Architectural Feasibility Study: Questions to Address

Based on the site features alone, we had tons of questions that we needed to explore. We needed to gain a comprehensive understanding of the site’s challenges, opportunities, and potential constraints. Here are some key inquiries that became the focus of our architectural feasibility study:

1. What’s the situation with the utilities? We need to investigate the availability and proximity of water, sewer, and power connections. We need to determine the feasibility of connecting to these essential services.
2. Is there enough room to build a house on the upper part of the lot above the ravine? We need to evaluate what the buildable area is. We also need to ensure there is sufficient space for a driveway, two parking spaces, maneuvering distances (per code), and a house footprint. We need to do this while considering setbacks, zoning regulations, and site constraints.
3. How will the driveway access work with only 9 feet of right of way? We need to examine potential access solutions, including obtaining necessary easements or variances. We also need to address the impact of this construction project on neighboring properties.
4. What are the subsoil properties? How deep is the shale rock since we can observe exposed shale on the face of the cliff? We will need to conduct geotechnical investigations to determine the soil composition and bearing capacity, as well as assess the depth of the shale rock to identify any potential challenges for the foundation design.
5. Will we need variances due to the tight site constraints? We need to review local zoning regulations with planning officials. We need to determine if variances or special permits are necessary due to the given site constraints.
6. How costly will it be to build? How structurally challenging will it be? We need to analyze the anticipated construction costs and complexities associated with the unique characteristics of the property, such as the steep terrain, limited access, and any required site modifications.

Challenges of the Ravine Lot & What We Discovered

Tree clearing

Tree removal is a prerequisite for any new custom home on a wooded lot. For this project, the entire upper plateau needs cleared for the house, parking, and driveway access. As good stewards of the environment, our clients did not make this decision lightly. They vow to revitalize the surrounding landscape with new plantings after the house is constructed.

We also learned that the area MAY be home to endangered migratory bats, which build nests in the trees and raise offspring during the Spring and Summer months. Depending on what the Ohio Department of Natural Resource says, we may be limited to December through February for tree clearing.

Terrain & Subsurface Issues

Building on this ravine lot poses significant challenges. There is a 40-foot exposed rock face cliff that separates the buildable land from the creek below.

The densely wooded and uneven site prevents large soil boring equipment from getting on the site without clearing a driveway path. Clearing a large access path is not preferable at the early stages of the project. Instead, we employed geophysical investigations as an interim solution to assess the subsoil properties. This method involved directing electrical waves into the earth and measuring the reverberations to determine the depth and composition of the shale rock. The findings indicated overburdened soil (spoils) for the upper “plateau” area that is about 7-8 feet deep. Weathered shale starts to occur below that. The transition to more solid shale rock occurs at an elevation of approximately 20 to 25 feet below grade.

While these readings provide valuable insight for foundation design and the possibility of dynamite excavation, it will be important to conduct more accurate soil borings prior to construction to confirm our assumptions and adjust the foundation design accordingly.

Driveway access

Due to the limited 9 feet of right of way, we have two options for the driveway access.

1. We can obtain a variance to allow a 9-foot driveway instead of the standard 10 feet
2. We can secure an easement from the neighboring property.

The adjacent property already has an existing access easement for the neighbor on the opposite side. We aim to explore the possibility of utilizing the same easement for our lot. However, since the neighboring property has changed ownership over the years, this may require delicate negotiations. Despite the potential complexities, pursuing the easement option is the most convenient solution. Our client wishes to pursue it in lieu of the more invasive approach of utilizing the 9-foot right of way.

Utility connections

Utility connections present challenges on this ravine lot. While water, sewer, and power are available on the street, the investigation revealed unexpected complexities.

Water – Discussions with the utility commission unveiled that tapping into the existing water main is not feasible. It is already overburdened with the number of existing taps. As a result, we learned that to obtain public water, we would need to replace the 1.5″ main with a new 6″ main. The new 6″ main would have to extend to the street intersection (100 feet away!). Moreover, our clients would be responsible for the costs of new taps for neighboring properties connecting to the new main.

Sewer – Tapping into the sewer line at the street is feasible. But, it requires careful consideration to ensure proper drainage because the sewer line elevation is not very deep. Depending on the house layout and plumbing fixture elevations, a sewage ejector pump might be necessary to accommodate the elevation difference.

Stormwater – There is an existing storm drain line at the street so we can tap into it with our rainwater conductors.

Below is the document we received from the utility commission documenting the services at or near our project site. We’ve highlighted water, sewer, and storm lines for clarity.

Gas – Fortunately, the client’s preference for an all-electric house eliminates the need for gas hookups.

Power – An existing utility pole stands precisely where the driveway will be located. Relocating the pole and stay wires to accommodate construction and connecting to the power grid will require coordination.

Routing all public utilities through the 9 ft frontage on the site necessitates meticulous planning. Additionally, upgrading the water line to a 6″ main requires a new fire hydrant, further adding to the project costs.

