Putting a basement under my garage (& back yard) ?
- Thread starter someguy11
- Start date
Tyberius
Well-known member
I would move the garage onto the neighbor's pad behind his garage.
Maybe his lot isn't wide enough?
Your garage will encroach upon the alley, but you can permit the blocking of the alley.
ETA: Looks like there is a tree blocking the way. Maybe dig out his tree and store it. I suppose it would really depend on how much he would take for storage of your garage.
Maybe his lot isn't wide enough?
Your garage will encroach upon the alley, but you can permit the blocking of the alley.
ETA: Looks like there is a tree blocking the way. Maybe dig out his tree and store it. I suppose it would really depend on how much he would take for storage of your garage.
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a) city has a regulations governing how long the back alley can be blocked and it isn't an option.
b) the garage would still encroach over where we need to pour the south wall. We'd still be working under the garage
Like I said before, either it gets demolished or it gets lifted right where it is.
The ramp going to the bottom of the hole would go between the garage and the trees on the side of our lot.
Even if the garage was gone you can't get a large excavator into the alley, at least not at the end of the dig.
bczygan
Well-known member
OK,
Photos give some indication of the size issues.
We have a 1,250SF house with a one car attached garage, on a 40x100 corner lot, so I can see how you are shoehorned into your space.
I know your original post only asks about how to build under an existing garage, and that you are working with an Architect and Engineer.
This project is complicated. I would be looking at the entire lot and existing house and all the functions you wanted to accommodate, and would do a comprehensive plan based on every possible thing the city and your budget would allow.
But your question is simple. And the answer is:
Move the garage out of the way in the least expensive way.
On the one end, you could box up the existing garage and move it completely out of the way, either off the lot or up in the air, far enough that regular construction wouldn't be impeded. At the other extreme, you could leave it where it is and excavate under it with greater difficulty and expense.
Play with the different methods and their associated numbers to get the most economical balance.
Right now, without measurements of the lot and structure and photos of the structure, it's hard to say what can be done.
Bill
Photos give some indication of the size issues.
We have a 1,250SF house with a one car attached garage, on a 40x100 corner lot, so I can see how you are shoehorned into your space.
I know your original post only asks about how to build under an existing garage, and that you are working with an Architect and Engineer.
This project is complicated. I would be looking at the entire lot and existing house and all the functions you wanted to accommodate, and would do a comprehensive plan based on every possible thing the city and your budget would allow.
But your question is simple. And the answer is:
Move the garage out of the way in the least expensive way.
On the one end, you could box up the existing garage and move it completely out of the way, either off the lot or up in the air, far enough that regular construction wouldn't be impeded. At the other extreme, you could leave it where it is and excavate under it with greater difficulty and expense.
Play with the different methods and their associated numbers to get the most economical balance.
Right now, without measurements of the lot and structure and photos of the structure, it's hard to say what can be done.
Bill
One wild *** thought I had was to lift the roof off with a big crane and set it on the street. Then lift out the 4 walls, hoping they don't crack too much. Then one would have quite a bit of room to work.
Lifting the roof by itself would basically wreck it though.
Lifting the roof by itself would basically wreck it though.
I've done that. All numbers point to trying to excavate with the garage in place.
I've given you all the relevant measurements, over and over. And you can see scaling the Google Earth image what we are up against and why we want to work under the garage.
I think this is one of those ugly projects that you can sit and think about forever, but there is no easy or quick way to do it. You man up, dig in and tackle it and enjoy it when its done.
I could spend $40K to remove the trees to get the garage out of the back yard.
I could spend $40K removing and replacing the garage.
Or we could jack it up and work under it. Excavation will cost a bit extra, and productivity will be a bit less, but it won't be $40K less. Last fall one company gave me a ballpark quote to excavate the hole with the garage in place for $20K. We'd have to handle the lifting and blocking of the garage.
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bczygan
Well-known member
A picture is worth a 1000 words!
Lift it up in the air as far as you can with beams that are long enough, and cribbage, to give you space to work with the most economical equipment.
Now, let the house moving and excavation contractors give you their best options.
By the way, what are the limits the city will allow the alley to be blocked?
Bill
Lift it up in the air as far as you can with beams that are long enough, and cribbage, to give you space to work with the most economical equipment.
Now, let the house moving and excavation contractors give you their best options.
By the way, what are the limits the city will allow the alley to be blocked?
Bill
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Generally, days, certainly less than a week, for full blockage anyway. We can do a partial block for longer. Putting the garage on my neighbors pad would be a full block.
bczygan
Well-known member
You certainly have the 10 pounds of **** in a five pound bag problem.
I would change things around and make the smaller structure the house and the larger one the shop.
I would change things around and make the smaller structure the house and the larger one the shop.
