As an experienced contractor in Phoenix, Arizona, stabilization is key for building ADUs on unstable soils. One approach I've used is compaction grouting, where we inject a cement mixture into loose soils below foundations. This strengthens and solidifies the soil, providing adequate bearing support. On a recent ADU project, the existing garage had cracked walls and a sloping floor from sandy, compacting soil. Rather than demolishing it, we drilled holes around the perimeter and pumped in compaction grout. This lifted and leveled the structure by stabilizing the soil below. The owner saved $15,000, and we finished the renovation on schedule. Another method is rammed aggregate piers, where we drive out loose soil with a hydraulic ram and backfill the voids with crushed stone. The piers extend down to stable layers, transferring the structure's weight and providing lift. We recently underpinned an old barn with rammed aggregate piers, leveling the floor and walls to convert it into an ADU and studio. No two sites are alike, so innovative solutions are key. By choosing the right method for the soil conditions, we provide safe and code-compliant foundations without defaulting to expensive piles. Compaction grouting and rammed aggregate piers have provided cost-effective solutions for many ADU projects on unstable ground.
As president of Lee & Cates Glass, a commercial glazing company, we've faced many soil stabilization challenges over the years. One innovative approach we've taken is using helical piers for foundation support on unstable soils. These steel piers are screwed into the ground, past the point of weak soil, to reach more solid bearing strata. The piers are then attached to the existing foundation to provide uplift resistance and lateral support. We used this method on a commercial building with differential settlement causing cracks in the facade. By installing helical piers around the perimeter of the foundation, we were able to lift and relevel the structure, then stabilize it for the long term. Glass curtain walls and storefronts require a stable foundation, so we're always researching the latest geotechnical methods. Another technique we’ve used is soil mixing - injecting a chemical grout directly into on-site soils to solidify granular deposits. On a project with loose, sandy soil, we mixed the soil with a hardening agent that permeated 8 feet down and out, strengthening the soil. For deep foundations, nothing beats concrete-filled steel pipe piles driven to bedrock. We’ve used pipe piles up to 60 feet deep for multi-story buildings on soft soils. Although more expensive, piles provide the most robust and permanent solution when variable or weak soils threaten a structure.
As an owner of a roofing company for over 25 years, soil stabilization is crucial for any roofing project. One innovative approach I've taken is using helical piers to provide foundation support in unstable soil conditions. By installing piers around building perimeters and attaching them to existing foundations, we're able to lift and level structures before installing a new roof. On a church roofing project, the building had settled differentially due to loose, sandy soil. We installed helical piers around the perimeter, attaching them to the foundation. Lifting the structure and stabilizing it allowed us to install a seamless, level metal roof despite the challenging soil conditions. For larger commercial projects on soft soils, nothing provides more robust, permanent support than concrete-filled steel pipe piles driven deep to bedrock. Although more expensive, pipe piles gave multi-story buildings in our area a stable foundation for us to install and warranty roofing systems. By investing in the right geotechnical solution upfront, we're able to avoid issues from soil settlement down the road. Stabilizing soil and foundations is key to any long-lasting roof. By using helical piers, pipe piles, and soil mixing, I've overcome many soil challenges to install premium, high-performance roofing for our clients. Community support and referrals have driven our success, as we work to address roofing needs and provide lasting solutions.