DIY Vacuum Excavator Using a Squirrel Cage Fan?

I've spent a good deal of time crawling around and digging underneath houses, and I gottah give you credit for thinking of such a system. I've got very strong doubt that any regular sort of shopvac would have the strength to do much. One time pumped sand around and roiled it so as to pole axe twist pilings for a pier into the ocean sand. Can't see that sort of thing as practical either underneath a house. The varieties of soils I've had to deal with recommend common digging tools. I often use the GI foxhole shovel in tight spots. For transport out of the crawlspace I've heard of pvc used as slip rails for buckets, or wheelbarrow pans detached from handles and wheel rope pulled out. I've also used large electric hammer drills, and even 4" gas powered augers in some situations. Sure enough a machine could be made to do what you propose, but haven't touched one yet myself.

How about a cyclone-type dust collector like one shown in the link?

Jerrell captured better than I did what you want to do. I didn't grasp you wanted to dig out completely under the house, and only thought you wanted to do another area. Another option would of course to be to raise the house, but I doubt you want to do that.

dont think vaccuum. think blower. while under the house fill a container that seals - say a trash can, the narrow low profile kind like in a kithcen. On one end a 4" diameter hole and a dryer hose or multiples. On the other end; a hole to receive your everday lawn and leaf blower (electric) and some foam rubber to make a sealing gasket. You could even manifold a couple of blowers on to a 2 to 1 "Y" type fitting for 4" hose and use the blowers from outside the crawl space.

hope that is clear-ish

Please give a little more detail about how the dirt gets out of the crawl space?

thanks,

Ben

use a shovel to fill the trash can. Seal up the lid. Plug in the blower and blow it through the drier hose(s).

You could try using an Artesian screw connected to a smooth bore flexible pipe to excavate the dirt and push it along the pipe to the outside. The leading edge of the screw, if hard enough could do some of the digging. I don't know where you would get such a device but this forum is probably the best place to look for it. The screw would have to be turning at a slow rate and you might have to cut a hole in the outer wall to keep the pipe horizontal and reduce the pushing effort required.

I'm sure such a small machine would find a use in many home building projects and there might be a market for it!

I like this idea the best. Start with a 'deep' hole and cut it wider with a pressure washer or high pressure hose that would really get the dirt stirred up and suspended in the water...pump whatever is pumpable out and the big rocks and chunks can be removed by hand afterward.

I don't know what the soil is like or the state of your footings/foundation but if you didn't get too close you could probably get a good deal of material out with a minimum of fancy tool rentals (conveyors or screws).

Sorry didn't get a chance to finish before battery got low . But you are right you can dig a hole or dig a hole big enough to put a wash tub in fill half with water and half with dirt and use the trash pump to pump it out of the crawl space! works pretty well because after awhile you just keep dumping water and dirt in the tub and it will be a continuous motion.

You got a GA from me for this one, there are more then a couple good ideas popping up on this thread but this one seems to be the most accessible and the least likely to involve custom manufacturing... Depending on your soil you should be able to 'pressure wash' the unwanted dirt into a small hole to be pumped out... Seems very efficient to me.

I can't really picture what you have in mind. Is it like a smaller project than this ? Guessing you have the structural aspects sorted out, but what do you mean by 'earth' ? It could mean a multitude of things. Vacuuming it out doesn't sound that realistic, and the conveyor approach sounds better (but is it worth the expense ?).

Not sure if this helps or not. What about hiring a compressor and blowing shovel loads out via a second pipe ? You might need that air supply down there.

Ichpcbl,

I have a similar situation in my 200 year old house. The dirt is about 6 inches from the floor joists.

I am not sure that a vacuum system would work very well unless you live in a particularly sand environment. In the autumn I grind up the leaves that fall in the yard for compost. I have a 8HP leaf grinder that creates a formidable vacuum. When I am sucking up the leaves the vacuum will pick up loose stones and the like but it will not suck up the underlying dirt with any ease. The surface layer of dirt in your crawl space might be removed by this system but as you get down the compaction of the dirt will hinder your efforts. I think that type of system works only under water as many of us have seen on undersea archeological recovery documentaries.

Any way good luck and happy digging

I think you'd best be served by a lawn vac type blower/vac for this type of work. They are much more expensive than a shop vac but you won't have to worry about intermediate collection tanks. Just set it up outside and run the hose in through a convenient opening or window. Try finding a used lawn blower/vac one with a 5 or 6 horse motor.

The idea you had of using a rubber maid garbage can is problematic because it may collapse. I've used a similar idea to use a shop vac to suck water out of a pond or off the floor but I used a 5 gal can and it works great.

5-6hp leaf blower?!?!? Wow...I could unintentionally clean the whole neighborhood with one of those! I guess if you consider filling other peoples pools with their leaves "cleaning".

I'm not sure about the blower ideas since rocks will damage the fins of the blower a lot faster than leaves and sticks would. I just imagine breaking fins, imbalance and vibration.

I have thought about doing the exact same work on my house. Here's what I've researched and seen.

The wastewater and utililitie industry performs "hydroexcavation" and/or "potholing"; all the time. Full commercial/industrial machines are sold to perform this work. Check the web under "hydroexcavation".

Homebuilt apparatus; I would start with a high-pressure washer to slurry the soil, it then becomes readily flowable.

