Three helical piers and brackets have been installed under the sagging porch foundation. The Atlas Piers crew is ready to jack up the porch! This project is continued from Porch Foundation Repair – Helical Pier Installation. The problem overview and project introduction is explained in Sagging Porch Foundation Repair with Helical Piers.
Helical Foundation Piers
Recall that three helical piers were driven 15 to 22 feet deep to reach load bearing soil as illustrated in the following diagram:
Porch Foundation Repair – Jacking with Helical Piers
Each Earth Contact Products, LLC helical pier can support up to 40,000 lbs. A 25 ton hydraulic ram placed between the lift head and foundation bracket:
Two piers are installed on each side of the sidewalk under the porch foundation. The 3rd pier is located just out of view to the right:
View of the foundation bracket, lift head and ram:
Raise the Porch Foundation
A high capacity hydraulic hand pump connects to a manifold and valves with hoses to each hydraulic ram. The valves are individually controlled (opened & closed) to vary the recovery height at each pier to evenly raise the foundation. The pressure gauge is monitored to ensure the load on each pier remains within limits:
A crewman operates the hydraulic pump:
The corner porch post was plumbed and spirit levels placed on the porch and roof. The workmen placed the tip of a shovel on a scratch mark to measure how high the foundation has been raised:
Because the porch is supposed to have a slight slope for rainwater runoff we decided to stop raising the foundation when the roof was level. The porch was raised slowly – it’s almost uneventful – there’s no noise, cracking or other sounds. It took about 4 hours to install the piers but only 20 minutes (with several pauses to check the levels) to raise the foundation. The three 25 ton hydraulic rams (75 tons total!) easily did the job.
The foundation was raised over 2 inches as shown by the gap between the sidewalk and subsoil:
Post Foundation Lifting
After jacking up the foundation, the threaded lift rod lock nuts are tightened and the lift head removed:
The hydraulic ram is recovered leaving only the Tee-Tube showing on the foundation bracket:
The excavation pits are filled to cover the foundation brackets. The crew worked carefully around the landscaping then hosed everything clean:
The porch after foundation lifting. The right side of the porch is no longer sagging! A nice surprise is my front door opens perfectly now that the stress on the front wall is relieved! Had to tell the kids not to slam the door. (Note: The apparent roof sag at the center is where the shingles overhang the gutter guards. The left and right ends don’t sag because they’re supported by kickout and drip edge flashing.)
The crew was polite, worked hard and did a fine job!
Pressure Grouting – Soil Stabilization and Void Filling
Pressure grouting injects a cement slurry through 3/4 inch diameter holes drilled through the slab to stabilize the soil and fill voids after lifting. This is necessary to support the porch slab and prevent cracking:
This project is continued in Porch Foundation Repair – Cement Pressure Grouting.
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