Help with floor pour issues.

[Lx460]

so, your still going to put a lift on that floor with out rebar in it for the lift pads ?

6" slab rebar or not is more than sufficient.

I know your ordeal was a PITA but it looks like you'll have a nice floor out of it all in the end. Even a slab done by a good crew will have some minor high/low spots. Yours is nice and flat now. Enjoy it, it will be nice.

 

[grinthock]

LX460.. I agree, none of the lift specs anywhere for less than 12-15K require rebar, most 10K lifts only require 4".

 

[Gcrop]

Looks great.

It was a PITA and a lot of unneeded stress but the end result looks great. Thanks for posting and helping others know what to ask and what to look for.

Hopefully that contractor learned some valuable lessons as well.

 

[grinthock]

Yeah so lessons learned here.... Remember, it costs 3X to replace a floor. So unless you want to pay basically 4X for your floor.. Please read.

when you are getting a floor poured you want to do the following

A1) GENERAL CONTRACTORS HAVE NO BUSINESS DOING A CONCRETE FLOOR. Get a concrete professional who does floors. Do not let just anyone do it.

1) Ask for a floor plan, including location of all contraction cuts, and reinforcement.
2) Ask how the site will be prepped, how will the soil be remediated, is gravel going down and how will it be compacted
3) Ask about reinforcement options, mesh, rebar, fibre or steel fibre and decide what is best for your application. Reinforcement should never be "layed down" it has to be mid slab.
4) Discuss how the floor will be sloped.
5) Plan your contraction cuts to avoid areas that might be a problem like hoists. Ask about how the slab will be isolated from the foundation (if necessary)
6) Ask about how the floor will be finished, ask about the method, what the finish will look like. Get a commitment. Get an example. Ask about timing, is misting required.
7) Agree on a flatness tolerance based on the American Concrete Institute F System.
8) DO NOT let them add water to the mix on arrival, this is a no no unless part of the plan
9) Get a copy of all mix sheets for the loads.

Don't be bullied by your contractor for asking too many questions, if they see you as a smart a$$, remember, it's your money you have the right to ask. Don't let your GC or Contractor do your floor - get it subbed out, or arrange it yourself. Finishing concrete is an art.

Last but not least - get it all in writing. I know more about concrete now than I ever did - I wish I didn't have to learn this way, but hopefully someone else will read this, and learn a lesson that I didn't.

I would rather just have concrete, but now I have this. Not relly looking forward to putting wood under jack stands, and covering the floor to weld, but I wasn't interested in the legal battle headache.

 

[NZ0J]

Yeah so lessons learned here.... Remember, it costs 3X to replace a floor. So unless you want to pay basically 4X for your floor.. Please read.

when you are getting a floor poured you want to do the following

A1) GENERAL CONTRACTORS HAVE NO BUSINESS DOING A CONCRETE FLOOR. Get a concrete professional who does floors. Do not let just anyone do it.

1) Ask for a floor plan, including location of all contraction cuts, and reinforcement.
2) Ask how the site will be prepped, how will the soil be remediated, is gravel going down and how will it be compacted
3) Ask about reinforcement options, mesh, rebar, fibre or steel fibre and decide what is best for your application. Reinforcement should never be "layed down" it has to be mid slab.
4) Discuss how the floor will be sloped.
5) Plan your contraction cuts to avoid areas that might be a problem like hoists. Ask about how the slab will be isolated from the foundation (if necessary)
6) Ask about how the floor will be finished, ask about the method, what the finish will look like. Get a commitment. Get an example. Ask about timing, is misting required.
7) Agree on a flatness tolerance based on the American Concrete Institute F System.
8) DO NOT let them add water to the mix on arrival, this is a no no unless part of the plan
9) Get a copy of all mix sheets for the loads.

Don't be bullied by your contractor for asking too many questions, if they see you as a smart a$$, remember, it's your money you have the right to ask. Don't let your GC or Contractor do your floor - get it subbed out, or arrange it yourself. Finishing concrete is an art.

Last but not least - get it all in writing. I know more about concrete now than I ever did - I wish I didn't have to learn this way, but hopefully someone else will read this, and learn a lesson that I didn't.