Higher construction costs

The unique site conditions of this lot will inevitably result in higher construction costs due to safety concerns, limited access, and complex logistics. The steep slope terrain introduces safety risks during construction, necessitating additional precautions and specialized equipment. Since the house abuts the city park, bringing materials or personnel through the park onto the lot is prohibited. Contractors will need to employ rappelling techniques or hang off the cliff face to build the house.

Limited construction access and material storage space at the top of the lot add complexity and logistical challenges. Delivering the entire lumber order to the site is not feasible, requiring daily deliveries for a just-in-time installation sequence. Additionally, a smaller job site dumpster will need to be utilized, emptied, or replaced weekly to facilitate construction waste removal.

The foundation design will incur higher costs and require more engineering. Furthermore, there will be increased site development expenses for utility connections, lot clearing, excavation, and access.

On the bright side, providing our clients with the necessary infrastructure improvements and related costs early on empowers them to decide whether and how to proceed with the project.

Feasibility Study Process and Methodology

Research

Given the extensive coordination and communication required with city officials and outside experts, it was important to prioritize this effort. Never underestimate how much time it takes to get the information you need. From playing phone tag to in-person meetings and waiting for responses from various parties, the process can be time-consuming. To ensure efficiency, we initiated this process early and maintained momentum whenever possible.

For this particular property, we spoke with no fewer than a dozen city officials to understand the project’s limitations and possibilities. This included the planning official, building official, water engineer, traffic management engineer, utility commission, flood plain official, wastewater engineer, and others like the power company, surveyor, civil engineer, geotechnical engineer, and geoelectrical engineer. Managing correspondence, follow-ups, and identifying additional parties for sign-off was an integral part of our efforts.

Site Analysis Studies

While we waited for people to give us information, we analyzed the site plan to gain insights into access requirements and parking limitations. We developed preliminary site layouts that showed how to accommodate a driveway, two parking spaces, and a compact house footprint on the small lot. Parking requirements almost always result in headaches on small lots. There are specific dimensional criteria that need to be met in order to get planning approval. Columbus codes dictate two parking spaces measuring 10×20 feet, with a 10-foot-wide driveway and 20-foot vehicular maneuverability.

Balancing these components became akin to an advanced game of Tetris, while also juggling cost implications, structural considerations, code compliance, and overall feasibility. We arrived at three site plan variations that would influence the overall massing of the yet-to-be-defined house.

Here are the site diagrams showing how the parking, driveway, and house footprint could work. Remember, we aren’t designing the house yet. We only provide scaled placeholders representative of the approximate amount of space needed.

Massing Schemes

When it comes to building on steep slopes, there are a few viable approaches. To provide our clients with a clearer understanding of the available options and the advantages and disadvantages of each approach, we curated a collection of precedent images showcasing these strategies. Although this is not the stage for detailed house design, we aimed to spark initial reactions and gather feedback on each method. This would enable us to engage in a more informed discussion regarding the overall project costs.

Finalizing the Report (Findings & Recommendations)

The comprehensive feasibility study for this complex site took 4 months to complete. In addition to thorough research and analysis, we engaged with qualified surveyors and engineers to accurately document the topography and geophysical properties of the shale earth.

With all the gathered information, we diligently organized it into a user-friendly feasibility report. This report encompassed an executive summary, detailed analysis and findings, drawings, relevant research, historical documents, supporting exhibits, and contact information of the various experts we consulted. To provide the clients with an initial understanding of the project costs, a rough estimate of site development expenses was also included in the report.

The Aftermath: Making Informed Decisions

Before approaching us for this study, our clients were venturing into uncharted territory, uncertain if their ambitious vision could become a reality. They had a vague idea of the challenges they would face but didn’t have full confidence that they could pull off something so ambitious.

However, after reviewing and discussing our findings and carefully considering their options, they made the bold decision to forge ahead with the project. With our help, they gained a better understanding of the challenges and associated costs, enabling them to make an informed choice.

Driven by their tendency to lean into engineering activities and an appetite for challenges, they viewed this project as an exciting opportunity to create a lasting legacy.

We’re very grateful and humbled to continue working with them on the architectural design to turn their dream into a tangible reality. Be sure to stay tuned for future posts for a future post on the design process for this exciting project.

Benefits and Value of the Feasibility Study

An architectural feasibility study proved indispensable for this particular project. Our clients gained invaluable insights, identified potential issues, and made well-informed decisions. While not all feasibility studies are as complex, they all serve the common purpose of uncovering challenges, risks, and opportunities for better decision-making.

Whether it involves reallocating resources, addressing problems early on, taking a proactive approach to design, adjusting project goals, or even considering project abandonment, the ultimate objective remains the same. A feasibility study equips you with the necessary information and empowers you to make sound decisions, providing peace of mind and minimizing uncertainties to optimize your desired outcomes.