The garage is going to be a long way in the air from the basement floor. I think we could pour 1 or 2 temporary or permanent concrete pillars for the cribbing under the beams. Its no problem to get beams to put under it or jacks to lift it up. We could drill a 12' deep hole for a pillar at the start of excavation and it could sit on that for the entire time. We could knock them out when we are ready to set it down permanently.
These are the sort of ideas I'm hoping to hear about from this group.
These are the sort of ideas I'm hoping to hear about from this group.
You certainly have the 10 pounds of **** in a five pound bag problem.
I would change things around and make the smaller structure the house and the larger one the shop.
Did I mentioned I'm married and I'd like to stay that way ? LOL.
FWIW, I wanted to build from scratch in this area, but this house was a relative bargain. I couldn't build it for what we paid, even with the reno costs factored in. Plus I didn't spend a year of my life (or more) managing a new house build.
bczygan
Well-known member
The more standard you can keep the raising of the garage, the less expensive it will be.
If you have room for standard cribbing, then that would be cheapest. If you need the supports to be narrower, you will need bracing to triangulate things. You need to talk to people locally who have done this on this kind of constricted lot. Architects and Engineers, unless they have experience with this, or are design build guys, won't have real world answers. Find and pick the brains of excavators and house movers.
Perhaps there are some of these guys here on GJ as well. And you can use Google. I personally haven't done a job like this. I am surprised at how completely you lot is covered and how close you are to your neighbor. Tight indeed!
Thank you for the photos, and keep the thread going. This is very instructive for a lot of guys in similar situations.
Bill
http://whimfield.com/pouring-a-concrete-foundation-under-an-old-house/ <- This guy was smart enough to not post on the Internet until his project was done !
It probably goes without saying that this project would have been a piece of cake to do if done when the house was built. Something to keep in mind if you are building a house and want this sort of garage setup.
Does anyone think we could lift the roof off the garage without wrecking it ? Put beams under the eaves ? The walls should be easy to lift out without damage ?
It probably goes without saying that this project would have been a piece of cake to do if done when the house was built. Something to keep in mind if you are building a house and want this sort of garage setup.
Does anyone think we could lift the roof off the garage without wrecking it ? Put beams under the eaves ? The walls should be easy to lift out without damage ?
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tacostand
Well-known member
Thank you very much for the pictures. They are a great help in assessing the situation.
1. You mention enlarging your garage from 22x31 to 22x34. Can you give any more details about this?
2. Can you sell your garage to your next door neighbor and move it next door?
3. Can you demo your neighbor's garage, store yours on his property, move yours back and then build him a new one?
4. Can you remove the front wall of your garage to give clear access to the site through the alley and garage?
Maybe you could build the bunker between house and garage, bring in precast roof panels this way, etc. to complete that phase and then pick the garage up and put it on that part of the bunker while you do the portion under the garage.
5. Can you locate the lift outside of the existing footprint of the garage (between garage and street fence?) so you don't disrupt parking space, etc.?
Maybe you do a sidewalk lift type of elevator (http://www.aclifts.com/material-handling/Sidewalk-Lift.asp).
Looking forward to more on this thread.
Dave
1. You mention enlarging your garage from 22x31 to 22x34. Can you give any more details about this?
2. Can you sell your garage to your next door neighbor and move it next door?
3. Can you demo your neighbor's garage, store yours on his property, move yours back and then build him a new one?
4. Can you remove the front wall of your garage to give clear access to the site through the alley and garage?
Maybe you could build the bunker between house and garage, bring in precast roof panels this way, etc. to complete that phase and then pick the garage up and put it on that part of the bunker while you do the portion under the garage.
5. Can you locate the lift outside of the existing footprint of the garage (between garage and street fence?) so you don't disrupt parking space, etc.?
Maybe you do a sidewalk lift type of elevator (http://www.aclifts.com/material-handling/Sidewalk-Lift.asp).
Looking forward to more on this thread.
Dave
SALIV8
Well-known member
structurally, would anything you do possibly affect the neighbor being as super close as they are?
are you worried about the neighbors structural integrity being compromised at all?
are you worried about the neighbors structural integrity being compromised at all?
bczygan
Well-known member
bczygan
Well-known member
Yes,
I would investigate this. Figure a 45 degree load from his foundation down and outward. You will need to consider this.
Going to move the wall out to the property line. I'll fill in the details later.
Nope. He is retired. No interest in my garage.
Sure, but I doubt it would be cost effective.
Yes. We'd have to put a beam across to hold up the roof trusses. Interesting idea. Where are you going with that ?
You can do it that way. Precast roof panels are out of the question due to weight. Too heavy.
You also end up with the skid steer stuck at the bottom of the hole at the end of the dig. Could lift it out with a small crane though.