I would rather just have concrete, but now I have this. Not relly looking forward to putting wood under jack stands, and covering the floor to weld, but I wasn't interested in the legal battle headache.

Why do you say to not add water to the mix on arrival?

 

[boobag]

i would still cut the floor, because over time, the earth may move.

 

[KDXSR5]

Why do you say to not add water to the mix on arrival?

Adding water changes your cement to water ratio in the concrete. This makes the concrete easier to work, but also changes the entire nature of the mix as specified. Sometimes concrete is ordered as a "drier" mix with the intention of adding a specific amount of water once on site. This is usually accompanied with slump tests.

I don't have any of my references right now to get into detailed specifics (as I just moved into a new house), but a basic Google search may get you more info. A local library more than likely has several concrete engineering oriented books.

There is more research and info on concrete and related products than the average person would ever want to know. It's unreal how much info is available.

 

[boobag]

Adding water changes your cement to water ratio in the concrete. This makes the concrete easier to work, but also changes the entire nature of the mix as specified. Sometimes concrete is ordered as a "drier" mix with the intention of adding a specific amount of water once on site. This is usually accompanied with slump tests.

I don't have any of my references right now to get into detailed specifics (as I just moved into a new house), but a basic Google search may get you more info. A local library more than likely has several concrete engineering oriented books.

There is more research and info on concrete and related products than the average person would ever want to know. It's unreal how much info is available.

exactly. the more water you add, the weaker the mix and finish. also, the more you trowel the surface, the weaker the finish also. but being indoors, its not as big of an issue as exterior concrete that is exposed to the elements and freezing. for outdoor concrete, you want to pour it as dry as you can, and keep troweling to a minimum. otherwise the surface may spall.

 

[Rock knocker]

8) DO NOT let them add water to the mix on arrival, this is a no no unless part of the plan

You need to be careful about this one. Senselessly demanding no more water because you read that it was bad while you were in the library or on the web is just plain meddling of the first degree. It is the contractors job to follow industry guidelines and the design specs of the architect and engineer in your pour. Too much water is bad, more water can be helpful. You yourself knew nothing about concrete less than a month ago, now you are giving us a play by play on how to do the pour, including the design mix. This can come off on the job site as somebody newly book smart declaring themselves as an expert. In reality, get a good contractor who has a good concrete sub and everyone get on the same page of what you want.

Then go to the museum the day of the pour.

 

[grinthock]

But read my entire comment. Don't let them add water -- UNLESS that was part of the plan. The key is ask questions don't simply blindly trust.

Sent from my SM-G900W8 using Tapatalk

 

[NZ0J]

You need to be careful about this one. Senselessly demanding no more water because you read that it was bad while you were in the library or on the web is just plain meddling of the first degree. It is the contractors job to follow industry guidelines and the design specs of the architect and engineer in your pour. Too much water is bad, more water can be helpful. You yourself knew nothing about concrete less than a month ago, now you are giving us a play by play on how to do the pour, including the design mix. This can come off on the job site as somebody newly book smart declaring themselves as an expert. In reality, get a good contractor who has a good concrete sub and everyone get on the same page of what you want.

Then go to the museum the day of the pour.

This is spot on.

I was actually sort of baiting when I asked my question about not letting water be added. I manage a ready mix concrete plant for a living. There are too many variables to just demand no water be added on the job. There is a reason when we design mixes that we figure out what the water/cement ratio is at different slumps. If the batch man accidentally sends a truck out at a 2" slump for a garage floor, there is no reason whatsoever that water couldn't be added on the job.

The o.p. got a **** job, we all know that, but just because his contractor wasn't knowledgeable, doesn't mean all are like that. The good ones know what kind of slump is needed, and what is too much.

 

[Rock knocker]

But read my entire comment. Don't let them add water -- UNLESS that was part of the plan

It's too much to expect your contractor to submit a concrete design mix for a garage slab, and even if he did, who would authorize this submittal? You? Frankly, I don't think you're capable.

If you have a good sub, sans any design mix requirements, which in this case are zero, they should be able to judge whether they need additional water or not themselves. You can't decide this, you don't have the information or knowledge.

