Concrete Construction Magazine, March '99

SEEN AT THE WORLD OF CONCRETE '99

(Concrete Construction Magazine, March 1999)

Two innovative fabric forming systems reduce the time, labor and lumber typically required to cast strip or pad footings

By Anne Balogh

When he was only seven years old, Richard Fearn, with the help of his father, poured his first concrete foundation - an undertaking the young builder found to be exceptionally difficult. Fearn is now much older and wider, with plenty of additional construction experience under his belt. . But he still feels the same way about foundations - constructing them can be the most difficult and labor-intensive aspect of a building project.

One problem Fearn often encountered was the difficulty of using straight, rigid lumber forms to cast concrete footings on uneven ground, a situation that required building an interface between the lumber and ground to bridge the gaps. Convinced there had to be an easier way to form concrete footings, Fearn invented and patented two fabric forming systems that overcome many of the disadvantages of using lumber. Both products were on display at World of Concrete '99 in January and are sold by Fearn's Company, Fab-Form Industries Ltd., Surrey, British Columbia, Canada.

Footing pad system, Fastbag®

The first product, the Fastbag®, is in a non woven polypropylene bag with a hole in the top. To form a footing pad, workers simply place the bag in position ion the ground and fill it by pumping concrete through the hole. No leveling of the ground is needed because the concrete-filled fabric conforms to uneven surfaces. The bag is left in place, which helps prevent rapid drying of the concrete and eliminates the need for form stripping.

Fastbags® come in six standard sizes, ranging from 18 to 48 inches square in 6-inch increments. the amount of concrete pumped into the bag determines the footing thickness. Bags 36 inches square and larger are available with zippers so workers can install reinforcing steel, if required before filling the bags with concrete.

Because they eliminate the need for form lumber, Fastbags® can cut forming costs in half, claims Fearn. The bags range in price from about $5 to $12, depending on size. Zippered bags cost a few dollars extra.

Fastfoot® Strip Footing System

The second product, the Fastfoot® Strip System, reportedly allows three workers to install 100 lineal feet of wall footing in an hour. The system uses a woven, coated polyethylene fabric that's stapled to 2X4 lumber supported by steel yokes. The lumber serves as kicker plates for the wall forms and is laid out around the perimeter of the proposed foundation workers then install the steel yokes by driving spikes into the ground through the yokes' base plates and attach the kicker plates to the yokes to hold the lumber the correct distance apart and at the correct height. Telescoping legs allow for easy height adjustments.

To install the Fastfoot® fabric, which comes in 100-foot-long by 52-inch-wide rolls, workers simply unroll the material under the yokes and staple the edges to the tops of the 2X4s with a hammer stapler. After placing the concrete into the fabric footing form, workers float the concrete level with the bottom of the kicker plates. Each step in system assembly is illustrated below.

As with the pad system, the concrete-filled fabric footing form conforms to uneven ground. A single width of fabric can accommodate changes in ground height of up to a foot; lines on the fabric serve as adjustment guides.

The day after concrete placement, workers nail the kicker plates to the concrete with duplex nails and remove the steel yokes. The wall forms can then be installed using the kicker plates as the template.

Though this system doesn't completely eliminate the need for lumber, no stakes, cross bracing or edge lumber are required to form the footing itself. Moreover, the lumber required for the kicker plates can be reused because the fabric protects it from the concrete. The cost of a roll of Fastfoot® fabric is about $41. Contractors can rent or purchase the yokes, depending on how often they plan to reuse them. Outside yokes are $58 each and inside yokes (for inverted-T foundations) are $70 apiece.

Sean McBride, president of Cowal Construction in New Westminster, British Columbia, says his company began using the strip footing system last year and saw its advantages after the first use. "On average, we save $300 to $400 per job just on labor", he reports.

On a recent job requiring the placement of 243 lineal feet of out-side footing and 46 lineal feet of interior footing with a monolithic curb wall, it took a three-man crew 2-1/2 hours to set up the yokes and kicker plates and only an hour to install the fabric. For the footing with the integral curb wall, special yokes that allow up to 12" dimension lumber to be placed on edge were used. After concrete placement, one man was able to remove the yokes for both footings in half an hour.

"The system works great for excavations that are off level", says McBride. "With the Fastfoot® fabric suspended between the 2X4s, all you have to do is let out more of the fabric to allow for the slope of the excavation.