Hi, is anyone out there familiar with pad & post foundation systems? I understand they are fairly simple, relatively inexpensive and can be placed directly on a gravel pad, is that correct? I am planning on building a small (~18'x26') vacation cabin, with a half loft and was wondering if this type of foundation would be appropriate? The property is located in a cold climate region of the northeast. The building site is high ground and is of a gravel, sand and silt composition with very good drainage. I plan to build this cabin out of pocket and do as much of the work as possible myself - cost and time are a factor. At some future date I may want to move the cabin and build a more larger permanent structure on the site, thus my reason for a simlpe but (hopefully!)fairly reliable foundation system. Any suggestions about this or other less labor intensive systems would be much appreciated. Thanks. Pete
Pete, slab on grade is much cheaper in my area, but since you may be planning on moving it, your on the right track. I would put in a 2 block high foundation wall, and I would guess that you wouldnt need any beam work, if you chose your floor joists correctly. Check out the span ratings of say, a 14 inch TJI, and see if it will fit the bill. If not, you will need a small beam, and probably two posts for your 26 foot run. If you need the beam, then you may want to increase the height of you foundation by a block, in order to get underneath the beamwork for utilities.
I grew up in upstate New York and my father is still a contractor there. I would advise against building on any type of post on pad system in that region, simply because the frost goes too deep and its bound to heave. Even on a hill. I'd suggest as an alternative you consider post on piers. A Sonotube pier system will serve the same function, yet get your support below heave level. From there up, its basically like any other post-supported structure.
If you can find one, get ahold of a copy of Wood Frame Housebuilding - An Illustrated Guide by Bette Wahlfeldt. This is a simple to understand and well illustrate book. There are several types of foundation systems explained in good detail in this book, complete with instructions for the do-it-yourselfer type.
Good luck with your project.
ONE TEAM - ONE FIGHT!!!
Bungalow Rescue, Seattle
I just finished shelling in a cabin in Michigan's Upper Penninsula near Lake Superior. In many of these areas, post and pad or pier and post are very popular, both for their low cost and simply because of the inaccessibility of the sites. Even though we go below the frost layer in our area, it's not a big concern because of the huge amount of snow that blankets the area; I'm told by the inspector that they rarely get frost below a foot or so.
We simply drill and pour a couple bags of hi-strength concrete, put in 8x8's, then set the beams on top. Very easy, very strong. Email me if you'd like to talk more; it sounds as though what your planning on is exactly what we just built.
I have used a post and pier system for low-cost structures several times and have had great long-term success. A number of years ago I built a garage where I placed sono-tubes every ~8 feet on center. The bottom of the tubes extended below frost. I cut the top of the tubes at grade and then installed a triple-laminated pressure treated grade beam onto the tops of the poured concrete tubes. You can do the same and simply add joists to the top of the beam. Build the floor in modules and/or with relocation in mind. This project was written up in JLC and is posted on the Umass site if you want to read it. The web address is