Expert: Bruce E. Johnson - 6/18/2005

Question
I'm building a shed.
30x40
using 9 12' telephone poles rough cut at 12'.
3 down each side and 3 down the middle.
I will be using 6 20' 3x10's.
2 down each side and 2 down the middle.
i will be using an instrument to cut off poles and a string to cut notchs for beams.
my first Questions are .
How deep should the holes be and what diameter;; if im gonna use quickcrete?
thanks cliff


Answer
Hi Cliff, depending on your soil conditions I would use at least a three foot by three foot pad two feet deep with at least one foot of concret under the pole.  In that one foot I would have a grid of reinforcing steel #5 rebar 8" on center each way and elevated off the ground at least 3" to insure good concrete coverage.  You are building a large structure that requires more than just some sacrete poured around the post if you want it to be stable and last.  You will be supporting a lot of weight and also experiencing some horizontal wind load.  If you have some good galvanized steel brackets you can pour just a pad footing 3'x3'x 12" deep and set your poles on top of the pad and bolt the posts to the brackets with 1/2" galvanized lag bolts.  This is actually preferred because pouring concrete around a pole will eventually lead to the embedded pole rotting out.  By setting your pole on top of the concrete it doesnt trap moisture around the pole.  I hope this info helps feel free to write again regarding this or other matters, sincerely bruce e johnson