Crawlspace Hand Excavation

[Kaplin261]

I have been contemplating digging a part of my crawlspace out and making it into usable space for a workshop/beer cellar for my homebrews. The costs I see here is a concrete truck and concrete pump to get into the space.

14'x14' area that is currently 5 feet tall and I would like to get it to 8 feet, some area are only 4 feet tall. I figure I will have to hand excavate about 25 cubic yards of dirt. My soil is sandy loam with not to many rocks.

This project has a bonus, about 10 feet the excavation site is a hillside that I would like to place a retainer wall and add the dirt to fill the space. While pouring the floor in the crawlspace I would also pour a patio for this area as well.

Another bonus is I would avoid a gym membership for a couple months by dedicating a hour to this project a day.

If my calculations are correct the cost of of the concrete for the crawl space will be around $1500 and that shares part of the fee for the pump truck. The cost of labor will not be factored because this is labor that would have been wasted at the gym. So $1500 for 196 sqft workshop with concrete floors and somewhat heated/cooled.

Should I even attempt something like this? I am aware of what is needed to keep the integrity of the structural engineering of the home. I am also well versed with dirty/labor intense work.

[CowboyAndIndian]

You could potentially undermine your foundations. That is not a good thing.

[Kaplin261]

You could potentially undermine your foundations. That is not a good thing.

I am aware of what is needed to keep the integrity of the structural engineering of the home.

[Shane]

A few years ago we did a similar project on our house, and it turned out well. It took us months of digging by hand, but we were also able to utilize the soil we removed from under the house elsewhere for use as needed fill. It's relatively cheap space because you won't need to put a roof on it. Good luck!

[Papa bear]

Posting to follow.  I have a crawl space that I'd love to do that with as well.  How are you planning on shoring up the existing foundation?  I hear you need to leave plenty of base for the existing footers and then pour new footers inside? 


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[10dollarsatatime]

I'm hoping to do the same thing for a root cellar.  I just haven't decided yet if I'm going with an outside entrance, or a trap door in the kitchen.  Trap door in the kitchen enables me to avoid dealing with foundation issues.  I need to pick dad's brain a bit more on the project.

[paddedhat]

Generally, in stable soil, you follow a maximum 1 to 1 ratio of depth and distance when you dig below the level of the of the footer. So, if you want to end up cutting 3 feet, you stay three feet away from the edge of the footer to the edge of your new excavation. Now, like everything else you read on a web forum, individual results may vary ,and certain soil types are so tightly compacted and cohesive that you could get away much tighter to the structure and cut the sides a lot more vertical. In other cases you may need to go to 1-1/2  horizontal to 1' vertical or less, if the ground is less stable.

[Fishindude]

Unless you have a construction background and concrete experience I would not recommend taking this project on.  Lot's of opportunities for serious problems.

Having said that, many folks have done this, but it is not an easy project.   
A few things you should consider before starting:
a. Is bedrock an issue?   Can you dig another 5' without hitting bedrock?
b. Where is the water table.  Will you be down in the water table 5' down?
c. How are you going to get the dirt / concrete in and out.  Best solution generally is to excavate outside and create an opening through the foundation and an access ramp.   A conveyor is a real help for getting dirt out, concrete is best pumped.   A bucket a time will be miserable.
d. Make sure you design this so you don't have water infiltration problems and a wet basement to deal with; water tight concrete joints, sump, drains, etc.
e. Will any temporary shoring be required to hold things in place during excavation?
f. Are their any utilities in this space that will be in the way?
g. The excavation in this tight area will likely take at least three times that labor, the same would take in an open area, so be prepared for that.

Good luck if you take this on, post progress photos.

[Gone Fishing]

I moved 30 yards of sandy loam by hand a few years ago.  It was delivered so it was already broken up pretty well, but it wasn't that bad. I did it over the course of several months.  As others have mentioned, a good method of getting it out would be the key. 

Could you live with 7 ft?  Would save you 7.26 yards...

[Jack]

I've been thinking of doing something like this too. The older half of my house is full-height basement; the previous owner cheaped out on the addition and made it a crawlspace. Unfortunately, my house is built on hard clay that you almost need power tools to get through, and if I were to do it I'd want to dig down far enough that even a 1/1 slope would take up half the floor space, so I'd want to put the addition up on cribbing and rebuild the foundation. And then I'd still need to find somewhere to get rid of the dirt (off site).

[Kaplin261]

Unless you have a construction background and concrete experience I would not recommend taking this project on.  Lot's of opportunities for serious problems.

