Need foundation advice

[robert_t_wallace]

I am wanting to build a cabin/garage out of 3 shipping containers such as some of the garages I have seen here. I want to put them in a "U" shape with 2 - 20 footers as the 2 sides and 1 - 40 footer as the back side. My thought was to put trusses across the top of them building the cabin on top of the steel shipping containers. I would have locking space in the containers and a parking area in the middle. I wanted to have rock or concrete in the parking area, but I need to know what kind of footer for the containers to sit on. I really did not want them on the ground so they would not rust. Concrete has gotten so expensive that I was wanting to limit the use as much as possible. There will be a lot of weight on them with the cabin on top, so I need somethign that will support them.

What are your thoughts???? Cheap but long lasting is my goal as I do not want problems down the road.

 

[robert_t_wallace]

Do you think it would support the weight of the storage container and the cabin?

 

[blkhonda1991]

how wide are shipping containers anyway? i dont know how you would live comfortably in a single wide one

 

[robert_t_wallace]

I think there is some confusion... I won't be staying in the containers..I will be staying in a cabin above them. The containers are eight feet wide, but when you lay them out like I want, you get a 28x40 footprint. Two twenty foot containers running parallel and One fourty foot running the length. When you put the twenty footers against the fourty footers (eight foot wide) you get a 28x40 cabin sitting on top of the containers.

 

[Junkman]

It all depends on where you live, and the type of soil conditions you have. If the ground is very dry and stable, then there is no problem placing them on the ground, or on railroad ties. If it is a wet area, or an area that is subject to frost heaving, then you will need to prepare the ground differently. Removing the top soil and putting in a thick bed of compacted gravel and crushed stone would be best, along with good drainage so the ground around them stays moderately dry. Also, you don't want any trees near by that will cause you root problems, or keep the ground from getting sun to keep it dry. There are so many variables that it is difficult to give a definitive answer to this question without knowing more about the location and the physical characteristics of the site.

 

[1320stang]

You might consider piers.

 

[DHill]

You should put in a footer to your frost line to avoid any undulation that may occur as the ground shifts and possibly heaves as a result of freezing/warm/moist conditions.

You should also consider the codes - any kind of wall structure should usually be fastened to the footer so that a strong wind doesn't pick it up. I realize your shipping container is probably several tons and no wind will pick it up but code is code... just doing it is likely easier than finding a way around it. You will also have to find a way to attach your upper story to the lower story. The gist of the code is to have continuous mechanical fastening from top to bottom so that the entire structure is anchored to the footer.

Don't put them on the ground. Rust is inevitable and if you can take measures to prevent problems now, do it. I am a materials scientist... people come to me every day with corrosion issues (not just for steel) and 100% of all problems could have been solved if they would have designed for it in the first place. Unfortunately most think that if they make the steel thick enough, it can rust but never penetrate. Don't underestimate.

Rust will not be a problem if the steel is not in sustained direct contact with water. You could conceivably use individual post-type footers spaced periodically instead of a continuous perimeter footer, but I guess that depends on your code. That would be much cheaper and you could likely do it yourself with a post hole digger and a bunch of Quikcrete. If the bottom of the container is off the ground you have provided adequate run-off so that water is never sitting in contact to the steel for any sustained period of time, your containers will last forever.

 

[kbs2244]

1320 has the idea.
Rent a dirt drill for 4 to 5 foot deep holes.
Insert some Sono tube and level all the top ends to each other.
Pour your concrete to the top.
If you like you can put some treated 4x6 from pier to pier, it may make it easier to slide your containers into place. But they should bridge the piers by themselves OK.
If you are going to put real heavy stuff in them, I would put the 5 feet apart.
Otherwise 8 feet.

 

[robert_t_wallace]

The lot is in Emory, Texas which does have freezing and rain. The gound is a dirt type topsoil and it is a very heavily wooded lot with Pin Oaks and Red oaks that are very large. The lot is 100 feet wide by 220 feet deep. The sloap is from front to back at a noticable grade. I do see standing water in the back of the lot from time to time. I cleared/mulched all the cover and left just the big trees.

 

[robert_t_wallace]

Engineered footing meaning a concrete footing?

 

[robert_t_wallace]

I was looking at those big foot footers with a column of concrete above them. If you can imagine the shape of a square "U" with the twenty footers as the parallel sides and the fourty footer as a base. How many peers would you think I would need for this structure? or would you build a stem wall on the outside of the containers supporting them and peers on the inside every so often? Just trying to get a feel as to the amount of structure to build...