I’m a foundation contractor in MA and have done many garage foundations exactly like this. The wall thickness on all of them has always been at the very least 10” with extensive grids of rebar especially at the retaining wall. I would even go with a 12” thick wall on a 30-48” wide footing at retaining wall only depending on soil conditions. The rest of the walls/footings could be 10” with 20” wide footings. I would offset the retaining wall on the footing so that most of the footing overhang is on the inside of the building so that the weight of the fill/slab would prevent overturning of wall. Also, The cost difference between an 8”, 10”, and 12” wall for something this small would be negligible as the labor and larger form tie cost is the same. The extra concrete would be minimal.
I always appreciate tips like yours and thank for sharing. I like the retaining wall offset, but for viewers reading this comment, keep in mind that the size and height of these retaining walls around the perimeter of foundation might need to be larger and designed differently.
Wife and I bought a house about 1 1/2 years ago, and it came with a fabulous 25' X 30' separate garage (Man Cave!). Both house and garage are built on a slope. The house is built closer to the street where the slope is gentler. The garage has a slope very similar to your illustration (rather steep). I always thought (knew, sort of) that the foundation was fairly complex. I suspected much of what you presented (glad I was right!), but wondered about much of the rest (footings, etc.). Fascinating stuff! Must mention that my retaining walls for the foundation are cinder block (same for the house). I wonder (and hope), that the cinder block hollows were filled with cement grout joined by rebar. The garage itself is all steel-- basically commercial grade. It's a tank. And it's insulated! I love that. Anyway, thank you for this great information! Just wondering what kind of stuff would be used as fill, especially for the very deep section?
Rebar video would be amazing! I know there's a lot of work that goes into making this content, so speaking for all viewers of your channel "Thank You!"
the way the architect, first homeowner, and construction got around this type of situation at my house i purchased was to create a livable studio under the garage. of course, time, money, height, codes, etc. all come into play. good luck everyone!
I always appreciate hearing from viewers about how much they are enjoying the videos and learning and the next video will be on its way sooner than later.
Amazing idea , i have question excuse my ignorance in those matters , what can hold the whole foundation/structure from shifting toward down ? Isn't should be beams in the front to go down in the ground ?
Great video. I am thinking of building a walkout basement in the lower end of the slop, whereas the garage will be sitting on a concrete slab on the upper side. So, the lower and higher-end sides of the foundation will be different. Do you think there's a risk of getting concrete cracks in the middle of the foundation?
@@gregvancom I am a subscriber, I have watched a lot of your content and it has been very helpful in the planning of my new house. I appreciate the advice!
I would very much like to see how you might lay out the rebar for this structure. I am a little concerned about the back wall of the foundation being strong enough to hold the load.
Is it mandatory to step the footings? I’m a DIY homeowner and am working on the foundation for a metal garage kit I purchased. I’m just doing strip footings on each side since my building has openings on each end to drive through. I dug all the footings to the width and depth called for by my buildings engineers and then I realized my location slopes 7” over the 21 ft footprint for the building. I would like to just leave the slope at the bottom of footings and pour concrete in them and then into my stem wall forms that will be perfectly level. Is this an issue with such a building?? Thanks for all the helpful videos!
It's not mandatory to step footing, but you will need to check with the garage kit manufacture for more information about what they require for foundations.
I would personally like to put a grease pit in a garage like that... most likely just another couple footings running parallel down the middle like the ones you showed for the sides.. then similar retaining walls on top of them as well... yep looks like a lot of rebar work..
The problem is fire codes. I have heard you have minimum size requirements and must have two exits. That makes it take up more space than I think people want to use, so you rarely see them. Also a lift is only a few thousand, so the cost of a pit quickly competes with it.
If you had a question, feel free to form as a question, but if you're only asking if this design can be modified to create some type of a slot in the center with a set of stairs, then yes it's going to require a little more work. I would also do as the other person suggested and that would be to check with your local building authorities for more information about the design and safety requirements.
Might be late,, but I have the same problem,, my plot needs alot of backfill just to level up to floor height, trying to find a way around this challenge and get away from backfill and compacting etc etc.
