# Cutting concrete slab to make it square



## de-nagorg (Feb 23, 2014)

If that contractor is a decent person, they will correct this for nothing. 

Wait and see what they offer.


ED


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## joecaption (Nov 30, 2011)

Done right, (which we can see it was not) there would have been turned down edges to reduce erosion on the edges of the slab, you'll loose all of that.
https://www.google.com/search?q=tur...OAhVGqR4KHSM7CjAQsAQIGw#imgrc=DHCRV0aKYtW4eM:


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## HDS (Jun 21, 2014)

joecaption said:


> Done right, (which we can see it was not) there would have been turned down edges to reduce erosion on the edges of the slab, you'll loose all of that.
> https://www.google.com/search?q=tur...OAhVGqR4KHSM7CjAQsAQIGw#imgrc=DHCRV0aKYtW4eM:


Don't think they turned down the edges as it hadn't specified for it. Plus I don't recall seeing that feature when they were forming it. It was one of those things I didn't come across in my research, and made the assumption (yeah, yeah) that they would recommend the proper techniques. But a 5.25 thick, rebar reinforced pad, probably won't have much if any issues.


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## kwikfishron (Mar 11, 2010)

14" out of square??? I'd make them replace it (any reputable company would).

Did this "concrete company" do the prep and setup or did you give them the box and they just placed the concrete?


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## de-nagorg (Feb 23, 2014)

I believe that he stated in the first posting that he had difficulties getting them to place it parallel to a fence line, and this was the results of a disagreement.

Still it should have been right the first time.


ED


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## HDS (Jun 21, 2014)

kwikfishron said:


> 14" out of square??? I'd make them replace it (any reputable company would).
> 
> Did this "concrete company" do the prep and setup or did you give them the box and they just placed the concrete?


I set up some stakes as to the general area (did not square them up) and they excavated the site, put in the base materials and did the forming. The issue was when they first started. The guy doing the forming thought the shed should be at an angle and started forming it that way. My wife called and she told him in person, and I on the phone, we wanted it parallel. An hour later they are adding the base material/compacting, and my wife calls and said they didn't move it. I come home, talk to them, and get them to make the back and front parallel to the fence/property line as well as the back of our house. They had 3 of the forms set, with the fourth out so they could use the bobcat to bring in the base material. they adjusted the back 10' form so it was parallel, and then moved the 16' sides. We check from side to side, back to front, it was oriented properly at that point and I went back to work. There was no measuring diagonals as they still had the front 10' form off to bring in base material and compact it. The assumption was after that, they would square it up.

Overall, their finish work was excellent, they did our 600 sq ft back porch, and we were going to use them to replace our driveway (~10k job).


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## kwikfishron (Mar 11, 2010)

HDS said:


> I set up some stakes as to the general area (did not square them up) and they excavated the site, put in the base materials and did the forming. The issue was when they first started. The guy doing the forming thought the shed should be at an angle and started forming it that way. My wife called and she told him in person, and I on the phone, we wanted it parallel. An hour later they are adding the base material/compacting, and my wife calls and said they didn't move it. I come home, talk to them, and get them to make the back and front parallel to the fence/property line as well as the back of our house. They had 3 of the forms set, with the fourth out so they could use the bobcat to bring in the base material. they adjusted the back 10' form so it was parallel, and then moved the 16' sides. We check from side to side, back to front, it was oriented properly at that point and I went back to work. There was no measuring diagonals as they still had the front 10' form off to bring in base material and compact it. The assumption was after that, they would square it up.
> 
> Overall, their finish work was excellent, they did our 600 sq ft back porch, and we were going to use them to replace our driveway (~10k job).


Well that sucks. It sounds like they gave you what you asked for. If the house and the fence are not truly parallel to each other then based on your request the slab could never be square. 

That said, if they new that you were building a shed there someone should/could have brought up that what you were requesting would not work for what you're wanting to do.


