slabjacking DIY?

higgledyMarch 22, 2013

I am not sure which forum to post this question.

The one section of sidewalk in front my house has sunk. My town is making me level my sidewalk by Jan 1, 2014. The section of sidewalk is not cracked, just sunk by about 2" the entire length of one of the long sides. I was thinking of slabjacking as the best way to repair because pouring a new section will make the remaining sidewalk not match. In researching my options I came across this website, Does anyone have any experience with this method of DIY slabjacking? I have yet to call for quotes from local slabjacking companies, but I definitely will because who knows, it might be cheaper than I think. (yeah, right). Thanks for reading and thanks for any advice.

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In order to lift a slab - they have to drill a hole or two to inject a thin cement. Do your neighbors have any sunken slabs? I say this cause it may be more cost effective to get them done at once.

The slab jack looked like the biggest kludge I've seen - excavate under the slab by hand? We first of all - there may be several inches of crushed rock used as a base. Secondly you are supposed to drive a 2" PVC pipe into the soil? What happens if your soil is rocky or clay?

Forget the DIY.

    Bookmark   March 22, 2013 at 9:48AM
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Why is this your responsibility? Did you do something that caused the sidewalk to sink or is there some erosion taking place that will cause more problems in the future?

Around here, it's the county/city that maintains the public sidewalks, except for shoveling off the snow. Having every homeowner find ways to make repairs on their section doesn't sound very cost efficient.
Just wondering.

    Bookmark   March 22, 2013 at 4:05PM
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I agree with the DIY slabjacking seems a kludge at best and possibly a lot of wasted time and money if it does not work.

This is my responsibility because where I live the town owns the sidewalk, but the homeowner legally has to maintain the sidewalk. Yes, I know it is a ripoff, but that is the way it is in Maryland. The town is on this big push to get all sidewalks repaired--I guess some kid tripped and fell walking to school and the mother complained. IDK.

    Bookmark   March 22, 2013 at 6:38PM
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The city of Long Beach CA. poured the "public" sidewalks 6" into the property lines and then planted elm trees in the 4' parkway between the curb and the sidewalk, without root barriers.

    Bookmark   March 23, 2013 at 12:34AM
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"This is my responsibility because where I live the town owns the sidewalk, but the homeowner legally has to maintain the sidewalk."

I would pay an attorney to make sure they have the power to do this.

    Bookmark   March 24, 2013 at 5:45PM
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In most cities the maintenance of the sidewalk and curb is the propery owners responsibility. When the city replaces curb or sidewalk, it is common to have a 'special assessment' added to your property taxes over a period of 10-20 years.

    Bookmark   March 25, 2013 at 10:56AM
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Being a Canuck I was flabbergasted when I read the homeowner has to maintain the sidewalk. It seems other Americans think that bylaw isn't normal as well. Does that mean if that kid falls and breaks a tooth on the crack on my sidewalk that is on city property I'm liable and might end up on Judge Judy.

What if a city garbage truck or the snow plow damages the sidewalk, I have to repair it????

As far as slab jacking, that's more than a few bucks for a maybe repair by someone with zero experience, I would rip out the questionable area and pour new, then send the bill to the city or town. By the way do you need to pull a permit? I might even have it patched with blacktop, the city would be thrilled with that repair. I certainly would to make a point, heck if I couldn't afford a fix, what about patio stones. Sidewalks in the UK and Japan are mostly all patio stones, I've even seen blacktop in Europe in a few countries.
What a can of worms I would open.

    Bookmark   March 27, 2013 at 3:07AM
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I don't know about slabjacking, but here are some thoughts. In Michigan yes, the city owns that area, but the homeowner is responsible fo it. Snow removal, personal injuries & repairs are all on the homeowner. And in Canton, the homeowner is required to get a permit before any work can be done. The city sent a letter stating that the permit, inspections and the work doing it yourself is equal to the price of having their people do the work. So check with your town's offices to see what is required before you start doing anything. Hate to do all that work, only to have to get it removed and redone at your expense. Slabjacking may not be an approved repair method by your town.
In Canton the County/city/town have the right to demand a new house have sidewalks, even if it is out in the county, before a Certificate of Occupancy is issued--and don't get me started on those dumb street side trees!!!!

