Dr. Mor & Associates

I am not good at all with concrete but i must pour a concrete pad to enhance my driveway. I want to extend it to make a basketball court for my kids. I can not afford to have it done so i must do it myself. My father can make the forms but how do i go about leveling and ordering the concrete? How do i start this project and do it right? Can you help. Thanks

A few points:

1. You should order concrete with at least 2000 psi, but go for the 3000 psi if the price is ok. You tell the ready mix company what you are going to use it for and they will know what you need.

2. Make sure you pour the concrete in separate sections. No more than 15'x15'. Even better if you can go with the 10 or 12 feet. This is very important for crack control. You can also pour it in one large section and cut it later, but that takes more experience.

3. Level the ground, wet it and keep moist up till the time you pour. This will keep the concrete from drying.

4. If you plan to drive over it you may want to use steel reinforcement in the form of wire-mesh. Make sure you place it in the middle of the slab and not lying on the ground.

5. You can use a straight 2x4 over the forms to level the concrete. When it starts to dry you can use a trowel to make it smooth, or rough broom to give a non-skid finish.

6. VERY IMPORTANT - start wetting the concrete after 4-5 hours (or sooner if it looks hard and dry) and keep it wet for 3-7 days. The longer the better. You can cover it with wet burlap or plastic to make sure it stays wet.

These are just some of the important points. You should either find someone who has done that before to help you, or go to the library (or book store) and check one of the many books on "Do-it-yourself" projects. You can get good step-by-step instructions for beginners

I am currently involved in a project to create a office type building. After examining the site, I found the building is to be place on 4" thick asphalt. The building is 112' x 40' x 14' high, steel 2x6 channel frames at 16" centers, probably vinyl exterior. To prevent this building from blowing away in a storm, we are considering having concrete footings in the asphalt. In these concrete footings, we will drill a oversized hole, fill it with epoxy, then insert an all-thread bolt that will be used to foundation the building. For 100% strength of a 5/8" diameter insert, we need to go at least 5" deep into the concrete. I have no idea the number of footers required or the size. Is there some type of standard I can use, or how would I find the answer to this question? Thanks for any help you can provide.

From your letter it sounds like you are concerned only (or mainly) with overturn forces caused by wind. This is a relatively simple problem for any structural engineer. They have tables that show the expected wind forces at any location and from that - and the dimensions of the building - they can calculate the expected loads. These loads will then determine the number and distribution of anchor bolts. The tables themselves can be found in the UBC or better still, ask at your city building department what standard wind loads they recommend using for your location. By the way, why drill and epoxy? Why not insert standard anchor bolts into the fresh concrete the way we do here in California for earthquake anchoring?

Many driveways that were going to have texture sprayed on have many random cracks. (hairline --1/2 " wide). I would like to know the best way of patching these cracks. to minimize reoccurrence through texture.
Thank you very much

I would need more information. Are these concrete driveways? What distance between cracks? When did the cracks appear? Do the cracks keep growing or are they stable? What type of texture coat are you talking about? Where are you? What is the weather like? Is it freezing? large temperature differences? How is the soil? Expansive? Whatever you know will help. NO FURTHER RESPONSE FROM THIS PERSON...

I don't know if this is something that is in your area of work, but if it is not maybe you could direct me to someone who can help. We have a driveway at our home in Lake Arrowhead that is about 6 years old, approx. 25' x 35' and is sloped. The driveway has developed many cracks. I am wondering if the driveway was built to code, there are no expansion joints.

From your description this is a very simple case of not following the rules (and codes). ACI (American Concrete Institute) recommends joints at 10-15' max. (depending on thickness and strength of concrete). If you do not do that, you can expect cracks where the joints should have been (and some extra). If the concrete was not cured and protected correctly during the first week, it could explain some additional cracking.