Like most things in construction, back filling with gravel could cost more and if gravel provides 100 percent compaction rating, then it should be better. I would also recommend checking with a foundation contractor in your area for more information.
I was a concrete foreman in Chicago area all my life, 18x18 footing for a retaining wall will not work for a four foot high wall I would give it a minimum of a 36 inch wide footing, offset of course.
Thanks for the good information and If I didn't mention it in the video, always contact an engineer for footing and other structural material sizes in your area.
I would think the step foundation would require less concrete, forms, labor and digging, but if I got the same price, I would probably choose the full dig and make some type of storage or room out of it with a concrete floor.
Definitely another option and I like to half-inch drops in areas where it rains and snows a lot or if you have some type of a grade running towards the garage like a sloping driveway that slopes down from the street towards the garage and then of course you would need some type of a drainage system.
Do you have a book on building a garage under a garage in a hill, going for the boat and one for the cars. In other words a two-story garage and home edition on third floor. none built yet. We are formerly a concrete family so two guys and one professional licensed will be doing the cost is not the question.
It's difficult for me to answer your question, because I don't know exactly what you're doing. However I can tell you that 6 inches is going to be better than 4 inches.
Is there any professional or official name for this type of foundation? I just toured a home built in 2000 with exactly this type of design for the garage foundation, but there are vertical cracks at the corners and periodically along the length of the tallest face of the wall, and a number of diagonal cracks converging somewhat towards the center. It seems that the fill soil is starting to push out the retaining wall. Is this a disaster waiting to happen, or can that be rehabilitated?
It's a raised floor foundation with stem walls or retaining walls. It sounds like you might need to consult a professional and sometimes bracing can be installed if it's not going to be in the way.
Actually, I did get in touch with a pro! He sees a lot of this specific construction in the area(PNW), and said the defect is extremely common as well. What happens is the stem wall is leaning out because soil under the footer is settling, and unevenly so (because of course its on a slope). According to him, the only permanent solution is to drive piles down to bedrock and attach to the footer along the leaning wall. If not, the wall will likely inevitably topple over. Bracing would not actually be a solution there, because the footer is still gonna keep settling.
Curious, what's the most efficient way you've come across to do a steep 100% grade hillside foundation layout for excavation and forms involving a cut up and segmented floor plan?
It sounds like you're asking for step-by-step instructions for your project, I won't be able to provide you with that, but might be able to provide you with a series of videos if that's something you're interested in. If you are asking for something else, feel free to provide me with more details.
Why would u put French drain on inside of the foundation of garage? I’m pretty sure I would want to catch it on the outside of said structure and right either on top of footing or right along the side of footing. Just don’t see to much of a benefit doing it on the inside of pad. Now if it’s just the back up for the one on the other side then tht would make a lot of sense. One them insurance thang’s incase the outside one gets plugged up,there would always be the back up one ready to catch and disperse the water away from structure.
No matter the drainage you have on the exterior of a building, water will still get into that area. Moisture can come up from below. Plus it's a great insurance
Why are the footings so wide? My area only the stem wall is technically required due to the soil bearing capacity, but the city arbitrarily requires 12in footings. Seems that has got to be pretty soft soil to need 18in unless there is some other reason.
@@wompbozer3939 I found a footing table for LA and it looks like for a 2 or 3 story building in low bearing capacity soil the wide footings shown here would be needed. I would think that few sites have that low bearing capacity, but maybe this is a soft sandy hillside.
Keep in mind that this is only meant to be an example of how it can be done, but not how it can be done in your specific area, country, state or city. I've seen footings a lot wider than the ones I've drawn for something like this. Where exactly are you located?
Your end wall, I'd build it double block with a cavity of 3" tie together with 5" tie bars, built into block work spacing about every 30 - 36" apart ever 2 blocks high, fill this with concrete. Fitting 18" deep? Depending on the type of found your working on, determined a lot of things. Another option, if it's 5' deep, dig out another 2 - 3'akevit pillar and beam, either put beam block floor/ concrete floor, you have anothervróm under you garage.
Putting a basement under the garage would be a nice way to get more space. I would say to let a professional registered engineering firm do the design work. If it is under designed the whole structure can fail and lives can be lost!