    Bookmark   March 27, 2013 at 8:44AM
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Wow, thanks for the advice. I'm the kind of guy who'd pay the money to do it myself just to f the authority.

    Bookmark   March 27, 2013 at 8:58PM
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" When the city replaces curb or sidewalk, it is common to have a 'special assessment' added to your property taxes over a period of 10-20 years."

That is a capital improvement, not maintenance.

    Bookmark   March 28, 2013 at 11:09AM
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By nationality I am 50% American but am Canadian by birth and have never had a problem seeing ourselves living in the US as Americans, however when I read threads like this one concerning municipalities passing on responsibilities to homeowners I reconsider eh.

Good luck on your repair, let us know how you make out.

    Bookmark   March 28, 2013 at 4:33PM
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Most Americans know little about Canada and readily admit it. Many Canadians I've met think they know and understand the US profoundly, though the reality in that regard (I've found) isn't quite what they think it is.

As when comparing any two countries, there are similarities and differences. People can prefer one approach over another but it's wrong to think different approaches to the same issue can easily be categorized as better or worse, right or wrong. Differences are differences, it's best to stop there.

    Bookmark   March 28, 2013 at 8:19PM
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In Tawas MI, where my mom finally received City water--as their whole area had awful well water, the $8,000 tab was added to their taxes to either be paid outright, or over a 10 years under a 'special assessment'. Yearly interest was added. I don't know the percent that she paid in interest. This had to be paid when her house was finally sold. But was so worth it to have drinkable water come out of the tap.
For a smaller bill of $100 to $200, I do not know if that is an option, or just a bill that is 'due upon completion of repair'. You would need to talk to the town to see what you payment options are. But in Canton, if the whole tax bill is not paid by the due date, you get charged with interest and penalties/late fees.
Yes things are different in Canada. In Florida we visit with our Canadian snow bird friends, and campare notes. Nothing is perfect in either country, just different. For instance, our friends can't understand why we in the US own guns. Or why politicians campaign so long in the US, while in Canada they say campaigning is 3 months tops. That's not such a bad idea, as I got so tired of all those political adds, TV shows and phone calls.
Asphalt sidewalks are not an approved material repair, The material list is very specific about what can be used in Michigan. Sometimes patching is not approved either, you need to replace the whole sidewalk slab. Note-- the sidewalk is thicker where the driveway is located vs just the sidewalk. Please come back and tell us what happens and a general idea where you live. We all want to learn details about this.

    Bookmark   March 28, 2013 at 8:38PM
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Fori is not pleased

I lived in MI where the city would replace a slab of their sidewalk and then bill the homeowner for it.

The city I live in currently recently changed the policy of city maintenance and now expects homeowners to maintain the sidewalk (I don't follow city politics and don't know by what means this change happened) but I suspect the city is too broke to enforce it.

It doesn't sound like your sidewalk is a tripping hazard. I'd sure be perturbed.

    Bookmark   March 28, 2013 at 10:03PM
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Much off topic but I probably misspoke when I said I would have to reconsider living south of the border full time, yes it's ridiculous to compare countries as it is to compare states or even counties in the same states. The variances can be huge.

I pride myself in having a better understanding of folks in the US, Mom is American and I have spend years down in the US living and going to college. 2 years at Youngstown State and 3 at Miami of Ohio. Own property in south Fla. Off and on for 24 years.

    Bookmark   April 2, 2013 at 5:29PM
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There are 50 separate states and thousands of smaller political subdivisions in the USA.

There is no consistency in how things like this are handled from place to place.

One of the Virginia counties just got into trouble with allowing the sidewalk right of way to be used for using a mole to place fiber optic cables.
It turns out many of older versions of the easmet did not allow that use of the easement.

