Est. 1998 — 27 years of woodworking knowledge
Seasonal Movement, Then and Now
Don Stephan
Somewhere I once read that seasonal movement of wood in furniture was not as much of a problem before about 1900 because the houses were not airtight and the winter heat did not dry out the air like today. That I think was offered as the reason cross grain construction was not avoided as much, such as drawer runners glued across the vertical sides of chests, and the explanation for splits today in those antique chest and highboy sides.
Malarky?
Re: Seasonal Movement, Then and Now
Barry Irby
Wood changes Moisture Content (MC) in relation to Relative Humidity. MC will equilibrate at about 1/5 of RH.
Until recently many houses had as much as three Air Changes (ACH) per Hour. The target now is 1 ACH. Any tighter than that and humidity builds up and disease pathogens can be a problem along with mold.
Way back, house were not nearly as warm an toasty as they are now. My grandfather had his house insulated in 1921. Thought it was a miracle because he did not have to break the ice out of the pitcher to wash his face in the morning. He had an indoor jacket and an outdoor coat.
So, the indoor humidity may have been higher. They cooked and bathed in doors, at least after they installed indoor plumbing. They had house plants. They kept a pot of water on the stove all the time to help with the humidity.
So, the MC inside the house may have been more even than now unless you have a Humidifier/mold factory.
Re: Seasonal Movement, Then and Now
Dick Coers
That is the common held belief, but I've seen a lot of broken antique furniture anyway. Lots of splits, lots of failed hide glue caused by wood movement. I have some 70 year old stuff in my garage that was my Mom's bridal bedroom set. Failed dovetails, failed bridle joint, cracked shelf, etc....
The idea for some craftsman is that "I've never had a failure" giving them the excuse to break the law of nature. We put too much effort into making fine furniture to randomly break the laws of wood movement.
We had an add-on bathroom in our old farm house. In a hard winter, we barely took any baths because the cast iron was brutal to touch. You sat in the center of the hot water pool. In our home, we were never allowed more than 2" of water in the tub. Any more was just wasteful! The drain trap almost always froze up. Our coal furnace did not have a stoker, so Dad would get up at least once or twice to shovel coal through the night. In the morning, we stayed under the quilts until we could smell heat coming back into the house! That smell always had the light scent of coal to it, lol.
Re: Seasonal Movement, Then and Now
John K Jordan
>>>Our coal furnace did not have a stoker, so Dad would get up at least once or twice to shovel coal through the night. In the morning, we stayed under the quilts until we could smell heat coming back into the house! That smell always had the light scent of coal to it, lol.
Ha, I grew up much like that too. The whole-house heat was a big cast iron grate above the furnace in the basement, banked at night with ashes then stoked in the morning. When it was sub-zero outside the heat in most of the house was just a suggestion. I suspect the wall insulation was old newspapers.
A glass of water left by the bedside would be frozen solid in the morning - the only upstairs heat was through holes cut in the floor with grates. Before school the bravest soul would run downstairs and stoke the banked coal in the living room fireplace then the others would grab their clothes and get dressed in front of the fire. Have to turn like a rotisserie to keep from getting too well done on one side and freezing on the other. Good clean living. I'm spoiled rotten now with heat and air in the shop.
JKJ
I don't buy it
Bill Tindall, E.Tn.
Houses in that day were not well sealed. Outside air in the winter can have single digit humidity, even here in TN and for sure in MN. Brought inside and warmed even slightly the humidity of this air will near zero. The opposite in the summer. No humidity control. Humidity swings stress joints. I can not see how anyone can make a case that humidity swings were less in 1720 for a table sitting by a fireplace.
I believe antique furniture suffers joint failure because it was stored in the chicken coop for 20 years when it fell out of fashion. I also believe that antique furniture suffers joint failure because someone short of lumber in 1720 hoped they could get by using wood less dry then optimum, or they had no idea how dry it was.
An there is ignorance or stubbornness. For a time English used cross grain drawer bottoms. Every one I have seen is busted. How can it not be!?! regardless of central heating.
Re: I don't buy it
Paul in NJ
I agree with Bill that the humidity swings were much greater yesteryear than currently. In England the humidity is more constant and the wood movement is less.