Has such a thing ever been done i.e. a space where humans walk underneath a garage slab with SUVs parked on it? I pray not. The engineering of course could be done but too costly and too risky and backwards imo. Relocate the garage itself and put the first floor living space on the slab.
@@gregvancom idea is to use 3 to 4 columns having shape of letter E with some 10 feet gape. Where I will obviously bear the load and other 3 legs of letter E will retain the columns to its place. And 3 legs should be stuck inside load bearing walls. Letter L shape retaining walls are weak at the 90 degree angle point. And top of L should have some type of ancor like anchored retaining wall.
![ร้อยพ่อพันแม่ - WanMai [Official MV]](http://i.ytimg.com/vi/XY2pNYASEbg/mqdefault.jpg)
Here's a link to the video with rebar th-cam.com/video/qwHEHGhAHPY/w-d-xo.html
I’m a foundation contractor in MA and have done many garage foundations exactly like this. The wall thickness on all of them has always been at the very least 10” with extensive grids of rebar especially at the retaining wall. I would even go with a 12” thick wall on a 30-48” wide footing at retaining wall only depending on soil conditions. The rest of the walls/footings could be 10” with 20” wide footings. I would offset the retaining wall on the footing so that most of the footing overhang is on the inside of the building so that the weight of the fill/slab would prevent overturning of wall. Also, The cost difference between an 8”, 10”, and 12” wall for something this small would be negligible as the labor and larger form tie cost is the same. The extra concrete would be minimal.
I always appreciate tips like yours and thank for sharing. I like the retaining wall offset, but for viewers reading this comment, keep in mind that the size and height of these retaining walls around the perimeter of foundation might need to be larger and designed differently.
Wife and I bought a house about 1 1/2 years ago, and it came with a fabulous 25' X 30' separate garage (Man Cave!). Both house and garage are built on a slope. The house is built closer to the street where the slope is gentler. The garage has a slope very similar to your illustration (rather steep). I always thought (knew, sort of) that the foundation was fairly complex. I suspected much of what you presented (glad I was right!), but wondered about much of the rest (footings, etc.). Fascinating stuff! Must mention that my retaining walls for the foundation are cinder block (same for the house). I wonder (and hope), that the cinder block hollows were filled with cement grout joined by rebar. The garage itself is all steel-- basically commercial grade. It's a tank. And it's insulated! I love that. Anyway, thank you for this great information!
Just wondering what kind of stuff would be used as fill, especially for the very deep section?
Rebar video would be amazing! I know there's a lot of work that goes into making this content, so speaking for all viewers of your channel "Thank You!"
It looks like it will be coming sooner than later and thanks for the wonderful comment and you're welcome.
Here's a link th-cam.com/video/qwHEHGhAHPY/w-d-xo.html
Thank you, finally some good stuff...after so many tries to find a simple, decent explanation for creating a foundation on slopes.
Glad it helped!
WOW!!! BEST VIDEO I"VE SEEN EXPLAINING THIS!!!!!
AWESOME!!!!!
Great video! Please make more videos for hillside construction. Thank you so much for sharing your knowledge!
More to come!
the way the architect, first homeowner, and construction got around this type of situation at my house i purchased was to create a livable studio under the garage. of course, time, money, height, codes, etc. all come into play. good luck everyone!
Thanks for sharing!
Yes, I would like to see the rebar video. good work!
Ok thanks!
Great rendering.
Thanks
The rebar video would be great, thanks! ;)
Coming soon!
Very concise and helpful video
Glad you think so!
Let's get to 20 comments to for part 2 of this video. The videos and information are amazing!
Glad you enjoyed the video and comments like yours are always sincerely appreciated so I will count your comment as two votes.
Rebar video would be great 👍Thanks for all your detailed videos, I've enjoyed them all and learn a lot from them.
I always appreciate hearing from viewers about how much they are enjoying the videos and learning and the next video will be on its way sooner than later.
Amazing idea , i have question excuse my ignorance in those matters , what can hold the whole foundation/structure from shifting toward down ? Isn't should be beams in the front to go down in the ground ?
