Case Study: Custom Home in Hayward, California
The case study this article will address is concerning a custom home build in Hayward, California. This home has some engineering issues that concern the need for a fire apparatus turnaround on a steep slope.
The house in question is part of a two-lot minor subdivision. The engineer must find a way to provide a fire apparatus turnaround and avoid drainage issues. Let’s dive into what we discovered!
Thinking about the accessibility of the two-lot split in Hayward for a custom home, we must consider the fire access and steep slope regulations. In the next portion of the article, we will highlight some ways this project can be completed successfully.
Identifying the Project Issues
The design of the custom home in Hayward has identified some issues that can be mitigated by onboarding a geotechnical engineer, landscape architect, and civil engineer for design purposes.
A geotechnical engineer will investigate and evaluate the soil and structure foundations in order to make recommendations on the steep slope issue.
The landscape architect will provide insight on drought tolerant species for the landscaping in order to bring a water quality use to those areas.
Lastly, the civil engineer will provide a safe and healthy design based on the codes and regulations of Hayward.
Later in the article, we will look into the requirements of a project developing on a steep slope.
We will start with understanding how a fire access turnaround at the top of the slope can be provided without complications. The first thing that will need to be looked at is the specifications of a fire access road.
Fire Access specifications within Hayward, California.
Hayward, California, is within Alameda County (referred to as the County), so the City of Hayward Fire Department follows the Alameda County Public Works Agency standards.
Fire apparatus access roads are required upon identification by the fire code official. In addition to the official identifying the need for the roadway, several specific California Fire Code regulations need to be met.
These include the dimensions, surface materials, and turning radius of the road. The Fire Code also has specific requirements for the allowable grade of a fire apparatus road, such as - the design of private streets, including fire apparatus roads, shall be designed to withstand 75,000 lbs. gross vehicle weight of fire apparatus.
This standard applies to pavers and decorative concrete surfacing materials commonly used for drainage purposes and aesthetics. All private streets and turnarounds must have all-weather surface pavement and meet the turning radius requirements of the Hayward Fire Department. This road shall maintain a vertical clearance minimum of thirteen and a half feet (13’6”). The road must also be a minimum of 20 feet wide per the County Standards.
Another important thing to note is that a fire apparatus road should not exceed a 10% grade. The grades that exceed 10% have to be approved by the Fire Chief, such as steep slopes, which exceed a 25% grade.
Getting the road’s design made is essential as the drawing looks into the design of utilities required for identifying underground fire service lines. The County requires both permitting processes from Hayward Fire Department and their own permits to install a service line. This serves as a permanent water source for supplying fire fighting services. The installation of a hydrant requires a clear recovery zone that is free from any obstructions and has accessibility during the home’s construction. The hydrant must be clearly marked and have a 300-foot spacing from any existing or proposed hydrants. The County code requires all buildings to be within 600 feet of a fire hydrant.
The construction requirements include a final landscape plan in the County. The landscape plan is prepared by the landscape architect and shall include an irrigation plan, planting and staking details, tree protection details, and a maintenance program. The mature tree canopy of the existing and proposed trees shall be accounted for. These canopies must not interfere with the utilities and the access road.
The trees cannot overhang the access road because this can create a detrimental drainage issue to the surfacing material used for the fire apparatus road.
Now that we are aware of the requirements from a regulatory standpoint, we will need to look at the project development on a steep slope while simultaneously looking at the type of professionals involved in this process.
Developing a project on a Steep Slope
Homeowners are seldom aware of the engineering definitions of common terms. Hence, let’s look at the definition of a steep slope from that perspective.
Defining a slope – an inclined ground surface, the inclinations of which may be expressed as a ratio of horizontal distance to vertical distance or as a percentage.
In the City of Hayward, it is required to acquire a grading permit for any grading activity where the area’s average slope to be excavated or filled exceeds a 5 to 1 ratio. A clearing permit is needed when the area to be cleared is greater than 7,500 square feet with an average slope exceeding a 5 to 1 ratio. A grading permit is required to create the building pad and prepare for drainage facilities while building a house. The Grading and Clearing Ordinance for the City of Hayward requires a preliminary engineering geological report if deemed necessary by the plan reviewer on behalf of the City Engineer.
The custom home in Hayward has steep slopes and drainage issues, so the reviewer will require a geological report from the engineer-of-record. The geological report will require a professional’s opinion on the geological conditions of the site, which may include the following:
- adequacy of the natural ground to receive fill and/or cut;
- slope stability of fill and/or cut areas;
- analysis of subsurface drainage and how it relates to landslide susceptibility.
The engineer, in this case, shall establish best management practices (BMPs) to combat erosion issues or sediment build-up for the drainage conditions. This may include adding fiber rolls, desilting basins, and hydroseeding for slope stabilization.
Involving the landscape architect in the design for landscaping and for water quality purposes is valuable. Some of the trees along the access road can be used to treat the runoff from the developed site. Also, a landscape architect can assist the engineer in choosing stable vegetation for the check dams or basins established to treat the drainage. Landscape architects are to find drought-resistant plant species for the slopes of a basin used to treat the drainage.
The geotechnical engineer and landscape architect make recommendations based on their findings for the site and present them in a technical memorandum and develop a landscape plan. The preliminary grading plan will also need to be reviewed by the City of Hayward in order to approve the design and then move forward with the constructability reviews.
The details of the requirements for the custom home are laid out clearly. The engineers and architects have an opportunity to work on a design that the fire chief will be willing to approve.
Benefits to the Developer
The Design Everest team can provide the experience and necessary professionals to complete the custom home that requires a fire apparatus road in the City of Hayward. The developer benefits from having a team of professionals that have experienced these cases and are familiar with the regulations of the area.
Design Everest has a professional team of architects and engineers that can develop single-family homes in the Bay Area. The ideal team that you are looking for to ensure a safe and feasible design is a phone call away. Call (877)615-3628 for a free consultation.
*Note: The content published above was made in collaboration with members of Design Everest.