Rost Architects Design Development Process For Your Custom Home
Project Phases
Construction Administration
Design Development Phase
The design development phase of a project is the pivotal phase where the design starts to become real. During this phase, the Architectural team takes the owner approved schematic design and dives deeper into the more technical related components of the building, continues to refine the design from many different angles. Below is a breakdown of the key tasks that our team will be working on during the design development phase of your custom home project.
Holding meetings with the city to review the preliminary design
At the start of the design development phase, our team will typically schedule a series of meetings with the different agencies required to review/approve the home before permit issuance. During these meetings we review the Schematic Design with the department and triple check to be sure that the proposed design conforms with their requirements. The goal of this exercise is to minimize design changes required by the agencies, as early in the design process as possible.
Holding meetings with our engineers/consultants to develop the systems in the home
During Design Development we will begin onboarding and issuing RFP’s to our engineers and consultants for the project. Check out our article about the Typical Consultants for a Custom Home. When we onboard consultants we will typically price out three different engineers for each specialty and present them to the owners with their associated costs and a services that they will provide on the project.
When all required consultants are hired, we hold a series of kickoff meetings to familiarize them with the project and get started on engineering. From this point on we will be coordinating with all of our consultants and modifying/updating our document set to accommodate for their systems. This part of the process is all about the details. Seemingly small items can turn into large construction issues if not solved during this stage. Our goal during this phase is to minimize the amount of discrepancies and conflicts between all consultants as much as possible. We will never vet out all of the issues however, but the more items we solve, the smoother construction will go.
For example if the structural engineer needs to shift a steel beam in the framing plan, we need to be sure that this works with the architectural design and that all other consultants are aware of this shift as it may effect other systems in the home. One small shift will require cross checks with all the major consultant drawings to be sure this will not cause issues with the design.
A good way to coordinate with consultants is through the use of BIM or Building Information software. Check out our article on BIM if you are interested in learning more about this tool. n short, BIM is a type of software that allows each consultant to 3D model their specific systems. For example, we typically have a structural 3D Model, Mechanical 3D Model, etc. Our architecture team collates all of these models into one “central file” were we can overlap and see the relationship between all the systems. Our team analyzes and reviews the central file to identify potential conflicts that could cause issues during construction. Budget permitting, we prefer to have all of our consultants use BIM software to model their building systems. We usually see roughly a 10-20% increase in consultant fees to provide BIM modeling. For example a structural engineer may charge an additional $1,500, on at $10,000 contract, to provide BIM modeling. In many cases, this this initial investment can help eliminate construction issues that could easily amount to $1,500 in the field.
Rost Architects design for custom contemporary home in Orange County California. Copyright 2022 Rost Architects
Further refinement of the floorplan and design for economy, ease of construction and aesthetics
During the design development phase of the project we are continually reviewing, analyzing, and studying the home to make it more economical to build, better looking and more pleasant to inhabit. Refining the floorplan and providing alternative options to the owner is one of the priorities especially at the start of design development. We will often go through 3-5 rounds of communication with the owner to dial in the floor plan so it is truly something custom and unique to them. Ideally we like to make these floorplan adjustments, as mentioned above, at the beginning of the design development. This way when we begin to coordinate with consultants, typically about half way through the design development phase, the floorplan is finalized and approve.
Concurrently, our team will be working in the 3D model to refine the exterior of the building, materials, and site features as these will all effect the consultants as well. The goal is that when we begin to coordinate with consultants, the design is at least 90% stable. If design changes are made after the consultant starts their work, there is a strong chance they will issue an invoice for additional services to make these changes. Some consultants are more accommodating than others. As a general rule of thumb, we like to make sure the design is as stable as possible before consultants start their work.
During the design development phase we will also be reviewing and refining the project to make it more economical and easier to construct. For example, two large cost drivers that we aim to minimize are large retaining walls and significant grading/excavation that will result in shoring. These items can escalate construction costs quickly. That is not to say that sometimes these systems are always easily avoided, but when feasible, we try to eliminate or at least reduce the size.
For example on a project in Laguna Beach, we were asked to design the home with a lower level garage embedded under the house on a hill. Intuitively, we knew that this would be a large cost driver on the project. We performed an option with the subterranean garage. With this option we also performed a preliminary cost estimate to excavate, shore and construct the retaining walls for this garage. The cost estimate amounted to roughly $350,000. We decided to design an alternative option with the garage up on street level where no excavation was required, virtually eliminating this cost. After seeing the two options the owners were able to make an educated, well in formed decision on which direction they preferred. It was decided that they like the design of the option with the garage at street level and it also eliminated a $350,000 construction cost for their project. This is a good example of the exercises that can be done in Design Development.
