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Hangar Concrete Floor Problem

UnPossible

Well Known Member
Hey - we are just a few weeks out from moving into a new home at the airpark in Pecan Plantation. However, we have run into a minor snag with the hangar that we are having built. In the pic below, you can see that the concrete floor rises as you move to the left... it looks like for whatever reason the last 10 feet or so is 3/4" higher than the rest of the floor. The rest of the floor to the right (which you can't see in the pic) looks to be level, as the gap appears consistent.

We are working with the contractor to figure out a solution, but they are coming up blank, so I figured I'd turn the the VAF experts. Is there anyway to grind down the last 10' or so by the required 3/4" to get things back to level?

If not, what is the least bad approach to fix this? Jack hammer it out down to 6" and repour?... entirely cut out that section and repour?

Thanks,
Jason

cuypd.jpg
 
Grind and polish while you are at it.

There are grinders that do just what you need. You may need to call a concrete finishing company. They can grind that area down and feather it into the original - then if you want to drop more $$$ - have them polish the entire surface - just like they do at the big box stores. Looks great and no slip hazard.
 
Are you sure that the foundation is level? Double check framing plate heights and double check door dims too. Its amazing what a 1/4" difference here and there makes during construction. Just something else to cross check with.
 
There are grinders that do just what you need. You may need to call a concrete finishing company. They can grind that area down and feather it into the original - then if you want to drop more $$$ - have them polish the entire surface - just like they do at the big box stores. Looks great and no slip hazard.

+1

get a concrete contractor to polish/grind that down. http://www.csda.org/

Also, check to make sure your door is level and vs the concrete being out of level.
 
Door Seal

You may want to check with the door manufacture and find out what tolerance their door seals have. If you have a bi-fold door the frame probably won't be in contact with the concrete, just a big wide rubber gasket.
 
Having built an airpark hangar and home fairly recently, I would suggest that you don't have a problem - your contractor has a problem, unless you've already bought off on the job "as is". We ran into a few of those snags during our build, when our contractor wanted to make it my problem, and I simply pointed out that until I bought off on the final build, it was up to him to meet the specs.

Paul
 
Having built an airpark hangar and home fairly recently, I would suggest that you don't have a problem - your contractor has a problem, unless you've already bought off on the job "as is". We ran into a few of those snags during our build, when our contractor wanted to make it my problem, and I simply pointed out that until I bought off on the final build, it was up to him to meet the specs.

Paul

Paul - you are totally correct... the problem lies somewhere between the GC and the concrete contractor... I was just looking to see if anyone has any solutions that I have not thought of, as they appear to be having a hard time finding a contractor to grind down the unlevel concrete.
 
You may want to check with the door manufacture and find out what tolerance their door seals have. If you have a bi-fold door the frame probably won't be in contact with the concrete, just a big wide rubber gasket.

Hey Jason I have the same question, are you sure it's not the door frame or building that's the issue. I have a couple of long levels if you need them. Call when your back out and I will come over.
 
I would try...

... a water level and plumb bobs... They will give you a highly accurate measure of how things really are that you can share with the contractors and then expect them to make it all square within say, a quarter inch.

Jerry
 
Paul - you are totally correct... the problem lies somewhere between the GC and the concrete contractor... I was just looking to see if anyone has any solutions that I have not thought of, as they appear to be having a hard time finding a contractor to grind down the unlevel concrete.

The longer it sits the worse it will be. I am with others - a contractor issue - even if they have to hammer it out and repour. Just make sure if they do a section it is properly tied into the parent, so you don't get shifting later.

Man - I hate then these things happen. :eek:
 
First I would say to make sure that the issue is understood. You seem to have a handle with one direction, directly under the door, how about in the perpendicular direction, see how far into the hanger it it is. If it is just a foot or two, probably cut it out, but that depends on if it part of the footing. If it is part of the footing, I would say float it out. They can use a smaller aggregate with fiber for strength, and then have them paint the entire surface with an epoxy based paint for appearance. The codes are different in different parts of the country are are generally driven by soil type. In my area, the soils can be very expansive, alluvial, with moisture. The changing moisture of the soil will be non-uniform, and can result in foundation issues if you break the continuity of the foundation (by cutting it out). Alluvial soils expand and contract with moisture content. So it depends on if the slab is part of the structure, how much steel was used in the footing, and the local soil conditions. If it were me, if it is part of the structure, I would float it out. If is just a slab on top of a structural footing below, I would cut it out. Grinding the area down is acceptable in both cases. One advantage of grinding it down, if you have a blowing rain and water seeps under the door, it will drain out with the slope that was ground into the floor.
Also use a laser level to figure out what you have, they can be a cheap as $20.
 