I am a small developer. Constructed a road on steep terrain which has developed large 2-3 inch cracks along one section on the fill side which seems to follow the underground utility trench line. The road has been down for 4 years & we have continuously patched before each winter; however, each time we patch, the cracks reappear and become wider. A visual inspection and probe reveals that the cracks are fairly deep, possibly 2-3 feet in some areas. Also, some sections of the crack area seem to be subsiding. We have done some investigative borings to rule out a water leak. Could this possibly be a compaction problem. All work was supervised by a qualified soils engineer and completed by a qualified contractor. Would appreciate any input you can supply. Thanks,

From your description it sure sounds like a soils problem. As far as compaction is concerned, the practice in my area is that the soils engineer specifies a certain compaction level (90-95%), and a qualified inspector verifies it during construction. If that was not done then you may have a problem that should improve with time (if you keep repairing) and eventually go away after the soils compact naturally. Is it possible that you have a slope failure on the side of the road? Probably not, because that would have been the most obvious thing to check. You may need to retain an experienced Geotechnical Engineer to do site investigation, if things do not improve soon. Actually, you may want to do it ASAP while the original soils engineer and contractor are still around to fix their errors (if any)

My name is EE and I am an Aerospace Engineering student at the University of Texas at Austin. I am doing a feasibility study for a civil engineering technical communication class. I am comparing the use of concrete and asphalt for the reconstruction of a tennis court. I have discovered that the soil on which the reconstruction is to take place is very expansive(35% ferris soil). I was wondering if you could answer a few questions to help my comparison? 1. Can you estimate the average life expectancy of a concrete tennis court under normal conditions? How about under soil shifting conditions? 2. Can you provide me with a rough cost estimate for a concrete or asphalt tennis court? 3. Would you expect a concrete court or an asphalt court to perform better under soil shifting conditions? why? 4. Have you ever encountered a similar situation, what decision was made? why? 5. Can soil swelling be combated by certain construction techniques? 6. What type of concrete would you recommend for a tennis court? 7. Could the type of concrete be changed in order to decrease the likely hood of it cracking in soil expansion conditions? Thanks a whole bunch for your time.

Most of your questions require more time and space than I can provide here, but I will try to give you some guidelines and direction: 1. I don't. I doubt that anyone can do it accurately. Usually the main issue with asphalt erosion is water and traffic load. From economical standpoint it is common to use 15 years for asphalt pavement (not tennis courts) after which you need to either redo it, resurface, or replace). Serious soil shifting could cause the court to be unusable after a few months by creating cracks, bumps, and uneven surface. Asphalt has no resistance to these stresses. 2. No. That depends on market conditions. Tennis courts are very specialized work and will require a premium over normal pavement costs. 3. Depends. Concrete can be reinforced so it does not crack. Asphalt will flex and move with the soils. If done correctly, concrete (reinforced or post tensioned) will outlast asphalt without maintenance or damage by a factor of 3-4. However, you can expect the cost to probably be higher by similar factor. A lot also depends on soil preparation, proper base, proper compaction, pre-saturation... 4. Not with tennis courts. 5. Not easily. You should provide a properly graded and compacted base under the court and make arrangements to keep water content in soil constant. That can be done by either preventing water from getting there, or by making sure that it is always saturated and fully expanded. The changes are what causes the damage. 6. Any good quality material will work. I would recommend using the conditions for concrete exposed to earth (maybe sulfates) - water/cement ratio of 0.45 and type V cement. 7. Only by providing reinforcing, preferably post tension. A post-tensioned court will be more expensive, but will be the only way to assure performance. You are welcome

Thanks for your quick response. You are very helpful. If you don't mind my partner and I would like to list you as a reference in our evaluation.

I have a newly poured large concrete driveway (it took 79 cubic yards). The concrete is 4,000psi, 6 inches in thickness, with wire, and in the first section poured fiber was added, along with rebar. The concrete drive sits on 6 inches of washstone and the soil (clay) is properly compacted. The contractor poured one large section 3 weeks before the remaining drive was done. The first section poured had about 6 inches of rebar extending to tie the next section in place. A control joint was place right at where the two sections joined. A small hairline stress crack goes the entire length of the control joint, and is about 1/8" actually from the control joint. I understand from reading some of your other A&Q's about the rebar canceling out what the control joint's purpose is to be for. My question is the new (last poured sections) concrete is four days old, we are keeping it watered down, and we are not driving on the driveway for a full 30 days - can a new control joint be sawed at this late date past where the rebar is, without any harm of additional cracking? The other cracking situation existing is at another control joint near the end of the driveway -- because the contractor stated the section was not cured enough a control joint was not sawed until 36 hours after the pour. The contractor said the crack would need to be opened and repaired. Does this cause that section to become weaker because of this crack and then a repair - or should this section be completely sawed through - removed and new poured? One more question - the first section has some real defects in the finishing. You can see real bad uneven marks from the trowel machine, light footprints, etc. Is there anyway these marks can be taken out - like sanding the surface or? Your comments will be of great help. suggest: None - Your site is wonderful - full of great information. Lenoir, NC