Selecting major equipment and appliances
It is important to begin selecting appliances and major building system during the Design Development phase. These include kitchen appliances, mechanical systems, electrical/PV systems, plumbing systems, and any other specialty equipment requested by the owner. Also understanding what equipment will be needed for exterior site features such as pools, spas, heaters, gas fire pits and fountains is essential.
Understanding these equipment needs allows us to perform preliminary load calculations for the home. Although the consultants will be performing the final calculations, we want to have a general idea if the systems we are proposing in the home are feasible before bringing on the consultant. For example, if we know that the total available power supply at the site is only 400 amps and we are designing in a massive HVAC system, multiple exterior fountains, and multiple car charging stations, we need to be aware that this power supply may be insufficient and could result in the need to upsize the electrical supply or reduce the amount of equipment in the home.
Specifying door/window systems
Dialing in the door/window system/manufacturer during this phase is critical. Verifying glass panel width, height and operability is key. If a specific system cannot meet the size shown in the Schematic Design, alternative systems must be considered. Understanding the detailing of each system and performance values is also critical at this point in the project. For example, if the owner is requesting a flush sill transition from the interior of the home to the exterior, this requires a specific make and model of door system only provided by a few companies. The owner should be made aware of the cost implications of his request. In many of our projects the size of the glass door/window systems is very large. Only a select handful of companies are able to produce these large panels.
Specifying major architectural materials
In the design development phase of the project it is key to select the primary material pallet. This typically consists of floors, exterior façade cladding such as stone, stucco, metal, wood etc, roof materials and outdoor hardscape materials. Each of these systems has varying thicknesses and technical requirements that need to start being incorporated and considered in the design documents at this state. For example, if a client wants authentic stacked masonry walls, this will require an additional 3-4 inches of thickness in each wall and typically a mechanical fastening system to fasten this stone to the primary structure. The owner should be made aware of the effects of selecting this stone, the cost implications of the selection, and the engineering requirements associated with this selection.
Performing cost analysis on the preliminary design
Typically, towards the end of the design development phase, when the structural, electrical, mechanical and plumbing systems are generally in place, we perform another round of cost estimates on the project. Internally, we update our initial cost estimate from Schematic Design to account for changes in square footage and other major additions to the project. We have also found it beneficial to engage potential contractors at this point in the project to perform preliminary pricing estimates. This is done in the form of a pre-construction service agreement between the owner and the contractor. We advocate for these services because the contractors will be able to perform much more precise cost estimates on the projects as they will bid the home out to their actual sub contractors. To read more about how Pre-Con services work, check out our article here.
Develop the Interior Design
Interior design for our projects is usually started in the Schematic Design Phase however, it is necessary to note here because we go into much more depth during design development. During Schematic Design, we consult with our interior design team to discuss general space planning and floor plan arrangement. They often provide valuable insight on the space plan of the project, as they are looking at the home purely from an interior design perspective. I cannot stress enough on the importance of brining on an interior designer to the team as early as possible. Our interiors team in collaboration with the architectural team will continue to develop the floorplan and space plan through Design Development. Check out this article to read more about our Interior Deign team and how we collaborate during the design process.
Begin dialing in the landscape, exterior hardscape, pools and other site features
During Schematic Design we will typically locate the general areas for pools, hardscape, site features and general landscaping locations. In design development we will refine these features by developing details, materials, equipment locations and sizes. For example, in Schematic Design, we will show the general location and size of the pool and spa on our plans and in the model.
In Design Development we will look closely at the pool edge detail and how that transitions to the pool deck. Does the pool have a zero edge detail? If so have we provided proper space for the drains around the edge of the pool to collect the spill over water? Is there an infinity edge on the pool? Does the owner understand the cost implications of an infinity edge detail? The pool engineer will also need to know/understand this detail so he/she can provide the adequate foundation to minimize deflection on the infinity edge to ensure an even spill over. The foundation for an infinity edge often requires deep piles driven into the earth that can be costly to construct.
Landscape, hardscape, pools and site features can range in cost drastically depending on the material selection, paving system (pedestals vs. thin-set) pool location/detailing and required grading/foundations for all of these features. The design development phase of the project is the time to dial in these items to be sure they are within the owners budget.
Rost Architects design for custom contemporary home in Orange County California. Copyright 2022 Rost Architects
We hope this article gives you a good understanding of the typical tasks that we performing during the Design Development Phase of your project. This is a brief overview of the major items we will be working on at this point in the project. If you have questions or would like to learn more about this phase, do not hesitate to reach out to us at www.rostarchitects.com/contact
