building garage on slope

[jmorgan1221]

hey guys. was looking for some suggestions or advice. i am interested in having an all metal garage installed on a empty lot that i had purchased. the size of the building is going to be 30x45. the problem i am having is that the ground will have a 3 to 3 1/2 foot difference from one side to the other. i was going to build a retaining wall with 6x6 treated posts in the ground (think pole barn) 4 foot apart and building it up with 2x6 treated boards. i was going to fill the area with 57 limestone and pour a 5 inch pad for the building.

would this be a bad idea? any suggestions on what would be the best way to go about doing this?

thanks.

 

[PWC Repair]

You will want something permanent if the building will sit on top. Footer and poured retaining wall. A good dirt guy can probably shift the existing dirt around depending upon composition to save on fill.

 

[The Cobbler]

yes, I think you'll want/be required to pour footings

 

[Corsair4360]

We are having a shop / garage built now that is on a slope (about 7 feet) from one corner diagonally to the other. The road slopes as well (about 15 percent), so the basement of the garage is the apartment (required by the city for zoning) and shop. The actual garage is level with the street entrance at the northeast corner of the lot. The building is 50 foot wide and 35 feet deep. We are in Northern Utah, so frost and snow are a real consideration.

 

[jmorgan1221]

You will want something permanent if the building will sit on top. Footer and poured retaining wall. A good dirt guy can probably shift the existing dirt around depending upon composition to save on fill.

the building will not be directly on top of the retaining wall. the pad will be a few feet back from the wall.

 

[OccupantRJ]

A guy I know had a garage shop in his back yard on a fairly abrupt slope front dropping to the rear. He cut a doorway into the back wall and built a set of trays like a trestle on the slope outside the garage to drive a car out on to do oil changes and other under car work. He also had a set of steps for access between inside and out. It was pretty nice.

 

[ransil]

I cut into the hill , down about 10 feet, used that dirt as fill to level , compacted in 6-12" layers.

I just slopped off the hill leaving 5 feet from the bottom to the garage, french drain and gravel fill.

36x60 pole building no footers just poles into the ground 4 or so feet.

Sent from my SM-G920V using Tapatalk

 

[PWC Repair]

the building will not be directly on top of the retaining wall. the pad will be a few feet back from the wall.

I didn't mean directly on top, just 10 years down the road you don't want wood falling apart and your pad washing out during a heavy rain. It would be disasterous.

 

[coldh2o]

I didn't mean directly on top, just 10 years down the road you don't want wood falling apart and your pad washing out during a heavy rain. It would be disasterous.

^^^This. I would want something a lot more permanent than wood for a retaining wall that's essentially holding up a building.

You say it's 3-3.5' from one side to the other. Can you split the difference - cut the high side and use the fill for the low side? Then you save on imported fill and only have 1-2' of elevation to make up on either side, which depending on your lot size could be done with sloping rather than a wall.

 

[ConCretin]

I'm not seeing a major problem here. I wouldn't mess with a retaining wall. Just strip off the topsoil and organics and bring the pad up to the desired elevation. Use a structurally stable material and compact in lifts. Taper the fill out at a 45 or preferably a 60 degree slope. You'll be fine to build whatever you want.

 

[garagelogician]

I design retaining walls. Your plan is a bad idea, even if you used a concrete block wall. Wood that is in contact with the ground rots out over time. Segmental block walls move with frost, settlement and active earth pressure.

Do you have space to bring in fill and grade out the area?

If so...I would strip back all the topsoil and organics, bring in fill if necessary and grade out a pad with a 3H:1V to 4H:1V slope down to existing ground from the pad.

 

[jmorgan1221]

I'm not seeing a major problem here. I wouldn't mess with a retaining wall. Just strip off the topsoil and organics and bring the pad up to the desired elevation. Use a structurally stable material and compact in lifts. Taper the fill out at a 45 or preferably a 60 degree slope. You'll be fine to build whatever you want.

I design retaining walls. Your plan is a bad idea, even if you used a concrete block wall. Wood that is in contact with the ground rots out over time. Segmental block walls move with frost, settlement and active earth pressure.

Do you have space to bring in fill and grade out the area?

If so...I would strip back all the topsoil and organics, bring in fill if necessary and grade out a pad with a 3H:1V to 4H:1V slope down to existing ground from the pad.

what would you recommend as fill if i just graded the area? i was going to use a limestone mix like a 411 or something similar. to prevent settling, i was wanting to stay away from dirt fill. thanks.

 

[My Old Tools]

This will give some ideas...
https://www.garagejournal.com/forum/showthread.php?t=365026&highlight=shop

 

[jloehlein]

I had a pretty good slope in the area I cleared for my shop (at least 15' over a 200' distance). We cut into the hillside enough to create a smooth grade 30' behind the shop and used the dirt to level out the parking area in front of the shop. The slab was all on the cut grade, no fill. We covered the new slope in mulch and it's been fine. I'd avoid walls as much as possible, it's just more to worry about. Any reason you couldn't do similar?

Before grading:

After grading:

Before:

During:

After:

 

[jmorgan1221]

thanks for all the suggestions.

 

[JamesW84]

The far end was about 5 ft higher than the front. I dug it all out semi level with zero fill. Used the spoils to Level part of the lot and kept some for backfill

 

[38Chevy454]

Is your front higher than back? Or rear higher than front? If rear is higher, best solution is dig into the slope. No worry about fill and building up. If front is higher then you need to consider what can be done to minimize fill.