BTW, just talked to a crane contractor and they won't work in the area, ie lift over the trees or the garage due to the power lines.
Nope. See above about the crane.
I want the elevator inside the garage.
Might become the bane of my existence !
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"Infill" homebuilders face this all the time.
If his garage has a proper foundation and he doesn't park his car on that side, we are fine, or so I'm told. We'll get to this level of detail a little further along.
bczygan
Well-known member
I would start by excavating the existing slab and subsurface under it, deeply enough to install cribbing and beams. Access would be through the alley and removed garage door.
Without seeing the structure of the existing garage it is hard to say exactly what size and placement would need to be.
Then, after the garage is raised, demolition and removal of the existing garage foundation would occur, and additional excavation needed for installation of the new basement walls.
Then new footings, block or poured walls would be installed, insulated and drainage installed along with pouring the floor.
The next thing needed would be a floor for the new garage. The easiest and quickest floor would be a pre-stressed concrete panel system, but I don't know how you would install them. The usual method would be by crane, but the existing garage and cribbing would be in the way. If the beams were longer and the cribbing was outside the building area (Space permitting), the garage and beams would still be in the way. And there is the problem of the loads the cribbing produces adjacent to the excavation.
Another type of floor is the commercial steel reinforced concrete 2 way slab. It is usually installed on steel decking supported by a system of bar joists and beams. This could be installed and cured and the garage lowered down onto it if the cribbing was outside of the floor area.
Anyone have other ideas?
Without seeing the structure of the existing garage it is hard to say exactly what size and placement would need to be.
Then, after the garage is raised, demolition and removal of the existing garage foundation would occur, and additional excavation needed for installation of the new basement walls.
Then new footings, block or poured walls would be installed, insulated and drainage installed along with pouring the floor.
The next thing needed would be a floor for the new garage. The easiest and quickest floor would be a pre-stressed concrete panel system, but I don't know how you would install them. The usual method would be by crane, but the existing garage and cribbing would be in the way. If the beams were longer and the cribbing was outside the building area (Space permitting), the garage and beams would still be in the way. And there is the problem of the loads the cribbing produces adjacent to the excavation.
Another type of floor is the commercial steel reinforced concrete 2 way slab. It is usually installed on steel decking supported by a system of bar joists and beams. This could be installed and cured and the garage lowered down onto it if the cribbing was outside of the floor area.
Anyone have other ideas?
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I think we should dismantle the roof and throw away the plywood sheeting and the shingles. Then cut apart the 4 walls and store them somewhere close by, standing up. Hopefully the stucco won't crack too much ?
We'd then have an open back yard to work with. We could then build the bunker unimpeded. Once its done we stand up the 4 walls and rebuild the roof, reusing the trusses. Its probably less costly to rebuild that roof than it is to lift the garage and do the fancy blocking and work around it with a skid steer.
Myself with 2 carpenters @25/hour each could rebuild the roof in a week ? $2,000 labor. Materials would be about 1000 ft^2 of sheathing plus shingles.
It would be pretty reasonable to dig the hole unimpeded with a mid sized excavator.
??????
We'd then have an open back yard to work with. We could then build the bunker unimpeded. Once its done we stand up the 4 walls and rebuild the roof, reusing the trusses. Its probably less costly to rebuild that roof than it is to lift the garage and do the fancy blocking and work around it with a skid steer.
Myself with 2 carpenters @25/hour each could rebuild the roof in a week ? $2,000 labor. Materials would be about 1000 ft^2 of sheathing plus shingles.
It would be pretty reasonable to dig the hole unimpeded with a mid sized excavator.
??????
ez-duzit
Well-known member
bczygan
Well-known member
Just went back and read the original post.
One thing I don't know if you have checked.
If you build this addition that connects to the house, even of the connected portion has grass over it, will that be considered lot coverage area? If so, you are probably exceeding the zoning requirements for lot coverage. You've checked all the zoning requirements?
Even if it is allowed, you need waterproofing over the top of the structure and enough depth of soil so that grass will grow, or another method of covering that area.
In addition, some consideration of how you will place beams to lift the garage, needs to be made. You can place beams along the bottoms of the short walls of the garage, for support and lifting. But since you want access through the long wall from the alley, that beam needs to be placed, at least initially, near or at the top of the wall, and lift from above. If you want to access the area between the garage and house, so you can excavate that area along with the other initial excavation, then you will also need to place this beam at the top of that long wall. If you lift the structure enough, then you can excavate under that wall and into the area between the garage and house. If not, then a portion of that wall will need to be removed.
Do you understand this sequence of events?
One thing I don't know if you have checked.
If you build this addition that connects to the house, even of the connected portion has grass over it, will that be considered lot coverage area? If so, you are probably exceeding the zoning requirements for lot coverage. You've checked all the zoning requirements?