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## HDS (Jun 21, 2014)

kwikfishron said:


> Well that sucks. It sounds like they gave you what you asked for. If the house and the fence are not truly parallel to each other then based on your request the slab could never be square.
> 
> That said, if they new that you were building a shed there someone should/could have brought up that what you were requesting wold not work for what you're wanting to do.


I'm not as worried about the turn down on the slab, but it should have been squared.


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## kwikfishron (Mar 11, 2010)

HDS said:


> I'm not as worried about the turn down on the slab, but it should have been squared.


I'm not talking about the turn down. 

Is the distance between the house and the fence the same at both ends, are they truly parallel to each other? From the way you describe things in post 7 and what you're left with it sounds like they are not.


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## HDS (Jun 21, 2014)

The house and fence may not be exactly parallel, we just didn't want the shed 30 degrees off/askew from the back fence. Our neighborhood has a lot of sheds and they are all basically parallel to the back property lines. I didn't stake it out that way initially, my wife told them parallel, I told them parallel on the phone, and finally in person when after two conversations they still weren't getting it right. We never took measurements from the back fence, or the house, just eyeballed it and expected them to square it up off that back form. We asked for a 10x16 rectangular pad for a shed, not a 10x16 rhombus.


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## HDS (Jun 21, 2014)

Measured from the fence to the back of the slab, it was off by 7 inches. They didn't make it parallel off it.


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## kwikfishron (Mar 11, 2010)

I revert back to post 5 line 1.


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## Bud9051 (Nov 11, 2015)

Just want to add, without going back over the entire thread, but to correct the slab, you could cut one side and pour new concrete on the other. Being just a shed the loads will not be terrible and the new patch can be tied to the slab with pins of rebar. The patch can also extend under the existing slab several inches to help tie them together. 

This would return you to the original size and in the end close to where you wanted it, give or take a foot or so.

If you need to eliminate the "foot or so" that is not parallel to where you wanted it, remove whatever perimeter you must and frame around what is left and then pour a new perimeter as described above. You would end up with a stronger perimeter than current and the resulting slab would be exactly where you want it.

Bud


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## HDS (Jun 21, 2014)

Bud9051 said:


> Just want to add, without going back over the entire thread, but to correct the slab, you could cut one side and pour new concrete on the other. Being just a shed the loads will not be terrible and the new patch can be tied to the slab with pins of rebar. The patch can also extend under the existing slab several inches to help tie them together.
> 
> This would return you to the original size and in the end close to where you wanted it, give or take a foot or so.
> 
> ...


Thanks for the idea Bud! I'd prefer an eas(ier) fix that is going to last, than tearing it all up.

Was thinking about this a bit more Bud, basically you are saying put in retroactive footers, like for a house foundation wall? I could even go a bit bigger, adding a foot to each side for a 12x16 shed. Was already thinking a bit bigger wouldn't be a bad thing.


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## HDS (Jun 21, 2014)

Talked with one of the contractors this morning, at least one half of their team. They initially tried laying the blame on us moving the orientation. They seemed to think that I was upset that the pad wasn't square/parallel to the house. It took a bit more explaining that the orientation was spot on, that the pad itself is out of square by 14 inches and the shed company can't build on it. Waiting to hear back from the contractors partner (it is a husband/wife team), and go from there.


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## de-nagorg (Feb 23, 2014)

You are needing to have both on-site, at the same time.

Measuring as proof that an error happened.

Rhombus ain't a rectangle.


ED


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## HDS (Jun 21, 2014)

Didn't hear from them today...Did take some new measurements and got the angles, 86 degrees for the narrow corners. To square it up, need to take off 14" from the 16' side.


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## HDS (Jun 21, 2014)

I did pull out the contract, they had the following line, "All work to be completed in a workman like manner according to standard practices." Could anyone point me to generally recognized standard practices for forming and acceptable variation in measures. There should be something official that would say, should not exceed x amount/percentage, etc... out of square.