There is a difference between being a informed home owner and a PITA OCD'ing about some minor issue that you only have a very marginal knowledge about.

Just because you hired a crappy contractor is not a reason for you to write a book telling others how to run their contractor off.

 

[lakeroadster]

LX460.. I agree, none of the lift specs anywhere for less than 12-15K require rebar, most 10K lifts only require 4".

I'd like to thank the OP for starting this thread, it is and will be helpful to folks having a concrete slab poured.

As for slab requirements for an automotive lift, what a manufacturer recommends is typically the minimum. Since I am having a pole barn built and will be erecting my Rotary 10,000 lb 2 post lift I figured I'd give them a call.

I just got off the phone with a tech. @ Rotary and he was reluctant to offer any advice, other than what they publish, which is shown below. So I kind of "lead him along" in the discussion as follows:

When I asked: "Your chart specifies 4-1/4" thick 3,000 psi min. concrete, so should I just have them pour 5" thick?"
Rotary Tech Stated: "The minimum is 4-1/4", 5" would be better".

When I asked: "I see no mention of rebar? Should rebar be used?"
Rotary Tech Stated: "Adding rebar is better than no rebar".

When I asked: "Couldn't rebar under the posts interfere with the anchor bolts?"
Rotary Tech Stated: "Lay out an area around each post and don't put the rebar under there."

When I asked: "Your instructions say: If anchors do not tighten to specified torque, replace concrete under each column base with a 4’ X 4’ X 6” thick 3,000psi minimum concrete pad keyed under and flush with top of existing floor. then wouldn't it make sense to pour the concrete under each column that way when the slab is poured?"
Rotary Tech Stated "That sounds like a good plan."

Just seems silly. I blame lawyers for this.

http://www.rotarylift.com/uploadedfiles/faq1.pdf

_____
John

 

[KDXSR5]

That info is a good addition to the thread lakeroadster.

So everyone is beating up the OP on one point of his list of things to be aware of, as the owner, when having concrete poured. Maybe he overstated a little on the water point, but I can't blame him after what he has had to deal with. Let's turn the discussion to his other points and make this a more in depth discussion to further help others. What are your thoughts on his other points?

Yeah so lessons learned here.... Remember, it costs 3X to replace a floor. So unless you want to pay basically 4X for your floor.. Please read.

when you are getting a floor poured you want to do the following

A1) GENERAL CONTRACTORS HAVE NO BUSINESS DOING A CONCRETE FLOOR. Get a concrete professional who does floors. Do not let just anyone do it.

1) Ask for a floor plan, including location of all contraction cuts, and reinforcement.
2) Ask how the site will be prepped, how will the soil be remediated, is gravel going down and how will it be compacted
3) Ask about reinforcement options, mesh, rebar, fibre or steel fibre and decide what is best for your application. Reinforcement should never be "layed down" it has to be mid slab.
4) Discuss how the floor will be sloped.
5) Plan your contraction cuts to avoid areas that might be a problem like hoists. Ask about how the slab will be isolated from the foundation (if necessary)
6) Ask about how the floor will be finished, ask about the method, what the finish will look like. Get a commitment. Get an example. Ask about timing, is misting required.
7) Agree on a flatness tolerance based on the American Concrete Institute F System.
8) DO NOT let them add water to the mix on arrival, this is a no no unless part of the plan
9) Get a copy of all mix sheets for the loads.

Don't be bullied by your contractor for asking too many questions, if they see you as a smart a$$, remember, it's your money you have the right to ask. Don't let your GC or Contractor do your floor - get it subbed out, or arrange it yourself. Finishing concrete is an art.

Last but not least - get it all in writing. I know more about concrete now than I ever did - I wish I didn't have to learn this way, but hopefully someone else will read this, and learn a lesson that I didn't.

I would rather just have concrete, but now I have this. Not relly looking forward to putting wood under jack stands, and covering the floor to weld, but I wasn't interested in the legal battle headache.

 

[coldh2o]

When I asked: "I see no mention of rebar? Should rebar be used?"
Rotary Tech Stated: "Adding rebar is better than no rebar".

