Ask Me Help Desk - Steps for constructing reinforced concrete piers and beams

Hi guys, I need you help.
I am interested in building my home on a lot that slopes 10 feet from front to back. I wish to use poured reinforced concrete piers and beams with a suspended poured reinforced concrete floor. Can anyone provide a step by step guide as to what has to be done and how?
Thank you

I'm not sure of the logic here. How is the access to the back for heavy equipment?

The reason I ask this is since you already have a slope that steep. To dig out a bit more you could have a full basement.
So transfer the concrete floor sitting on the piers to the basement floor. The offset in buying stone for the basement and the floor not needing all that rebar is in as the floor on the piers the trade off is a lot closer then you think in money diff especially compared to what you gain.

Also the piers need a footer dug down and roughly 12' apart. So to dig a full footer and lay block as opposed to ply forming the piers and the reabr used in them, again the trade off is close and the full basement gain is even more.

Usually what you are asking to build is for a garage or there is so much rock to hammer out.

So more info would be good.

I build stick home and all concrete homes and there are some trade offs here.

Also what's you Geo/location?

Thank You, 21boat. You are very practical and I appreciate that. There is no problem with frost as the temperature is above 70 degrees year round.
Access to the back of the lot is very easy as at the end of that 10 foot slope the area is relatively level.

When a home owner wants to build a garage on a heavy sloped site in there mind and many builders mind want to fill in the foundation for the "Garage floor"

I usually talk them out of it just using numbers. I already have to go below grade in the back and sides/front for frost. As we put the footer system in we step it up the natural grade.

This is where the change difference starts. We already had to dig a footer and pour it. So the footer is the same in Crete. The back wall is already full height in block. The side walls are already at a 45 deg. Angel. Those sides walls only need 3 or so feet on average to reach a full basement wall height same as the front because 3' is the set footer depths here for frost.

Now the bigger trade offs. To truck dirt and mechanically tamp the fill in the sloped inside area to reach the height of the new garage floor is expensive. A lot cheaper to dig out the 45 deg. Slope to get a full basement.

The garage floor needs 4" crushed stone under Crete of a filled in foundation. So lets lower that and buy the same amount of stone for a full basement.

We form up the elevated garage floor and use Ply cover with plastic. The added cost is the rebar in that new floor. However after we form and pour the elevated floor we able to drop the ply forms and recycle it for sheeting for the trussed roof. The plastic kept the ply New. The bracing we use on the inside of the formed floor is also 100% reusable for stud walls on the new garage. We never need to buy studs simply because we used 2bys and steel post for bracing the floor.

So the recap is
1. 2/3 less cost to dig out the slope for full basement as opposed to trucking in dirt and tamping.
2. The crushed stone is used for that dug out basement is used there instead of it on top of the filled in dirt
3. Spend 1/3 more for a full block walls to reach the full basement height.
4. Added labor forming and rebar to build a raised form but not costing money for the wood forming. All of that is re used for the structure above the garage slab including the roof sheeting.

So over all for around 1/3 more cost for the foundation you save 66% of the cost to have a full basement under garage for double the space and value of the property. In the end it's a wash or better plugging in the assessed value of the garage with possibly living space underneath it

Concrete Pier forming is time consuming. A Crete pump truck is needed. There's a lot of rebar that goes into the piers and beams. Add the 3/4 ply that's used up and wasted. I've done a lot of post and beam in concrete and its labor intensive to form perfectly.

Okay boat, but what if he lives in California?

There is more to consider then right? And the soil/water table?

Cyberheater

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Okay boat, but what if he lives in California? There is more to consider then right? And the soil/water table?

And ?

Already did that. Asked the Geo to get that answered. Got (70s )answers back.
I considered that I build concrete structures in the Crib where its min 70s.

Also considered there's mini earthquakes there and it Rains real HEAVY in the fall not to mention Tropical storm Depressions/ hurricanes. Also took into consideration the property has A Slope for water runoff.

"The Soil" would simply be a wider footer

If in California obviously its highly regulated in building codes or should be. The fact is a Wood structure takes more to shake apart then concrete piers suspended concrete floors. Thought it was well covered. As opposed to the few answers here.

The part missed is how much distance it takes to drop 10'. Either or the answer remains the same.

Boat, was asking for your opinion. You did cover some, but should asked in more detail.

Have a garage I am at that was placed on piles. Wet, frost heave problems. They too sloped it at an angle as you suggested. So, I took notice to your response. Thanks.

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but should asked in more detail.

The detail is not always necessary in building foundations. How should I say this, back in the 80s my crew and I were pumping out 2.5 to 3 house foundations a week.

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They too sloped it at an angle as you suggested

. Don't know what your reading on my post. When a foundation is on sloped hill the footers and the block is Stepped and not sloped. It only appears that way after backfill.

Your problem is the footer is Not deep enough and or also the pier pads aren't wide enough for the weight its supporting unless someone was crazy enough to poor the footer itself sloped and not level.

Hi cyberheater. I understand where you are coming from. I'm in one of the toughest areas in the U.S. to build in temp range and freeze not to mention inches of rain through out each summer storms. Wet fall and very rainy springs and thaws. Temp wise from 18 below to over a 100s Form soft soil to rock chipping.

I didn't ask a lot of details because this is what I do for a living. But I do miss things now and again so thanks for the reminders