Construction sites are full of moisture. Unconditioned ones even more so. Installing floors at their highest moisture content is always going to result in problems with gapping at the lowest moisture content time of the year. Which is why a climate controlled environment is required. Then moisture readings of the subfloor, the flooring, and the RH of the air should be taken.

If no climate control was operative and no documented moisture texts done, that's 100% your issue.

Don't take this the wrong way, but how is that my issue? I was just writing the checks, not calling the shots deciding what happens and when. My builder was responsible for that, that's one of the things I was paying him to do. That's like me going into a restaurant, ordering a meal, and when it comes out underdone you saying it was my fault as the patron, because I wasn't in the kitchen participating while it was being cooked?

It could be worse, they could've been installed now and then buckle in the summer. Small gaps are common, especially with 5" planks. In a few years you'll have gaps everywhere and your floors will look like those coveted antique floors. People will be envious.

This would be between the floor installer and GC. The installer should know not to install the wood floors until humidity is brought to normal living conditions. Generally between 30-50%, unless specified by flooring manufacturer.

It would have been better phrased as "your root cause issue" The GC of course is responsible for the incorrect order of operations. And the questionable product selection. 5" wide plank is better done as engineered, and glued and stapled both. Solid wood of that size will always experience a lot of movement, which create some some cupping and some gapping.

I'm with these fellas. Site finished wood should be installed after HVAC, so it is installed in the condition it will perform in. Your GC is probably more accustomed to engineered. An easy fix doesn't come to mind.

If you don't like the gaps, turn up the humidity. If you don't like the buckling, turn down the humidity.

I'm sorry but the non-conditioned install allowed your wood to PUFF UP beyond the regular size of wood. Now that your home has been conditioned, the wood is shrinking down to what it should have been had the HVAC been up and running at time of install. Let's imagine the humidity at time of install was 65%...just for fun. Now you have 35%-40% humidity (which is as it should be...just so you know). Your wood has just experienced a shock of 25% - 30% REDUCTION of humidity in a very short amount of time. The floor had nothing else to do but to shrink or "dry out".

And the reason why you might be seeing more in small areas could be as simple as reduced air flow/humidity balance in small spaces.

You should have a builder's warranty that should still be applicable (all labour and quality of materials). At this point, you will need to bring the General Contractor in to face up to the oooopsa that was allowed (under his/her watch). And the reason why builder's don't like to turn on the HVAC is one of simple economics. They do NOT want to pay for several months of a "conditioned" space. It is too expensive for them so they put it off for as long as possible.

What to do? Well you could test the theory and pump up the humidity to 50% (or to the top of the chart at 55%) and then watch the gaps of the floor close up. If they close up almost completely then HIGH humidity at the time of install is the answer.

How to go about getting what you want....you need to start the conversation with the builder as soon as possible. Warranties have a tendency to elapse as we sit around trying to figure things out.

Of course, at the end of the day you will need to make a choice about what you will accept as compensation for an issue (should it come out that an Independent Flooring Inspector states that the unconditioned install of the floor is the reason for the gapping). You will need to decide whether or not you want a whole new floor or if you want financial compensation to "live" with the oopsa.

Contact your Builder. If s/he is non-responsive, let them know that you will bring in an NWFA Certified Flooring Inspector to find the root cause of the gapping. That normally wakes them up...NWFA Inspectors are taught how to write reports that stand up in court. Normally just the THREAT of bringing out an NWFA Inspector is enough to get the Builder back to the table.

www.nwfa.org (just in case you want to go in that direction)

I would also ask whether or not the Builder used a "flooring professional" or if s/he cheaped out and used a "guy" who swings a hammer. That's often the most telling answer.

That independent flooring inspector is going to ask for records from the installer/contractor showing they checked humidity levels in the flooring, subfloor, and relative humidity in the home. They will also look into how long the flooring acclimated and to if the home had HVAC running for any length of time etc etc.

