Column and Beam Construction
I can tell you for a fact that every week I get an email from some adventuresome person who is in the midst of or contemplating a structural modification to their abode. They want me to size a beam for them. My answer is ALWAYS the same...... Call a structural engineer!
The reason for this is simple. For one thing, each situation is different. The loads above the beam location can be significant or there may be very little load. The column locations at each end and under the beam are critical as well. Columns concentrate beam loads. These concentrated loads must rest on solid materials. A rookie often forgets this vital aspect of beam construction.
There are seven common beam materials. Some are lumber products, some are steel, and others are combinations of the two. A simple beam that most people forget about is a traditional floor joist. In fact a floor system is simply a collection of beams that span between two points. Beams that we place in walls often combine one or more pieces of lumber to increase the load carrying capability of the beam.
Beams are complicated beasts. When you use lumber, not all lumber will support the same weight. Douglas Fir lumber is stronger than hemlock for example. There are vast beam sizing tables that allow you to size lumber according to its species and grade. Leave this to professionals. Don't try to do it yourself.
My own home contains three different types of beams. I have 12 inch high W12 x 31 steel I beams in my basement. The 12 stands for how many inches high the beam is. The number 31 stands for how heavy the beam is for each foot. In this case it weighs 31 pounds per foot.
I also have some neat laminated veneer lumber beams that support second floor exterior walls. These beams are basically 1 and 3/4 inch thick pieces of plywood. I also have traditional built up beams where I have nailed two or more 2x10's or 2x12's together to create a header over an opening for a doorway or a window.
There are also four other beams you can use. You can purchase fancy laminated lumber beams. These are made by gluing 2x material on top of one another. Imagine stacking 10 or more 2 x 6's on top of one another. These beams can be made to enormous sizes and can often be seen as architectural beams in public buildings. We have them exposed in my church.
You can also use a giant sawn timber as a beam. These are found in post and beam construction or a simple log home.
Imagine taking a 1/2 inch steel plate and putting it between two 2x10's. This is a flitch beam.
You can make a simple box beam by taking plywood and nailing and gluing it to 2x4's or 2x6's. This is called a box beam. I don't like using these unless an engineer calls for it.
The strongest of all beam materials is steel. You can span greater distances given the same beam height using steel in lieu of any other material.
That is why I chose to use 12 inch high steel beams in my basement. I don't have steel columns every nine feet in my basement. My steel beams span 15 feet or more without support.
To make sure I didn't hit my head in the basement, I also poured nine foot four inch high foundation walls. This gives me plenty of clearance under my steel beams.