length of 2 X 12 board needed to build stairs

[jocaan]

I plan to make stairs that are to attach to a back porch. I plan to make the steps with a 7in rise and 10in run. How long must the 2 X 12 be?
Frank C.

[suemarkp]

What is the height that the stairs need to cover?

[jocaan]

41-3/4 in.

[suemarkp]

It depends on whether your top step will be at the existing deck level, or you'll start the 2x12 at the height of the first step down. If you do the latter, then you should need about a 61" length. If it needs to do the full 42", then you'll need about a 74" length. The exact length depends on how you cut things at the ends, but this should be close.

If I've done the math right, you should need 12.2" per step cut into that 2x12.

[Piper]

Stair building involves alot of factors. Maybe This Link (http://www.fieldshomecenter.com/how_to/Stairs_and_Landings.php) will help you out.

[Under_Miner]

No. of Risers => 6
Riser size => 6 15/16"

No. of treads => 5
Tread size => 10"

Stringer length => 61"
Angle of Incline => 34.7939º