Finally got around to taking some pics... Got to thinking, if this were humidity related, wouldn't the gaps be on the ends of the boards, instead of along the length of the boards? Currency in the pics is a quarter.

The construction guidelines under the mandatory warranty programme I built under say cracks in excess of 2 mm have to be corrected. A US quarter is 1.75mm wide.

I would be surprised if that was anything other than humidity related. It's very common in older houses. WHICH OBVIOUSLY YOURS IS NOT, BUT THE POINT IS VALID ANYWAY. The gaps between planks widen and narrow seasonally. It's along the length of the planks, not between the ends. It's the wood swelling, which happens width wise not length wise.

emho23,

"I had my house built last year by a custom builder"

The wood used these days is far less stable than the wood used in older houses.

@millworkman, wood will always be wood, and its tendency to swell from humidity remains unchanged, regardless of when it was installed or how fancy the custom builder was. (Old houses were all built custom!) Of course the wood can be more or less stable, depending on the species, the sawing method, etc., but age of the home fundamentally has nothing to do with it. I was merely pointing out that it's common to see in older homes, maybe because it was less possible to test for and control for humidity back then.

My real hardwoods were left to sit in my house 3 weeks after the AC was turned on before being installed. I'm in Texas and they were installed in the summer, when it's very humid. If they were installed prior to being acclimated to an air-conditioned/dehumidified home, my gaps would be huge. Overall, I don't have any gaps but I do have one that is noticeable that runs through my kitchen and family room. I wouldn't say it's the size of a quarter though. It doesn't bother me and I'm embracing the character of my floors. The only fix for it would be to wood-fill the gap, sand and re-stain and oil/wax on top. I may do that next year if I decide to freshen up my floors anyway. Until then, I'm living with it.

.... and when you lose power for a few days you'll have all kinds of "character".

Hi, Mike,

The answer to the question: "What is acceptable...?" depends on the standard against which the defect is being measured. We use Residential Construction Performance Guidelines for Professional Builders and Remodelers which is published by the National Association of Home Builders. The Guidelines state "At the time of substantial completion of the project, gaps between hardwood floor boards should not exceed 1/8 inch in width."

1/8''= 3.175 mm. vs. ONHWP (Ontario New Home Warranty Program) standard of 2mm.

Could that be the difference between a government set standard and a builders' standard? Or maybe more lenient to accommodate all those soggy Southern swamplands improbably sporting homes to be swept to sea by the next hurricane.

Hi, Worthy,

I can't speak for the NAHB or how they arrived at their standard; I'm just a single, soggy southern swamp dweller. NOFMA (The Wood Flooring Manufacturers Association) says this about gaps in hardwood flooring:

"Normal gaps may vary in width from "hairline" gaps thickness of stationary, to more significant gaps, up to or greater than the thickness of a quarter. The larger gaps are expected in those geographical areas associated with an extended dry heating season, and warm, mild humid summers that require little air conditioning, i.e., the Great Lakes or New England area...Plank floors, because of widths involved can shrink individually up to 3+ times as much as 2 1/4" wide strip floors."

Sorry, I see it's wood strip flooring in the Okefenokee that fares best.

Here in the land of the six-month winter, followed by a/c summers that wood flooring moves most. I've had more than a few complaints from buyers about how my floors shrink in winter. My lack of standards, cheapness etc. Once the dynamics of wood contraction and expansion are explained by the installer, the complaints fade. The OP cites some gaps large enough to punch in a quarter. Well within any standards, despite what may not have been ideal install. Spare change anyone?

Wood behaves like wood, whether it's milled into flooring, beadboard ceiling or raised panels installed in a raised-panel door. Its behavior (that's behaviour for our friends in the frozen north) isn't easily controlled.

Engineered flooring is definitely more stable with respect to changes in relative humidity. For widths over 3 inches (conversion of this dimension to metric is left as an exercise for the reader) I think the use of engineering flooring is a must.

We let our house get too dry and have cracks in our wood floors. It was our own fault. Our wood stove really dried the heck out of the house.