This is the red flag: "The sellers are aware of a leaking sliding door off of the living room which would be directly above this point, but one floor up. They said they are going to completely replace the sliding door with a contractor before sale. They are also going to fix the skylight that has a leaking issue but that is in a completely different part of the house." If they intend to correct the known problems, why are they showing the house as is? What are they waiting for? Do they plan on using the info from your home inspection to develop a repair list? Why would they let such problems persist? Have they lived there the entire 21 years? What other maintenance issues have they ignored during their ownership of this property? Think about buying a used car. After the test drive, the seller says they plan to get a tune up to fix that knocking noise before you actually buy the car. When you check the fluid levels you discover the oil is very low and the dipstick is dry. There is no extra coolant in the radiator reservoir. 3 tires are bald with uneven tread wear. Obviously the previous owner is not keeping up with the maintenance. Do not buy that car. Houses are only a little different. You can restore them. But it costs lots of money. If your heart is set on that particular house, buy it "as is" and require a significant reduction in list price in order to restore it properly. Do not trust the current owner to do it right. Without a doubt, they will have a cheap and dirty band aid solution, if anything gets done at all.

The structural engineer said they fixed all the issues so I closed on the house on Feb 1st. Structurally I have confidence in the home as it was looked over by a very meticulous city inspector as well as a structural engineer who did end up finding some things on top of what the city inspector found. The finishing work on the inside was done very poorly however. I blue taped the hell out of the house during the walk through. There were paint runs on the trim pieces and stair railing. There are some arched and crooked ceilings where they should be flat. My hardwood floor creaks because it is not flat in some areas. There's a blue halo on the ceiling where it meets the walls, might be from the painters tape. I had a toilet that felt too close to the side wall and there was plenty of room to move it over a few inches. There's too many cosmetic issues to list but I blue taped them all. They fixed few of the cosmetic issues but removed all the blue taped. They said I had to close because they had the certificate of occupancy. They said any remaining issues would be taken care of under the home warranty. Many of the cosmetic issues I can learn to fix myself and I know I'd do a much better job than what they would do. Some other issues however I'm trying to get fixed through them. Like the toilet being too close to the wall, I came to find out there's a code requirement for how close it can be to a finished wall and mine was closer than code. The builder tried to tell me the distance was measured from the studs and not the finished wall but I had already looked into this heavily and knew it was from the finished wall. He agreed to move it 1.5 inches which brings it within code. I'm not sure what to do about my hardwood not being flat. The house is level from one end to the other but within that there are high and low points. The variance is between 1/4 inch to 1/3 inch in a 2-3 foot space and is noticeable without a leveler. The builder says this is "industry standard" and normal. I might be able to get it fixed if I prove it's not, but not sure how to go about that. Are there inspectors I can hire? Would I go with this builder and do it all over again? Definitely not. And they probably wouldn't want another home buyer like me I'd imagine.

PPF: All materials have a coefficient of linear thermal expansion. Coefficient of linear thermal expansion for concrete is roughly the same as for iron which is why it (rebar) works well with concrete. Expansion/contraction is significant for long linear surfaces such as the large concrete slab with the crack OPs thread. Though there is a much more to material science, especially concrete and types of concrete, hopefully the following excerpt provides an adequate explanation. THERMAL EXPANSION AND CONTRACTION Materials expand or contract when subjected to changes in temperature. Most materials expand when they are heated, and contract when they are cooled. When free to deform, concrete will expand or contract due to fluctuations in temperature. The size of the concrete structure whether it is a bridge, a highway, or a building does not make it immune to the effects of temperature. The expansion and contraction with changes in temperature occur regardless 0of the structure’s cross-sectional area. Concrete expands slightly as temperature rises and contracts as temperature falls. Temperature changes may be caused by environmental conditions or by cement hydration (the exothermic chemical process in which the cement reacts with the water in a mixture of concrete to create the calcium silicate hydrate binder and other compounds). An average value for the coefficient of thermal expansion of concrete is about 10 millionths per degree Celsius (10x10-6/C), although values ranging from 7 to 12 millionths per degree Celsius have been observed. This amounts to a length change of 1.7 centimeters for every 30.5 meters of concrete subjected to a rise or fall of 38 degrees Celsius. Thermal expansion and contraction of concrete varies primarily with aggregate type (shale, limestone, siliceous gravel, granite), cementitious material content, water cement ratio, temperature range, concrete age, and ambient relative humidity. Of these factors, aggregate type has the greatest influence on the expansion and contraction of concrete. Severe problems develop in massive structures where heat cannot be dissipated. Thermal contraction on the concrete’s surface without a corresponding change in its interior temperature will cause a thermal differential and potentially lead to cracking. Temperature changes that result in shortening will crack concrete members that are held in place or restrained by another part of the structure, internal reinforcement or by the ground. Forexample, a long restrained concrete section is allowed to drop in temperature. As the temperature drops, the concrete tends to shorten, but cannot as it is restrained along its base length. This causes the concrete to be stressed, and eventually crack. Joints are the most effective way to control cracking. If a sizable section of concrete is not provided with properly spaced joints to accommodate temperature movement, the concrete will crack in a regular pattern related to the temperature and restraint directory. Control joints are grooved, formed, or sawed into sidewalks, driveways, pavements, floors, and walls so that cracking will occur in these joints rather than in a random manner. Contraction joints provide for movement in the plane of a slab or wall, and induce cracking caused by thermal shrinkage at preselected locations. One of the most economical methods for making a contraction joint is by simply sawing a continuous cut in the top of the slab with a masonry saw.

I would bring it up with the condo association. Amass as many of your fellow owners so you don't go it alone. Multiple locations of this kind of cracking in exterior walls points to a significant foundation or settling/soil problem