I've seen this a few times in this thread. You do understand that the thickness of the concrete and addition of rebar are to a very large degree unrelated? Thickness provides strength in compression (bearing), rebar provides strength in tension (bending). Lifts are essentially a point load so you're looking for bearing strength. Rebar might help spread the load a bit, especially if you have poor underlying subgrade, but it won't help support the lift.

Looking at the provided table, it appears the most important part of concrete depth is being deep enough to provide adequate length of anchors, regardless of concrete strength or addition of rebar. Makes sense, the major concern is probably tipping of the hoist.

 

[SALIV8]

That turned out great. Thanks for the follow up and glad everyone stepped up for your project.

 

[AndyCBR]

I've seen this a few times in this thread. You do understand that the thickness of the concrete and addition of rebar are to a very large degree unrelated? Thickness provides strength in compression (bearing), rebar provides strength in tension (bending). Lifts are essentially a point load so you're looking for bearing strength. Rebar might help spread the load a bit, especially if you have poor underlying subgrade, but it won't help support the lift.

Looking at the provided table, it appears the most important part of concrete depth is being deep enough to provide adequate length of anchors, regardless of concrete strength or addition of rebar. Makes sense, the major concern is probably tipping of the hoist.

When you have a 2 post lift there is a significant moment applied to the slab under the bearing posts. It is not 100% vertical (compression) load applied. That is why slab thickness and some type of reinforcement can be important. On a 2 post lift the outermost anchors are in significant tension.

I don't know all of the specifics of the OP's loading/lift conditions but saying that concrete is very strong in compression is only part of the story especially with a 2 post lift.

 

[NZ0J]

That info is a good addition to the thread lakeroadster.

So everyone is beating up the OP on one point of his list of things to be aware of, as the owner, when having concrete poured. Maybe he overstated a little on the water point, but I can't blame him after what he has had to deal with. Let's turn the discussion to his other points and make this a more in depth discussion to further help others. What are your thoughts on his other points?

Oh, there is more than just the water thing in his list, that was just the one that really made me scratch my head.

I can shorten the list up considerably.

1- Hire a reputable contractor and let them do their thing. End of story.

I get calls all the time asking for references on my contractor customers. I also get calls from homeowners looking for contractors to do their work for them. I don't give the names of fly by night outfits, I give out the names of the guys that do the best work. I see on here a lot where people hire buddies, or friends of buddies to do the work, seems like more times than not it ends badly. Do yourself a favor and call the local ready mix supplier and see who they recommend.

 

[grinthock]

You go ahead and short up the list all you want by saying that. That's what I did and I got screwed.

This guy had references, previous jobs, pretty well known in town. He cut a corner, that's what happened. Had I known what was going on, had I been more involved and no "let them do their thing, end of story" maybe this wouldn't have happened.

Sounds to me like you are a concrete contractor, so you taking offense to my recommendation that people be involved is understood.

The key here is ask the questions, and keep asking them until you feel comfortable that the job they are going to do - is properly done.

I recommend things like getting copies of mix sheets because if you get into a fight later (as I did) you might need them. Adding water is ok - IF IT IS PART OF THE PLAN - but blindly adding water is VERY often a corner cutting attempt to slow the curing process to aid in finishing.

The end of the day, my problems were a 3 day mistake. My GC got pissed off because the Concrete guy he hired, couldn't show up for 3 days - so he ordered the Concrete (pulled the mesh to save money) and did it himself. He didn't have the requisite skill to do it, the floor got ahead of them, and at that point the floor was screwed.

Had he told me about the 3 day issue I would have said "Floor's important, wait for the concrete guy" -- however I didn't find out until AFTER that's what happened.

 

[NZ0J]

You go ahead and short up the list all you want by saying that. That's what I did and I got screwed.

This guy had references, previous jobs, pretty well known in town. He cut a corner, that's what happened. Had I known what was going on, had I been more involved and no "let them do their thing, end of story" maybe this wouldn't have happened.

Sounds to me like you are a concrete contractor, so you taking offense to my recommendation that people be involved is understood.

The key here is ask the questions, and keep asking them until you feel comfortable that the job they are going to do - is properly done.

