Installing Perpendicular Joists for Temporary Support

What You'll Need
2 x 4 Lumber
4 x 4 Posts
Hydraulic Jack
Scrap Lumber
3 Inch Nails

Whenever a project that requires working with load bearing walls, joists, or overhangs is being worked on, a temporary support is needed to shoulder the load. One of the most common projects where a temporary support is needed is the replacement of a porch column. Many homeowners are intimidated when it comes to doing any type of project that requires using temporary supports to hold up a roof, ceiling, or wall. With the use of a temporary support, a homeowner can easily perform many tasks that will usually cost them a lot of money by hiring contractors. Here are some steps to follow in installing a temporary support that is perpendicular to the joists.

Step 1: Determine Load Being Supported

You will not have to have an exact weight in mind for this step. However, you must realize the amount of stress that the temporary support will be under. For holding up a porch roof, the load is going to be considerably less than a support that is needed for holding up the floor joists in the basement. Take into account where the support will be needed and use the appropriate lumber and spacing.

Step 2: Calculate Materials

If you are going to be supporting a porch roof that runs the front side of your home, you can use simple 2 x 4 lumber. You should have a spacing between each support of 4 feet, plus two in each corner. For a 20-foot porch roof, you will then need to have five different temporary supports. For larger applications, like supporting floor joists in the basement, 4 x 4 posts should be set at 6-foot intervals.

Step 3: Set Firm Footing

The temporary support that you use will need to have a firm footing in order to hold up the weight. For a perpendicular support you should use square pieces of 3/4-inch plywood, or other scraps of wood that are at least 10 inches wide. Place the wood on the floor, or ground, and hold in place with small screws.

Step 4: Jack Up Section

In order to remove the column on a porch, or a beam on a ceiling, or studs in a wall, you must jack up the section a little in order to remove it and set a temporary support in place. Use large hydraulic jacks as they have a large span and can handle tremendous loads.

Step 5: Place Temporary Support in Position

Stand the support in place where it is going to be needed. Place two blocks of scrap 2 x 4 lumber on each side of the support and nail them together. Toenail nails into the bottom footing in order to hold the support stationary. Place two more pieces of scrap lumber on each side of the top and nail them together. Again, toenail some nails into the joist for added support.

Step 6: Release Pressure

With the temporary support in place, start to release the pressure on the jack. You may notice some noise coming from the lumber, but it will stay. If you feel uneasy, install crossmembers between each support for added strength.