Vacuum suction power must be large; especially if significant transport distances are required. I have read of gold prospectors building gasoline powered vacuums for sucking river and stream sediments; they use pvc pipe for the wand and a steel barrel for the dirt reeceiver. An older, used gas powered leaf-blower mounted into the top of the barrel sucks the air from the barrel - creating the vacuum.

Remember, some sort of water level shut down switch (once the barrel approaches full) might be needed to not suck water and dirt into the leaf-blower.

An alternative might be to use the vacuum inducing device on a seconnd container, say a 5-gallon metal bucket (with top and gasket, e.g. roofing tar bucket) hooked to the barrel with pvc. A floating ball in a ball valve would protect the engine from water.

good luck.

sean

I have a similar project to do as well. I was thinking of using a grain transfer auger. Any thoughts?

If you can build a small slip pan that you could pull with a winch from outside of your house I think it would work better than a vacuum. I have done this once for a 4" pvc pipe and it worked pretty well. It is slow but not near as slow as a shovel. the one I built was about 2ft wide and 2ft deep and I put 4 teeth in it like on a box blade scrape for a tractor if you ever seen one. I didn't have a winch but I had room to use my 4 wheel drive truck to pull the thing through. I had the wife drive the truck and I pulled it back by hand but a winch could do this allot better. After one day I had a 30 ft long ditch 2 ft. wide and about 2 ft deep in packed clay under the house. I would think if you had a small winch on each side (if possible) you could pull the contraption back and forth and move a good bit of dirt from under the house. Be careful using the wife though cause she jerked a knot in my tail several times that day.

I think the easiest way to accomplish what you want is to start to excavate outside the house to the depth you want. This will give you the elbow room. You can rent a backhoe to do this part of the job. Once you have this starting point done, you can then work in under the house, hauling out the dirt into the exposed area for removal. What about your foundation? The other methods mentioned, (slurry, etc) could undermine the foundation.

Ron,

This sounds like the best idea yet, so long as the house is raised a bit above the surrounding area. Would precipitation creat a problem if it welled upinthe hole? I would think it could compromise the nearby soil and weaken the surrounding support. In my situation it would work perfectly as the house is on a hill and built up from the nearby surrounding land.

Bob

Ben, This is getting scarier all the time. Be sure and think through whatever approach you decide to take to prevent any unexpected scenarios that might compromise the integrity of the structure or your safety while working. I would recommend staying away from any sucking, blowing or hydraulic method of excavation under a structure. The amount of moisture you will introduce to the underside of the structure will permeate throughout and could cause swelling that would damage many aspects of the structure, could promote mildew or the growth of mold. This could also make it more appealing to termites. Proceed with caution an preserve the integrity of the structure for another hundred years. J.Conway

I don't plan on using any wet methods that get the foundation area wet, but I appreciate everyone contributing their thoughts and ideas. It turns out I'm obsecive about keeping water away from my foundation and crawl space. The closest to a wet method I would consider would be digging a hole and placing a large vessel to put water and dirt into and then suck out the mixture.

I really appreciates everyones contributions. feel free to send this link to friends you think might want to contribute.

thanks,

Ben

Wasn't logged in at #9.

I hesitate to mention this, but have you ever read about the Rotherhite shaft ?

Can you clarify the total volume you're going to excavate, and also proximity to supporting walls. I'm intrigued by your project. How much has the house subsided since built, how is is constructed, and has it subsided evenly etc ? What about a cylindrical vessel with a long rope at each end - someone pulls the thing out, and you pull it back in. A bit of planking or something to guide the 'torpedo'.

Kris - I am disappointed on two points.

1) your low tech, practical solution.

2) the lack of offense taken by suggesting a squirell cage fan.

.......I like to slide in all quiet and innocent sometimes.......

seemed a bit big.....

...now we're getting somewhere.....all I need to do is harness the cat when it gets back from Saturday at the 19th. Eat one end, puke it up the other. Del's too nice to rip him a new ***-hole, and he wouldn't be able to see, so genetic experimentation is the only way to go. Mike the headless chicken is long since gone, and he'd need filling at one end;

Ben,

Your wise to avoid any 'wet' methods.

The squirrel cage fan design simply has to much 'slip' to create the negative PSI your looking for.

I used a shop vac and a trenching shovel to excavate a 2' X 2' by 4' hole under my house.The only real trouble was the hose getting plugged because of large dirt clods (clay actually).Mind you I opened the floor to gain access to the work site however I do plan to use a similar technique to smooth and slightly lower (6-10") the existing grade level under the house.

For your much more extensive project I would recommend setting up 2 or 3 good quality shop vacs connected to a 55gal. steel drum (collector) and adapt a 3-4" dia. hose to the drum for use under the house.The multiple vacuums won't necessarily increase the available suction power but will provide Much more flow capacity and transfer more material with reduced risk of clogging.

If you need help dislodging the soil,a variant of the wet methods described using compressed air and a high PSI nozzle will cut through the dirt as well as create a choking dust storm.Otherwise, typical garden implements can be used to scrape away the surface.Then once a sufficient area is excavated you will have more room and a 'face' to work against.Just like the big tunnel jobs they show on TV 8-).

Enjoy,and mind your foundation.

Jay.

You could also use a company called Guzzler. In my construction company, we often use them to remove damaged concrete and debris from job sites. We recently removed an 8x15 foot area of soil 8 feet deep. They use a 6in hose attached to a vacuum truck. Their equipment can carry a bowling ball the length of a football field. Good luck.