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First I would say to make sure that the issue is understood. You seem to have a handle with one direction, directly under the door, how about in the perpendicular direction, see how far into the hanger it it is. If it is just a foot or two, probably cut it out, but that depends on if it part of the footing. If it is part of the footing, I would say float it out. They can use a smaller aggregate with fiber for strength, and then have them paint the entire surface with an epoxy based paint for appearance. The codes are different in different parts of the country are are generally driven by soil type. In my area, the soils can be very expansive, alluvial, with moisture. The changing moisture of the soil will be non-uniform, and can result in foundation issues if you break the continuity of the foundation (by cutting it out). Alluvial soils expand and contract with moisture content. So it depends on if the slab is part of the structure, how much steel was used in the footing, and the local soil conditions. If it were me, if it is part of the structure, I would float it out. If is just a slab on top of a structural footing below, I would cut it out. Grinding the area down is acceptable in both cases. One advantage of grinding it down, if you have a blowing rain and water seeps under the door, it will drain out with the slope that was ground into the floor.
Also use a laser level to figure out what you have, they can be a cheap as $20.

I don't know jack about construction, but if they cut out a section, could that provide a path for moisture to enter the hangar (and result in corrosion of the airplane)? (Just asking because we have some hangars at our field with serious moisture/efflorescence issues...not mine, thank heavens...)
 
Floor construction.

Most good foundation repair companies can analyze the entire floor with electronic levels to a tenth of an inch that will map out the floor and tell whether it is level, high or low in any area.

If the floor is new construction it is a lousy pour. If it is existing construction it may have moved. Texas soils in some areas heave and sink routinely unless measures are taken during the pour, especially if the floor will carry heavier loads.

The floors can be cut, ground and/or polished to alleviate some issues. Other wise a small tapered piece can sometimes be attached to the bottom of the door to make an even seal. Not the best esthetically but it will be a better than a huge gap at the bottom.

My bet is your contractor did a less than stellar job. With the laser equipment they have now, getting a floor even and level is not that hard.
 
Levelling compound

This doesn't seem to be mentioned yet, but you may want to check into a levelling compound. I'm no expert on the subject, but I have seen it used in projects I have worked on. It's a fairly soupy concrete mix that is poured on the floor (after the concrete base is preped) since it's quite thin, it fills in the low spots quite well. From what I understand it can be quite tough.

It may be a solution to jack hammering, it may not. Just something to check into
 
Jason,
Having worked in the architecture field for 35 years (10+ of those designing hangars for the aviation industry), the first thing I'd do is check that the hangar door is plumb, square and level. It doesn't happen often, but they can get hung otherwise. If the door is plumb, square and level, then the contractor has some grinding to do. I like the grind/polish idea stated earlier...it makes for a nice finished look.

Best of luck with getting it fixed!
 
Jason,

Jason I have many years experience with concrete and construction. First if you hired this poured the contractor should fix it, but don't settle for 2nd rate. I poured my hanger in Wyoming about 4 years ago, did it myself but we had a bad batch of concrete. I made the concrete plant pay to have a section about 20'x20' removed and repoured.
You can rent grinders and grind which will take a long time with as much as you are talking plus they will hit you supper hard on cost of the disks for grinding.
A couple bad points about grinding if you don't do all of it will look funny, most people may not notice but you will, 2nd is that when you grind it takes away the sealed part of the concrete and they can reseal it with a chemical but the chemical they use will not stop oil and other things from soaking into your concrete.
I just talked to a specialty concrete company about this about 2 month ago because I just built another hanger in Alaska and we just poured concrete in September.
You need concrete cuts in your concrete anyway for expansion. My suggestion is to mark out the bad area, cut it out. Drill for #4 bar to go into the old concrete and pour new concrete. The #4 bar will tie thee new to the old and will prevent any uplifts. You might already have your concrete cut if you take out cut to cut nd repour. You will be much happier with this if it is your concrete that is low. You can add special patch but I would stay clear of that method if possible.

Good Luck.
 
I spoke with contractor today and he assured me that they checked door and it is square and level.

My understanding is that the concrete contractor will begin grinding the area that is higher in the morning.... They will be painting/sealing the entire front 10' or so of the concrete to hide the area that will be ground down..... hopefully this will work.
 
I spoke with contractor today and he assured me that they checked door and it is square and level.

My understanding is that the concrete contractor will begin grinding the area that is higher in the morning.... They will be painting/sealing the entire front 10' or so of the concrete to hide the area that will be ground down..... hopefully this will work.

