High performance homes and buckling wood floors?
I have a meeting tomorrow w a great builder who has really embrased high performance buiulding. In climate zone 4. Closed foam in walls. ERV to prescribed amount 139 cfm x 24 hours per day. Floors have buckled and been a headache for builder and homeowner. Builder needs strategies in order to build high performance or tempted to back off on building “so well.”
Builder has put in 2 dehumidifiers along w fixing the floor. The floor guy wants to blame it on houses w ERVs though I can deal w this objection. I believe the time for the dehumidifiers is when house is initially closed up for the first 6 months of occupatiuon.
Have any of you enough experiance w this issue to tell me what you keep in mind to keep floors from buckling.
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Replies
Rick,
Some questions:
1. Is the flooring installed over a slab, or a crawl space, or a basement? If it is over a crawl space, is the crawl space vented or conditioned?
2. Has anyone measured the relative humidity of the indoor air over the past few weeks?
Rick ,
What kind of HVAC system is installed in this house ? The floor guy needs to learn more about floors and high performance homes they are installed in . I'd be willing to bet the HVAC guy has a much bigger part in this than anyone else . Buckling hardwood is almost always moisture related .
the builder could possibly call a building science professional and investigate why this happened and address the issue in future houses . I do not believe the flooring guy here is without blame . For years flooring guys and manufacturers blamed radiant heat for these when all the while it was due to HVAC issues with moisture and / or the lack of it seasonally
Thanks men. I have been at this for a while so I appreciate your questions and answers. It's a 96% N Gas furnace. Morew importantly, the AC is a 16 SEER unit that I should do a load calc on. I am meeting w the builder, HVAC, Flooring guys tomorrow. The floor is over basement that is finished and well insulated. Basment below grade walls have an R-10 rigid taped at seamed plus R-13 batt. To me, it's a matter of wettness in the house installed before high humidity summer. The house was finished and closed up in May before high humidity seaon in midwest. There was probably high moisture in concrete slab and fondation walls and building materials that then got closed up and it didn't get noticed until 90 degree july. Richard, I probably should have done a load calc myself- the light bulb just went off. I will do a load calc on it tonight to check to see if the HVAC systems aren't oversized. I trusted the HVAC guys load calcs and probably shouldn't have. Will let you know. Any experianced high performance passive house guys who've got experiance in buckling floors, please share w me your thoughts.
Martin, I will check on humidity measurements through time.
What kind of floor? Solid hardwood, engineered hardwood, or laminate? Nail-down install or floating floor? Have you verified that the floor itself was installed correctly with the required expansion gaps around the edges?
I agree with the idea that it's likely related to construction moisture + ERV + the timing of closing it up in May, but not getting the dehumidifiication of the A/C until July. With an ideal ERV system and a tight house, there's no way for humidity to escape unless you are running A/C or dehumidifiers. A real ERV does allow some moisture to escape, but not as much as a leaky house or an HRV.
I think monitoring humidity in a newly constructed tight house for the first 6 months would be wise. Actually, I think monitoring humidity in any house is wise.
Little to do with high performance house and all to do with bad installation.
I am going to bet not one standard was followed for floor installation.
Allow flooring to acclimate for weeks
leave spaces at edges
think about it
Is every floor in a un air conditioned house in the south buckling?
Climatizing the hardwood before installation won't of course help much if the humidity levels in the building are over the top. Then you are installing a wet floor that will have a mind of its own in the heating and dry seasons.
Seems to me this is a no-brainer. A builder/contractor in this day and age has humidity meters in use throughout the entire project. A professional hardwood installer should be testing wood moisture levels as standard practice.
It is my belief that an ERV has the ability to keep some moisture out that and HRV would let in. That's the only difference between the two, I think.
A very common problem with high humidity.
How is the underside of the floor insulated, if at all?
Did the installer allow the wood to acclimate to the house prior to installation?
Did the installer test the wood moisture and compare to the house moisture (RH) and the surface the wood was being installed over?
What kind of wood was used?
What is the RH in the room below the floor in comparison to the room the floor is located in?
Note: I found in my own house that exotic wood floors are very moisture sensitive. They definitely do not perform like red oak, white oak or fir flooring which are the most common in zone 5. A dehumidifier will usually fix the problem providing the floor was not allowed to remain in a cupped state for to long or the process can take several month's for the floor to lay flat again.
