There has been new building materials, commonly called engineered wood products, on the market for quite some time. One of those materials we are using in the Cottage is laminated veneer lumber (LVL) for the main beam supporting the floor.
Similar in appearance to plywood, LVL is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. It offers several advantages over typical milled lumber: it is stronger, straighter, and more uniform, and is much less likely than conventional lumber to warp, twist, bow, or shrink due to its composite nature. LVL is typically used for headers, beams, rimboard, and edge-forming material.
LVL is still a relatively new product; it was developed in Canada in the late 1990s. High-tech, computerized sawing systems are what makes it possible to produce large-size, top quality construction material using relatively small trees.
The beam we are using is made up of three pieces of 1.25" x 9.5" LVL that are each 33 feet long. These things are long, awkward and heavy. Two people can pick up one of them but three pieces would be impossible without a crane. So we assembled the full beam by inserting each piece into the slot formed in the concrete wall on opposing sides of the foundation and then nailing them together while in place. We used clamps to hold the pieces while we nailed them.
Like all framing, any wood must be insulated from the concrete using a thin bit of plastic called a sill gasket. Hence we lined the inside of the slot in the concrete wall with a sill gasket. From the picture you will notice that we also used some wood spacers to 1) raise the beam so that the top was flush with the sill board, and 2) to fill the gap on one side of the beam (essentially filling the rest of the slot.
The picture at right illustrates the slot, the wood spacers, and the sill gasket. If you look closely you can see that the beam is actually made up of 3 LVL beams.