Great video. I am thinking of building a walkout basement in the lower end of the slop, whereas the garage will be sitting on a concrete slab on the upper side. So, the lower and higher-end sides of the foundation will be different. Do you think there's a risk of getting concrete cracks in the middle of the foundation?
It's hard to tell with concrete. I won't be any help here.
This video was so helpful!! Thanks so much for sharing!
Glad it was helpful!
Excellent presentation, the layer by layer was very easy to understand.
Great to hear!
Helpful video - thank you
You're welcome!
Awesome 👌
amazing work. thanks
Our pleasure!
Great video. Thanks for sharing.
Our pleasure!
Great video, thank you. Unfortunately it came a few months too late, I ended up putting the garage in the basement of the house
Glad you liked it and let's hope it helps the next people. Was this your video suggestion?
@@gregvancom I am a subscriber, I have watched a lot of your content and it has been very helpful in the planning of my new house. I appreciate the advice!
@@h8tower594 Glad it helps and thank you for the kind words.
What approved backfill do you recommend
Good short video, thx this helps
You're welcome and thanks for watching.
Great video!
Thanks, great video!
Glad you liked it!
I would very much like to see how you might lay out the rebar for this structure. I am a little concerned about the back wall of the foundation being strong enough to hold the load.
Which backwall are you referring to? The wall that is 5 foot tall?
@@gregvancom The wall at the bottom (lowest point) of the slope . I appreciate your efforts and the type of work you are dealing with.
Can this same concept be done for a house? I am planning on a 61’x48’ foundation. The slope is on the 48’. I have about 7’ drop over the 48’.
It's been done plenty of times for homes.
Is it mandatory to step the footings?
I’m a DIY homeowner and am working on the foundation for a metal garage kit I purchased. I’m just doing strip footings on each side since my building has openings on each end to drive through. I dug all the footings to the width and depth called for by my buildings engineers and then I realized my location slopes 7” over the 21 ft footprint for the building. I would like to just leave the slope at the bottom of footings and pour concrete in them and then into my stem wall forms that will be perfectly level. Is this an issue with such a building?? Thanks for all the helpful videos!
It's not mandatory to step footing, but you will need to check with the garage kit manufacture for more information about what they require for foundations.
Would that be a good opportunity to build a storm cellar under the garage floor?
I would think so.
The garage floor is a slab and it would not be wise to have any hollow cavities underneath it. Someone say if I am off base here.
Good job
Thanks
I would personally like to put a grease pit in a garage like that... most likely just another couple footings running parallel down the middle like the ones you showed for the sides.. then similar retaining walls on top of them as well...
yep looks like a lot of rebar work..
The problem is fire codes. I have heard you have minimum size requirements and must have two exits. That makes it take up more space than I think people want to use, so you rarely see them. Also a lift is only a few thousand, so the cost of a pit quickly competes with it.
If you had a question, feel free to form as a question, but if you're only asking if this design can be modified to create some type of a slot in the center with a set of stairs, then yes it's going to require a little more work. I would also do as the other person suggested and that would be to check with your local building authorities for more information about the design and safety requirements.
Any thoughts on laying slab on a pan, carried by steel beams instead of backfill? I’m always curious when this cost-benefit breaks even.
This would probably be cheaper for this project, but maybe not for larger ones.
Might be late,, but I have the same problem,, my plot needs alot of backfill just to level up to floor height, trying to find a way around this challenge and get away from backfill and compacting etc etc.
Awesome video
Glad you enjoyed it and thanks for letting us know.
Nice work thanks for sharing
You're welcome and thanks for watching.
Does this type of foundation have a name?
Awesome video, thanks so much!
I would call it a raised stem wall foundation.
Any benefit of Placing a grid of Concrete filled Sonotubes into the Central Slab area, for better Support of the Slab?
It would depend on the slope, soil and design.
Would you compact the fill in the garage with a plate tamper or would that put too much stress on the walls?
It will depend on the fill materials. I think gravel is 100 percent compacted, but loose soil might need compaction.
Could and would it be better to fill with 3/4 clean stone and geogrid every 6 to 12” or so to really lock this fill in place?
Like most things in construction, back filling with gravel could cost more and if gravel provides 100 percent compaction rating, then it should be better. I would also recommend checking with a foundation contractor in your area for more information.