Re: I don't buy it
Sgian Dubh
"I agree with Bill that the humidity swings were much greater yesteryear than currently. In England the humidity is more constant and the wood movement is less."
Do you mean England, the United Kingdom, or the British Isles, Paul? The climate here in the UK varies quite a bit across these islands, as it does to an even greater extent in North America. I think you really need to be more specific about which two climates you are comparing to make such statements, e.g. are you comparing the climate of, say, Arizona with eastern Essex, or perhaps you're comparing the climate of British Columbia with western Cumbria? You don't say. Slainte.
Re: I don't buy it
Paul in NJ
My apologies Richard, I could have been more specific. I was under the supposition that the North Atlantic Drift moderates the climate in much (?) of the UK and comparing that to much of the USA with greater extremes. With that said, you might agree with wider temperature extremes you will see more wood movement.
Regards,
Paul Dzioba
Re: I don't buy it
Larry Clinton At Frankfort, (Central) Indiana
I agree 100%, I was raised in a home built in the 20's, it was heated (somewhat) by 2 oil burning space heaters. In the 1940's windows leaked air enough that I have seen snow on the window sill and edge of my bedspread in the morning.
Almost all the home in my small town were heated with wood or oil space heaters. These used "inside" air to burn. All the air / smoke rushing out the chimney was replaced by dry winter air coming in through the cracks in the windows, doors or walls. Few if any of the homes in that period had any insulation. As Bill said there were many daily air exchanges in the winter with effective near 0 humidity in the home.
My exiting home built in the 1880's was in the same condition when I purchased it many years ago. Today it is insulated, with new windows, and heated with a gas furnace with sealed combustion chamber, burning using outside air. Most new furnaces work this way. My shop also uses this type furnace and central air conditioning.
Adding in the fact that the water vapor from showers, baths and cooking are retained in the newer homes elevates the humidity level far above the older homes, reduces the "drying" of the furniture in the winter.
Most homes today also have fairly effective windows that seal and are insulated. Most are also Air Conditioned reducing the humidity in the summer. The temperature is also regulated far more closely compared to yesteryear.
The combination of higher humidity in the winter and much lower humidity in the summer, makes the possibility of the wood moisture content changing rapidly or extremely, far less likely.
Re: I don't buy it
Sgian Dubh
Paul, you are correct about the North Atlantic Drift affecting the coastal north western European climate, even all the way up the coast of Norway into the Arctic - the Russian navy can access the Atlantic all year round from Murmansk. Still, the west coast of the UK, places such as Cornwall, Cumbria and Scotland's Western Isles have a significantly different climate to the eastern side of the country, e.g., Essex, Aberdeenshire, etc, and even each of those places on both east and west vary significantly one to the other.
However, to the original question, as others have mentioned, houses worldwide have changed significantly over the last two or three centuries, especially in more advanced societies, or perhaps I should say more industrialised societies. In general, modern houses feature much better climate control measures which undoubtedly modify typical seasonal RH readings found in them compared to old houses with their poorly sealed windows and doors, intermittent heating and relatively poor insulation.
I strongly suspect the cause of shrinkage and splitting problems in wood, joint failure, lifting or buckling veneers, and so on in antiques sited in modern dwellings has less to do with the seasonal relative humidity range of typical contemporary housing and is related more to the typical moisture content of the materials used at the time of manufacture back in, for example, the seventeenth to nineteenth century. Here in the UK about the lowest MC air dried wood will achieve through seasoning is 18% MC anywhere in the country, and even that's rare. Additional drying is possible through moving air dried wood into relatively dry sheds, to perhaps 14 - 15% MC. So, prior to the twentieth century when kiln drying became more common, and nowadays pretty much the norm, antique furniture was built with wood that was rather well suited to the sort of seasonal MC range it might experience in service. Move those antiques into contemporary housing which tends to have lower seasonal RH numbers, then naturally there's going to be some additional shrinkage. Antiques simply weren’t designed for modern conditions and suffer because of the unexpected stresses they must cope with. Slainte.
Interesting points, Richard. Makes sense to me.