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## Bud9051 (Nov 11, 2015)

"All work to be completed in a workman like manner according to standard practices."
That is a very general statement and I've never seen anything specific that might put some numbers on it. However, the resulting slab you have is so far out that NO contractor would have any doubts that it fails to meet the above statement. I had a foundation off by 1/2" and found it a pain to have to shift the framing to overhang that amount so the house would at least be square. Yours is impossible.

Looking at your diagram above I was wondering if you kept the long sides as they are and cut the short sides if it would be easier? Slight rotation in the final position but I believe you said that wasn't critical. End result would have the original width only slightly shorter.

Best I can do for 4 AM.

Bud


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## de-nagorg (Feb 23, 2014)

Standard practices are to measure the X diagonals to insure that the thing is square. They obviously skipped that part.

Will probably offer some lame excuse.


ED


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## HDS (Jun 21, 2014)

Apparently standard practices don't apply if you have to ask them 3 times to put the shed pad in the orientation where it was originally staked and not where their foreman thought it should go. She kept repeating, we put it where the customer asked us to put it, and you were happy when we left. It did look fine, didn't think I would have to measure for square. 

One company wanted $3900 (minimum charge) to come out and remove and replace. It'll cost probably 700-800 to rent a skid steer and get a dumpster to get rid of it myself. Not to mention having to put in a new shed base, probably gravel, and paying for a floor for the shed.

At this point, maybe just going a bit shorter, with the 10' ends having a 6" triangular sliver of concrete at both ends. Could maybe even cheat a bit, with the sill plates hanging a tab bit over the sides.

Yes I'm venting...yes I've contacted a lawyer to see what they think.


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## Bud9051 (Nov 11, 2015)

If you have a circular saw, a diamond blade is not very expensive and you will be surprised at how easily it will cut through that slab. Full depth with a 6.5" blade will be about 2.5". You should be able to smack it with a sledge and break it off or drill some holes with a masonry drill bit to be sure. A rental shop would probably have a larger blade to do it all in one shot, no sledge. If you need to smooth over the front edge a grinder would easily do that.

Or pour both front and rear triangles as discussed before.

Cut the front triangle off and pour the rear one to make it square or pour both. Then take the mason company to small claims court for all related costs, no lawyer required, unless they are willing to pay up.

Bud


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## HDS (Jun 21, 2014)

It looks like it'll be an easy fix to just cut one side square and then add to the other to get everything straight. But now my mind is jumping to the issue of no turndowns. How important are they? I'm in SW Ohio, so we do get our fair share of cold, but will a 5" thick slab with 1/2 rebar on 3' OC be okay? Even before all this, was this slab doomed to failure. It's just a shed, but it is going to be a nice shed, and I don't want it ruined or not lasting.


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## Bud9051 (Nov 11, 2015)

A haunch or turndown is good, but there are many slabs in cold country just poured flat. With an unheated shed the ground under and around it will freeze. If the soil/gravel is well drained the risk of frost is reduced but if it forms the hope is it will lift the entire slab uniformly. 5" with rebar is your real protection. A haunch all the way around would be more for load concerns. 

If you increased the slab size by 6 to 8" all the way around and created a turndown that extended under the existing slab and was pinned with rebar to it it would be a better slab, but a lot of work.

Bud


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## de-nagorg (Feb 23, 2014)

If you decide to add the turndowns to it, you could square it at the same time, by adding the wedge shapes and pinning them at the same time, plus adding an apron to both ends.

I suggest 10 inches more all the way around, but squared up, so this will have a wedges on the sides and a rectangle on both ends to square it.

Then you have plenty of room for a bigger shed, and a square base. 

Maybe you can suggest this to the contractor as an acceptable fix.
And maybe a BIG discount on the price.

That way you both win something.