Here's the installation guideline published by the National Oak Flooring Manufacturer's Association;
"Installing Hardwood Flooring"
http://www.crescenthardwood.com/nofma/hfim.pdf
Rick ... HRV-ERV, makes little difference. They are designed to regulate fresh air, not to dehumidify. If you were told that they are for dehumidifying you were misled. And by the way, no normally sized dehumidifier or air conditioning system could resolve the excess humidity of the construction phase and drying phase of a new house, anyway. You are not on the right track with this.
Flitch I just went to read Martin's article "HRV or ERV" to get clarification. Like you say,it doesn't make much difference, both allow humidity in. I knew it wasn't a dehumidifier. The truth lies more in other things, humidity, moisture content, over-sizing of AC unit, installation of the hardwood. I will have the load calc done by tomorrow afternoon and am armed by new questions for the builder, the floor guy, and the HVAC guy. The ERV was the best option available in this tight house,
Richard, the underside of the floor was uninsulated except by batts for sound attenuation. Thanks for the installation guidelines.
Rick,
We built a pretty well air sealed, insulated house in upstate SC over piers. The oak floors were installed in the winter time when it was pretty dry. The wood was acclimated for over a week. It took us awhile to finish the house included insulating under the floor. By the time we did that the floors were cupped due to exterior humidity. It makes sense that the more wet side would swell more than the dry side.
The floor has leveled out somewhat now that the area underneath is air sealed and insulated, but it's still a little lumpy. We're pretending it was designed that way.
Do you think it could be exterior humidity that is affecting the floor?
Acclimatizing flooring by leaving it in a construction site makes no sense. The length of time it is left is immaterial if it is simply adjusting to levels of humidity it will not experience in the finished house. Flooring should be laid when it reaches a specific moisture content for the climate. Charts are available online. (Here in the PNW I think it is 6.8%.) If the floor is put down this way, and the occupants maintain reasonable levels of humidity, you generally don't have any problems.
Malcolm,
From page 2 of the NOFMA installation guidelines...
"In warm
months the building must be well ventilated; during
winter months heating should be maintained near
occupancy levels at least five days before the flooring
is delivered and until sanding and finishing are
complete.
Because materials used to provide energy efficient
structures trap moisture in a residence, it may be nec-
essary to delay delivery and installation of flooring to
allow the excessive moisture trapped during
construction to evaporate. The average moisture con-
tent of framing members and subflooring should be
below 12%-14% before delivery of the flooring. Moisture
contents above 12%-14% can cause moisture related
problems.
When job site conditions are satisfactory, have the
flooring delivered and broken up into small lots and
stored in the rooms where it will be installed. Allow
4 to 5 days or more, for the flooring to become
acclimated to job site conditions. If flooring is pack-
aged, open or remove packaging for acclimation.
From the time flooring is delivered and until occu-
pancy, temperature and humidity should be main-
tained at or near occupancy levels. After occupancy,
continue to control the environment. Extended times
(more than 1 month) without HVAC controls can pro-
mote elevated moisture conditions which can adverse-
ly affect flooring."
Richard and Flitch are on the right track.
I build homes slowly as they are custom and complicated and I wear many of the trade hats. My homes have perfect hardwood floors almost seamless.
Where I have found bad floor problems have been when all are in a rush get it done boys, get it done. Portable heaters, uncontrolled humidity, fast 3 month builds... etc.
Malcolm, I always stack flooring out of packages if packaged and leave it in the room to be installed. I have such a set up right now in a house. There will be no problems.
For me Spring and Fall are good install times, August and January are the worst. This may not be a real factor but I saw a horrible floor problem from an August install, so I now have preferences for flooring seasons.
AJ great points! Unfortunately around me it's all about "time" construction due to loan and bank mandates. Banks have not caught up to modern construction techniques.
Lucy asked; The floor has leveled out somewhat now that the area underneath is air sealed and insulated, but it's still a little lumpy. We're pretending it was designed that way.
Do you think it could be exterior humidity that is affecting the floor?
Answer is Yes and interior conditions could be also. How did you seal off the underside of the floor?
What type of insulation did you use? Please describe from the finished floor down to completion. I'm sure someone here has built a home using your assembly.