The two major cost models relative to the project design are; cost to design (CTD) and design to cost (DTC).cost to design n simply means putting up a design first and then estimating the total construction cost from the design usually without formally trying it to any budget while design to cost entails stating your budget for the project first, then enduring that the project is the project is designed to be completed to within that budget. For instance using the recommended DTC model, a project owner can approach a designer/ contractor with say 4 million naira to construct a simply bungalow and achieve his/her desires within it in the following simply steps:
- First, you discuss the development idea/concept with the designer/ contractor,
- Thereafter you reveal your initial budget, say 3.l5millionnaira and retain the balance,
- Then request that the designer/contractor provide two or three design options that can be achieved within your budget and based on your specifications (e.g it should consist of 3beds –all rooms en-suit, French-style windows, an ante-room, slanting height, a court yard etc). However it is strongly recommended that you employ the service of a designer/contractor with good knowledge of both design, estimation and construction from the start as it is in common knowledge that most independent designers/architects aren’t good estimators or alternatively you co-engage a quantity surveyor to achieve your cost goal (you will have to pay for this service say around 5%of the total project cost)
- Once the preliminary site investment is completed and the building designs and cost estimates are ready, you then choose the most appealing design.do not hesitate to per-inform the estimator/contractor to simplify the cost estimates by breaking it into two main sections one showing the materials cost /schedule and the other, the labour cost/schedule (which will include the contractor’s profit so that it can be negotiated separately). You have to study the estimate carefully and compare for consistency with the design.
- Because some features would have been deliberately excluded in the design in order to make it fit into the cost plan, you may have to add some much desired feature(like special finish, fittings and fixtures, etc)within your retention budget (in this case, the 500,000 NGN left)but don’t use all of it; keep a fraction for contingencies, and
- You are good to go
However in the cost-to-design model, the project owner/landlord is highly disadvantaged in that the designer/contractor may come up with fabulous design that may be far beyond you budget because there have been little or no consideration of the cost implication of the design at the initial stage. This is the most common case in practice. When this happens, subsequently the project owner lured to expensive design begins to run shelter skelter to source for additional funds to complete the project and this is not a funny experience.
Think carefully and make thee the right choice of cost model to adopt for your next building project.