Having said that, many folks have done this, but it is not an easy project.   
A few things you should consider before starting:
a. Is bedrock an issue?   Can you dig another 5' without hitting bedrock?
b. Where is the water table.  Will you be down in the water table 5' down?
c. How are you going to get the dirt / concrete in and out.  Best solution generally is to excavate outside and create an opening through the foundation and an access ramp.   A conveyor is a real help for getting dirt out, concrete is best pumped.   A bucket a time will be miserable.
d. Make sure you design this so you don't have water infiltration problems and a wet basement to deal with; water tight concrete joints, sump, drains, etc.
e. Will any temporary shoring be required to hold things in place during excavation?
f. Are their any utilities in this space that will be in the way?
g. The excavation in this tight area will likely take at least three times that labor, the same would take in an open area, so be prepared for that.

Good luck if you take this on, post progress photos.

What a great checklist!

Do you have a construction background and concrete experience?
I poured my side walk 4 years ago, mixed bags of concrete by hand. Ended up being 30 bags. Side walk has held up perfectly with no cracks. I also have construction experience flipping houses.

a. Is bedrock an issue?   Can you dig another 5' without hitting bedrock?
My home is on top of a hill, so no bedrock where I'm at.

b. Where is the water table.  Will you be down in the water table 5' down?
I'm on a hill so I'm good.

c. How are you going to get the dirt / concrete in and out.  Best solution generally is to excavate outside and create an opening through the foundation and an access ramp.   A conveyor is a real help for getting dirt out, concrete is best pumped.   A bucket a time will be miserable.
One side of my crawlspace has a 7' wall and a entryway, dumping area is 10' from that exit.

d. Make sure you design this so you don't have water infiltration problems and a wet basement to deal with; water tight concrete joints, sump, drains, etc.
This is one of the areas I will go to great lengths to insure against. I currently have no water problems down there and don't want to introduce them.

e. Will any temporary shoring be required to hold things in place during excavation?
Not in the space I'm going to be digging out.

f. Are their any utilities in this space that will be in the way?
No electrical or communications. However there is a sewage pipe that is going to limit this space to 12x12.

g. The excavation in this tight area will likely take at least three times that labor, the same would take in an open area, so be prepared for that.
I'm planning to do this in short intervals of 1 hour a day.

[paddedhat]

f. Are their any utilities in this space that will be in the way?
No electrical or communications. However there is a sewage pipe that is going to limit this space to 12x12.
I'm planning to do this in short intervals of 1 hour a day.

If you have what it takes to do the job, don't let a sewer pipe limit you. Expose the thing, keep I properly supported with some temporary blocking while you dig around it, and finish the area you want to open. Then reroute the pipe. Even it it's cast iron, it's pretty easy. A few sawzall blades, a few Fernco couplings and a new run of PVC pipe, and you are good to go.

BTW, the doubters here would have the "greatest generation" rolling in their graves, and recommending that you grow a pair. In my youth it was nothing to attend a family function in a tight little ethnic neighborhood, only to listen to some ancient looking uncle brag about creating a 8' tall basement under the house with nothing but a pick, shovel, and an old metal bucket to toss the dirt out with. When you lived in a row home, with a bedsheet sized back yard, that was taken by the garden, there was nowhere to go but up, or down, if you need more room. Since it typically was a two story with a full walk up attic, there was no up, and if you went down, it was not only cheap, but the tax man couldn't catch you.

[Spork]

If it helps you in the confidence area: I had an under-the-slab plumbing leak in a previous house.  A crew of 2 dug out a Hogan's Heroes style tunnel that was about 3'x3'x15' in horrible clay soil in about a day.  (Then packed it all back in faster than that.)  The second guy was only there for bucketing the dirt in/out.

[Kaplin261]

f. Are their any utilities in this space that will be in the way?
No electrical or communications. However there is a sewage pipe that is going to limit this space to 12x12.
I'm planning to do this in short intervals of 1 hour a day.

If you have what it takes to do the job, don't let a sewer pipe limit you. Expose the thing, keep I properly supported with some temporary blocking while you dig around it, and finish the area you want to open. Then reroute the pipe. Even it it's cast iron, it's pretty easy. A few sawzall blades, a few Fernco couplings and a new run of PVC pipe, and you are good to go.

