October 26, 2007 8:39 AM PDT

Start-up crafts waterproof concrete

Posted by Michael Kanellos

It's a water-based molecule that repels water.

That's Hycrete's business in a nutshell, according to CEO David Rosenberg. The company has a molecule--which consists of a water molecule with a long hydrocarbon attached--that links up to metallic ions in whatever it's mixed into. In the right circumstances, the molecule behaves like an oil and pushes water away.

The company currently sells its material to concrete manufacturers and contractors who use it to replace the bound-to-fail plastic membranes employed to keep water out of building foundations and freeway pilings. With Hycrete's molecules mixed into the cement, water can't get into corrode rebars or start wicking into the foundation where it can create long-term problems.

"One of the fundamental problems with concrete is that it is a hard sponge," he said. "Through capillary action it sucks water in."

So far, contractors have mixed the substance into 53 major projects, including sound barriers on a freeway in New Jersey. In the future, the company may mix its material into drywall to prevent moisture seepage. You could also mix it into roofing material and then put a green roof--rooftop lawns are getting bigger in urban environments like Tokyo--on top of your house without worrying about trickle down.

Grandpa's invention
Hycrete is something of a family affair. Rosenberg's grandfather, Michael Rhodes, actually invented the material about twelve years ago. A serial inventor, Rhodes worked on a number of projects for NASA, including a solid rocket fuel.

With the growth of the clean tech market, concrete is suddenly hot again. (It hasn't been this way since the Roman Empire.) Building contractors are vying to green up their projects by installing environmentally friendly HVAC systems and carpets. Concrete, which invariably goes into every project, is a natural extension of that.

A couple of building supply companies already sell concrete made of fly ash, a leftover byproduct of coal-burning power plants. Putting in concrete cuts down on the pollution utilities would have to otherwise dispose.

Hycrete allows contractors to not use plastic membranes, which in turn lets the builders earn points under the Leadership in Energy and Environmental Design (LEED) standards. The more LEED points you get, the greener your building is.

More importantly, though, it can cut down costs and risks. In the building world, no one likes the waterproofing contractor. The membranes often fail and the end result is legal disputes.

"A lot of people get into this big fingerpointing game with the waterproofing contractor," he said. By using Hycrete's additive, the membrane is eliminated. The company also promises to warrant its performance. Hycrete, in fact, sticks around for about 90 days after the building is complete to make sure things worked out properly.

Traditional waterproofing also takes time. One builder estimated that construction time was reduced two months by using the additive.