I should mention that I have photos (which I will upload, shortly). And I should also mention that this is floating, "click-lock" EH.

Your observation is valid and if you're going to have a prefinished wood floor subjected to lots of surface water, an extra coat of polyurethane would help. Basically the end grain of wood is like a bunch of straws that will soak up water and expand. Prefinished floors generally don't have the end grain thoroughly sealed. I've seen the finishing lines and there's no practical way I can see to apply finish to the ends.
You need to consider all of the potential negative consequences of applying another coat. It would help seal the ends but it invites all the issues you have with recoating a floor and it's almost certain that the finish you apply will be inferior to the factory applied finish in regards to scratch resistance and durability.
Most people would likely not say that a shinier floor with an extra coat of polyurethane "looks more natural".

Sorry. I was not able to post my photos because of phone issues, which is very disappointing. I very much disagree with your statement regarding sheen. While "natural" may not have been the best word, I do think most engineered floors have a "fake" appearance due to the plastic-like sheen, which masks minor grain variations and imperfections. I think that most people can distinguish between engineered and 3/4" based upon this factor. The coat of polyurethane actually does make the engineered look more like 3/4" board. Based purely upon my observations and intuition, I would say that it might take me a moment to determine that 2.5" or 3.25" engineered with a poly coat was not real 3/4" board.

...Assuming it was quality engineered and installed properly, of course.

"You need to consider all of the potential negative consequences of applying another coat."

Honestly, I still have the board outside, exposed to the elements, and while the polyurethane side, after months of exposure has finally started warping at the ends, it suffers from no such "consequences" with regard to surface durability. I am currently using it as a table for a mitre saw, and the polyurethane side is no more scuffed or scrathced than the prefinished side. Further, as I mentioned before, I did subject each side to durability tests, and the polyurethane side performed admirably, if not better. What is more, if scratches occur, it is MUCH easier to repair a polyurethane coat, than a prefinished coat. I see no drawbacks. You would have to be more specific.

This post was edited by CraigdPGH on Fri, Sep 6, 13 at 16:21

In the past I hd a house that had the EF it looked fine... I agree it looked plastic... we were concerned about water damage ( and we had 3 dogs)and consulted professionals about applying a sealer/poly. They said it was totally unnecessary d would damage the "quality look" of the flooring ( it already looked plastic.... give me a break) However we did as they recommended and did NOT apply a sealer... and yep.... we had a hot water heater leak... heavily damaged the flooring... our next EF we coated it with a sealer/poly... LOVED it.... water beaded and was not a problem. EF is Never my favored flooring now... I go all natural.. real or something else

So let's see if I have this right Craig. The factory finished floor looks plastic but adding a coat of semi gloss poly will make it look less so.
Right.
The coat of oil based polyurethane you add will wear as well as the factory finish and be just as scratch resistant despite all the laboratory testing to the contrary.
Right.
How many years of experience do you have in the wood flooring industry?

I said it looks more like 3/4" hardwood, which is what most people are used to. 3/4" hardwood is generally coated with polyurethane. Polyurethane does not look like plastic. It looks like polyurethane. Engineered hardwood looks like plastic. As for touch-ups and damage repair, there is no question that polyurethane is easier to repair than factory finish. If you dispute that, then I really cannot help you. Listen, buddy. I am giving you facts as I have observed. I have no interest in this game and I really do not care what the outcome is. You want to be snide, go elsewhere.

I'm sorry that you think I'm making snide comments. Actually I'm trying to point out that you're largely giving subjective information based on limited observation and trying to pass it off as fact.
I'm a professional in the wood flooring industry, selling, installing and refinishing solid and engineered wood floors.
What is your experience in the wood flooring industry?
Most prefinished floors have urethane finish, whether they're engineered or solid. Most urethane finished, prefinished wood floors look plastic because of the factory finish application and curing method (unless they're hand scraped or wire brushed). Many solid floors (and some engineered floors) are site finished. They don't look as plastic because there is a different finish application method.
Most people, professional or not, would not say that adding a coat of polyurethane to any floor, makes it look less plastic. Most people, professional or not, would not say that semi-gloss finish looks more natural. Of course that's my subjective opinion but it's one based on dealing with thousands of people who own wood floors.
Now if you wrote that lightly sanding a prefinished wood floor to smooth out the ripply texture and applying an additional coat of polyurethane looks better to you, I could agree with that. But that's not what you wrote.
I agree that adding a coat after installation will help with water absorption but I feel you have underestimated the risks that one exposes themselves to if they do so.

I apologize if I'm being dense here. I'm really not trying to be stupid or stir the pot....I guess I don't understand the risks of coating an engineered floor with some site-based finish.

I don't like the plastic look of my engineered natural oak floor.

To me, I think it would simply look nicer if it had a site finish. The prefinished boards don't have that uniform top coat I'm used to seeing. I don't know how to explain this well, other than to say each individual board looks like an individual board. (I don't know if that makes sense?)

