Bob again meets up with insulation contractor Joe Sheridan in the main house where the Cocoon insulation in being blown into the original plaster walls. To accomplish this, Joe's crew has drilled holes every 16 inches so that they are into every stud cavity. They drill one high and one low to acheive the proper density. First they apply it to the bottom and fill till it's solid in there - about 30 seconds on a bottom cavity. The installer can tell when it's filled from the pressure of the hose. The product will start backing into the hose. With experience you can hear it. Thge goal is to create maximum density in the cavities - leaving no air pockets. When the insulation process is complete a plasterer will have to come in and patch each hole individually.

Bob joins Bob Fragakis, a plastering contractor. Bob, along with his helpers Joe and Larry, will be installing blue board and then applying a plaster skim coat over the blue board. Blue board is used as its paper makes a ready surface for plaster adhesion. Fragakis� helpers show how to install the twelve-foot sheets to the ceiling and walls. He then explains the tools and materials used to smooth the plaster, deal with joints and corners, and prevent future cracks.

Here s another great tip from BobVila.com. U.S. Gypsum developed a way to sandwich plaster between two paper faces and make wallboard as early as World War I, but the manpower shortage of World War II is what really made it catch on. Before drywall, builders nailed lengths of wood, called lath, to the studs and then applied several coats of plaster to that for a smooth finish. As many of us with old houses can attest, lath and plaster walls can last a long time but they re hard to deal with if you re having rewiring, insulation and plumbing needs. Drywall comes in various thicknesses. For interior walls, one-half-inch works fine but won t stand up to heavy abuse. Five-eighth-inch is required for fire hazard walls like garages and basement entries. Standard paper-faced drywall is grey and comes in 4x8 or 4x12 sheets, designed to make it easy to cover from stud to stud with minimal cutting. But even cutting is made easy. Most drywall scores and snaps with a simple utility knife. Holes can be cut by hand with a short keyhole saw or a small rotary tool. Special fiberglass-faced drywall was recently introduced to help prevent mold problems that can develop when traditional paper-faced drywall gets wet. This new product finishes just like paper-faced drywall with tape and joint compound. Behind tile, in bathrooms and in other wet areas, it s important to use cement board. This denser product is waterproof and faced with fiberglass mesh that won t degrade or mold when it gets wet. In the past, some builders used a product called green board in bathrooms, but time has shown that this product is not a good substitute for cement board. Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com