. Under-specify, and the window system can deliver disappointing results.

Another consideration is relative humidity. Some windows perform better than others in humid environments. Specify the wrong window and expect to see condensation, which can cause a host of structural concerns including warping, rot and mold.

Windows receive a rating for their condensation resistance factor, or CRF. This rating assists facility executives with accurately choosing a window that will perform appropriately in a building’s relative humidity.

— Robin Suttell

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  posted on 3/1/2007   Article Use Policy

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