log structure foundation design 2

[kgmjeric]

The structure is 35 x 45 3 sided with one 45ft open wall. the corners will have 18-24in post and the walls will be stacked logs. the ground is made up of mostly rock. everything i have read so far says that i need the first row of logs 12-24in above grade. I was planning previously planning on concrete piers with rebar holding the first row of logs down. the location is ne oklahoma frost line is very shallow.

My personal experience is in metal finishing and mechanical design. I dont have industrial experience for rules of thumb in the building industry and need some help.

How do i go about determining the number of piers and spacing for this type of structure.

 

[msquared48]

A log structure has many issues to consider, not just the foundation. If you have never done this before, I would contact a local structural engineer who has in your area.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[MiketheEngineer]

M^2 is right - there are a lot of things to consider. Some wood can be used for foundations - if treated or naturally resistant.

You now have to look how all the loads, gravity, snow, wind, etc will be transferred from the structure to the footing to the ground.

And one other thing - log structures shrink - A LOT and this must be considered.

Get some local experienced help.

 

[oldestguy]

All are right. From the sound of your job, I question it right away as proper design. Sounds like a animal shelter or enclosure, right? Are building permits needed in your area?

From my experience and actual construction, there are many things needed to keep walls vertical, not bowed, treated against insects, rot and birds who like to peck into the wood looking for insects, etc. How about electrical wiring in the walls? Insurance? Windows? Replacing rotted logs is very difficult.

The height of wood above ground usually is to be according to local codes for termite control.

If this is to be a permanent building, that you don't want it to rot away, I'd not go for the cheapest wood treatment, since they usually are good for only very few years.

I'd at least get a contractor on board to get the design right and the initial construction. Once underway, you can then get a good start. It's hard to fix a log structure later.

Hey, maybe a different form of building material? I'd never live in a log cabin again. Too much maintenance.

 

[kgmjeric]

I dont have any building codes needed although i am in the process of obtaining a copy so that i will have a basis for decision making. there are not really any windows with the planned doors in place. this is not a living structure for humans it is equipment storage and animal shelter.


I wasnt thinking of logs as a foundation but rather that i would have concrete piers up to 24in above grade and begin the first course of logs there.

yes i am also looking for a local expert in the area while in the mean time i am trying to gain as much knowledge on this myself.

I have in the mean time found the snow load and weight of the structure. I am looking for the method of applying this to foundation size. looking to see what the variable is that must be overbuilt into the foundation. in order to appropriately space size and control the make up of the piers

 

[MiketheEngineer]

Unless the logs are free - go check out a Pole or Post Frame Builder in your area. They do these all the time and have some very attractive packages. You can even buy a kit and build it yourself.

Built in place is usually around $10 - $12 per square foot. +/-

If you still want a log structure - just google it. There are plenty of sites and some have some pretty good details. Or find a book on log construction.

 

[RockEngineer]

It sounds like you are mixing several types of log building methods together which can cause problems. With the corner vertical log columns and log infill the structure is usually designed and built as a post and beam structure with the log infill just filling in space. The log columns take all the vertical load to the foundattion. In this case though you would have to have more intermediate log columns because you don't design the logs to take out the vertical loads from the roof and your beams aren't going to span 45 feet between columns supporting a roof truss spanning 35 ft.

If you plan on the logs holding the vertical load from the roof trusses then you don't want the vertical columns in the corners because the horizontal logs and the vertical log columns will have a lot different settling and shrinkage.

If you will be using someone to help you design the structure so it doesn't come falling down or have a lot of shirinkage and settling problems, you need to sit down with them and discuss the method they are familiar with before you worry about the foundation.

There are many log building styles and each has it's good and bad points. When you mix them you get a whole lot of problems.