If it moved anything approaching 3/4 of an inch it would tear the nails out. There is still some skill to installing strip flooring. Let it acclimate for multiple days out of its bundles and spread out where it will be installed. Tighter in high humidity (it is going to shrink), looser in low humidity (it is going to expand). Strip floors that are to tight for the moisture content at install can buckle up and pull fasteners part way out. The humps then decrease when the humidity falls. Most of the hump will disappear. Trying to face nail (or even screw) the area will not usually work. The forces generated are larger than the fasteners and/or wood can take. Splitting is not uncommon. You have to remember that if you have 5 inch wide strips 10 feet wide you have 24 strips of wood. If each one move 1/32 inch from damp to dry, the total movement you have distributed is 3/4 inch. It only sows as the joints between the strips opening and closing by 1/32 inch though (and yes it is probbaly off by 1/32 since 24 strips only have 23 joints).

There are a lot of reasons why there are excessive gaps in a hardwood installation. A good way for you to check if your floor has excessive gapping is to look at some of the other hardwood floors in your neighborhood and see how much gappingis in their floors. Some questions would be; what kind of subfloor do you have; what kind of vapor barrier was used; was the floor installed running across the joists and not with them; and what was the finish used? Also, I don't recall how stable Brazilian cherry is but that would have a bearing. Some examples. The floor in my house is quarteer sawn 4, 6, and 8" planks glued togather from 1 1/2" glued up boards to make the planks which are then beveled and decorated with pegs. There are no readily visible gaps. I just refinished my sons red oak hardwood floors installed in the late 1940's when the house built. Some areas of small gaps, not readily noticible, but as a whole no gaps. A job I did was for a friend so I get to look at it over a long period of time. That was about two years ago and no gaps that are apparent without getting down on your hands and knees. As I explained, check out your neighbors and see how their floors look. I have seen some of this Brazilian cherry installed in new homes recently and I didn't notice all of this gapping, Some gapping is inevitable but if it jumps out at you, you might have some installation issues.

