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wood shrinkage question12/18/19
We have a job that was completed during the winter months a year ago. The homeowner insisted on solid wood raised panels vs. MDF and furthermore insisted on Maple vs. Poplar. Many of the panels were very large, such as refrigerator panels, end panels, etc. There was plenty of dialogue about the amount of shrinkage and movement that could be expected, but they were insistent. Needless to say, the shrinkage was extensive and we spent several days re-caulking and touching up cabinet doors and millwork joints all over the house, as did the contractor for the extensive amount of paneling and millwork that they had done.
The homeowner is now asking if they should invest in a whole home humidifier to mitigate the amount of movement they have been told is likely to happen with every seasonal change.
What say you all?
If this was a paint grade job and you told them the reasons for using mdf instead of solid wood for those panels, I'd say "I told you so!" and then hand them the bill for all the rework. You shouldn't be held responsible for defects when they were the ones insisting on the materials to be used were against your recommendations.
We have told them that future touchup work will be extra and that is the reason they are considering the humidification system. My question that I'm hoping some wood experts on this forum can answer is: will this idea work to mitigate future problems?
Ignorance and reluctance to listen to trained professionals, on the part of some customers is astounding! It is impossible to eliminate wood movement.
It's totally possible to do it, but the investment could be significant, depending on the size of the house, geographic location and type of HVAC in the house. Assuming they started out with properly dried wood, movement is almost entirely related to the relative humidity in the house. Most whole house humidifiers are tied in with a forced air heating system, which only runs when it gets cold enough.
A home humidifier will help, but it won't eliminate wood movement. They will have to keep the temperature and relative humidity of their home as consistent as possible throughout the seasons. Like I said, this won't eliminate wood movement, but it should minimize it.
Museums that house large collections of wood objects - primarily furniture - are required by their insurance companies to place a chart recorder in with the valuables to get reliable readings on temperature and humidity.
If there is no change in RH in a space, then there can be no change in MC in a wood object (kitchen). The chart recorder is there to insure the environmental system is doing its job and protecting the collections.
If your customer uses a real environmental systems analyst and installs their recommendations, then there is a good chance the movement is over. Even if they skimp some and go with less than recommended, thee will be some mitigation of the MC problems in the house.
More facts are needed to get a complete picture: MC of the lumber when you received it at your manufacturing facility. MC of the work when it was delivered. RH of your shop during storage and manufacture. RH of the jobsite when the work was delivered.
As you can see, a complete picture is a rare thing. But, what data you an collect will help you understand what is happening, and better how to respond to that.
If the home is of any value and quality the HVAC contractor should easily be able to get the home to a point where the swings will be minimal enough that no visible wood movement will ever happen. The problem you will run into if its a super high end home and in a location where the owner wants to open up massive wide walls, windows, natural cross ventilation, is that no HVAC system will compete with that. Spring and fall moist air will saturate the space and the HVAC will struggle to keep up.
The only hope is a home that is kept relatively closed and a well designed and maintained HVAC system with active humidification in the drier months of the year.
We had a similar problem happen in one of the big houses. Luckily it didn’t have any effect on the beaded inset ff kitchen.
It was a well built house. Tight & well insulated. We trimmed it in the middle of summer in CT. We left the miles of wide poplar trim in the living room for a couple of weeks. Installation went well. Everything was perfect. Come winter time he ran the hvac system without the in built humidifier. Everything shrank and dried out. He had to repaint all of the trim in the whole house. Many rooms had wainscotting.
I had built the kitchen in my shop in the fall which is not humid in CT. mdf panels glued in maple.mitered,glued & nailed door moulding. Maple beaded face frames. Semi gloss paint. No movement whatsoever. It’s been there for over 10 years. Still perfect. It’s a $75k set of cabinets so I got “lucky” that it only affected the trim.
6” wide poplar trim moves a ton.
If you knew the panels were going to shrink as you say, you should have painted the panels with at least one coat of color before assembly. No idea why you needed caulk, I've never used it. It's also not against the law to add center stiles to make the panels narrower. Also exponentially better to use quarter sawn in the panels for very minimal shrinkage.
This is an easy question to answer.
1) If the house has no trouble at all staying below 50% humidity and keep fairly stable, then no they don't need a dehumidifier.
2) If the house is going to swing the humidity a lot or they struggle to get it below 50%, then absolutely yes a dehumidifier.
Now, unrelated to cabinets, if they can't keep their house below 50% then the best money spent isn't a dehumidifier but rather finding out where the humidity is coming from and fix that. Leaky ductwork, oversized HVAC units, dirty coils, bad envelope sealing, poor bathroom ventilation, huge-ass aquariums.
If I were you I wouldn't be talking to them regarding whether they need a new machine (dehumidifier), that's the HVAC guy's job. You need to be clear to them that they need to keep the humidity 40-50% stable. Let them decide how that needs to happen.
For what it's worth we used hard maple on nearly all our paint grade jobs for various reasons. We seldom have more than a little caulk here and there that we have to deal with regarding wood movement. Maple isn't exactly one of the worst offenders here.
Matt, I always heard that maple had a lot of movement? I heard the other day that some are turning away from poplar. I think in general, the quality of poplar has gone down, at least what we get out here in the west.