I recommend things like getting copies of mix sheets because if you get into a fight later (as I did) you might need them. Adding water is ok - IF IT IS PART OF THE PLAN - but blindly adding water is VERY often a corner cutting attempt to slow the curing process to aid in finishing.

The end of the day, my problems were a 3 day mistake. My GC got pissed off because the Concrete guy he hired, couldn't show up for 3 days - so he ordered the Concrete (pulled the mesh to save money) and did it himself. He didn't have the requisite skill to do it, the floor got ahead of them, and at that point the floor was screwed.

Had he told me about the 3 day issue I would have said "Floor's important, wait for the concrete guy" -- however I didn't find out until AFTER that's what happened.

Look, I'm sorry you got a **** job. Sounds like you hired the wrong GC.

I'm not a contractor, I manage a ready mix plant, so I supply contractors. I've seen the good ones, as well as the bad ones. It sounds like your GC was the one building the building, so he hired his concrete guy. I would never do that, but I also work in this industry so I know what goes on. Most carpenters don't care about the concrete, they just want it done cheap to keep their cost down so they can get the job. If I were to ever build a shop, I'd get separate prices for the building and the concrete. I want the best guys doing the work, the ones I know don't cut corners, not the cheapest guy the builder can find.

But, it's also not a good idea to try to tell your concrete guy he can't add water, especially with your minimal amount of concrete experience. I'm very familiar with what can happen when too much water is added. We have our drivers document water added on each load, just in case a situation like yours arises, that way we can look back and say yeah, this guy added too much water, he poured this at such and such W/C ratio which is excessive.

 

[lakeroadster]

Before I retired I was a QA guy. What I was taught many decades ago was "Trust But Verify"

I'll be specifying to my GC that I will be on site and no concrete shall be poured until I review the concrete mix sheets. The fact that we are asking for them tells the GC and the Mix Plant that the end user wants to ensure the job is being done right.

So NZOJ, can you help educate us on what we should be looking for on the concrete mix sheets, and maybe post up a copy of one for reference?

Thanks,

_____
John

 

[NZ0J]

Before I retired I was a QA guy. What I was taught many decades ago was "Trust But Verify"

I'll be specifying to my GC that I will be on site and no concrete shall be poured until I review the concrete mix sheets. The fact that we are asking for them tells the GC and the Mix Plant that the end user wants to ensure the job is being done right.

So NZOJ, can you help educate us on what we should be looking for on the concrete mix sheets, and maybe post up a copy of one for reference?

Thanks,

_____
John

Unless you know anything about mix designs, it really isn't going to make sense to you to look at the mix sheets. They are going to have aggregate weights, cememtitious weights, water, and admixtures in the load. Your best bet would be to find out what the max w/c ratio is of the mix you're using and find out how much total water can be added and not go over that amount. When we do work for the DOT, we have tickets that show what the total water is in the load, that includes mix water and moisture in the aggregates. The DOT specifies a maximum w/c ratio on their mixes, so on the ticket it show how much water is in the load from the plant, and what can be added on the job. Typically on their mixes, the max w/c ratio is around a 4" slump.

Now, on our non DOT work, where we're using our own mix designs, we over design our mixes. Typically a 4000 psi mix should break 4000 psi in 28 days. It's not uncommon for our 4000 to hit 4000 psi in 7 days. This is generally based around a 4" slump. The reason we do this is because we know people are going to pour wetter than that, and this is just a little insurance for us that if they do, we should still hit design strength in 28 days and hopefully avoid any issues down the road because thing were poured to wet. You will still have guys that pour WAY too wet, that go over the max w/c ratio, but it's because of them that we record the water added on the job. If problems arise, we can look back and say hey, this load was fine leaving the plant, but you added 50 gallons to a 4 yd load way exceeding the max w/c ratio.

 

[lakeroadster]

If problems arise, we can look back and say hey, this load was fine leaving the plant, but you added 50 gallons to a 4 yd load way exceeding the max w/c ratio.

It appears to me that you are making a case for the end user / GC to ask for the mix sheets. If there is an issue, either at pour or in the future, the only way the end user / GC can prove the mix was bad or the concrete guys on site added to much water is if the end user / GC has the mix sheets, right?

