Stabilizing Watts Elementary School's Sinking Classrooms

Wednesday, July 10th, 2024 by Danielle Vilchis

Challenge

Watts Elementary School is an urban public school in Los Angeles, California, serving 348 students from kindergarten to fifth grade. As part of the Los Angeles Unified School District (LAUSD), the school faced a significant structural issue with multiple classrooms and the library sinking in the middle. This problem compromised the safety and usability of these spaces. With plans to revamp the classrooms during the summer of 2024, the school sought a solution to address the underlying foundation problem and contacted Saber Foundation Repair.

Objectives

Client Goals:

Stabilize and level the classrooms.
Ensure the safety of the students and staff.
Minimize disruption to school operations.

Saber Foundation Repair Goals:

Provide a cost-effective and efficient solution.
Implement an environmentally friendly method.
Achieve a permanent fix without the need for new concrete pouring.

A significant challenge was lifting the slab without causing cracks due to its continuous nature.

Solution

The solution involved injecting polyfoam across the slab in increments and then backtracking to inject more polyfoam as needed to achieve the desired lift.

Results

Immediate Outcomes: The lifting process was successful, with the classrooms and library restored to their original level. The polyfoam cured in just 30 minutes, allowing for immediate installation of tiles.

Client Feedback: Ligia Murdock, the lead designer, praised our cost-effective and efficient approach, and now LAUSD is considering using this method for more classrooms!

Project Summary

The Watts Elementary School project was a success, stabilizing and leveling the classrooms and libra:

Initial Assessment: The sinking problem was identified over time, with the school administration planning to work on the classrooms during the summer. Measurements were taken using string lines to gauge the extent of the sinking, revealing that each classroom was sinking towards the center by approximately three inches.

Planning: The planning phase involved designing a 4-foot grid system and strategically placing holes for polyfoam injection. Given that the classrooms consist of one giant slab, careful planning was necessary to inject polyfoam incrementally without causing cracks. The string lines were used to monitor the lift in real-time.

Drilling and Injection: The team used a 5/16 drill bit to create small, unobtrusive holes every 4 feet. Polyfoam was injected into each grid incrementally, monitored in real-time using the string line to measure the lift. This method ensured uniform lifting of the slab without causing cracks.

The lifting process was successful, with the classrooms and library restored to their original level. The polyfoam cured in just 30 minutes, allowing for immediate installation of tiles.