It was worded as a 'sidewalk' easement and NOT a utility easement.

All the utilities in this area are still overhead with their own separate 'easements of necessity' to feed houses in the deeds, and clearly defined 'utility easements' for the overhead lines and their poles.

    Bookmark   April 3, 2013 at 11:15AM
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Slabjacking requires a powerful pump and someone who knows how to use it. they are usually mounted on a large truck . IMO it would be foolish to try to do it yourself.

    Bookmark   April 4, 2013 at 10:27AM
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Not too many DIY reports on slabjacking so I figure let me add mine. My 40ft X 15ft floating slab dropped 6 inches center line the entire lenght due to hurricane sandy. my 2000 a year flood policy paid 800 bucks on it. Local tear it up and repair esitmates was in the 40K area. An out of state poly slab jack estimat was 15k if no gaurentees. My neighbors just poured cement on their slabs. My approach was to buy the foam and buy the pumps and do it myself. results were excellent. so far, I raised the slab 5 inches with 1 inch remaining. my cost are at 50% of the out of state poly esitmate. My thought was to lift it as far as I could, then cement over the rest. this why voids will be filled before pouring cement. My total costs is far below the out of state estitmate and I am working to my end result results are guarenteed.

so tips.

do it your self should be a last resort. yuo really need to be put into a jam to take this on.

but if you insist on doing this.
use 2lb foam which comes in parts a and b. read all about how this foam works and limitations. you need to pump this fast and basically all your lines will clog after each use and have to be replaced. garden hoses work and were cheap enough to make disposable.

pumps is a tougher issue. I initally used 20 gallan air tanks and added 15 gallaons of poly to each tank, then pumped up the air to 100psi. flipped a lever at the bottom and connected both hoses to a y adapter and a minute laster, 30 gallons of poly was injected. after each round, the hoses had to be replaced.

the injections spread out to about 8ft radis. start at the low point and walk the dip.

later I switched to deseil transfer pumps and found this to pump more poly in a shorter period of time.

this worked well enough to raise the slab 5 inches. took 320 gallons of foam to do so.

I ordered another 80 gallons to see if I can lift the remiaininig 1. problem is subsequent injections in the same area require hi PSI pumps. the transfer pumps were not adequate for that tasks.

so I ordered the engine and pumps used for log slitter applications. these pumps run off a angine, have a high flow rate and can generate 3000 PSi. the previosuly injected foam will displace at 60 PSI so the 3000 PSI pumps will easyily inject.

so now Im faced with a high PSI environment. need pipes threaded on the outside and need these pipes inserted into the holes using hydrawlic cement to keep the pipes locked in during operation.

my plan is to go back and inject about 25 more gallons every 10 feet an monitor the lift. I think that will raise it another 3/4 of an inch and from there, I'll just level cement the rest.

so sure, it can be done.....but unless you are faced with an overly complext local code, and cost restraints. it's not something that the average joe should consider under taking.

certainly not just for a side walk.

cost to have a contractor slab jack is about 4000 an hour. no guarentees since they do not know how bad you voids are and the older the cement, the more brittle and it will crack.

if i had to do all over...i would...but only difference would be to use the log splitter pumps from the begining.

1 Like    Bookmark   April 23, 2014 at 2:51PM
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I wish my next door neighbor was still in that house. When they sold it, they had a portion of the front entry or walk that was not level and created a gap -- possibly where the front steps met the walk. They had to have it repaired as part of the inspection/repair process and the owner told me at the time is was so simple and relatively cheap (hundreds, not thousands -- you are talking sidewalk, not structural foundation here) that they would have done it sooner if they'd known how to.

Can't say as to whether a DIY would work, but have questioned the same thing for a gap I have similar to my neighbors but at the back of my house. Part of the answer may depend on how large and heavy the section of walk is, but I'd get a bid or two before making any decision.

    Bookmark   April 24, 2014 at 3:02PM
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thank you for your well written post.

I am going to try a project using foam at pressure.

where did you buy your foam from???

