Question storage building under sunroom

Hopefully I can explain this well enough. I have a Sunroom that is off the main level of the house, but no basement beneath, just 3 support beams on one end and attached to the house on the other. I have a walkout basement and would really like to use the space under the sunroom to create a storage area. I'm wondering a couple of things. First how much dirt is required to be next to the basement foundation wall. The area in question is a poored cement basement wall about 4 ft high. At the front corner there isn't any dirt at the back of this wall there is about 3ft or so. Is that dirt required for insulation or any other reason or can I just remove the dirt? This would allow me to have an area beneath the sunroom that I could put a cement slab and the place a storage shed. I wouldn't attach it to the house or dig out the whole area just enough to put an 8x10 structure and appropriate retaining wall on the side and back of the area I dug out. The sunroom is 14' wide so I would be able to leave 3' of dirt next to the footings of the sunroom (since someone mentioned this was required, but I don't know that for sure either).

Maybe this crude drawing will help... maybe not

|
|
|
F-----------+
| |
| | Basement
| |
F +------+
| |
| Sunroom |
| | 9'
| |
F------------------+---------


|
|
|
F-----------+
| |
| | Basement
| |
F +---+------+
| | |
| | proposed |
| | storage |
| | building |
F------+-----------+---------

the F's are footings.

Thanks
-Jason

xxxxxxxxxxxx|
xxxxxxxxxxxx|
xxxxxxxxxxxx|
F-----------+
|xxxxxxxxxxx|
|xxxxxxxxxxx| Basement
|xxxxxxxxxxx|
Fxxxxxxxxxxx+------+
|xxxxxxxxxxxxxxxxxxx|
|xxxxSunroomxxxxxxx|
|xxxxxxxxxxxxxxxxxxx| 9'
|xxxxxxxxxxxxxxxxxxx|
F------------------+---------


xxxxxxxxxxxx|
xxxxxxxxxxxx|
xxxxxxxxxxxx|
F-----------+
|xxxxxxxxxxx|
|xxxxxxxxxxx| Basement
|xxxxxxxxxxx|
Fxxxx+-----+------+
|xxxx|xxxxxxxxxxxxxx|
|xxxx|xxStoragexxxx|
|xxxx|xxBuildingxxxxx| 9'
|xxxx|xxxxxxxxxxxxxx|
F------------------+---------

the F's are footings.... sorry for the crudeness of the drawing.

Thanks
-Jason

[Wgoodrich]

You have several options. Point of those posts is the foot print. YOu could jack up the sun room, dig out from under your posts and dig a footer then pour a concrete retainer wall under the post to retain the earth and support your post directly under the post.

You could again jack up to support the sunroom temporarily dig to about a foot from the posts then pour a concrete retainer wall drilling the wall then installing metal screw anchors into the earth horizontally about 45 degrees and use washers and nuts supporting that retainer wall as well as the post original foot print.

If you dig up the basement wall you are fine as long as long as this part of the wall is not exposed to weather. If this part of the exposed basement wall is exposed to weather then insulate the inside wall of that basement with styrofoam or install a stud wall with about 1" air space behind for air circulation and use normal friction fiberglass insulation with no vapor barrier.

Hope this helps

Wg

Yes that does helps with the dirt issue against the house, but I don't think I explained about the posts holding up the sun room well enough or at least that part of your answer didn't make sense to me. The posts holding up the sunroom are 14' from the edge of the basement wall. The structure I plan on building is 10' so I'd put one side of the building against the house (not attached) and dig a flat area roughly 10x8. I would then put up a retaining wall as the dirt would be about 3' at the back and an angled wall on the side closest to the posts. This would leave 3-4' of earth between the side of the structure and the posts. Is this acceptable?


Thanks,
-Jason

[Wgoodrich]

When you take dirt out beside and below the foot print supporting the upper building you comprimise the foot print even if you are 3 feet away. Be sure to install a supporting retaining wall that is well anchored horizontally at least 10' into solid earth if you are using screw anchors. If you are using an "L" foot at the bottom of the retaining wall as a counterlever then that "L" must be reinforced and tied to the middle of the wall to the outer edge of the "L" foot print.

Problem is you dig out under the level of the posts even 3 feet away this invites the earth to shift in wet spring and fall conditions thus erroding from under the foot print of hte posts.

I understood what you were saying where you wanted your storage area but was trying to give you options to allow a larger storage area if so desired.

Good Luck

Wg