Has anyone has used hemlock lumber successfully in the fabrication of sash and door?
(Architectural Woodworking Forum)
From contributor S:
Some of the characteristics that make hemlock desirable for covering barns also make it a decent choice for exterior applications such as doors and windows. I've used it a bit for both and find it holds up well and it pretty stable. It is not pleasure to work with, being coarse and prone to splinter, but is stronger and more rot and bug-resistant than pine, as well as being cheap.
I respect the work of those that have done the research, but think there might be room for some new information. There is a reason hemlock has been used extensively for siding in its native range and you can be darn sure it's not because it rots quickly (pretty much the first criterion for siding). If you have access to yellow or Port Orford cedar you'll find them much more suitable for doors and sash. I would go with those any day over hemlock, but I would not discount it out of hand as some do.
Spanish cedar, some western red cedar, Honduran mahogany and other woods considered stable and durable are in fact old growth cuts, while the current crop of redwood, cypress, some western red cedar and others are second or third generation cuttings. What they have in common is a low annual ring density. What the durable species have is high ring density.
If my wildly unscientific conjecture is true, it could be that some first growth hemlock - reclaimed, logged or risen from the waters - could be a good stable wood for exterior work. It may be a better choice than some recent growth in redwood, cedar, VG fir or cypress.
In the Western Woods region, the 12 contiguous Western states plus Alaska, there are approximately 20 commercially important species well suited to softwood lumber production. While each has unique characteristics, physical and mechanical working properties, making it appropriate for specific applications, these Western softwood species are grouped into six primary combinations. These combinations simplify production, inventories and distribution, and facilitate engineering and product specification for design.
Hem-Fir is a species combination of western hemlock (Tsuga heterophylla) and five of the True Firs: California Red Fir (Abies magnifica), Grand Fir (Abies grandis), Noble Fir (Abies procera), Pacific Silver Fir (Abies amabilis), and White Fir (Abies concolor). While western hemlock and the true firs are sometimes marketed separately in products graded for appearance, these species share similar design values making products graded for structural applications interchangeable. The Hem-Fir species combination is one of the most important in the Western region, second only to the douglas fir-larch species group in terms of abundance, production volumes, strength, and versatility in end use.