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.
Messages In This Thread
- Seasonal Movement, Then and Now