Another option, as opposed to grinding, would be to float up the low area, or level per se. As mentioned earlier the issue may be more global than just at the door threshold. http://www.ardexamericas.com/sp/Documents/TechData_En_K15.pdf

At this point whether it is ground down or leveled up, it will look like poo if they only address the first 10'. I think an epoxy painted floor over the entire hangar is in order ;) Or at least a pigmented sealer.
 
Cut It Out

Cut it out and pour it again. The paint/sealing idea may look good initially but in the long run you will be unhappy with it. Especially when you get gas and oil dripped on it, and worse yet, rubber tires rolling across it. Haven't found many products that will not lift under this kind of use and then it will look really bad.

Do it right and cut it out...
 
Sorry to hear of your problems. I would definitely not cut it out if it is stable. This may be to $$$ but what would be really nice is to put a self leveling overlay on it. This would provide you a very level surface that is also very hard like 5000 psi and up.There are several products out there like Ardex, Rapid Set TRU and many others. The main thing is to get someone who really knows how to do overlays. There are plenty around the DFW area. And if you want to polish it you will have a very nice floor like in many stores. You can also stain it. http://www.ctscement.com/rapid-set-tru-self-leveling/
 
Have the Contractor use a transit / level, measure the floor, you will know from the measurements if it's the floor or the door. My guess, it' s the floor.

rv6bldr
Retired builder, I have built a few 1000 + houses the past 40 years.
 
floor

I would do the overlay and cap it off right next to the inside of the door were it is a half to three quarters higher and let the bottom of the door sit lower than the cap so no water can run under the door and inside.
Bob
 
Only seeing as much as you can show and describe in your post, I would lean away from messing with trying to level the concrete. Going the way of adjusting the door/door frame and/or adjusting with the bottom door seal would be how I would study it.

Cutting/grinding the concrete may be a solution but only in a strip that coincides with the seal area of the door frame bottom.
 
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If it was me, I would have them saw cut the perimeter of the bad part, remove the slab and repour it. Every other proposed fix on this post is a bandaid that will save the contractor money now, but will cost you headaches and money in the future. You are paying for a new concrete floor installed correctly, that is what you should get.
 
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I'd shy away from trying to float and level. Nothing I've found works long term and it will eventually separate. I run maintenance ops for a large retail business and have had no luck, especially over large areas or has much traffic/usage.

Grinding is an option. How thick is the slab? Three quarters of an inch could be a significant percentage of total thickness. Less total thickness weakens the concrete.

Best solution is cutting out and repouring. Drill and pin with rebar every 12-18" to ensure the sections are well tied together. Ensure base is proper for the soil type and compacted prior to repouring. Ensure control joints are cut within 24 hours of pouring to keep cracking within the cuts. Control joints should be on a rule of three. Four inches of concrete should have control joints cut no more than every 12 feet (4 inches times 3, scaled up to feet). Six inches, 18 feet. Personally, I never go less than 15' and prefer 12'. Thicker concrete can also make up for lots of other errors.
 
Grind concrete floor

My hangar has a 12' x 10 foot area that was ground down by some method, long before I got the hangar, to remove a hump in the floor. Who,how or how much I do not know, but it worked well. It is flat in those areas and does not hold water.
 
If you have it ground down you are reducing the cover on the reinforcing steel, that is assuming it is reinforced. You are also reducing the thickness, neither of which is a good idea. With it that far out of level I would assune the contractor who poued it was not competent and would not assume that the depth was correct or sufficient.
Topping is OK but you end up with a thin skin, which is difficul to bond to the existing surface. Before long you could have drumminess leading to surface failure. Cut it out and re pour, with dowel rods into the adjacent slab.
 
Hey - we are just a few weeks out from moving into a new home at the airpark in Pecan Plantation. However, we have run into a minor snag with the hangar that we are having built. In the pic below, you can see that the concrete floor rises as you move to the left... it looks like for whatever reason the last 10 feet or so is 3/4" higher than the rest of the floor. The rest of the floor to the right (which you can't see in the pic) looks to be level, as the gap appears consistent.

We are working with the contractor to figure out a solution, but they are coming up blank, so I figured I'd turn the the VAF experts. Is there anyway to grind down the last 10' or so by the required 3/4" to get things back to level?

If not, what is the least bad approach to fix this? Jack hammer it out down to 6" and repour?... entirely cut out that section and repour?

Thanks,
Jason

cuypd.jpg

What did you end up doing? I just poured 3 hangars and was thinking about painting the floor just to make it nicer looking.
 
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