http://ths.gardenweb.com/discussions/2256276/how-long-should-foundation-concrete-cure?n=48 long discussion but heres a quote: macv Concrete does not actually harden by "curing" nor is there any point in time when concrete would be considered "cured." Concrete naturally hardens over time by "hydration", the chemical reaction between portland cement and water in the concrete mix. "Curing" describes a procedure that an installer may choose to use to insure more complete hydration of the portland cement (and therefore greater concrete strength) by controlling moisture loss during the critical early part of the hydration process (ie 3 to 7 days). In the case of a residential footing curing might consist of simply covering the concrete for 3 days. In any case the curing procedure would not normally continue beyond 5 or 7 days depending on the temperature of the air. 28 days has nothing to do with the maximum strength of concrete; it's just an arbitrary time chosen because the strength gained after that time period is normally not important from a design point of view and there has to be a standard measuring point in order to allow enforceable specifications and uniform strength testing. As long as moisture and a favorable temperature are present for hydration of the cement, the strength of new concrete continues to increase long after the early curing phase and the 28 day mark. Since the actual strength of the concrete in a residential footing is not particularly critical, testing is not required so the 28 day mark has no practical relevance in the field. In fact, if the concrete hasn't reached the minimum strength required by code in 7 days, it's unlikely to get there. The IRC requires a concrete footing to have a minimum compression strength of 2,500 psi which is a low value and easy to achieve (most specifications would be higher). If a concrete footing is reasonably protected for 3 days, it should have reached 70% of the minimum required strength and it should reach 100% by the 5th day. A lot of what they talk about is if the concrete is cured enough to continue construction on it. The general consensus in that thread is that it takes 2-3 days before continuing construction but I personally would wait at least a couple weeks if not a month in your application so extra moisture may release before the floor is laid. My biggest concern is with the moisture of the new slab affecting your floor. Any moisture that gets in engineered flooring will ruin them and cause expansion/buckling

I routinely design installations with floors well over 1" out of true in 12'. I've had 1" in 6' happen. That's the reality of old houses! There are ways of doing this that do not impact the overall look. Designing the toe with extra room to be scribed to the floor is one way that works if you are creating a custom installation that features design details at the floor level. It does require extra skill from the installer, as it all rests on his shoulders to make happen properly. It's the same for the crown. If there is some sag in the ceiling, using a multi part crown, and planning for some drywall mud as well will disguise it to the human eye. This room is off 1 1/2" from one side of the kitchen to the other. Because the wall cabinets are in 3 separate sections, and the molding is a 4 part crown, and we fudged the backsplash spacing a bit, we were able to disguise it to 98% of the people that see the install. Without using custom cabinets, the only way to disguise the base cabinet issue was shoe molding, and a custom cut toekick to hide the shimming. If this were a custom cabinet line, that would not have been needed as m custom cabinet maker could have scribed everything to fit and then made custom toe details.

Thank you HerrProfessorDoktor, I am glad you are letting others know about the issues you are having. It is too bad you regret the dark, perhaps you could restain them lighter in the future? I am very fortunate as I have had dark hard wood floors in my last house and plan to install them again in this house. I love the look and had no regrets last time with care so I think I will be okay. However, I do think it is wise of you to post as there are others who may not know the challenges of dark hardwood floors looking pristine. A rumba is always is a nice little feature to help with much of the dust. ~boxer Here is a great link / poll that talks about this topic. [light or dark hardwood[(https://www.houzz.com/discussions/poll-light-or-dark-hardwood-dsvw-vd~5047868?n=235)

As ever, the answer will be found in your choice of product and the value of your home. And location. And install....and...and...and...Sigh. You get the point. In an area where engineered hardwood is the NORM (Mississippi flood plain), then it would be unusual to see solid hardwood (and if you know anything about flooring it would be a MASSIVE worry for the next home owner). If you are in an area where solid hard woods are de rigueur then engineered hardwoods *might pose a concern...but might not. The actual value of your home is something to consider as well. For instance a $1.4M home in NE USA would be a place you would EXPECT to see solid hardwood (and something stunningly beautiful at that!). A $3.99/sf Home Depot product installed into a mansion in Boston would be a poor investment choice. The revers is also true. A $200K home in the middle of nowhere would not benefit from a $15/sf solid European Oak hardwood. The amount of money put into the floors would never be recovered with resale.