BTW, the doubters here would have the "greatest generation" rolling in their graves, and recommending that you grow a pair. In my youth it was nothing to attend a family function in a tight little ethnic neighborhood, only to listen to some ancient looking uncle brag about creating a 8' tall basement under the house with nothing but a pick, shovel, and an old metal bucket to toss the dirt out with. When you lived in a row home, with a bedsheet sized back yard, that was taken by the garden, there was nowhere to go but up, or down, if you need more room. Since it typically was a two story with a full walk up attic, there was no up, and if you went down, it was not only cheap, but the tax man couldn't catch you.

It is a 4" PVC pipe making it even easier to put a couple elbows on it and move it out of the way. The main reason I'm hesitant to cut and move it out of the way is not because of lack of experience but because of how nasty that sewer pipe is going to be on the inside. It would allow me to go up to 12x17 if the pipe was moved. I just don't know if I need that extra space or if it will really increase my homes value adding 60 more sqft in a area that can not be counted on the MLS listing if I ever sell. Not counting the time to dig that extra space out and the cost of the extra concrete it would probably cost me $100 in materials and 6-8 hours worth of skilled labor to add 60 more sqft.

I have also thought about adding radiant heat to the slab before pouring,plumb up a space for a shower and commode in case I ever wanted to use it as guest apartment.

[Gone Fishing]

PVC sewer pipe is probably not as bad as you think on the inside.  If you are really worried, flush some hot (even boiling) water and some bleach (as long as you are not on a septic) down it ahead of time.  If you are on septic, substitute washing soda for the bleach.

[paddedhat]

yea, I'm with So Close on this one. As a lad, my dad recruited me as a helper to cut out a lot of rotted, cast iron sewer line in the ole' family homestead. I assumed it was going to be about as nasty as it gets, but it really isn't anything all that bad. If it really is something you would find hard to deal with, then grab some cotton balls, dab a bit of wintergreen rubbing alcohol on them, and stick them in your nose. With these in  place, and a pair of surgical gloves, there isn't anything too gross for me to tackle, including stuccoing the inside of a septic tank, and changing more than few sewage pumps on rural septic systems. Good luck.

[jba302]

I talked some people about doing this in one part of my house, because I wanted to get higher ceilings for the gym room (7' to 8 or 9, whatever I could get away with). The general consensus was that I was nuts, other than my grandpa who said I was probably nuts and then described how they used to dig out basements starting with a 2' crawl space exactly like paddedhat talked about. Took them forever and a lot of bullshitting with the local permit guy once in a while (one story was that the permit guy drove by seeing a cement truck pouring into what should have been nothing, walking downstairs and telling my grandpa "we're going to talk about this once you're done").

Take some photos if you don't mind, this is a hell of a project and it would be cool to see the progression.

[paddedhat]

and then described how they used to dig out basements starting with a 2' crawl space exactly like paddedhat talked about. Took them forever and a lot of bullshitting with the local permit guy once in a while (one story was that the permit guy drove by seeing a cement truck pouring into what should have been nothing, walking downstairs and telling my grandpa "we're going to talk about this once you're done"). .

Some of the old birds were real pissers, eh?  I once put an addition on a single wide trailer for a wonderful, ancient carpenter who spent his career working for a big city.. The first issue was that he simply refused to get permits for anything. The second was that he did a lot of his own work, while he was still able,  and there wasn't a single piece of building material on the property that wasn't "borrowed" from the city. When I opened the stick framed roof that was built over the whole mess, the rafters had "POLICE LINE-DO NOT CROSS" routed in them. They were part of crowd control horses. The skirting was stolen highway signs, nailed up with the back sides out, and all coated with roofing tar. The trailer wasn't worth a fiddler's fuck when I started. It was 40 years old, and sat on piles of railroad ties, but the owner couldn't of cared less. Even when he asked my opinion, and I recommended a gallon of gas and a match,  he just laughed.

 Near the end of the job I showed up to do some punch list,  and he was all smiles. He just got a good "talking to" as we call it in these parts. The building inspector stopped and reamed him good, for the sin of not getting a permit for the deck he was standing on. Old Fred just leaned up against the wall (of his new 500 sq. ft. addition) and looked downright guilty, and full of remorse, as the inspector droned on. He agreed to immediately drive to the township building, and pay a small fee for the deck permit, and mend his ways. The fact that his trailer was twice the size he was paying taxes on, and the township STILL didn't have a clue, was something he didn't feel the need to bring up, as he atoned for his sin.

His name was Fred, he was one hell of a character. Fred, I still miss you, RIP.

[jba302]

I love that story. I am going to have to ask my gramp for more to share now.