ED


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## jomama45 (Nov 13, 2008)

Lot's of suggestions on "band-aid" repairs so far. I wouldn't suggest most of them, other than sawing both sides down and building a smaller shed. A 5" slab with 1/2" rebar should suffice for a light weight shed w/o issue, there's undoubtedly 10's of thousands of them out there in cold climates.

BTW, the slab is actually 7" out of square, not 14". It would require each corner to come in 7" to be perfectly square.


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## HDS (Jun 21, 2014)

Had a guy over to take a look and help with repairs. The easiest ads cost effective maybe to go down to a 9x15 and cut all four sides. Hate to lose the sq ft though.


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## HDS (Jun 21, 2014)

The lines were laid out for an 8x14.


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## Fix'n it (Mar 12, 2012)

why would you cut the ends if they are parallel ?

idk if this would be ok, i'm thinking it would, if done right, or a bad idea.
use construction blocks to build this,and make it square. then backfill over the exposed slag.
cost, under $200 and some effort.
http://www.fla777.com/uploads/deriv...3a32b2bc-2926ace153028e2ebc7f7b3773262a9e.jpg


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## zircon (Sep 24, 2007)

If you are not familiar with the 345 rule Google it. A triangle with any multiple of 3,4, and five will form a 90 degree angle between the 3 and 4 side. Place a stake at the lower right hand corner of the slab. Place another stake 16' up along the side of the slab. It should meet at the upper right corner. Tie a 12' string to the lower right corner stake and attach another stake to the end of the string 12' away. Head past the lower left corner of the slab with the stake at the end of the string. Pound the stake into the lawn where the stake is 20' away from the upper right corner stake and is 12' away from the lower right corner stake.

Where the string crosses over the bottom of the slab is your cut line. Cut the same amount off the upper side of the slab. Confirm by repeating the string procedure from the upper left corner of the slab.


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## HDS (Jun 21, 2014)

*Walk behind concrete saws*

Can anyone share their experiences with using either a handheld concrete saw in a cart vs the larger walk behind saws? Looking to rent one or the other to cut 50+ feet of 5 inch thick concrete. 

It does have rebar in it, so the cut will need to be fairly deep if not all the way through. 

Thanks!


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## kwikfishron (Mar 11, 2010)

You know that if you use anything with wheels that you'd have to build up the outside of the slab with something for the wheels to travel on. 

Also you only need to cut the 10' sides to get that square enough for a shed. You want the shed to overhang the slab slightly anyway. Ideally the siding on the shed would hang an inch or so below the plate line to cover the plate to slab joint.

I'd just use the handheld saw for what you have. Lay a board down and use that for a straight edge, make a pass only cutting a 1/2-3/4" deep at first. Get rid of the board and then use that initial cut as a tract to cut the rest of it.


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## HDS (Jun 21, 2014)

Went with a cut off saw in a cart. Can't inagine doing this with a circular saw and diamond blade.


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## HDS (Jun 21, 2014)

My diagonals were only off by 1/2 inch...not that hard to do.

I did have to use some scrap wood to keep from falling off one corner, but could maneuver the rest.

My lines ended up a tad crooked, but I chalk that up to my learning curve.


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## HDS (Jun 21, 2014)

I ended up consulting with an online structural engineer who provided detailed stretches. He recommended cutting 1 foot off to make square then digging down 30 inches with it narrowing to 8 inches at the bootom. Then rebar every 5 inches around the perimeter. Also rebar embedded into the existing slab 1 ft oc around perimeter that turned 90 degrees and down the footer. I calculated needing 7 yards of concrete and 500 feet of rebar.

Also talked with county building inspector and a local structural engineer. They both were fine with just a 5" slab with rebar. The BI even mentioned doing that recently at his house.

I'm going to go in between, 2x12 forms with rebar into existing slab and perimeter rebar as well. Basically retrofit the turn down.

Will upsize to 10x17 as that will save one of the 10' cuts.


