I've heard from a few people that homegrown timber shouldn't be used for roof construction because it grows too fast and grains end up being further apart than slower growing imported Northern European wood.
Could anyone tell me if there is indeed a difference between homegrown and imported C16 timber? Will homegrown C16 tend to sag over time?
If it is certified as C16 then it makes no difference where it comes from.
Often it is inferior but it will be sold thicker to compensate. Years ago rooves were all done in oak. Now we use knotty spruce and pine but they all work