Building on a slope?

I’m wanting to build a big garage on my property with a solid concrete slab as the floor but the only spot I can put it is narrow and on a hill so half to garage would be sticking about 15-20ft off a ledge with a decently long and steep slope. What would be the best way to support the garage without being too expensive. I’ve thought of doing concrete pillar type of thing but I’m not sure how expensive that would be. I don’t wanna dig into the side of the mountain to make a flat area cause I’d have to worry about water flow and building a retaining wall. Any suggestions?

10 Answers

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  • 5 months ago

    Especially because of the weight of vehicles in the garage, you need to talk to an engineer.

  • 6 months ago

    it has to be dug into the slop so that is anchored and it has to be all in concrete

  • 6 months ago

    Before you do anything, go to your local building and zoning commissioner and find out what the rules and regulations are in regard to building a garage on tall pilings. The building inspector could also have some suggestions on how to build your project so it passes inspection.

    Then, proceed from there.

  • Anonymous
    6 months ago

    I still think I would dig in. The alternative is pile posts, which is perfectly doable. I once looked at a house built on a steep slope and it had wood piles under it. The realtor told me how easy it was to true them up now and then. But that house stood there 100 years and is probably there still. The electric wires were on ceramic posts.

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  • Anonymous
    6 months ago

    Talk to the excavator boys. Have them come by and look at your proposal and bid on it. Get more than one outfit to come and take a look. Even building contractors know what has to be done to the ground first. Big garage may mean a 3 car garage size(or not). While they may seem like "dough heads"; they have the experience of digging all sorts of properties. They can eyeball it up and tell you what they can do. (Not all properties are on flat land.) They will be digging into the hill because THAT IS YOUR PROPERTY. The water is a minor issue (as homo sapiens has learned how to ditch and divert water into man made channels that are buried underground.(aka sewers) They know how to do this. When they dig out the side of the hill, you are going to have a windowless wall facing the hill to hold the hill up...should it move. at some future date....maybe after you been "laid to rest 10 years".(so YOU really don't care anymore)

    You are not on flat land so it is stuff you got to do. Retaining wall is par for the course. It is never going to be as cheap as working on a flat piece of land...so if you are not interested in buying another separate Lot for your big garage...this is what you got to do.

    I was involved in the building of a house and attached garage that was dug into a mountainside of clay. So clay absorbs rainwater and moves toward the lake...below it. It is easier to pour a concrete floor with lots of re-bar when there is dirt under it, so there is never an overhang. Your driveway is going to go up sideways first and then turn straight to make the hill climbable for the vehicles.

    This is something the excavator guys have to see first hand. A picture would have helped here too.

    Many would have experience in building in mountainous regions...either highways or subdivisions.

  • d00ney
    Lv 5
    6 months ago

    It largely depends what rock you are building on. Presuming that it is erosion free, would suggest employing the principles of suspension. You could excavate on the landward side, to give more weight so it holds the overhanging part. Do take expert local advice, it could save you heartache and pennies.

  • 6 months ago

    My garage is built on the side of a hill. I dug down about 5 feet on the up hill side. The first 6 feet of the wall on that end is concrete blocks water proofed with a French drain. I then dug a drainage ditch so water coming down the hill will be diverted away from the wall. It has been in place for 23 years and the inside of the garage is dry as a bone.

    The soil from digging down that end of hill was used as fill to bring up the other end so the foundation slab would be level.

    • Lv 4
      6 months agoReport

      excellent answer & example

  • Jesse
    Lv 5
    6 months ago

    Grade or excavate the ground until you have enough area to build it on. Another Idea would be to stair step it. Have a foundation for a cinder block wall on the lower part, on the slope then match it up with the top. You’d then have to back fill it with gravel then put your foundation slab on.

  • 6 months ago

    Removing the hill is most likely that least costly option.

  • Will
    Lv 7
    6 months ago

    If you don't want to cut into the hill to create a flat surface, you're out of luck. Excavating might not be so bad. You can just reinforce the ground with concrete, even the vertical wall of the rear of the garage, to provide extra support. To deal with water you could try to building a little channel that will divert flowing water away from the garage. Say 5ft behind and uphill from the garage you could have a channel dug out that running water will enter and be diverted away from the garage and off to the sides. It sounds like and probably will be a lot of work, but there is no other way to adequately build a garage on a hill without creating a ramp (additional slope) to enter the garage.

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