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## de-nagorg (Feb 23, 2014)

Really a crappy deal that you have to do this yourself, when you paid for something that you did not get. 

At the least they would not be on my call list again, at the most I would submit to them a detailed bill for the repair work.

I am glad that you decided on a plan to repair, and get a semblance of what you wanted.

ED


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## HDS (Jun 21, 2014)

Ed, I've filed with the BBB and plan on small claims court if that doesn't get it resolved. Followed by lots of online reviews with pictures.


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## HDS (Jun 21, 2014)

Finished up the cuts this morning. Better planning and would have finished yesterday. Think I'll outsource the cleanup. Even cut into small chunks they are quite heavy and it'll take 3 loads to the recycling center at $30/load. Maybe cheaper and easier for someone else to handle.


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## Bud9051 (Nov 11, 2015)

Did you hit any rebar?
I cut out a 5' x 10' hole in a 7" slab with rebar and it was a task. We slicer the piece to be removed into 3' x 5' pieces and the tractor we were using could barely lift them. We had room so they ended up buried out back.

In the end you will appreciate the sweat investment.

Bud


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## HDS (Jun 21, 2014)

There is rebar but much of it was deep enough that the saw went over it.


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## HDS (Jun 21, 2014)

Those 3x5 pieces should be close to 1200 lbs each!


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## HDS (Jun 21, 2014)

Took the day off, guess a real Labor day weekend start. Junk removal company wanted $500, but the bagster will do. Figured I'm pushing 3000 lbs and .75 cubic yards, under the 3300 and 1 cubic yard limit. 

Did have help though, the trusty 318. I pushed the limits lifting up that section, not a lot of traction but made it there.

Talked with a concrete guy, he wants to do rebar every 2 feet, just hammered into the concrete, no epoxy. He didn't think the turn down was needed, that 5 inches and rebar but will do it. Also nixed the idea of gravel base. He does seem open to other ideas so we shall see.

Going to fix the drainage to the left of the shed base, is a bit high and plan to slope it correctly.


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## de-nagorg (Feb 23, 2014)

That bagster looks CROWDED, I hope that it performs correct.

Would hate to see you pick that up again.


That looks much better,, no rhombus no more. 

Just hammering in the re-bar, might be secure enough, but epoxy, and it definitely will.

I suggest a PL construction adhesive, I have had excellent results with it. 

What size cut does the 318 have, I am looking for a similar mower, that can withstand weight like you just applied to that one. 


ED


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## Bud9051 (Nov 11, 2015)

Not sure why he dislikes the gravel base and the turn down. Just extra measures that will ensure "all is well" long after he is gone. 

As for the epoxy or the construction adhesive as de-nagorg suggested, seems easier to drill a slightly larger hole than to hammer the rebar into place. Also, no risk of the slab splitting from the tight rebar.

I also like the idea of the turn down flowing under the edge of the existing slab. Just ties them together better.

After all you have been through it seems like now is not the time to agree to short cuts.

Bud


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## HDS (Jun 21, 2014)

de-nagorg said:


> That bagster looks CROWDED, I hope that it performs correct.
> 
> Would hate to see you pick that up again.
> 
> ...


Thanks for the tip on the PL Construction adhesive. I've got two tubes from a project last year that I haven't used and will put them to good use. Definitely won't be skimping on rebar or the turn downs.

I did a bit more work around the slab today, made a few passes around the perimeter with my tiller to help with the digging. If it wasn't so many bags, I'd probably just try and mix it myself and finish off the project on my own. 

My 318 has a 48" deck on it. It is the newer style "replacement" deck that came with it when I bought it. They originally came with a 46 and a 50" deck. It cuts decent, but if you are going for the golf course look, there are better options than the 318.

If you are looking to do a lot of ground engagement, loader, blade, etc..., you might want to jump up to the 4xx series. They have foot controls for forward and reverse and it frees up your hands to work the hydraulics. You can still do it with the 318, but you lose some of the finer control. 

