Post question

[CThomp]

I was looking at a home the other day that was built on wood pilings. The pilings are 8x8's spaced at about 10ft and the subfloor is 13.5ft off the ground. The house has lots of cross bracing and the pilings are 5ft into the ground. The ground is well-drained sand/shell. The house is on a barrier island and its been there since 1972.

Would it be possible to build a house on 6x6's if the height of the subfloor was maybe 4ft off the ground and the spacing was less than 6ft between pilings?

I've seen older country homes with this style of piling foundation but am wondering if it is really possible based on loads and what not.

By the way this isn't a project i'm undertaking but just something that i've been wondering about. I find piling home construction interesting and I don't know much about it.

I'm assuming(?) a #2 PT 6x6 set in the ground 5ft with the normal post setting techniques.

[Cole]

You got me there.

I also find coastal homes very interesting.

[VALENT]

Oh I think that would be more than adequate BUT it depends a whole lot on the load bearing of the soil and the actual "normal post setting techniques" used. These piling foundations are done all the time near the coast as well as elsewhere. I was also interested in these foundations when I started looking into my house to be because I am in a flood plain and had to elevate.

[CThomp]

With the 8x8's the generally just pound them in with some gigantic hydralic pounder that sits on the front of the truck like a front end loader.

But I figure 6x6's could probably be set by hand. You'd have to auger the hole which i think here in Florida you have to have 4 inches or so on either side of the piling. I've carried a 16ft 6x6 with a friend. It was heavy but not unbearable. You'd wrap the 6x6 in a plasti-sleeve or a post-protector, attach some variety of bottom anchoring plate to the base of the piling, and set it in the hole. Then pour some high strength concrete around the piling and move on to the next one.

I guess it would just be post frame construction but elevated.

[CThomp]

Soil in S. Florida is generally sandy and well drained with limestone substrate not very far below the surface. I've drilled wells in parts of S. Florida that have stripped the auger bits to shreds from running into sand.

[Sweep]

only a structural engineer could answer your question. It is a matter of allowable soil bearing pressure and friction, not the strength of the posts.

[CThomp]

Interesting. Thats kinda what I wanted to here. The more I think about a house like what i've been talking about the more I like it. Plus, the more I think about the house i'm living in now the more I realize its a total tear down. Most people would say just sell it an move but i'll never find an empty lot in a better location.

[CThomp]

I have a feeling the if I do decide to use this design i'll probably use 8x8's instead. I'd hire a contractor to set them and the 8x8's would probably just make up the platform. They wouldn't be contiuous through the exterior framing. The island house I was talking about is built this way. The 8x8's just make up the platform for the stud walls to sit on.

[VALENT]

The stud walls would sit on the floor. In other words, you would set the posts, then build the support system of joists and blocking, then put down the subflooring and then start building the walls.

[CThomp]

Exactly. I'm going to have to do some cost comparisons to figure out if it'd just be easier to have block piers built. Like a contiuous footer with piers. Or maybe even a regular crawlspace if that would cost less.

[CThomp]

just thought I'd freshin this one up some. I eschanged quite a few emails with the owner/operator/manager/whatever of a companyout of Altamont, Florida that builds pole homes with raised wood floor systems. His company uses 6x6's.

cornerstonebuildingsystems.com