And I was trying to be so careful how I worded that :). Hickory is fine to use. NOFMA has a well written article on selecting a species that I will link to below. Checking is not a common problem one will run into everyday. It is where the wood drys out too much and starts to split in the top face (wear) layer of an engineered wood. Inside environments should be maintained at above 30% RH. Some parts of the country the inside RH will drop down to the teens or single digits during the heating season. That is where dry cupping or checking can occur. If you are partial to an exotic wood, most will work if they are manufactured correctly, installed correctly and maintained correctly. When i asked about non-vented gas logs, they can be problematic too because they emit huge amounts of moisture into the inside environment. If a house is too tight you can get condensation forming on colder flat surfaces. That can cause the wood to gain too much moisture, then when it drys out it can and will check. Too high of an RH level is just as bad as too low. Not every single home built in the US is a prime candidate for a wood floor. The manufacturers recognize that and throw the responsibility of maintaining the RH levels on the end user. Fair or not, that's the way the current system works. Here is a link that might be useful: NOFMA species selection

Thanks Charles -- I did look at the guidelines that you mentioned. However, it refers to gaps 'at completion' of the job and not within the 1 year warranty period. Everything I've read indicates that installing hardwood without controlling the temp / humidity for what the living conditions will be is a big no no. Re: your comment about the 'difference in moisture content of the wood floor & subfloor' -- if they are both swollen from the high humidity, then they would both shrink under the normal living conditions right? Do they both shrink at the same rate, etc? There are numerous gaps, face checking (cracks on the tops of boards -- some with the grain and some against the grain), and gaps under the baseboards (where I can easily insert a penny). I thought this was a GREAT article that directly discusses the topic of installing with no HVAC: http://www.floordaily.net/floorfocus/challenges_involved_with_installing_hardwood_wood.aspx I noticed many installers recommended waiting or turning down the job if necessary. It sounds like my builder and the installer both made a bad decision. So, isn't this something their insurance would cover? I just want my floor fixed -- not with a band-aid for a short term solution (until the warranty runs out). I just want a good quality floor and to enjoy our new home. Sigh.........

OK...so the NEXT question becomes 'where are you located'? Are you in Arizona or Maine? Are you in a wet/humid climate or high-desert? How cold/dry does it get in winter time? How hot/humid does it get in summer time? It is *possible (we won't know for sure until you have the floors inspected by an NWFA Certified Inspector) the gapping you are showing is due to winter 'dryness'. But we won't know for sure for a while. It is entirely possible the wood was delivered to your home on a wet day after sitting in an UNCONTROLLED warehouse (damp/cool). And it is entirely possible the floor was not allowed to dry-out enough in the 'home environment' for the required 2-3 WEEKS (again we need to see the documentation of the day it was delivered and the day it was installed with all the moisture readings). Your installation happened at the END of the Fall season...which means it was moving from a damp season into a 'dry indoor season' that we call winter. And *IF the wood was 'puffy' (swollen due to moisture in the air) when installed, it simply shrank down to the 'right size' once it was in place. And that shrinkage happened AFTER it was installed instead of BEFORE it was installed. So...to get this dealt with you MUST CONTACT the 'installer'. If you are not getting any response, you will need to step up your game. An NWFA Certified Inspector is someone who is recognised by the industry AND the courts as an expert. www.nwfa.org The inspection costs can be a few hundred to several hundred dollars (depending on how much flooring is to be inspected and how many issues found during the inspection). S/he who pays for it owns the report. What this does, if you have your floor inspected, is give you a BIG STICK you can use to coerce the installer into fixing his/her mess. Once an NWFA Inspector has a report that points to 'installation error' then your installer INSTANTLY becomes liable for the fix...and they KNOW IT. It makes then sit up and take notice. You don't have to 'go to court' to get this fixed...you just have to have 'court ready' documentation in your hand.

Your nailing pressure is probably too high. Lower the pressure on the compressor. Most nailers only need 90 psi. Unless, you're using a Primatech nailer, which requires 100 psi continuos. Also, make sure your nailing schedule is to manufacturer's recommended spacing. Standard is 6-8" spacing but mfg can specify differently. What gauge nails/staples are you using? Thin fasteners can bend, causing a lift. Checking for up and down movement to confirm this. If not any of these, are you sure the flooring is designed for nailing? Maybe only glue or edge gluing allowed for installation method by mfg. Check mfg recommended installation method.