Homebuilding: Setting Basement Steel

One of the first steps in the construction of a new home is setting the steel beams and columns in the basement and/or crawl space. This supports the floor joists and usually runs the length of the house at mid span in most homes. Not only does this system support the floor, but usually has the weight of bearing walls, ceilings, second floors, second floor bearing walls and sometimes roofs transfered down to it.

The first step is to install the sill plates on the foundation wall . This gives you a place to nail 2x4 bracing to hold columns and beams in place while you install them. Once set in place these braces hold the steel till the floor joists are nailed in to take their place.

Before I continue, a word of caution. Homebuilding can be a dangerous activity. Care and safety are a must in all phases of the construction process. Setting steel definitely falls into this category. Beams can weigh anywhere from 100 to 400 pounds depending on their size and length. Beams can be lifted into place manually but I would recommend the use of a crane. Not only can the beams be put in place safely, but it can also quicken the process.

With the sill plates in place the steel can be set. One end of the first beam typically starts in a beam pocket formed into the top of the foundation wall. The other end sits on top of a lally column. A typical column is 3 1/2" in diameter and filled with concrete. It has a flange welded to the top with holes in it that match holes in the bottom flange of the beam. The beam is lowered onto the column and then bolted together.

To make this happen, I like to use four people. One to hold the beam in the pocket, one to hold the column, one man on a ladder to guide and bolt the beam onto the column and one man to nail off bracing to sill plates. Braces (2x4's) are laid flat on the bottom flange of the beam on both sides of the web and then nailed to the sill plates on opposing walls.

The next beam is now ready to be set. With one person holding the next column, the next beam is lowered onto the new column and the previous column. Men on ladders guide it into place and bolt it down. Again 2x4's are used to brace the beam to the outside foundation walls. This procedure is repeated until you get to a beam pocket at the other end of the building, or a column that terminates at an opening.

To keep beams level and straight, I like to use a dry line from beam pocket to beam pocket (this can also be done with a laser). First I drive a nail in the sill plate corresponding with the edge of the beam. Most beams run pocket to pocket. If this is the case I'll drive a nail in the plate by that pocket at the same dimension as the first nail, measured from a common reference point, usually the front or back sill plate. I now have a reference point to line up the edge of the beams with and result in a straight installation.

Assuming the foundation and sill plates are level, this string can be used to level the steel beams (again, a laser can be used). After most beam installations a 2x plate is either bolted or shot with a powder actuated tool to the top of the beam. This is to bring it level with the sill plates and to provide nailing for the floor joists. Using a 2x block as a gauge, lay it on the top of the beam where it sits on a column. This simulates the plate that will be installed later. Shim the column till the block touches the bottom of the dry line. Repeat this for every column. Columns are shimmed with steel plates of various thicknesses. These shims are provided by the steel supplier.

The next step is to plumb the lally columns on their concrete pads. Using a 4-foot level, the columns are tapped into plumb with a sledge hammer. Make sure the steel shims remain under the columns. After all columns are plumbed up, the concrete floor can be poured. This holds the columns in place.

The next step is to frame the floor. Once the floor joists are nailed in place all bracing can be removed. The joists are now holding the steel in place.

Just like the foundation, setting the steel straight and level is important to producing a quality home.

(c) Mike Merisko www.sawkerfs.com

About the Author: Mike Merisko has been a carpenter for 26 years. Most of those years were spent in the homebuilding and remodeling industries. He was also in business as a carpentry and general contractor. While that is his forte, he also has experience in bridge building, commercial construction, and exhibit building which is how he earns his living these days. You can browse through articles by him and others at his website http://www.sawkerfs.com/ or visit his blog at http://www.sawkerfs.blogspot.com