    Bookmark   July 1, 2014 at 9:05AM
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"thank you for your well written post.
I am going to try a project using foam at pressure.

where did you buy your foam from???"


    Bookmark   July 1, 2014 at 9:20AM
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Speakerfritz; thank you for your well written post about foam slab jacking. What is the company your purchased your foam from?

    Bookmark   July 1, 2014 at 9:50AM
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To those who have reached out to me with questions.....yes my 40X15 slab which cracked down the middle length wise and dropped 6 inches is fixed.....DIY foam injection. I do not recommend anyone take this on themselves and should be a last resort.....but since you are going to not listen and do this are my notes

as we discussed.

a. U.S. Composites in florida sells the foam. I used 3lb foam density. the 5 gallon part a and part b works best.

b. hardware setup

-use at least a 9hp gasoline engine with a gear pump on it. you can buy a motor and pump assy on ebay that is sold for use as log splitter hydraulic drivers. don't use electric pumps. must use a gear pump which prevents the foam from backing up thru the system.

- drill a hole in the cement and insert 3/4 threaded black pipe into it. cap the end of the pipe with a threaded cap before tapping it into the hole. you need a tight fit.

-harbor freight sells hammer drills and bits. works good enough. you need a bit the size of the black pipe.

-get plastic sink/tub from home depot.

-get 3/4 braided 24" hoses with connectors

-get fittings to allow gear pump to accept the 3/4 braided flex hose

-connect the first flex hose from the bottom of the sink to the pump input

-connect the second flex hose from the pump out to the threaded pipe in the hole.

c. the process

-pour a quart of used motor oil in the tub...this will lube the gear pump and prevent the foam from clogging the system.

-start the engine.

-evenly pour part A and part B into the tub at the rate which keeps the flow into the pump going....too slow and the pump will run dry and the air will activate the foam too early....too fast and the level of the foam in the tube will fill up and harden in the tub.

-if you make a mistake and run the pump dry because you were switching 5 gallon pails, pour another quart of used motor oil into the tub to lube the pump.

- after each foam session, pour a quart of used motor oil into the tube and let it reach the pump before shutting off.

-if you live near water wells and there is a risk of contaminating the water with the motor oil, use cooking oil instead.

d. tips about the strategy

- it will cost you about 1/3 to half the cost of what a national foam injector will charge you....foam injection is not cheap and you need losts of foam. A $40,000 cement breakup and repour estimate came back as a $15,000 professional foam injection estimate, which I did for $9000. I probally wasted $2500 bucks worth of foam developing the best approach. bottom line.....why do you really want to foam inject....are you sure you want to take this on????

- the foam will ballon out to about a 4ft radius. so basically, start at the lowest point, but try to stay 4ft away from any walls or corners..

-make sure the slab has no holes, cracks, or otherwise open to the will get foam leakage and you could wind up carrying a ball of foam out the size of a car....seal all cracks and leaks.

- to minimize will get cracking since the slab is bowed and will crack as it gets lifted...use multiple inject points about 4ft apart. cap each threaded pipe. if you want to go back and re-inject in a previously injected but capped pipe....use a thinner drill bit to drill the foam out of the pipe.

- watch out for sewer, drain, and other pipes under the slab.

-you can minimize cracking if you start wetting the slab a week in advance and keep it wet...the slab will aborb a lot of water and be more flexible.

e. recomendations

-do not try to do a 100% lift....the higher you go the more chances of cracking and splitting of the slab

-once you get 2/3rds of you lift goal, consider pouring cement over the top to level rather than fill....the foam you poured that raised you 2/3rds of your goal will provide excellent support for a top coat of not try to top coat a sunken foundation without support as it will only crack and sink more since cement has trouble bonding to old cement

- foam injection should be a last resort...ask your self why are you doing this....I did it because I could not find anyone at any price that was willing to do the work and guarantee it.

best wishes and good luck.

1 Like    Bookmark   January 26, 2015 at 1:18PM
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