Buying a Ladder

Measured out 72 in. or 6 feet

In 2008, Hurricane Ike hit.  We were further north, but winds & gusts still hit hard enough to damage some roofs.  We had shingles knocked off, and insurance agreed to pay to get all new shingles.  My boss and I, along with kids, had done a roof before, so I was going to pay for us to re-shingle it.  The only problem was that I didn't have a ladder to reach the roof, and I didn't know how long of one to get.


When I went to Home Depot, I saw that the extension ladders were mostly in 4-foot increments: 16 ft, 20 ft, 24 ft, 26 ft, 28 ft.  I didn't want to spend too much money getting one that was way too long, yet I wanted it to reach the roof comfortably.


So I measured!  6 feet (or 72 inches) out looked like far enough out for the base to be.

Measured from bottom of window to roof (57 in) Hi, Zoe!

I measured to the bedroom window (175 in)

So I measured the height from the ground to the edge of the roof to be 175 + 57 or 232 in.

All that needs to be done is the Pythagorean Theorem!
72²+232²=x²
59008=x²
242.92 = x


So my ladder needs to be at least 242.92 inches or 20.24 feet.


Well, it looks like a 20-foot ladder wouldn't cut it.  In fact, with a ladder, I'd want a comfortable length beyond the bare minimum to actually climb up onto the roof.


Even if I were to find, say, a 22-foot ladder somewhere, I would probably want to just go with a 24-footer to be safe.  I might end up wanting the base further than 6 ft away, requiring a little longer ladder.


A 26- or 28-footer would be longer than I would ever need for any future house projects, not to mention more expensive.  So I'm saving a bit of money this way.


So I bought the 24-foot ladder and it worked great!


What you learn in class that applies:
1. Pythagorean Theorem
2. Unit conversions (feet to inches)
3. Square root (part of #1)


Q: Why did I do all these calculations in inches?
A: Well, it's a lot easier to work with 232 inches than 19.3333... or 19 1/3 feet.  Why convert it to feet to calculate when I can just convert it to feet after I'm done?  I'm using a calculator anyway.


Q: Why didn't I just measure from the ground to the roof in the first place?
A: From the ground, the tape measure was swaying and bending.  From the bedroom, I just wanted to be safe and didn't want to worry about hanging out 14-15 ft in the air or taking a screen out of the window.


YEAH!