So what is the danger of refinishing them?

It sounds like I get better water resistance? But perhaps less durability/resistance to scratches?

Again, my apologies if I'm being dense. I am not particularly concerned about scratches. My dog is small and old, I don't have kids, and we are not hard on our floors. I just want them to look better!

Hmm. I posted a reply which seems to have not posted.
In short, factory finishes generally wear better but that should not be an issue if you're easy on the floor.
Many finishes have aluminum oxide added and there have been adhesion problems when recoating. Abrading correctly and using an adhesion enhancer like Bona Prep can help insure that a new coat of finish doesn't peel off.
The other issue with recoating is that you're adding a human element. You could end up with streaks, misses, puddles, drips or hairs.
My recommendation would be to buy some type of penetrating sealer for the end joints where you might get more water exposure. Apply with a small brush or swab and wipe of the excess thoroughly.
Then live on the floor until you've marked up and worn the factory finish somewhat then recoat it.
Best Regards!

First a no post, now a double post. Very strange.

This post was edited by JFCWood on Thu, Sep 19, 13 at 13:55

Thank you for the information. What you say makes sense and I appreciate it!

JFC: Sorry, I was probably having a bad day. Rereading your posts, you make some good points and there is a lot of room for discussion here. There are also many factors and experiences that play a role - no question. My experience comes as a homeowner and renovator. I have refinished hardwood and lived with the results. I have also installed engineered and lived with the results. I like to be a curious consumer who helps others benefit from my mistakes and successes.

I wish I still had the photos - it kills me that I do not. Fortunately I still have some boards left, so if there is enough interest, I would be willing to conduct the study again and post the results. My engineered boards are Mercier hdf core click-lock, not plywood. So any other type may yield much different results.

As far as the look of the coating, I guess it is really subjective. I tried to convey that those were my thoughts not fact. And my thoughts were that the poly-coated boards looked more like real 3/4 hardwood. Some like the factory finish, some don't. I tend to think the pre-finished sheen is a bit "plasticky" or artificial. Take that with a grain of salt, because it is purely my opinion.

What ever your preference on the look, though, there is definitely no issue with adherence of the poly on engineered. and I feel (just me from what I have observed from this experience) that it can only add to the durability, life, and water-resistance of your engineered floor.

JFC: Sorry, I was probably having a bad day. Rereading your posts, you make some good points and there is a lot of room for discussion here. There are also many factors and experiences that play a role - no question. My experience comes as a homeowner and renovator. I have refinished hardwood and lived with the results. I have also installed engineered and lived with the results. I like to be a curious consumer who helps others benefit from my mistakes and successes.

I wish I still had the photos - it kills me that I do not. Fortunately I still have some boards left, so if there is enough interest, I would be willing to conduct the study again and post the results. My engineered boards are Mercier hdf core click-lock, not plywood. So any other type may yield much different results.

As far as the look of the coating, I guess it is really subjective. I tried to convey that those were my thoughts not fact. And my thoughts were that the poly-coated boards looked more like real 3/4 hardwood. Some like the factory finish, some don't. I tend to think the pre-finished sheen is a bit "plasticky" or artificial. Take that with a grain of salt, because it is purely my opinion.

What ever your preference on the look, though, there is definitely no issue with adherence of the poly on engineered. and I feel (just me from what I have observed from this experience) that it can only add to the durability, life, and water-resistance of your engineered floor.

No problems on this end. There's always room for a good discussion and even differences of opinion on such a subjective subject.

Have a safe and enjoyable holiday season!

JFCWood, I just decided on engineered hardwood, but then read a comment about the aluminum oxide finish leaving white marks. I have the money to get new flooring, but don't want to make a wrong choice. I only have enough money to do it once, lol! I was told I had to choose engineered because it will be laid over a concrete subfloor.

Is anyone still around regarding this post? We are still in process of installing engineered hardwoods at our home in Houston. We went to MANY retailers and no one wanted to install "real" wood flooring as a replacement floor in Houston with our high humidity levels - in fact ALOT of the stores only carry EF. So we eventually chose an EF. We previously lived in VA with "real" oak floors that we had refinished including polyurethane. The new EF is not even installed in all rooms yet and my son spilled a bowl of cereal that we did not catch immediately. And the end of one of the boards is curling up - like one of the original notes above says it seems to quickly soak into the ends of the boards and not be resistant in any significant effect. We were VERY HARD on our real polyurethane coated floors in VA and NEVER had any problems (although under the refrigerator the floors was a bit "wrinkled" but that was no big deal). This is an immediate warp of an edge of a board after a small spill. I googled the possibility of adding polyurethane to coat EF and found this discussion. I will talk to my installer but this seems like a good potential solution. I would welcome any input from anyone who may have tried this or who may have another solution. I am going to miss my ugly 8x8 ceramic tiles if this is an ongoing battle with damage and wood curling.

Thanks