If a two post lift wasn't being installed I agree this conversation is over the top for a simple garage slab.

I'm back to the "Trust but Verify". The end user will "Trust" the job will be done right by choosing a good GC, but the end user can verify that it is done right by getting the documents that show they are performing the task per the required specifications. What am I missing?

Or, lets put this another way, why would the mix plant / GC not want to provide the end user with the mix sheets for each load?

_____
John

 

[NZ0J]

It appears to me that you are making a case for the end user / GC to ask for the mix sheets. If there is an issue, either at pour or in the future, the only way the end user / GC can prove the mix was bad or the concrete guys on site added to much water is if the end user / GC has the mix sheets, right?

If a two post lift wasn't being installed I agree this conversation is over the top for a simple garage slab.

I'm back to the "Trust but Verify". The end user will "Trust" the job will be done right by choosing a good GC, but the end user can verify that it is done right by getting the documents that show they are performing the task per the required specifications. What am I missing?

Or, lets put this another way, why would the mix plant / GC not want to provide the end user with the mix sheets for each load?

_____
John

Most of our plants batching software will print this info on the delivery ticket, it's available right there on the job. Do you understand how to decipher it though?

 

[Rock knocker]

Most of our plants batching software will print this info on the delivery ticket, it's available right there on the job. Do you understand how to decipher it though?

There's the $64K question.

 

[NZ0J]

There's the $64K question.

I think too much emphasis is being put on water being added. There are a lot of other things to consider too that the mix sheet isn't going to tell you. Take this for what it's worth coming from a guy that batches and sells concrete, but we generally know if something is "off" before the truck ever leaves the yard. We don't knowingly send out bad loads. But, a guy can sure take our product that was good at the time of delivery and turn it into something awful, like what happened in this thread, and it usually comes back at us, because you know, by god, this contractor has been doing this 30 years and they've never had anything like this happen. We see it quite a bit, the bad guys just trying to cover their own **** and pass the blame. That is why I said earlier, call your local ready mix supplier when trying to find a concrete guy, they're not going to give you the names of guys they are likely to have issues with down the road.

 

[Peter Mc Mahon]

At the end of the day all that you got was a poor finish. Everything else looks like it went as planned/drawn. For a poor finish I think an offer of $4000 is very generous of the contractor.

 

[Rock knocker]

If the batch man accidentally sends a truck out at a 2" slump for a garage floor, there is no reason whatsoever that water couldn't be added on the job

 

[NZ0J]

Yep, but hey, adding water is bad.

I've actually had do it yourselfers tell me that adding water is bad, like I'm the green one when it comes to concrete.

 

[Rock knocker]

I'd think 2" slump was soupy enough without even more water

 

[NZ0J]

I'd think 2" slump was soupy enough without even more water

Do you know how dry a 2" slump is? Think like how dry you'd want it if you were building curb. You would think that was too wet for a floor?

 

[Rock knocker]

You're right, I got all messed up in my head. I've been the boss of pours of hundreds of yards, but that was many moons ago.

Egg on my face

 

[NZ0J]

You're right, I got all messed up in my head. I've been the boss of pours of hundreds of yards, but that was many moons ago.

Egg on my face

Lol, no problem.

 

[homebuilt burner]

Keep in mind that when you tell someone you are building a garage they think it is to park a car in and that most people never look at the floor. Now for those of us on here we are usually looking for more out of our garages and our garage floors. So, tell a GC I want a garage floor may mean less to him than " I want a beautifully smooth nicely colored floor that will make my cars look wonderful"

I am happy the OP got some results, I don't know if I would be happy with the floor for the same reasons he listed, but it is a better solution than what he had.

 

[coldh2o]

When you have a 2 post lift there is a significant moment applied to the slab under the bearing posts. It is not 100% vertical (compression) load applied. That is why slab thickness and some type of reinforcement can be important. On a 2 post lift the outermost anchors are in significant tension.

I don't know all of the specifics of the OP's loading/lift conditions but saying that concrete is very strong in compression is only part of the story especially with a 2 post lift.