Even if it is allowed, you need waterproofing over the top of the structure and enough depth of soil so that grass will grow, or another method of covering that area.
In addition, some consideration of how you will place beams to lift the garage, needs to be made. You can place beams along the bottoms of the short walls of the garage, for support and lifting. But since you want access through the long wall from the alley, that beam needs to be placed, at least initially, near or at the top of the wall, and lift from above. If you want to access the area between the garage and house, so you can excavate that area along with the other initial excavation, then you will also need to place this beam at the top of that long wall. If you lift the structure enough, then you can excavate under that wall and into the area between the garage and house. If not, then a portion of that wall will need to be removed.
Do you understand this sequence of events?
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roscoe2000
Well-known member
Boy I like your way of thinking...I have often dream about having a basement level to my detached garage with connection to the house as well. I just never had the dollars to make it happen. All that i see you have missing is a lift in the garage connecting the two levels. It would be useful is getting any large items (including cars) to the lower level and just think of the looks from your neighbors, when you are able to park 3 vehicle in a building made for 2. Go for it and post the build pictures!!!!!!
bczygan
Well-known member
Is this garage drywalled or insulated?
Is it due for a new roof, and shingles can be removed to reduce weight?
Is it due for a new roof, and shingles can be removed to reduce weight?
Yes, its an open excavation. Just like any other house basement. We'll be adhering to all necessary safety standards, just like any basement excavation. The city requires a soil analysis. My structural engineer will be monitoring the worksite, in addition to myself.
It isn't.
Yes. For the third time I took all my sketches, ideas, lot survey, etc. to the city and spent over an hour with 3 of their top guys going over everything. Both sides asked all sorts of questions. They love the project because when all is said and done there is no visible change to the property, yet it adds utility.
Yes. Or we may bring the concrete roof to the surface and have a concrete patio in our back yard. We are undecided on this aspect of the build.
Yes. Lifting a garage is tricky too because their are no floor trusses to a) lift from or b) tie it together. Lifting a garage is harder than a house.
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Nope. Purposely left bare inside until the completion of this project.
Nope, roof and singles are in perfect condition. Seems a shame to sacrifice them, but also seems to be the easiest way to do the project.
I wonder how much the stucco would crack if we lifted the walls and set them aside ? Maybe temporarily sheet out the inside of the walls with some plywood ?
Or 4 or 5 cars.
You saw in my previous post that I am definitely planning for a lift, right ?
My next step is to get a stucco person in to get their opinion of how much its going to crack and how much it would cost to fix up. I also need to get a quote from a framer on rebuilding the roof.
The more I think of it the more I think dismantling the garage is the way to go. Lifting the garage while doing the foundation is like trying to skip a step when removing something from a car engine. Do all the steps and it goes much easier.
Thanks for the replies, btw.
The more I think of it the more I think dismantling the garage is the way to go. Lifting the garage while doing the foundation is like trying to skip a step when removing something from a car engine. Do all the steps and it goes much easier.
Thanks for the replies, btw.
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ez-duzit
Well-known member
That's what I tried to tell you.
Nice try. Not one of your posts talks about dismantling the garage. Edits after now don't count either, so don't try.
bczygan
Well-known member
How about lifting the roof as a unit, supporting it outside the building footprint, removing and storing the walls, and doing the dig. Then set the walls back on the new floor slab and dropping the roof down. The roof has a better chance of moving up as a unit by itself. It's already triangulated. And you save all the savable components of the garage. The roof doesn't have to move up much, just enough for the walls to be removed.
http://hightechdormer.com/gallery/project1.html
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Playwme
Well-known member
That was pretty much the exact thing I was going to write once I'd caught up on new posts.
I'd also consider, if you're going to buy a machine to dig with then you probably should just get a truck and a conveyer unit as well. Bigger outlay in the beginning but if you buy smart then you get that money back at the end.
Playwme
Well-known member
Trees are going to stop that. It'll probably cost as much as sacrificing the roof and rebuilding it anyway.
bob15
Well-known member
Sounds like "perfect" garage !!It's how ALL garages s/b built !! I'd love for my garage to have a full basement under it, and tunnel walkway the short 10 ft to the house. The breezeway between would be great place for elevator as right next to driveway.
OP . . Curious where the "elevator" can be and still meet code for any potential flammable vapors that might seep into the underground "live-able" space??
Also, where is "north" . . . is that north Canada, north Florida, or north USA !!
Update GJ Profile with location.
Looking forward to this build . . . sounds awesome.
Could you fill out your location, even a state and general location.
Maybe I missed your location someplace, but winters and snow/ice/rain/frost line can give you issues. Have you addressed them?