"We installed hardwood over existing hardwood going in the same direction - although there was no subfloor, so pulling it up wasnt really an option. No problems at all." You had no subfloor? The hardwood was nailed every 16" directly to the joists? Did you do the work or did some contractor convince you that this was the situation? I Have not seen that in 40 years of remodeling old homes and will probably never see it. As I said before, TAKE UP THE OLD FLOOR!

Wow...that's a huge question. I know it sounds simple, but it is quite complex. So complex there are entire books on the subject (both professional and lay-man). So....solid hardwood is just that. It is solid. It is the same wood cut from the same tree, from the same plank at the mill. Traditionally it is 3/4" thick. Widths vary but the classic is around 3" wide plank. A 3/4" solid hardwood can be refinish 3-4 times with a total lifespan of 60-100 years. These are either factory finished or site finished. The industry has realized that some people are too afraid of large purchases so the solid hardwood industry has come up with the idea to make their planks THINNER and thereby making them cheaper. I've seen 1/2" or even 3/8" solid hardwood. They can be refinished once...maybe twice and have a lifespan of 20 - 40 years. These thinner solid hardwoods are often factory finished (cheap, thin and fast). And that's the easy part. Engineered hardwood...where to start. First off the TOP layer is the ONLY LAYER that contains the pricey hardwood that you are paying for. Everything else is like "plywood". The body of the plank is made up of cross-hatched layers of wood (not always hardwood) that are glued together. The top layer will range from 2mm - 6mm. The ability to refinish will depend on the thickness of the top layer (known as the wear layer). You need 3mm of wood to complete a full sand and refinish - just once. So the 2mm wear layer is a "one and done" type of floor. It has a life span of roughly 20 years (though many people rip them out after 15 because they look beaten up). The 6mm wear layer in a 3/4" engineered plank that is site finished is the Holy Grail of the engineered hardwood world. They are the most expensive, the most beautiful and offer the longest life cycle of all engineered hardwoods. They are so expensive that they are MORE expensive than solid hardwood floors. Whew. There is so much more but that's the difference in a nutshell. Shaw has had some complaints. The biggest issues with wood will be humidity and indoor climate control. Ask your builder to check the heating/cooling system. Ask them detailed questions about the unit's capability to handle climate control that is REQUIRED for a hardwood floor - regardless of the presentation.

We have red oak floors covered with carpet in our living room in our 50 year old ranch. That room opens up to our dining/kitchen area which is sheet vinyl on a subfloor (placed over old vinyl.) We were wanting to do glued down engineered hardwood over the entire area and the hallway. The guy who measured said we could put a subfloor over the hardwood to bring it up to the level of the vinyl. Sounded easy. Now the installer says we need to remove all the old hardwood and vinyl and do new subfloor over all of it. Who is right? Is a floating installation an easier/better option?

Traditionally (ie. by a pro who is paid to do things well/properly) the damaged substrate is removed and replaced. Patching is possible if there are minor spots that just need 1-3mm of fill. If the whole thing has a shredded surface then it is probably easier/faster to remove and replace with the same thickness. As G&S suggests: photos please.