ok, this is an area where I actually know something! I sold and spec'ed hardwood for a custom shop before my mommy-life. The information you are getting here is correct. Engineered floors will give you 1-2 refinishings ON A PERFECT SUBFLOOR. One of the issues that sometimes arises if there are inconsistanies in the height of your subfloor. Because there is thinner wood wearlayer (before you get to the engineered wood) there is the chance that you can damage the floor irreparably when you sand it. Now I only saw this saw this happen twice, once on a loft job and once in an older home. The loft was more subtle as it was over concrete, the old house more obvious as they were DIYers and picked engineered flooring to try to negate their irregular subfloor (they neglected to tell us that that was why they chose engineered, we would have talked them out of it had we seen the floor first) Neither of their claims to the manufacturer were fully settled because both times they did not follow the guidelines for floor prep. The loft job was also a materials only job for us with their GC laying the floors but he insisted he knew what he was doing. A good engineered floor will not be cheaper than most of your nail down options because the production costs are higher. Now having said that, GOOD engineered floors certainly have their place in places where you can't put traditional hardwood due to height restrictions or concrete subfloors. My boss had a great engineered floor in his basement and it survived a flood remarkably well (it was ash, Kahrs brand out of Scandinavia and one of the beefier engineered floors and one of the pioneers) My Grandmother also had a Kahrs floor in her ground suite condo and she LOVED it and I was impressed by the milling. I'm considering it for our basement because it's warmer and less echo-y than laminate There has been a lot of 2nd rate engineered flooring coming out of China and being labeled for all sorts of different companies. You should be able to tell an engineered sample because the layers are sandwiched together and the tongue will be a different wood than the top (showing) layer. Distressed finishes are usually more expensive because of the extra step in manufacturing to make it distressed. That is different than just getting a lower grade of hardwood like a rustic or tavern grade (in solid hardwood). Those grades have more character but they often don't carry a warranty and generally have a higher waste percentage. Another thing to think about---if you ever have to replace part of the floor, you will always be able to replicate 3/4" thick hardwood but engineered floors are more like tile, they change and get discontinued over the years. You could go pre-finished, save the hassle of site finishing but with the thicker wear-layer a 3/4" nail down floor offers. Only you will know if you can handle beveling or not. The changes in milling the last 10 years are huge. The bevel in your better milled wood is tiny. I like Canadian mills, Model or Mirage for pre-finished. Remember that if you ever re-finish, the bevel will disappear and you will, essentially have a site finished floor. One benefit that many people don't know about? With a prefinished tongue and grooved floor you can have a good installer cut out a single board (or more) from your floor if it gets damaged which is why we did a fair bit of pre-finished in new homes since inevitably we would get call-backs at move in to repair trade damage (@#$%^ plumbers and their big wrenches!). Prefinished hardwood deals the best with shinkage and expansion issues because the finish is on individual boards. Site finished floors are more labor intensive but the materials are cheaper (apples to apples). They are what many people consider the gold standard however there are more steps and you don't always know how it's going to look until it's done. There is more chance of finish contamination and trade damage during the rest of the building process. We refinished 100 year old floors. I loved the idea that there wasn't 4 generations of carpet and crap in the landfill. Definitely a forever floor and it can usually be re-sanded for all but the very worst water damage (think entire house under water for a few days) If you are going with a wide plank, keep in mind your species and humidity level (and your ability to keep humidity stable). The wider the plank (with 3/4" thick flooring), the more obvious shrinking and expanding will be. If you take a 2" wide board and it shrinks 2%, it isn't very noticeable. If you take a 6" wide board and it shrinks 2% the gaping will be more noticeable and in the case of a site finished floor *could* pull your finish apart. You'll need to find a flooring contractor in your area with lots of experience. Most of the best hardwood shops ONLY do hardwood. Beware of carpet shops and many of the big box stores in many instances. Make sure they are accredited with the NWFA (national wood flooring association) http://www.nwfa.org/member/ good luck!

It might be common for other applications, but with flooring you should only stain once when the stain will be covered with polyurethane. Flooring is subjected to the wear and impacts that other finished items are not. The bond of the finish can be compromised by an extra coat of stain. We mainly use oil poly when tinting finish and have had success adding up to 8oz. of stain per gallon of poly. More than that can make it difficult to apply without issues. Others here may have a suggestion as to what kind of colorant could be used if you're using a waterborne finish. Another option is to apply a second coat of stain then apply paste wax and buff. It's slippery, spots with water and requires upkeep though. There is also a product made by DuraSeal called Renovator that can be color keyed with stain. It softens the old stain allowing the new color to penetrate. I don't think it would be advisable to apply poly over it. Too risky. What type of wood do you have? There are a few chemical based options but you're getting out on a limb. On a few occasions, customers wanted to darken their floor after it was stained once. We scrubbed the floor with mineral spirits, let it dry, carefully applied a coat of strong ammonia (it tends to bead up so it requires a lot of attention), applied another coat of stain and coats of finish. Recently I had a similar situation where we used Rubio Smoke to darken a stained floor without resanding. It was as effective as the ammonia, is easier to get and doesn't require two workers wearing gas masks. In every situation the floor was White Oak which is more susceptible to the effect of these chemicals and each had only one coat of stain applied previously.

The acclimation you've been recommended to use is generally how we've done floors forever EXCEPT when using wider planks. As was noted above, have the plywood and wood checked. If they're too far apart the area can be dehumidified to bring the plywood moisture down and/or the wood will add moisture if it's particularly dry. Make sure the contractor is putting a vapor/moisture barrier (not retarder) between the concrete and the plywood. I don't recommend any barrier between the wood and plywood. Some pros have been burned using (probably cheap) water based finishes and refuse to use anything other than oil based. Others think you should use only the newest technology finishes and exclusively use water based. We use both. With a stained, hand-scraped White Oak, I would choose oil based polyurethane. No water based finish compares to the durability of oil modified. Considering the cost, it's a no-brainer unless you have special circumstances. As to staples vs. nails, we've used both and seen little difference in the performance. My preference would be for nails but the industry seems to have moved more toward staples.

JFCI, Will try increasing the concentration. CFI, I asked around - some went up as high as $1.25/sqft. One of them was more reasonable at $0.75/sqft, but after speaking with him I realized that I'd have to move all my furniture out of the way. My floor plan is a little weird - the main living area is split up into two halves by the kitchen in the middle. One side of the kitchen forms the living/dining/great room and the other my home office making this a two day job because of moving around the furniture. I will call upon the pros in the future for a complete floor facelift - right now, I'm just going to try this by hand so that my floors don't look like they've been pulled from a warehouse. I'm considering getting a handheld polisher like this one - http://www.homedepot.com/p/Ryobi-18-Volt-ONE-10-in-Orbital-Buffer-Tool-Only-P435/205975768 to help with removing the sludge. This will also give me the flexibility to work around my schedule/furniture. I couldn't find any mildly abrasive pads, but I reckon the microfiber/cloth pads that come with the tool should suffice at high enough speeds. Will update once I get out and but this thing! Thank you both for all the advice.