Design/Build Services

Decumanus Green provides both design and construction services. Whether you are looking to build new or remodel, we can help you to visualize and realize a new home that fits within your budget.



What is Design-build? In contrast to design-bid-build models, in which a project is designed by an architectural firm for a client and then put out to bid with several builders who compete to win the bid, the design-build model brings together a client and a single firm that is responsible for the entire process of designing, pricing and building a project. Besides Design-build’s substantiated track record for saving clients money, there are a number of other benefits to the model. These include the following:


The design-build model depends heavily upon a solid , trusting working relationship between client, designer and builder. The renovation of a home is a highly complex process; it involves inevitable areas of gray and requires effective communication. The fundamental ingredient for dealing with that complexity is trust. If the clients, the designer and the builder cannot trust each other, then no amount of checks and balances can safeguard the integrity of the building process. In design-build, the clients and the design/build firm make a commitment to each other: each works to the best of his or her ability to insure the efficiency and quality of the project. This is in contrast to the design-bid-build process in which the builder and client start off in an adversarial relationship: the client pressing to minimize cost , the builder pressing to maximize profits. This adversarial point of departure tends to color the proceedings of the entire project, as clients seek to get what they can, while builders seek to get away with what they can.


The design-build process assures that there is a single source of accountability. Clients have a single party to deal with. They cannot be made the victims of a buck-passing match between the builder and the architect. Problems that arise–and there will be problems–are the responsibility of a single entity, the design/build firm.


Because the design-build process is founded on trust, it is in everyone’s interest to constantly strive for the greatest possible clarity. The clients can be up front about budgetary constraints and the builder can be likewise with costs. Because the project is not being put out to bid, there is no risk of a lock of clarity in early drawings leading to a lack of commensurability in the resulting bids.


A single entity that designs and builds a project has a shared stake in the outcome of the project to a unique degree. This means that the builder is heavily invested from the start in how the project is designed and the designer extends his commitment throughout the building stage. In other words, a healthy sense of ownership is experienced by both the builder and the designer throughout the entire process. The result is a house that is better built and features a pleasing and buildable design.

The custom building industry is going through a fundamental change in practice. The late 20th century saw residential construction being dominated by what is called the “design-bid-build” process. But in recent years the practice of design-build has presented a serious challenge to that process. In fact , while the design-build model accounted for only 15% of the projects built in 1990, that number increased to 35% by 1999 and is expected to surpass 50% by 2010. The design-build practice has emerged with such force because it has proven itself effective in delivering an unmatchable combination of quality and value. For this reason all but five States have approved the use of the Design-build model for public projects.


Our contract process involves a number of steps:

  1. Initial contact. Generally we meet with client, discuss their ideas and desires for their home and get a sense of their budget. In this first meeting we also introduce clients to the method of our work and show examples of our work. if appropriate, we may make arrangements for a site visit to current or past projects.
  2. Design/Budget Contract. The next step involves drawing up a contract between Decumanus Green and the clients. This first contract authorizes us to begin to work on the design and budgeting process. This process leads up to the production of a set of plans and cost estimate for the proposed work.
  3. Construction Contract. This is the final step in the contract process. This contract authorizes us to begin construction work and clearly lays out the scope of work, costs and time frame for the project.


All design and budget work is billed at fixed rate. Construction is billed according to a cost/plus formula. This formula works as follows:

  1. Once a plan is developed, we work up an estimate for construction costs. This becomes a ceiling price for the job. Each month we will bill all costs (materials, subcontractors expenses, miscellaneous expenses, and labor at specific rates) and add 10-15% (depending on the project) for overhead and profit.
  2. For example: Let’s say our estimate for the cost of work is $100,000. The mark up would be an additional $15,000 (assuming a15 % mark up.) If the expenses of the job run over $100,000, then the client still pays the additional expense, but the markup is capped at $15,000. If the expenses of the job run come in under the $100,000, then we still get our $15,000.
  3. If the client makes changes or additions to the job once the construction contract is signed, then any additional costs directly attributable to those changes will be subject to the 15% markup. In such a case, in other words, the ceiling price is raised.
  4. Very much in the spirit of the design/build model, this pricing method recognizes the interests of both the client and the builder. In the interest of the client, the builder has a financial incentive to work efficiently and thereby not lose his overhead and profit. But at the same time, the builder benefits because he does not lose money if unforeseen contingencies increase the cost of construction. This method of pricing eliminates the need for the builder to inflate his cost estimate in order to cover every possible contingency. The result of this pricing method is a project whose costs are an accurate reflection of the scope and quality of the work put into it.