One of my concerns about putting a vapor barrier down on the dirt floors in my old house's cellar has to do with the risk of creating a super-saturated zone right at the foot of my dry-laid walls (some rubble, some much more carefully selected and laid, but all w/o more than chinking mortar.) The vapor barrier, in my view, is there to stop the inexorable rising of water vapor from the soil. (It rises due to constantly changing atmospheric pressures that no one can do anything about.) Blocking it at the cellar-floor surface level won't stop it rising, but it could channel it all outward to the edges of the barrier. If the barrier is tightly sealed to walls (as it ought to be) then where does all that accumulated water vapor go? It seems to me it will create a lot of sogginess in the soil at a very bad place: where the foundation of my house rests on what I assume was undisturbed soil at the time of construction c 1845-ish. I think it's important to differentiate between free water that comes in during periods of high soil water or the result of poor local drainage from roofs, flooding, etc, and moisture that comes from rising soil moisture vapor. The free water part may be containable, managable, or mitigated, but soil moisture vapor is probably not something you can stop. Moisture arising from the soil in very old houses may be a natural phenomenon that we have lately defined as a problem, or that has become problematic because of material changes we have made to our buildings by installing central heat, insulation, double-glazing and even running water. It may also be that our expectations have changed to cause something previously deemed "normal" to be seen as a problem in need of action to eliminate. Before there was electricity and air-conditioning technology I doubt that people were much pre-occupied with removal of air-borne humidity by dehumidification. But the fact that we can do it, may now make us feel that we have to do it. I also disagree with the notion that keeping cellar rooms closed up during the warm months is the best course of action. I do see the logic that keeping warm, summer, moisture-laden air away from the soil-cool stones of a foundation avoids condensation on the walls. But I am less concerned with condensation coming from warm-air atmospheric moisture, than with venting soil moisture vapor to the outside of my building envelope. Old people around here who lived in old houses like mine have told me of the careful attention they paid to opening up the cellar and airing it out after the winter. Since most of them lived and worked on the farms they were at home to attend to this and paid close attention to the direction of the wind so to maximise the flow-through pathways by opening different windows, doors, etc. I practise this as much as possible and it results in a dryer cellar, even though I still get some condensation on the walls, especially in the early Spring. In the years when I can pay the most attention to active cellar ventilation, my cellar - and consequently the rest of my first floor - stay the driest. But it often takes multiple changes during the course of a day, and I have to have my whole outdoor cellar stairway open all the time (during the day, it's generally closed at night to avoid dew-laden night air), which many people couldn't or wouldn't do out of fear of intruders. My cellar walls show evidence of multiple layers of white-wash (quick-lime and water). This is an effective preventive, curative and aesthetic disguise for dampish stones. It does nothing to reduce humidity in the air (adds to it for a few days as it dries off), but it makes the cellar seem less grungy. I struggle with this issue, a good deal, because I think a lot of the best-advice from old house "experts" may not be the best for the building's long-term survivabality. Info dump: My house is located in northern, NY. Foundation as described above, otherwise timberframed, two-story, wooden structure with its original plaster walls intact. Wall cavities are mostly filled with two separate layers of backplastering on wooden lath. Two layers of 5/4" X 10" T&G sheathing with clapboards nailed on top. Slate roof. Still no central heat, though now only two modern, more-effective stoves rather the original 4-6. Electrified (but not in every room) just before WW II; minimal indoor plumbing installed in 1960. In short, a oddly long-term survival of 19th technology, which I am slow to alter. If you're going to put vapor barrier down, and going to the trouble of sealing it properly, you should use material specifically intended for the purpose, not construction poly. I haven't solved this problem to my satisfaction, yet. Lately, I have been thinking that I should undertake a more active course of observation (recording indoor and outdoor temps, humidity and wind direction and speed) along with a program of trial openings and closing to gather better information to form a more thought-out moisture vapor reduction program. (I expect this was all empirically known a hundred years ago, but even old timers now have forgotten the details, alas.) This summer has been dryer than normal so perhaps this would be a propitious time to start. There is a guy, an engineer, (located in eastern MA, I think) who owns an old house and he has basically sealed up his entire cellar walls and floors from within. I'm drawing a blank on his name, but a frequent poster, Worthy, often posts links to his work so if you search for Worthy's posts on this forum you should turn up the link. I have read this guy's writing on his website, but remain unconvinced that it's what I should do with my old building. I don't think he's a crank, or anything - and he may be right - but what he does is essentially non-reversible. That irreversability is what's stopping me. L.

Here's how I would approach your situation: a. Read the great article on conditioning crawl spaces as with removal of the exterior vents, you inadvertently started down this process, which imho, is a good process. Here is the great article: Martin Holiday: http://www.greenbuildingadvisor.com/blogs/dept/musings/building-unvented-crawl-space b. Lay down the minimum 6 mm water vapor over the crawl floor. I did this myself and it wasn't very hard: Lowes and HD sell it. Just overlap the edges and use the water proof tape, ideally bringing it up the concrete walls 10 inches or so and securing it. If you can't do the later, just lay it all the way to floor-wall junction with no exposed dirt, until you can do it as it (water membrane over all exposed dirt) is like the main pivotal step in controlling humidity of the crawl space. It's all reviewed in above article. c. Get your HVAC guy back to cut a small 3" or so supply vent circular hole in your metal duct. This plus him connecting a return duct to a floor above the crawl should provide enough air exchange. The numbers of cfm are above. If he truly won't (and he should read Mr. Holloway's article and answer why not) then perhaps you need a new HVAC man as this is established crawl space conditioning components. Remember that "perfect is the enemy of good enough". It all sounds complicated, but you've already done the hard part: removing the vents, insulating the rims. Now just lay the waterproofing vinyl membrane and try to get some air active exchange through there and you will be way beyond what most crawl space owners have done to ameliorate crawl spaces. Then sit back and take pleasure in your Home Owner accomplishment! Regards, SW.