20' X 24' Pole barn on 25% slope - best method?

[EddieWalker]

If money wasn't an option, then the suggestions of a solid foundation would be the best choice. If it was me, I would listen to the Amish and build a deck from wood and put the barn on top of the deck. It would be very easy to build it strong enough to park a vehicle in there. That's actually very simple, but it does have to be done right. Not like most people build decks next to their houses, it will require proper sized beams and joists. There are span tables online to figure this out, but if you are unsure, an engineer could work this out for you in about an hour.

 

[Iowachild]

Side hill?

Dig into the side hill wider and deeper than than the pole barn. Dig & fill method. Get a nice gentle back slope to the excavation. If suitable use the excavated material to pad out in front of the excavation. Finally make a drainage ditch around the side and back of the excavation. Then use ordinary building procedures With cement floor.

Six foot depth may/will end up as less using cut & fill method.

This is what I did for my 24' x 40' building. That back bank is 7 foot high.

 

[DwayneB2021]

If money wasn't an option, then the suggestions of a solid foundation would be the best choice. If it was me, I would listen to the Amish and build a deck from wood and put the barn on top of the deck. It would be very easy to build it strong enough to park a vehicle in there. That's actually very simple, but it does have to be done right. Not like most people build decks next to their houses, it will require proper sized beams and joists. There are span tables online to figure this out, but if you are unsure, an engineer could work this out for you in about an hour.

Yeah the Amish barn builder gave me a tour of a huge pole building they erected near me, no doubt their work is exceptional. But they aren't cheap, about the same as the concrete slab approach.

 

[Bentrim]

Have you considered precast concrete walls? or possibly poured concrete walls and the backfilled with stone for a solid floor?

 

[DwayneB2021]

Have you considered precast concrete walls? or possibly poured concrete walls and the backfilled with stone for a solid floor?

Yes that's probably the leading candidate at this point. Finding a good contractor who will handle both concrete and the construction isn't easy though.

 

[jthibodeau89]

When i had the pad built up for my 36x66 shop we had the entry area at mid slope. Material was moved from up slope side (5') to downslope (6+'). The fill is compacted clay chirt. When i noted that the slope on one corner went too close to a boundary fence, the contractor pulled the slope back to original grade for the 10' clearance to the fence and brought in 17ea 2'×2'×6' blocks (3500lb ea) to make a retaining wall 5' off of the slab edges at the offending corner. The blocks are keyed and produced from excess concrete material. The exterior face of the blocks has a round river stone appearance. My wall was 3' high (2 courses). These blocks stack vertically. I should note that we are in TN, and our frost line is 6".

 

[ning]

What's the minimum setback per local code? 8' is legal, or are you just going for it? (Here we're at 30' minimum! )

 

[JWR]

It really depends on what you want to spend. If it is a forever building, doing it once and have the money then do it with poured concrete walls and foundation. Install some posts in the middle for load bearing and go up from there with whatever structure you choose. I see no need to fill the foundation with stone or soil or anything else. Make sure it is drained well around the perimeter. If surroundings allow/fit/you like I would still put in an access door of some sort on the high back side for storage.
If money matters, simply use the Amish and let them do the entire job. Do they have excavation equipment or access to it? So far as wood is concerned do not be that worried. You can by "ground contact certified" wood that is WAY better than typical so-called treated lumber these days. The Amish know this. Insist that it be used. If you are concerned at all with rot, find somebody with a stash of creosote and add creosote to treat the 6x6 or whatever sized vertical wood. I think they should be set in fairly thick concrete bases.
I built a garage for my tractor and tools and lumber for projects, etc. about 40 years ago. I used ground contact treated wood for the vertical posts including several "in the middle." Poured cement around each post. Framed around the posts with 2x10 lumber and then built the floor over that base. My floor was 3/4" treated plywood over structural joists, etc. That part should be done depending on what loading you want to allow. I had a removable section of floor such that I could stoop underneath and go up under cars without using a lift for oil changes, etc. Above ground was ordinary frame construction with vinyl siding and custom ports in the left and right eaves to allow insertion of long length lumber for storage on inside shelves built under the steep hip roof rafters. I did the entire job myself. Cheap and permanent.

My lot was about what you say -- 25% slope. Within maybe 4 feet of a fence on one side and 12ft in the rear but woods outside of that.

Post mortem: A huge poplar tree some 70 feet tall and 2 to 3 ft diameter came crashing down on my building (during aftermath of a hurricane.) I had sold the property around 10 years before that happened. My "Spare Garage" was demolished except that my floor supported the trunk of that tree. The newer owners rebuilt the building using my same floor and post foundation which was still in tact and sound.

 

[BoylermanCT]

My pole barn had a 4' slope from front to back. We brought in truckload after truckload of fill to bring the site level. We compacted it every 4" as we went. We had the fill extend 6' past the back wall of the barn so I could mow behind it to keep it maintained. Then it slopes down at a 45 degree angle 4' to ground level. A 16 yard load of fill is $250 here in CT. We brought in somewhere around 10-12 truck loads so it added up, but was the best solution for my site.

I do like the giant block retaining walls referenced earlier. That would have been my second choice if fill did not solve the problem.

 

[civilian]

Any way to move the building forward? Towards the garage door side? Gives the potential to have more slope to the road behind. Also your picture with the markers and sizes, seem lke the road is hidden by trees/bushes? This would be a lot easier if the ground sloped up and not down from the front. Good Luck. Jon