@@gregvancom thank you for your reply, as well as all your videos!!
Thanks Greg. If I want to use CMUs to create the stem walls instead of poured and formed concrete, any videos or suggestions for that design? Thanks
I don't have any videos yet, but you can build the block walls on top of footings with rebar, if that helps.
@@gregvancom Thanks for the suggestions. I'll give that some consideration.
I was a concrete foreman in Chicago area all my life, 18x18 footing for a retaining wall will not work for a four foot high wall I would give it a minimum of a 36 inch wide footing, offset of course.
Thanks for the good information and If I didn't mention it in the video, always contact an engineer for footing and other structural material sizes in your area.
Yo great video
Glad you enjoyed
What would be the benefit of a stepped foundation vs fill and dig on a slope? We received quotes from 2 different company’s and they are the same cost
I would think the step foundation would require less concrete, forms, labor and digging, but if I got the same price, I would probably choose the full dig and make some type of storage or room out of it with a concrete floor.
good
Run the concrete slab to the front edge with 1/2" drop to outside slab elevation. Your model has it aligned to inside face.
Definitely another option and I like to half-inch drops in areas where it rains and snows a lot or if you have some type of a grade running towards the garage like a sloping driveway that slopes down from the street towards the garage and then of course you would need some type of a drainage system.
@@gregvancom Run-on sentences make my head hurt.
If I were hire a company to do this for a steep slope, what cost could be looking at?
You should contact a contractor in your area for an estimate.
Does the footing on the back wall still have to be set under your frost line?
It depends on the area, but most footings should be below frost line or at least exterior footings.
Can this method be apply for a house?
It's not real common, because most designers use floor framing joist with a crawlspace underneath. Hope that helps.
Do you have a book on building a garage under a garage in a hill, going for the boat and one for the cars. In other words a two-story garage and home edition on third floor. none built yet. We are formerly a concrete family so two guys and one professional licensed will be doing the cost is not the question.
Not yet!
How thick would we need those diagonal sections to be so that enough rebar should be in there? At least 4 inches? We want rebar.
It's difficult for me to answer your question, because I don't know exactly what you're doing. However I can tell you that 6 inches is going to be better than 4 inches.
So what’s good backfill?
Contact local building material suppliers. I like gravel, but sometimes a loose fill like sand will work.
Is there any professional or official name for this type of foundation? I just toured a home built in 2000 with exactly this type of design for the garage foundation, but there are vertical cracks at the corners and periodically along the length of the tallest face of the wall, and a number of diagonal cracks converging somewhat towards the center. It seems that the fill soil is starting to push out the retaining wall. Is this a disaster waiting to happen, or can that be rehabilitated?
It's a raised floor foundation with stem walls or retaining walls. It sounds like you might need to consult a professional and sometimes bracing can be installed if it's not going to be in the way.
Actually, I did get in touch with a pro!
He sees a lot of this specific construction in the area(PNW), and said the defect is extremely common as well.
What happens is the stem wall is leaning out because soil under the footer is settling, and unevenly so (because of course its on a slope). According to him, the only permanent solution is to drive piles down to bedrock and attach to the footer along the leaning wall. If not, the wall will likely inevitably topple over. Bracing would not actually be a solution there, because the footer is still gonna keep settling.
Curious, what's the most efficient way you've come across to do a steep 100% grade hillside foundation layout for excavation and forms involving a cut up and segmented floor plan?
It sounds like you're asking for step-by-step instructions for your project, I won't be able to provide you with that, but might be able to provide you with a series of videos if that's something you're interested in. If you are asking for something else, feel free to provide me with more details.
@@gregvancom No project in mind. Just wandering if you had a more effective methodology than the standard step method?
@@Oldhogleg I got you, I don't, but if I do, I will make a video.
@@gregvancom 👍
Theoretically if it was cost feasible to just fill the whole cavity inside the retaining walls with concrete instead of soil, would it be better?
I actually think the weight of the additional concrete could cause this design to fail.
@@gregvancom Interesting! Do you say that because the ground is at an angle? What about a raised slab on level ground?