First, I am glad that you found earlier answers relevant and educational. It really sounds like a case similar to the earlier one where the extended rebars caused a problem. * Control joints can be added at any time to minimize future problems. I am not sure why you want to cut it past the rebar. If the joint spacing is correct, I would cut at the joint through the rebars. For the diamond-blade saw, cutting steel is as easy as cutting concrete. If the bars were placed in the center of the slab then all you need to do is cut through them and stop.* I tend to agree with the contractor that a hairline crack can be routed (opened) and repaired later. If it remains hairline I would actually leave it alone. * Repairing a crack like that should not create a structural problem but will be very visible. It will probably come to a matter of taste. * Surface defects can be removed by grinding. The same company that does the cutting will have the equipment. You need to realize that this area will look very different after grinding - you will see polished aggregates instead of the uniform grey finish of concrete. Even if done very lightly so that aggregates are not exposed the surface will still look different. * One last note - After the concrete stabilizes (1-3 months) seal all the joints with flexible compound designed for concrete joints. This will keep water from getting through the joints and causing problems with the soil. And the standard admonition - this answer is only as good as the information you gave me...

Thank you, for your quick response -- The reason I asked about a new control joint below the rebar is, the concrete in the first section poured is very thick (greater than 6") on one side that joins a retaining wall and near the center - and the new section that joins this first section starts a major slope downward in the drive. This new driveway came about because the original contractor on my house did poor to no compaction under the drive and when I say no compaction - (I bought the house new but was already finished) that is true because it was like going through butter when they did the soil removable (24 feet down) the soil was wet and had to be dried, and then properly compacted. I also have a large retaining wall that joins at the corner of my house (13ft high, 52ft length) that was damaged and repaired, as well as damage to my exterior garage wall (retaining wall moved garage wall outward) - the current contractor anchored the retaining wall (did over kill on this which was great) and then tied the retaining wall also into the driveway with rebar. The house is cement block, with full brick veneer over it. This has been a $40,000 repair job. I don't want any water to get under my driveway after what we've been through - so cracks make me feel very uncomfortable since they can be a source of water getting in. For as large as the driveway is, and to only have two cracks - I guess I should feel lucky. The crack at the control joint where the rebar is stayed pretty much in line along the control joint. The other crack down near the end of the drive - cracked as he was putting the control joint in and shoots across that section at an angle and does appear it is all the way through the cement. I say hairline - the first day it was hard to see - but now I can see it very plainly so it has opened some - however it is still a small width crack. As for the finishing -- I thought only the first section had surface defects but looking last night with lights on the driveway I really could see a major part of the driveway is terrible - not so noticeable during the day - but at dusk with lights on you can see it very plainly - even foot prints. The trowel machine marks are deep in some places. I thought - we go through all of this repair and everything went great and then at the end I ask how could they be so careless. I'm happy with most of this project - but the driveway is a major part of the curb appeal to a home today - and I would like things to be as a they should be. I also would like to have the expense to the contractor to be as small as possible. That is why I asked about grinding or sanding the surface defects out. I wanted to do some type of edge design to take away this sea of concrete look - which I could afford to do but to stamp or spray over this entire drive would be more cost than I could afford ($12,000 - $18,000) and again, I ask - why should I have to to fix something such as a bad finishing job. Also, if control joints can be sawed at anytime after - why am I seeing so much information about a window of time (6-12 hours) that control joints should be put in. The cracks did not exist until they started to saw the joint after 36 hours. The other joints were put in within this 6-12 hour window. Are you saying, the time limit does not matter? Thanks for your response -- and yes you have one of the best and most informative web site I've seen - just wish I had found you before the project was completed.

Are you suing the original contractor? If not yet and if the house is less than 10 years old, I suggest you get all your records and see a good lawyer who specializes in construction defects. - the reason for the 12 hour window for joint sawing is to provide the joint before the concrete shrinks enough to crack, but after it hardens enough to support the saw and keep aggregates from being torn out. In your case this process is over, so a joint can be cut any time. This joint is not meant for initial drying shrinkage, but for future fluctuations caused by temperature and humidity changes.