Not meaning to derail the thread but this is an interesting discussion. Good point, there is significant bending applied to the post, transferred through the outermost anchors in tension. However, I don't see how rebar is going to assist the anchors from pulling out (unless they were mechanically tied to the rebar). I think its still the concrete strength which holds the anchors in place (tension or compression). Again, referring to the hoist manufacturers table, depth of concrete is important to provide full coverage of the anchor and develop it's "grip" on the concrete (or vice versa, really), as is psi of the concrete.

Just my thoughts - I've been wrong before...

 

[lakeroadster]

Most of our plants batching software will print this info on the delivery ticket, it's available right there on the job. Do you understand how to decipher it though?

You keep saying that.... no I don't, and most of us don't, and we don't need to know. Getting the mix sheets and keeping them in the the event of a problem ensures documentation of how the mix left the mix plant. So if it was good from the mix plant and it's not good after the pour it's obvious who screwed the pooch.

Makes sense to me . Without the mix sheets there will be a ******* match in regard to why the concrete is bad.

_____
John

 

[Gcrop]

Kind of what I was thinking. Home owner has info/proof for later (though hopefully it never gets to that).


Sent from my iPhone using Tapatalk

 

[NZ0J]

You keep saying that.... no I don't, and most of us don't, and we don't need to know. Getting the mix sheets and keeping them in the the event of a problem ensures documentation of how the mix left the mix plant. So if it was good from the mix plant and it's not good after the pour it's obvious who screwed the pooch.

Makes sense to me . Without the mix sheets there will be a ******* match in regard to why the concrete is bad.

_____
John

Like I said, keep the delivery tickets, the info is most likely on them, but concrete isn't as black and white as a lot of people on here think, there is a lot more that can go wrong other than adding too much water.

I actually lol'd when I read the part about thinking having batch weights is going to prevent a ******* match. Concrete contractors are some of the most stubborn people you'll ever meet, they WILL NOT admit fault, they will 99 percent of the time try to pass the blame on to guys like me.

My point with all this is, like I said earlier, is make sure you hire a good contractor. Again, like I said, one of the best ways to do that is call the ready mix supplier and get their recommendation. A lot of these problems on this forum would never occur if people would just hire the right guy, but this forum would be a lot quieter too. I've got guys that I would hire in a second to do any of my work, I've also got guys I wouldn't let pour my dog kennel; which one do you think I'm going to recommend?

 

[bigfunwmu]

Trust but verify is the right way to go. If I was still living around Kalamazoo MI and I was having any kind of work like this done I would contact SME (Soil & Materials Engineering) on Western's engineering campus to review specs on the plans, on-site verify base compaction, and to both test slump and PSI of the concrete used. Tom there really knows his s**t.

I would go over this all with the contractor up front as well. Clearly state what is expected and required, and establish in writing exactly what happens if specs are not met. Mix not to spec, probably not the contractor's fault. Still not to spec, so who gets to deal with that? Floor out of flat? Spec ahead of time if a grind is acceptable or a repour is required.

All this will raise the price of the project, just have to decide if you want to pay the money up front for no worries or live with what you get at the end of the day.

The several projects we worked with the SME guys turned out very well, and still look good 12 years later. We had them on site to make sure we did the work right while we were still in process, both to prevent anything missed from becoming a future issue and to make sure we weren't going to have a do-over out of our pocket for something simple to fix ahead of time; like insufficient compaction 5 feet down below a bed of pavers due to poor subsoil.

 

[vettehouse]

Found this thread informative and helpful. Also agree that contacting the supplier is a good idea. I'm also installing a 2 post lift rated at 10K lb and was not comfortable with the existing slab. I've saw cut a section 15' X 4' X 12 " deep. The concrete contractor plans to use fibre reinforced 4000 PSI concrete and a "bridge mat" for reinforcement. additionally he will tie the new and existing slabs together using #4 18" long anchorage dowels spaced every 18" along with 6" key-ins around the perimeter of the slab. Overkill or sounds right. Any concerns with side drilling the existing slab to install the anchorage dowels. Thanks in advance for any thoughts / suggestions.