David Michael
Architectural Design & Building Specialists
CONSULTING GROUP
Renovation Timeline: The Design Phase
Working with a Architectural Design Professional
When working with a design professional, you can expect the design phase on most projects to run six weeks to six months, depending upon your decision making and communications style, and on the size and complexity of the project.
 
Some very small and simple projects might be designed in as little as two weeks, if they fit well into the designer's schedule. Some very large or complex projects, or projects in which you are really unsure of what you want or in which you may change your mind a lot, may take as long as a year - or more. 

When working with a Design-Build Firm and often also an interior designer to design a new construction house being custom-built for you, a year is a very common timeline for the design phase.
Renovation Timetable: Keeping the Construction Phase Shorter
Decreasing the Renovations’ Length of Time
Here are some ways to decrease the length of time your renovation is actively under construction, through effective preparation:

  Be fully prepared and highly detailed in design plans, specifications and material selections
     before beginning construction. 
  Have all necessary permit applications filed and permits issued in advance. 
  Be aware of potential building code issues. Your project consultant will discuss potential 
     problems in advance with building inspectors. 
  Have financing fully secured before beginning, including an emergency fund of at least 15% 
     of the budget in case of hidden problems encountered or items would like to add during 
     the process. 
  Order items far enough in advance that they will be available on site by the time they are 
     needed for construction, even if they come in as much as 50% later than promised by vendors. 
  Have your temporary housing lined up before construction begins, if applicable, and make
     sure it is available for as much as twice the scheduled construction duration in case of
     emergency. If temporary housing is not slated to be used, try to line up emergency backup 
     temporary housing in case of severe unexpected issues during construction, particularly 
     for a big job. 

Length of Construction Phase is Vital
If the length of construction phase is really vital to you, you can also design for efficiency of construction. Clearly these options can be limiting, and may not be appropriate for your project.

  Avoid additions, particularly ones that require a foundation. Consider going up rather than out. 
  Avoid taking out walls, particularly load-bearing walls. 
  Avoid relocating plumbing fixtures, gas fixtures, or high-load electrical appliances. 
  Consider finishes for floors that allow for speed of installation, such as sheet linoleum or vinyl, 
     wall to wall carpet, and floating pre-finished flooring (such as wood, bamboo, or cork). 
  Avoid custom cabinetry and other custom made items that require long lead times or long
     construction periods, in favor of stock and semi-stock items.

Finally, sometimes - but definitely not always- construction schedules can be speeded up by throwing more money at an unforeseen problem. 

  If you're paying for temporary housing and numerous unforeseen problems create delays that
    become a hardship, consider asking your construction manager how much more it would 
    cost to get more workers onsite to speed things up.
Renovation Timetable: The Construction Phase 
Construction Phase Will Vary
The construction phase will vary with the size and complexity of the project, and can be extended by difficulties uncovered during construction, by indecision, or by change orders. Most projects will last from two months to one year.
Here are some general guidelines:
  Kitchen renovation: Two to six months (many are three to four) 
  Bathroom renovation: Two weeks to four months 
  Partial overall renovation including kitchen and partial bath, with some other areas:
    Two to eight months 
  Total renovation: Four months to over one year
  Addition as part of the renovation: Three months to over one year