Friday, May 4, 2007

Estimating Labor

Friend: "I'm in over my head. I started to redo x and found out it also needed y, z, and a bucket of p & q when I got into it!"

Answer: The Bible rocks. Luke 14:28 has this useful advice for avid DIYers:

"For which of you, intending to build a tower, does not sit down first and count the cost, whether he has enough to finish it"

I heard this same quandary from at least two or three people this week as spring has motivated the hibernating "real man" in many of us to get to tackling that never ending list of things needing doing around the farm, castle, etc.

I think these experiences help validate a DIY estimating formula I have been working on for the past few years as projects around our house have often gone the same way. It's taken 4 years to do the basement and this formula has allowed me to more effectively schedule work in the past months.

(1 layer material * Square feet affected * [material factor] hr) = Total Hours

Sheet material factor: .3 (cutting, installing, measuring twice first...)
Mixed component material factor: .6 (grout, mortar, specialty floor coverings)
Unmixed component material: .25 (paint, plaster)

In practice, I've come to consider a layer of material as separate jobs. Tiles = 1 layer and grout = another, so tiling the 6 ft by 4 ft (- 2 sq ft for vanity/sink base) should work out:

Lay tile:
(4*6-(1*2)) * .3 = 6.6 hrs

(4*6-(1*2)) * .6 = 13.2 hrs

Total Estimated hours (not including beverage breaks, football breaks, naps, etc.)
19.8 hrs - or most of a weekend.

If I have to level the floor or cut and lay down sub floor ahead of laying tile, then I can figure on adding another sheet material time calculation:

Lay sub floor:
(4*6-(1*2)) * .3 = 6.6 hrs

I expect you could adjust for metric as well as factor in help. I typically have no help, but when my wife is available to lend an odd hand here or there it does speed things up considerably.

But obviously, this is far too general to be useful in all cases. The way I came up with it was to look back on all the DIY I have done in the past and honestly estimate the time it took. Really, football, basketball, beer... it really has to be factored in if you aren't getting paid by the hour to do this stuff. If you are your own boss, make sure you are honest with the boss. :-)

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