upstatefarm
New member
I'm building an extension on an existing shed, for a boat shed, the extension will be 16'W x 24'L. Doing 99% of it by myself. Due to the the large rocks in-ground I excavated the holes with a friend's backhoe... an auger just wouldn't cut it. So I have fairly large holes, about 2.5' wide by 3.5' long (and 48" deep). My soil is heavy clay (and with the huge amount of rain we've had, the holes filled with water right after they were dug.)
My question is this: Should I go with piers, or with a modified in-ground/backfill approach? Or use sonotube with the post set in concrete? I've read all the debates, and yeah, maybe I'm over-thinking it.
I'm also planning on making my own laminated posts, with PT 2x6's and 1/2" plywoood, making 4x6's; much easier to handle by myself, and straighter. But all I can find in ground contact 2x6's is .15 MCA, which isn't the .60 recommended by many. So is encasing this kind of post in concrete a mistake?
Piers would be a LOT easier for me to do, for many reasons. But how do I avoid the problems with piers... the wind shear problems, uplift, etc? I do plan to sheath all the walls, but it's in a pretty high wind area... there's about a 1000' open field to the west, and I've had up to 70 mph wind gusts. I don't want a collapse, etc. I'm not an engineer and I don't know much about bracing, and piers seem to hinge solely on a bracket... kinda scary to me.
So far the plan that makes the most sense to me is this "modified backfill":
Pump the water out, put a plastic contractor bag around a 12" (or 18"?) sonotube, drop it in, pour a footer, let cure overnight, put 8" of #2 crushed rock or gravel over the footer, set post, use a 2x6 cross piece at bottom of post to aid in uplift retention, backfill with about 12" more gravel, backfill with dirt. Tamp often during the process.
What I like is that I'll have pretty good drainage, avoid the issues with concrete and rot, avoid problems of piers, and it's fairly easy construction given my conditions. But what concerns me is this:
the ground is not undisturbed now... will my backfill hold it? Will the post uplift through the gravel and dirt, even though there's a 12" cross piece? Will the sonotube itself be more prone to pulling out?
Many thanks for any good ideas!
My question is this: Should I go with piers, or with a modified in-ground/backfill approach? Or use sonotube with the post set in concrete? I've read all the debates, and yeah, maybe I'm over-thinking it.
I'm also planning on making my own laminated posts, with PT 2x6's and 1/2" plywoood, making 4x6's; much easier to handle by myself, and straighter. But all I can find in ground contact 2x6's is .15 MCA, which isn't the .60 recommended by many. So is encasing this kind of post in concrete a mistake?
Piers would be a LOT easier for me to do, for many reasons. But how do I avoid the problems with piers... the wind shear problems, uplift, etc? I do plan to sheath all the walls, but it's in a pretty high wind area... there's about a 1000' open field to the west, and I've had up to 70 mph wind gusts. I don't want a collapse, etc. I'm not an engineer and I don't know much about bracing, and piers seem to hinge solely on a bracket... kinda scary to me.
So far the plan that makes the most sense to me is this "modified backfill":
Pump the water out, put a plastic contractor bag around a 12" (or 18"?) sonotube, drop it in, pour a footer, let cure overnight, put 8" of #2 crushed rock or gravel over the footer, set post, use a 2x6 cross piece at bottom of post to aid in uplift retention, backfill with about 12" more gravel, backfill with dirt. Tamp often during the process.
What I like is that I'll have pretty good drainage, avoid the issues with concrete and rot, avoid problems of piers, and it's fairly easy construction given my conditions. But what concerns me is this:
the ground is not undisturbed now... will my backfill hold it? Will the post uplift through the gravel and dirt, even though there's a 12" cross piece? Will the sonotube itself be more prone to pulling out?
Many thanks for any good ideas!
