Since in my project of building a house I merge roles of project manager and project sponsor there wasn’t any extrinsic pressure on deadlines. I could plan schedule quite reasonably since both main constraints: money and effort needed to run a project were under my control.
That’s untypical when compared to projects we usually manage. We most likely have a customer who generates a lot of pressure to cut deadlines and costs. When you work for big companies there’s also a problem of “burning down a schedule” when negotiations are prolonged by the customer so you can’t start the project, but the final deadline stands stiff.
OK, coming back to my coarse-grain schedule. At the beginning I wanted to start building early 2009, just when weather would allow starting work. Since we usually have snowy and frosty winters, first couple of months of each year is dead when talking about building anything.
At the end of 2007 I started asking friends (subject matter experts) who had built or were building houses how much time I need to prepare a house design and complete all paperwork, which we need a lot in Poland. And I mean a lot. I came into conclusion I need roughly half a year altogether to be ready to start building.
Another rough estimate was about a year to have a house completed and be ready to move there. It would allow me to do a house-warming party during March 2010 which was quite fine for me. However since preparing all the paperwork and building are two explicitly separate phases (in Poland you can’t start building until the final building permission is signed) I decided not to decide on schedules of the latter phase since I didn’t even know what exactly I’d be building.
I started preparation phase early March 2008 giving myself 100% buffer to planned kick-off of the second phase – a full year instead of a half. And I added the buffer to realistic estimations, not the squeezed ones, which we usually deal with at work.
That’s another thing we won’t really see in our professional lives. I know a round number of customers who are able to start a project half a year earlier then they think they have to start. To be precise the number is zero. What more, I know quite a lot of customers who wait far longer than it’s reasonable consuming more than a half of project time before they finally give green light to start work.
To summarize, my initial coarse-grain schedule was separated to two phases: preparation and building. I got rough estimates for both (half a year and a full year) and date for a milestone separating them (my personal constraint). The trick I used to get a buffer in the first phase was starting earlier. We do that sometimes when we start working on project before a contract is signed. It brings new risks (customer can reject to sign the contract) but we limit others (we gain buffer in the schedule). I decided not to plan detailed work for the second phase until I know house design and a company which would build it (a vendor).