Keeping Grey off the Ground: Stucco Management Practices in the Residential Homebuilding Sector
Stucco siding on the exterior of residential homes is a common facade associated with the real estate landscape in southern California, however it is one of the most challenging components of the California Construction General Permit to comply with. This study included a collaboration with local municipalities, AGC, BIA and residential home building developers to troubleshoot compliance with the Construction General Permit on this very challenging activity.
The stucco application process in residential homebuilding entails a 14-day, 3-part application process of “scratch, brown and paint”. This process results in material sloughing off of the side of the wall, both as solid material, mud, and liquid runoff.. This presentation will include a description of materials used, activities performed and a typical timeline.
BMP(s) needed to be selected that would keep material and rinse water from sloughing off the house over the course of the 14-day process. In the literal translation of the California Construction General Permit, there can be no rinse or wash water or material on pervious or impervious surfaces (reference the CGP Attachments C, D and E Section B.2.a (Prevent disposal of any rinse or wash waters or material on impervious or pervious site surfaces or into the storm drain system). Our southern California municipalities, inspecting residential homebuilding construction projects, often have even more stringent language that is extremely difficult for the industry to comply with since material is constantly sloughing off the side of the walls. The overall water quality concern wit the stucco activity is that the material associated with this activity tends to cause elevated levels of pH, which could result in the project having a Numeric Action Level (NAL) exceedance at their discharge location. In addition, there was a lack of specific BMP guidance material providing very specific recommendations for how to comply with the Permit language.
Acting as a Qualified SWPPP Practitioner (QSP), my team evaluated specific management practices and physical devices to aid in compliance. BMPs considered but ultimately rejected:
Visqueen covering the ground. The visqueen could be rolled up and properly disposed of. This idea was rejected due to the safety (slip) hazard that visqueen poses. Safety managers rejected the idea due to the slip hazard associated with visuqeen.
Filter fabric covering the ground. Filter fabric doesn’t have the same slipping hazard, and would capture all of the solids sloughing off of the house, but wouldn’t contain all of the liquid runoff since the fabric is porous. This idea was rejected since most residential homebuilders recycle the material that sloughs off, and they wouldn’t be able to anymore if it was stuck to the filter fabric.
Other BMPs evaluated: mulch, earthen berm, tarps hung down outside of the scaffolding
Our team also evaluated a suite of temporary construction BMPs to determine which BMP product could be physically installed, be effective in reducing pH levels, act as a physical barrier in containing some material, comply with safety requirements, and be satisfactory to the RWQCB and municipal inspectors. Fiber roll was originally proposed around the length of the scaffolding to provide a containment area of material to remain under the scaffolding and allow for desilting of material during rain events, however we ultimately used compost logs since they don’t need to be trenched or staked in.
Once we agreed to the temporary BMPs, we developed an effective training program outline the activities associated with stucco application: a mixing area, sand pile management, concrete bag storage area, washout area, hot zones to include under the scaffolding, and good housekeeping practices outside of the scaffolding area. This BMP strategy developed in this abstract has resulted in acceptable levels with storm water samplin
Kelly Doyle is a Principal Environmental Project Manager in the Water Resources Division of Rick Engineering Company. Ms. Doyle has over 15 years of storm water construction management and inspector experience. Ms. Doyle holds a certification as a Certified Professional in Erosion and Sediment Control (CPESC), Trainer of Record for the Industrial and Construction General Permits, is a QSD, QSP and QISP. Ms. Doyle has conducted expert witness work associated with construction site storm water inspections and BMP design for residential, commercial, and public agencies. She has conducted hundreds of inspections and trained thousands in the state of California.