I'm headed in that direction - however North Carolina has a 6 year statute of limitations on going back on the contractor. I bought the house in 1993, but the problem did not surface until 2001-2002. I may still try to pursue this - as fraud - because he held the highest type of contractors license NC has, and he simply did this to avoid cost -- he knew it was going fail - within time - there's no way he could not have known -- I did video tape as they removed the soil and all the huge rocks, construction junk, etc that was also sitting under the driveway. I just shake my head as to why a contractor would do this and I surely would have paid more for the home - what little money he saved - turned into a major expense to me. Thank you again for the info and the update.

I am a Gen. Contractor and hired a licensed grading and paving contractor to do a very large drive (14'x65' + 14'x45'). There are two cracks that are the width 14' of the drive and go right through to the soil. Pour is on native soil, compacted and he did use wire in pour. He says "cracks happen". Well they did happen two weeks after the pour. No one drove on them. Either I need a little education on concrete, or he does. So, whats the basic reason for these cracks?

Crack 'happen' when people do not follow the proper procedures... The reason concrete cracks is usually "drying shrinkage". Concrete is poured wet. As it dries and loses water, its volume decreases (it shrinks). Small amount of shrinkage results in "microcracks" that are not visible to the naked eye and do not create a problem. Larger amounts (which is normal) can result in cracks. To avoid cracks we try to use concrete with less water (less shrinkage potential). This is done by reducing the water/cement ratio through the use of admixtures, or increasing the cement content (both increase the cost). Higher strength is also achieved by these changes, further reducing the cracking (the concrete is strong enough to resist the stresses). Try to imagine the concrete is a very stiff rubber band. When it shrinks, the band is pulled and stretched. If it is not strong enough, it will break. If it is stronger, it will stretch without breaking. Keep stretching (drying) and it will eventually break. Another contributing factor will be the curing of the concrete. Curing is a process of keeping the concrete moist for as long as possible during its early days. As you probably understand now, keeping it moist will reduce the drying part at the early age when concrete is weakest. Drying that occurs later, after it gained more strength, is less likely to cause cracks. A rule of thumb (another one) is that concrete should be kept moist and protected for 7 days or more. Since cracking may not be avoidable, we must use joints in larger concrete elements. Joints are basically pre-created cracks in the concrete. We place those in straight lines at locations that are acceptable to us (sometimes as decorations). A rule of thumb for joint locations on a driveway such as yours would be every 10 to 14 feet, depending on the thickness of the slab (the thicker it is - the larger allowed spacing). When shrinkage is the cause, the cracks will develop between existing joints. If a crack develops near the joint it may indicate that the joint was not done properly and does not relieve the stresses in the concrete. Wire mesh has very limited ability to reduce cracking, even when it is placed in the center of the slab. When located near the bottom of the slab (as we see often) it can be practically useless. That's it in a nutshell...

I have an increte walkway and a white chalky substance is appearing. The walkway is sealed and it appears that it might be under the seal coating. someone told me that it could be moisture coming to the surface and being trapped under the sealer and that when things heat up and dry out it should disappear. what do you think? new york city

That explanation is not very clear. IF it was sealed to the point that moisture cannot pass through, then the white substance (efflorescence) would not appear. If it can move through, then the powder would appear on the surface. Besides, when moisture gets trapped under a sealant it will cause it to fail by de-bonding. That is why these sealants are designed to "breath" and let vapors pass through. Efflorescence is the result of moisture moving through the concrete and evaporating from the surface. Salts that are drawn from inside the concrete crystallize on the surface. Under a magnifying glass you may see the crystals. Drying does not make it go away. You can brush it or wash it away, but it will return as long as there is moisture in or under the concrete, and the top surface is exposed to dry air. Efflorescence is not considered a problem beyond appearances unless there are Sulfates in the soil in very high concentration. I really doubt that it would be a problem in your case. I am not familiar with the Increte brand name.

