For most projects, the most important and over-looked tool is the contract. Large or small, a clear agreement in writing and with signatures can avoid more damage ultimately than the shoddiest roof.
During the courting period and initial stages of projects, everyone is on their best behavior and words, far more than actions, are setting the tone. Purposes are aligned and the satisfactory completion of the project is beautifully envisioned.
When problems arise, however, the true strength of the relationship is tested, bending and relaxing under the stress or suddenly snapped by the weight of unforeseen pressure. A well-written contract can provide the support and recourse to keep negotiations and ultimately the project itself on track.
Like a pre-nuptial agreement, many people--especially hearing that it will only be a day or two, in and out, for sure--waive the formality. The implication of distrust may create animosity and feel like an insult to integrity, but a professional with experience understands the legal binder protects the contractor as much as the homeowner. There are as many nightmarish clients as bad builders.
The size of the job can determine the complication of the document, but for any project, the basic agreements should always be in place and well-stated. Similar to the journalistic rules of a first paragraph, the who, what, where, when and often the how should be clear in every contract. Most importantly are the clauses relating to "how much and when".
Smaller jobs can be a one page proposal with space for signatures to accept the terms. The vitals are still necessary, even if stated as casually as "replace the kitchen sink" at an hourly rate of "X" plus the cost of materials (with a mark-up). The proof can be in the process as long as the outcome threatens not to break either bank or back.
In my own business, the division came at about $1,500, more than a week's worth of work, or involving several distinctive components. A mid-size contract with more detailed specifications naming the type of door, quantity of siding and allowances for choices that could be open-ended ensures the two-headed purpose of protection and flexibility.
The larger projects invite multi-page, multi-tiered documents covering the basics, coloring the details, connecting the schedule of payments with performance, and carefully delineating ways to separate should that become necessary. Room for change is still important, even as details are crossed and contingencies dotted.
Architects and lawyers often advocate a standard contract which is easily available through the AIA. While it provides valuable clarity in commercial situations without a lot of expensive negotiations, home owners can be overwhelmed by inappropriate clauses and the builder too constrained by the stringent definitions. Simple is better and a contractor with enough experience to do the job should be able to produce a tried and true document off his word processor.
With a contract so specific, the temptation is to name a hard, fast and intractable dollar amount, but all of my experience--given a strong sense of mutual trust combined with a good estimate and specifications--an agreement based on actual cost is the fairest to all concerned. With clear parameters, solid budgets and honest communication, time and material contracts work very well.
Regardless of the best made and laid plans, things change and room must be made for Mr. Murphy to show an ugly face. Allowances and change orders are important parts of any agreement and coverage must be in place in case disaster leaks through a roof, spills out of a can or is short-circuited by a wire that should have been there, or worse, should not have.
Once a wall is framed, the view might invite a window that was not originally figured into the job. While the temptation and urgency of the schedule might dictate a quick decision to proceed and figure out the cost later, postponement of the cost implications can have serious repercussions burning a deep hole in the pocket of the builder or a terrible sticker shock long after the fact.
Regardless of size, a written contract is the best tool to ensure a project goes smoothly with as few negative incidents as the law of averages guarantee will happen. The comfort and ease with which one is negotiated will often be an indication of how well the parties will work together throughout the adventure.