Mine is an '85 year model with over 800 hours on it that I bought 5 years ago. Replaced the magnetic rotor/stator on the PTO wouldn't engage anymore. Also had to have the power steering hydraulic cylinder rebuilt. Not bad for a 31 year old tractor!


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## HDS (Jun 21, 2014)

If I remove all relevant names and such, can I put up the BS response the company gave to the BBB?


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## de-nagorg (Feb 23, 2014)

As long as the statement is not traceable to any specific company or person, you should be able to publically post their statement anywhere you want.

ED


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## Oso954 (Jun 23, 2012)

> Thanks for the tip on the PL Construction adhesive.


As good as it is, rebar dowelling is a job that PL was not designed for. I would buy the epoxy that is designed for the task.


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## HDS (Jun 21, 2014)

They basically said I moved it too many times and they put it where I wanted it after multiple moves. Still should have formed it up square off the rear form that would have been set properly if they had just put it where I staked it in the first place. 

Have heavier fish to fry now...apparently Bagster doesn't like the bag placement and won't pick it up. I followed the packaging instructions and complied, but not much luck. Need to drag it about 3 car lengths down my cracked concrete driveway. Could probably drag it with my truck, just worried about it tearing up the bottom of the bag. Maybe a towing company can lift/partially drag it for hopefully a small fee.


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## Bud9051 (Nov 11, 2015)

Since I'm certain they knew you had not placed your stakes in a square pattern, for them to install their forms and pour your slab as they did was pure arrogance and there is no lame excuse that can shift the blame to you. They are supposed to be the professionals and what they did is about the most unprofessional thing possible. To simply pour the slab to the roughly positioned stakes as a "get even" measure is not tolerable and they should not be in business.

If two guys delivering a couch for the lady of the house are becoming impatient because she had had them reposition it 6 times, they should just smile and keep on doing whatever makes her happy. They should not flip it upside down in the middle of the LR and stomp out the door. That concrete company flipped you off and said among themselves, "there he deserves that" as they knew they did it wrong. To make a mistake is one thing, but to deliberately mess up a job is criminal.

Personally, I would have them in court in a heartbeat for damages and compensation for all of the aggravation, and, IMO, they would lose big time.

Bud


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## HDS (Jun 21, 2014)

Gravel...one guy I've been talking to said it isn't needed, that the soil undisturbed is fine. He wanted a waiver if we went with the gravel. He's on board with everything else. Could this just be a local thing? The original guy was only using the recycled 304 aggregate for filling in the low spots. It is getting hard to find anyone wanting to do thus size job.


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## de-nagorg (Feb 23, 2014)

Undisturbed soil is always the best to use for a base to pour on.

It is already solid, and won't shift under the added weight.

Should be fine to not use any gravel, unless needed to fill voids.


ED


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## HDS (Jun 21, 2014)

Progress...Should be poured today.


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## HDS (Jun 21, 2014)

My wife thought it was the cutest concrete mixing truck she ever saw.


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## de-nagorg (Feb 23, 2014)

They also make them small enough that they are trailer mounted, and towed by your F250.

They fill them at the plant, you tow it to your job, empty mix, clean it up, return it.

ED


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## HDS (Jun 21, 2014)

Still need to paint, but shed is in.


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## de-nagorg (Feb 23, 2014)

Very nice. 

So are you still thinking on hiring the first concrete team to replace your drive and do other things?

I think that you found a better team that repaired your Trapezoid.


ED


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## Bud9051 (Nov 11, 2015)

Nice, certainly a bigger project than what you anticipated, or should have needed, but the results look good and it is where you wanted it. A bit larger if I recall and sheds always seem to fill up fast.

Bud


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## HDS (Jun 21, 2014)

Still need to go to small claims court for the first contractor. Will definitely give the second guy the opportunity to bid the driveway next year.

Is a bit larger, up from 10x16 to 10x18. 

Glad it is done though!


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