Dear Sir, We just had a new concrete driveway put down. 45' X 18' X 4" thick / Wire reinforcement ( 270 Cu. Ft.). They made the surface rough for safety. What can we put on it to protect it from oil and water and etc and make it last a long time. They put on a water sealer. We live in INDIANA. Thank you very much for your help. D. D. H Richmond, In

D., Good quality concrete should not require additional protection. Water, for example, is good for concrete. The longer it stays wet the stronger it will be and less chance of cracking. Usually, the water sealer the contractor uses is intended to keep the water in and not to prevent new water from penetrating. For appearance you may want to color it, but that is best done during placement. Oil is a different story. It will not damage the concrete, but will create dark unsightly stains that are practically impossible to remove. So, the purpose of the sealer is more to keep it looking good and not to make it last longer. A couple of things that can harm the concrete are acids and sulfates. This (photo) is what acid can do, but you need long exposure to high concentrations. Sulfates in the soil can damage low quality concrete exposed to very high concentrations for many years, but surface sealers will not protect against that. For a list of available products and uses go to my "LISTS" page and run a search through "BUILDNET" for "concrete sealer". For long service life you need proper joints (up to 10 or 12 feet apart) and good long moist curing. And for your peace on mind you may want to view imperfections on the surface as adding "character" to the concrete

Hello, I have a concrete problem... I built a new house last year and the last thing I had done was to have my driveway concreted so there would be no heavy traffic on it. We actually moved in and lived here nearly a month before it was poured. It was poured in June of last year. The Problem: About 30 days after it was finished (have photo's on July 4 1999) I started noticing cracks 1 to 2 inches from the expansion joint. it continued to get worse and then I noticed larger cracks (at a different location) 10 to 12 inches from the joint which now has started showing 1/2 inch separation. It's now chipping out in small rock like chunks. I paid "extra" to have a better grade of concrete. Instead of the standard 3000psi mix in this area. I elected to go with the 3500psi. I have 2X4 treated expansion joints. I have 1/2 inch rebar on 2 foot centers tied and lifted up into the center of the concrete before finishing. The contractor notched the 2X4 and let the rebar run into the next section about 1 foot. I expected some hairline cracking in the future but nothing like what I have. I can e-mail photo's if this would help... I have laid awake at night wondering what to do about this. It's a shame to work hard and sacrifice for 5 years to save to build our dream home to have something like this to happen. I don't know who's responsible, the contractor, the concrete plant, or NO one? I didn't have any idea who to call. I called the contractor right after I started noticing the cracks and he stated that he'd come by and look at it but I never heard from him. I would appreciate any advice or direction you can offer. Can it be repaired? I have put this off long enough because I was afraid I'd have to file suit on someone to get something done, but I am about ready to do anything I need to because If haven't found peace with by now I probably never will Thanks, BG.

Sorry to hear about your troubles. Sounds like something is wrong... A few points: 1. What is the spacing between the joints? 2. How much wet curing did the concrete get? 3. Whose idea was it to extend the rebars through the joints? Does he/she have good malpractice insurance? Sounds like that was one of those "the way to hell is paved with good intentions..." You did everything right (strength, rebar, joints...) and then negated the whole thing by extending the rebar through the joint. It practically canceled the joint. Any time we want to extend reinforcement through joints we use smooth dowels, greased, so that there is no bond to the concrete. The fact that the cracks started next to the joint points this way. Nature needed a joint there, and since you canceled the original one, it created a substitute. As for what to do. If the concrete can be salvaged, you should hire a concrete cutter, and saw the joints through the rebar. Once you do that you can patch the cracks. If the damage is already too large you may have to remove and replace. Remember that my analysis is based on your description. There may be other things you missed. Feel free to send me that photo and any other information regarding your location and the questions above. Good luck,

WE ARE GOING TO BUILD A HOME ON A CONCRETE SLAB AND WOULD LIKE TO KNOW HOW DRAIN PLUMBING IS DONE?

