I am not a big fan of installing nail down products on "chip board". I know that some if not all hardwood manufacturers will not warranty one of their floors if it is installed on this product. Problem is, it doesn't hold nails well. Since you have installed this directly on the concrete, which I assume is fairly level, you may not have a problem with boards coming loose.
The bigger concern at this point would be moisture or dampness. If there is any problem with this, you will likely get cupping of the floor boards, with the edges raised higher than the center. Maple is more susceptible to environmental changes than oak, for example. If this happens, it will stretch out the nails a little, then it will likely fluctuate in moisture content, and shrink. Then you could have considerable gapping between boards.
The time to ask the question you asked is before you install the floor, not after.:) However, lets hope there are no moisture issues in your basement and you won't have any problems.
Related questions about wood floor installation:
>Is it not true that the wood should have sat in the house for a week before moving in?
>What's the best wood floor for a kitchen?
>Will I need to install a new floor, or can I salvage this one?
>What is your ballpark figure for installation of hardwood?
Types of Flooring
>Hardwood and the hardness scale?
>Where can I find ebony flooring in Toronto?
>Is it a bad idea in general to screw/nail down part of a floating laminate floor?
>What is the best wood to install in a home with a large dog?
>Should we buy the thicker engineered hardwood?
>Would wide plank flooring would be suitable in the Edmonton, Alberta region, with its cold, dry winters?
>What is the difference between a varnished, laminated and pre finished floor?
>If a pre-sanded v-groove hardwood floor is laid, buffed and varnished 3 times, how much of a 'groove' will you see/feel?
>How do I prepare my sub floor?
>Tongue and groove flooring over concrete?
>Should we remove some of the multiple layers of subfloor before installing?
>Should a water vapor barrier be put down if the hardwood flooring is to be installed over osb over a full unfinished basement? How should the flooring be laid? Parallel or perpendicular to the floor joists?
>I'm planning to install 3/4" Hardwood in our rooms, but there are some uneven spots. Is there any kind of leveling compound we can use?
>Do I have to remove the old flooring in the kitchen for the transition to the rest of the house without having to put a subfloor under the rest of the house to bring it up to level with the kitchen floor or can I use some sort of transition strip?
>I understand that we have to install solid hardwood over 3/4" plywood. I'd like to install the plywood now and paint it. Can I later put hardwood down over the painted plywood?
>Is it possible to put something overtop the particle board before putting down carpeting or hardwood to help with sound proofing?
>Is it good to put a new oak floor over an old one, or is it better to tear up the old one and put new plywood boards and then the new oak floor?
>Can we lay the plywood over the parquet? (And a bit about bamboo!)
>Should I install laminate over hardwood?
>How can I level out the subfloor with the cement lips for installation?
>How do I correct the uneven, downhill slant in my floor before installing?
Ripping out Old Floors & Salvaging
>How do I remove an old floor?
>I want to salvage some oak flooring from a house that is being torn down.What is the best approach to avoid spliting and cracking of the flooring?
>How do I safely salvage a gymnasium floor?
>Is there anyway to remove and relocate 3/8 strip flooring?
>How do I tear up these floors without damaging them further?
>Should I remove the glue on the parquet I tore out before I install it somewhere else?
>How do we remove the plywood sheeting and tiles that are on top of our hardwood?
>My foyer has 1/4 inch plywood glued down over the old hardwood. How do I remove it?
>I'm in the process of removing laminate floor titles that had been glued on oak hardwood floors in the dining room. eventually, I'll be getting the floors in the whole house sanded and refinished, but until then, is there aneasy way to get the sticky glue residue off without harming the wood? Or canI at least put something down that won't be a problem come sanding time butwill keep me from sticking every time I walk on it?
>How do we get the old lanolium off the floor to get to the wood?
>How can we remove carpeting which was glued to wooden steps about 30 years ago?
>Installing damaged salvaged maple flooring?
>How do I remove tile to install a hardwood floor?
>How and how long do I dry this salvaged maple?
Radiant Heat and Sound Proofing
>Can I install hardwood over radiant heat?
>We have some concern about noise/sound insulation. what is the best product to use? How should it be installed?
>I would like to have my floors redone so there will no more uneven floor and sound proof a little in the process. What do you suggest here?