How to Install Basement Support Posts

Support posts are used to support a structure so that it doesn't cave in. Sometimes the original support system, such as, square brick lally columns don't hold up for long, and begins to disintegrate. When this happens, it is a good time to install new or additional support posts. Support posts in the basement hold up the house. While installing new support posts make sure to jack up the ceiling or supporting beams with temporary walls so that the structure stays secure while you are doing your work.

Things You'll Need

• Plumb bob
• Tape measure
• Pencil
• Rotary hammer
• Shovel
• 12-inch tubular fiber form
• Ready mix concrete
• Steel post
• Drill motor
• 2-inch lag screws
• Lead lag shields
• Screwdriver

Instructions

1. Tie a plumb bob to the basement supporting beam and let it hang down until it reaches the concrete. Have a partner mark the floor. Draw a circle on the floor around the mark, 12 inches in diameter.

2. Break up the concrete with a rotary hammer. Remove the dirt below the hole, 28 inches deep.

3. Drop a 12-inch diameter tubular fiber form inside the hole. Make sure that the top of the tube is just under the concrete slab. Fill the tube completely with a ready mix concrete. Let the concrete dry for a week.

4. Measure the area between the top of the tube and the bottom of the beam. Take the measurements to a steel manufacturer and have a steel support post made. Have the top and bottom plates added to the post and 3/8-inch drilled holes at all four corners of both plates.

5. Vertically level the support post between the footing and the beam. When it is properly placed, mark for your holes. Line up the holes already drilled into the plates, with the holes you will drill into the beam, for proper placement. Remove the post and pre-drill holes in the beam for attaching to the post with 2-inch lag screws.

6. Insert lead lag shields into the bottom of the post with a rotary hammer. Put the post on the concrete footing and install the lags. Tighten the lags when they are all in place.

7. Fill the hole around the post with concrete. Blend it in with the existing slab.

Tips & Warnings

• Lag shields are medium-duty anchors which expand to fill in the area of the pre-drilled hole when a lag screw is inserted and then tightened into the shield.

• The basement ceiling is only as strong as the posts supporting it. If the posts are not well secured, the ceiling is not stable.