I am not sure what you are asking. Usually, these lines are taken through an outside wall, but it is possible to run drains under the slab. In many homes you will find drain clean-outs in the garage, with the line itself 1-2 feet below. As long as you seal the penetrations well (tricky) you should be OK. Ask a plumber?!

had a new driveway poured and it has small mud spots come up in the surface. could this be caused by the concrete co. getting mud mixed with the concrete mix? any help would be app. thanks

YES. This is too common, and in many cases creates a real problem. These "mud balls" that get mixed with the concrete will dissolve with time and leave holes in the concrete. In some cases I have seen holes large enough to cause people to trip. Usually, these holes do not present a structural problem - the driveway will not fail - but it looks bad and could serve as a starting point for chipping or cracking. In some (rare) cases, large mud balls trapped under the surface may actually reduce a cross section of 4-5 inches to 1-2 inches. In these cases it may cause failure of the concrete in the future, but be invisible originally. Depending on the extent of the problem you may have to ask your contractor to repair his work. A good start will be to use high-pressure washer to remove all the mud from the surface. Once that is done you may be able to estimate the extent of the problem. In simple cases it is possible to grout the holes with "rapid-set" grout or epoxy grout. Just make sure the holes are clean without weak pieces. In cases where the holes are extensive, and you suspect hidden mud-balls you may have to remove and replace the concrete. Where are you? Good luck,

Thanks for the information on the mud balls in the concrete driveway . I believe this to be caused by the concrete co. not the finishers but the concrete co. denies this is their fault. i live in Cartersville, GA. about 40 miles north of Atlanta, GA. I have had a computer about a month and am just learning to use it but I sure do thank you for the information. do you know anyone in this area that I might contact about this problem if I need someone to look at this driveway. thanks

I am sorry, but I am not familiar with this area.

I have a sidewalk that has separated from the stairs leading into the house and has sunk about 3"-4". The sidewalk is in good shape, except for this problem, and I was wondering if there are contractors out there that could raise the sidewalk to its proper height? Another idea is to demolish the two blocks of the sidewalk leading from the steps, put in additional soil and compact, and re-pour these two blocks. Do you have any suggestions, or should I start over from scratch? Thanks SW, Laurel, MD

I am not aware of anyone raising sidewalks. It is simpler and cheaper to R&R [remove & replace]. Matching new concrete to 5 years old is practically impossible. Concrete appearance changes as it matures. I suggest you talk to the builder. The law gives you some rights beyond the 1 year period. A good builder will fix his errors. You may also consult an attorney for advise. However, that may be too much hassle and not worth the time and effort...

Thank you for your prompt response. Your assumption is correct, the sidewalk is the walkway leading to the front door of the house from the driveway. Our home is about 5 years old. Other homes in the neighborhood have experienced the same problem with the builder fixing it at the one-year point, so appears to be a local problem. There are no other symptoms like those that you mentioned. Unfortunately, we bought our home as a resale and it was an existing problem. Question concerning raising the sidewalk. What is the technique they use and why isn't it as good as remove and replace? It would seem to be similar to a hypothetical situation of lifting the sidewalk, putting more compacted soil underneath, and replacing(?). With repair and replace, is there a method to use to try and get the concrete to match the other (texture/color)? Thanks, S

When you say sidewalk, I assume you mean the walkway on your property and not the public sidewalk. I also assume that the landscape around it settled the same way. Raising the sidewalk is not a good idea. These are usually made of un-reinforced concrete that will not take such stresses. It will probably be as expensive to do it right as to start over. The R&R (remove & Replace) option should work fine and should not be very expensive. Make sure that the new soil is compacted well and wet before placing any concrete. Another option to consider is adding a topping layer of concrete to fill the gap. This may be tricky and not much cheaper than the R&R option. I, however, am concerned about the 3-4" settlement. It may indicate a serious potential problem for the whole house. How old is the house? How long before it started settling? Was there any event leading to that (such as heavy rains, plumbing leaks, slope failure...)? Are the foundations moving? I suggest you walk around the house and check all the openings (doors, windows) for cracks at corners. Any diagonal cracks starting at corners could be a sign of foundation settlement. Are any interior doors sticking? Check the gap above the doors. Is it uniform, or is the gap on the hinge side smaller (or larger) than on the lock side? If there are differences, are these everywhere or only in one direction (North-south...)? Do the neighbors have similar problems? If any of these signs are present (and seem serious enough) you should get a qualified Civil (Geotechnical) engineer to look at it. The sinking walkway may be just a symptom of a larger problem. Or, it can be just a local problem if the builder did not compact the soil under it. I hope that is the case. Feel free to contact me again with your findings. Good luck