Hi, is the overlap between the steps large enough? Is there a rule for the overlap? (We want rebar ! :) )
What overlap are you referring to specifically? Your vote has been counted and we are only a few more votes away.
@@gregvancom I'm referring to the stepped footing. Cheers for the work !
Rebar please, Greg. Thanks.
I think were only a few votes away.
Here's a link th-cam.com/video/qwHEHGhAHPY/w-d-xo.html
Why would u put French drain on inside of the foundation of garage? I’m pretty sure I would want to catch it on the outside of said structure and right either on top of footing or right along the side of footing. Just don’t see to much of a benefit doing it on the inside of pad. Now if it’s just the back up for the one on the other side then tht would make a lot of sense. One them insurance thang’s incase the outside one gets plugged up,there would always be the back up one ready to catch and disperse the water away from structure.
No matter the drainage you have on the exterior of a building, water will still get into that area. Moisture can come up from below.
Plus it's a great insurance
Why are the footings so wide? My area only the stem wall is technically required due to the soil bearing capacity, but the city arbitrarily requires 12in footings. Seems that has got to be pretty soft soil to need 18in unless there is some other reason.
California
@@wompbozer3939 I found a footing table for LA and it looks like for a 2 or 3 story building in low bearing capacity soil the wide footings shown here would be needed. I would think that few sites have that low bearing capacity, but maybe this is a soft sandy hillside.
Keep in mind that this is only meant to be an example of how it can be done, but not how it can be done in your specific area, country, state or city. I've seen footings a lot wider than the ones I've drawn for something like this. Where exactly are you located?
Your end wall, I'd build it double block with a cavity of 3" tie together with 5" tie bars, built into block work spacing about every 30 - 36" apart ever 2 blocks high, fill this with concrete.
Fitting 18" deep?
Depending on the type of found your working on, determined a lot of things.
Another option, if it's 5' deep, dig out another 2 - 3'akevit pillar and beam, either put beam block floor/ concrete floor, you have anothervróm under you garage.
Thanks for sharing and definitely a few other options.
fos a garage. i would want to be able to go down in the middle to be able to work on vehicles
please do another
I'm only a few more votes away.
Wow that just looks so beefy !
Yes, built to last until if falls apart:)
Approximately, how much would this kind of project cost? Let's say it's a two car garage.
You will need to contact a local builder for an estimate.
@@gregvancom okay, thank you.
$27,000
What about a slab on a slope built on a deck
Email me some pictures if you have them of the design.
Comment for Rebar video....!!
We want rebar x 20. 😉
Your votes have been counted. I gave you two instead of 20.
Here's a link th-cam.com/video/qwHEHGhAHPY/w-d-xo.html
What can be maximum slope of my garage ? On how much maximum slope i can park my car
I like 1/4 of an inch per foot maximum, but you will need to check with your local building department to know for sure.
I DEMANDS REBAR
Here's a link th-cam.com/video/qwHEHGhAHPY/w-d-xo.html
Putting a basement under the garage would be a nice way to get more space. I would say to let a professional registered engineering firm do the design work. If it is under designed the whole structure can fail and lives can be lost!
Has such a thing ever been done i.e. a space where humans walk underneath a garage slab with SUVs parked on it? I pray not. The engineering of course could be done but too costly and too risky and backwards imo. Relocate the garage itself and put the first floor living space on the slab.
We want rebar!
Just a few more votes away.
We want rebar
It looks like it will be coming soon.
Rebar???
It looks like the videos on its way and thanks for voting.
Hey man its joaquin. Whats ur email. I lost it. U helped me out alot b4
Go to our website and it's at the bottom, click on contact.
No its very costly plan. Give us plan using columns to retain the wall
I will need more details.
@@gregvancom idea is to use 3 to 4 columns having shape of letter E with some 10 feet gape. Where I will obviously bear the load and other 3 legs of letter E will retain the columns to its place. And 3 legs should be stuck inside load bearing walls. Letter L shape retaining walls are weak at the 90 degree angle point. And top of L should have some type of ancor like anchored retaining wall.
Should of filled it with stone not dirt
I like it.
we want rebar
Here's a link th-cam.com/video/qwHEHGhAHPY/w-d-xo.html