Article No: 187

2006-06-23 09:33:39
Complexity captures CFA award Balmer Brothers basement wins again
By: Carol McMichael


 

 

Photography by Randy Groome

 

In 2005, the sheer size—34,000 square feet—of a basement project by Balmer Brothers Concrete Work Inc. earned the company the Basement of the Year Award, acknowledging their skill in successfully handling a huge project. This year, the company won the award for the third time, gaining contractors’ votes for a large basement design dubbed The Dragon House because of its complex curved walls.


Each year, the Basement of the Year Award is conferred by the Concrete Foundations Association (CFA), an international organization that promotes improved quality and awareness of construction with cast-in-place concrete systems. Entries to the competition are judged on the project’s degree of difficulty and its execution.


The award-winning basement of the Hattersley residence in Eastown Township, Pennsylvania, has a 5,694-square-foot foundation, which includes some patio areas. It consists of 995 linear feet (345 yards) of cast-in-place concrete walls—the footing called for an additional 105 yards. The project also required 27,680 linear feet of No. 4 matt steel at 2 feet on-center within the panels. Wall heights range from 3 feet to 9 feet; wall thickness from 12 inches to 16 inches.


Although the project called for a full basement, it is windowless and not meant to be a living area. Only one small area, a stairway leading to the garage, is finished. The flow of the terrain allows for a large patio in the rear of the home with fairly large planters and garden walls that double as retaining walls.

The Dragon House
The Dragon House, alternatively called The Spaceship by the project’s crew, provided an in-depth lesson in building curved walls.


“We had a lot of different radius points, which is the point where you pull the curve from,” explains Randy Groome, superintendent of the Hattersley basement for Balmer Brothers. “We had eight different radius points. The smallest was 4 feet, 2 inches. That was for two stone walls, a design feature in front of the house. The longest was almost 92 feet. That went from the front to the back patio—the whole house was kind of on a curve. We were pulling radius points from down low, up over things and back down. It was very tricky.”


The construction crew used forms ranging from 1/2 inch to 3 feet to create the basement’s curving walls. “Depending on the radius, we used a smaller form on the inside and a bigger form on the outside,” says Groome. To create tighter arcs, he used more forms to ensure the curvature was smooth.


The exterior walls of the basement are stucco with stone ledges, 500 feet in all, which did not protrude from the wall. To achieve this effect, Groome put a block-out in the forms, removing it after the pour to allow the stone to be laid into the pocket to create the ledge. Very tightly curved walls required block-outs made from three separate pieces.


Groome remembers one especially complex wall transition: “We jumped one wall from a 9-foot wall to a 3-foot wall in the middle of a curve, where there isn’t anything to go off of.” The radius point began at one level, rose to another level of earth, then back down to a third level. Though complicated, “It would have been more expensive to level out the terrain,” he says. “There, they only needed a 3-foot wall for frost protection.”


Normally, basements have T-walls, but this project required Groome to create several transitions to join straight and curved walls. In these situations, he used ties of various sizes to bring a thicker wall, where two curves came together, into a smaller wall. The walls form a Y-wall.


“Corners were also a challenge,” adds Groome. “We had a lot of funny angles that we had to make and brace with vice grips. The traditional corner is the molded 90-degree. We were pretty much improvising and evaluated one area at a time.”

The forms
Having determined that removable aluminum forms are “pretty much the same,” Balmer Brothers purchases its forms from a variety of suppliers. Many companies offer a hinged-corner option that allows builders to create any angle they want. The only problem with these forms, according to Groome, is that the concrete can push an improperly braced corner out of shape. On some occasions, he has used more than 100 vice grips to keep the corner intact. He uses Rawl studs and extra walers, and sometimes bolts forms to the footer.


“To make sure the forms from various companies connect properly,” explains Groome, “we order the forms with the hole patterns designed to match. Manufacturers are constantly improving their products. If we have something that we want made, it may already be made—or they will work with us and make what we want. This helps us save on fillers.”


Groome is quick to point out that Balmer Brothers has been in business for 33 years. “I know this system works well,” he says. “Over time, we have built up a range of sizes and do a lot of replenishing and adding on. We have different sizes, from 1 foot to 8 feet in height. We also have some commercial 8-foot-by-9-foot panels that are set with a crane. We do mainly residential, but can do just about any project.”
 
The forms at work
Before excavation begins on any project, knowing as many details as possible is the most important thing, according to Groome. He likes to study the plans to determine what is going to happen inside the walls, and on the top, once the structure is framed. He also learns the type of ledge to be installed and anticipates materials that will be needed at the job site so work can move forward uninterrupted. 


Once these preparations were made for The Dragon House, the crew poured the footers. In spite of its complexity, the basement required only two footer sizes. The forms were erected and attached to the footers with steel nails. In some places, bolts were used because of the curves and hinged angles.


Filling the walls to their full height took less than four hours. Because of hot weather, the team was able to strip the forms the following day. “We keep the forms in good shape,” says Groome. “They are oiled before we pour and if they need it, we may do a little bit of hammering after we strip.” Groome adds that, though the process takes more time, Pennsylvania’s winter months are not cold enough to stop work. “If we have bad weather, we wait for a good day and keep the walls protected until then,” he says.


Because of this basement’s size, it required hundreds of forms, especially fillers—much more than the average project. The company owned enough for the job, but casting the whole basement at once would have tied up Balmer’s other projects. Groome decided to pour the basement in two sections. He determined where to break the framing according to what would create the fewest problems with moisture and soil backpressure. The placement of the doorways made it possible to split the house in two. The crew set up the forms in the front section in a few days, poured the concrete, and waited to remove the forms; then repeated the process for the back section. This left only two areas of cold joints—the fewer, the better, notes Groome.

Quality crew members
Balmer Brothers employs five or six full-time crews: 28 to 30 people during the winter, and an additional 10 to 15 in good weather. “They care about what we are doing,” says Groome. “It showed in the quality of work we ended up getting done. The house turned out great and it was because they cared as much as I did. We do a lot of large houses with unusual features. All of our crews are used to this.” 


 In addition to obvious technical skill, Groome possesses humility, too: “Any of our crews could have won this award; we just happened to get this job. When we send in our application, we try to pick the one with the most twists and turns. It is fun to do the challenging jobs, but it’s nice to have a normal one every once in a while.”


For more information, visit balmerbros.com.