Thank you for your advice. You were correct, a good builder will fix their errors. I contacted the builder (Centex Homes) not expecting to even receive an answer but, lo and behold, met with reps on site today and they will be fixing the sidewalk, no questions asked. Thanks again

Update 9/21/00: The sidewalk is complete. Approximately 1/3 of the sidewalk was removed, new fill brought in and compacted, new rebar installed to the entrance steps and concrete poured that matched up well with the existing sidewalk. I brought in new soil to ensure proper drainage from the sidewalk and steps and planted new grass which has started to grow. It took a few months after the start of the process before completion given the small size of the job (waited until the subcontractor was in the area doing another job) but it turned out well. Thanks for you assistance.

older home, originally 1 car driveway (concrete), widened on both sides about 15 yrs ago. The drive has sunk in a few places, especially on one side of add on...can this be fixed by adding about 2 in on top or will the whole drive need to be yanked up Texas

The situation you describe is usually related to soil settlement. Most likely, the soil under the new drive was not compacted properly before construction. Since that driveway has been in service for 15 years, it is likely that the soil reached it's needed compaction by now and will not settle further under these loads. If that is the case, leaving the original drive there to serve as a solid base would be the best bet. Two inch topping is a little thin, but may work if the base is stable enough. Make sure that the new topping is NOT bonded to the old, and that you provide cut (or formed) joints at no more than 10' distance. Preferably, match the joints already in the existing slab. I am assuming you are going to place new concrete that is at least 2 inches thick. If you are planning to "feather" it down at the edges the thin areas will likely break under load.

My new home was completed in Atlanta, Ga in January 2001. The weather was extremely cold in December 2000 and January 2001. My driveway began "flaking" soon after I moved in. It is getting worse and worse. The builder and the contractor are both trying to escape blame. What can be done to correct this problem and who is responsible for fixing it? The home builder, the contractor who did the work, or the company that produced the cement product? Atlanta

Unfortunately, the problem you describe is common in your area and especially this time of the year. The problem as you describe it could have two different causes. The first possibility is the so-called "Alkali Silica Reaction" where certain reactive aggregates and the cement products combine. The result is expansion at the aggregate surface which "pops-out" the surface in the pattern you describe. A clear telltale sign is the fact that in each hole you can see a stone. This type of reaction is very bad news. It will not stop until all the reactive material is gone - and most likely the concrete as well. The good news is that whoever sold you the concrete is 100% responsible since the codes require that they test the aggregates and prevent this problem. There are standard tests to determine if this is the case and it is done by a Petrographer who uses a microscope to look at samples of concrete. I suggest you contact the supplier and ask them to send someone to look at the concrete. Most likely they are aware of the problem by now. If they deny knowledge or responsibility you may have to hire your own testing laboratory to obtain and test a sample. The second (and more likely) possibility is "freeze-thaw" damage where water that soak the concrete freeze under the surface. I assume that there was some freezing and thawing in your area by now. It will cause spalling, but you will not have aggregate centered in each spalled area. To prevent such damage, it is common practice in your area to add an "air-entraining" admixture to the concrete. The air bubbles that are dispersed throughout the concrete allow it to absorb the expansion forces without spalling. In this case, again, the responsible party is the supplier who was supposed to add the admixture (if your contractor ordered it). The way to verify that is to take a sample of the concrete to a Petrographer who will look for these air bubbles under his microscope. I suggest you start by contacting your local Building Department and asking them about the local experience with ASR (Alkali Silica Reaction) and freeze-thaw damage. Then contact the contractor and concrete supplier and ask them to look at the concrete. Be friendly and firm - your best choice is to resolve it peacefully without a big fight and litigation. If that fails you may have to get a lawyer who specializes in "Construction Defect" litigation, perform the tests, and go after them. I don't know what is the warranty in your case but you should act as soon as possible. And keep good records. Take photographs and measure / count the spalls on a weekly or monthly basis to establish progression of damage. Legally, I believe you can only go after the entity who sold you the house. They are responsible, and they will have to go after the others who may have been involved. You do not have a contract with the supplier or the sub-contractor and they have no direct obligation to you. (But you should consult a lawyer about that...) You should also check with others in your area to see if they have the same problem. To learn more on the subject go to http://www.worldofconcrete.com/ and search the article database for ASR and for freeze-thaw. Good luck.