In your basement, there’s a blank wall staring back at you. Then there’s that hole you framed to support a staircase… Which might brings down ceiling. This is where carpentry intuition goes south.
Traditional timber doesn’t behave like engineered lumber. A laminated veneer lumber beam measuring eleven and seven-eighths inches may appear only as a plank. But it’s a structurally complex component requiring careful calculation. See the infographic to see how much weight each depth can hold, that prevents you from winging it.
How to Use LVL Beams Safely
DIYers think of LVL as dimensional lumber. If a 2×10 spans over some distance, they reason that twice as much. Say a 4×10; would be even stronger. This is where folks go astray.
LVL is made to consistent specifications. Its strength come from layers of veneer and glue. It isn’t just about raw mass. As the chart illustrates, more plies means something different than you think.
Maybe you’d use one for a small window header? You would probably use three or four for your garage door. A simple picture makes it all clear. Composites are made by stacking layers. Force on one end bend less than force on a solid piece.
For home owners, it’s difficult to understand what the load is. When you frame a beam, you are not only supporting the beam’s own weight. You’re also supporting whatever sits on top of the beam. That could be the roof or the floor above it. On top of that, there may be furnitures, people, or snow. The chart categorizes the loads in pounds per linear foot. It makes it easier to see how much pressure is being applied.
A floor with heavy tile on the second story have a large load. An attic with just some storage stuff has less of a load. A forty-pound load spans one way, but a two-hundred-pound load covers only half that distance. This can catch folks off-guard when they go to frame.
There are details that get overlooked like stiffness. How stiff is the beam? That’s its modulus of elasticity. The modulus of elasticity is what will cause it to sag. So the stiffer the beam (the higher E rating) the more you can span out based off of it. The graphic shows the difference between a one-point-nine E and a two-point.zero E. It provides a couple of inches of additional reach. Doesn’t seem like much, but those inches matter.
Those inches let you go with standard hardware. Those inches help make a beam fit in an awkward space. And you always want to match the table to the stamp on the wood. Using a lower-grade chart for higher-grade wood is safe, but using a higher-grade chart for lower-grade wood is a liability. But going up in grade chart when going down in wood could of been bad.
Beyond span issues, there are installation issues. Don’t think you can simply nail ply plies together. Structural bolts and screws must be used for proper fastening. Why? Because this makes it act like one piece. It won’t slip from board to board.
Bearing length matter too. If your beam bears down on concrete, watch out for that. Don’t have raw wood laying on wet concrete! Use a moisture barrier. And remember, the more complicated the support, the larger bearing requirement (see chart).
The LVL is a dry-use product. It can be damaged by storage in the rain. Damage from installation prior to enclosing house. Edges swell. Structural degradation. Keep the lumber flat. Keep the lumber dry.
Believe the numbers. To support the ceiling. And do it quietly. It does not creak or bounce. It should feel solid when you stand on the floor.
That’s what engineered lumber promises. Make the span work and then forget about the beam. Make it do its job invisibly. It will be there reliably for decades.
