Your idea of putting down the plastic floor mat is a good one. Also, there are two different types of casters -- the most common casters on office chairs have hard nylon plastic rollers (designed to roll on carpets) which will leave marks, but there are also soft rubber rollers for hardwood floors. Check the link below. Here is a link that might be useful: Casters for Wood Floors

Redroze, I'm just getting back online and seeing your questions, so I'll try to answer what I can. My new floor in the LR/DR was not pre-finished, it was all site-finished. I did put a pre-finished floor down in my office (no pics, sorry) because I work from home and didn't have time to be without my office for the week it would have taken to have floor sanded etc. The pre-finished does have a different feel to it than the site-finished. I wouldn't say it's grooved, just a more defined difference in between the individual planks. The office doesn't adjoin any other room, except the tiled hallway, so I didn't worry so much about the wood being different there. I see from your pictures what you mean about running the planks the same way and wanting to be sure things don't look odd. One idea might be to take up some of your FR planks, like the first 12 or so, and then put them back down interwoven with the new planks. That way there's not a clear line in between the 2 rooms, but rather a more gradual blending. Here's another couple of pictures, this time of my family room. The first one is a before shot of the hardwood floor + a rug-like carpet. The floor created a frame around the carpet. I had the carpet taken up and new hardwood put in where the carpet originally was, then everything sanded and refinished. You absolutely can't tell where the old wood was vs where the new started. In this case, the new is random width because it opens directly to the kitchen (as opposed to the LR/DR which is all the same width). So, one house, all new site-finished floors in the LR & DR, all new pre-finished floor in the office, original/refinished in the kitchen, and half&half refinished + original in the family room. Boy did we have dust! Hope this helps! New:

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!

My strong recommendation: continue the wood inside the office. It will give you the best looking result by a long shot even if you are not in love with the existing wood. A real hardwood is easy for a professional to match and blend. Do not, and I cannot stress this enough, do not use any fake imitation wood: laminate, vinyl, tile, etc. One "wood" material will make the other look horrible.