Ever see this type of splitting in a ridge board?
Ever see this type of splitting in a ridge board?
(OP)
This house was built in 1950's. We are in an earthquake prone area. The ridge board is a 25mm X 200mm sawn timber supporting purlins which in turn support a concrete tile roof. There is this weird split to the bottom end which I can't imagine why this would be. A theory could be a combination of deterioration and some seismic activity? Anyways, I thought I would share. I've not seen this type of splitting before.... any ideas?








RE: Ever see this type of splitting in a ridge board?
RE: Ever see this type of splitting in a ridge board?
The tear is so uniform it almost looks like Cedar, but probably is not.
Mike McCann, PE, SE (WA)
RE: Ever see this type of splitting in a ridge board?
RE: Ever see this type of splitting in a ridge board?
I don't feel that is strictly true. I think a better version of your comment is that the defect in the photo does not affect the roof structure capacity. I can envision a few other types of defects in the ridge that would be unacceptable and compromise rafter stability.
"It is imperative Cunth doesn't get his hands on those codes."
RE: Ever see this type of splitting in a ridge board?
B.E.
You are judged not by what you know, but by what you can do.
RE: Ever see this type of splitting in a ridge board?
Don't think you should mess with it unless (1) you see other problems or (2) they want to replace the roof for other reasons, in which sheathing and shingles will reduce seismic weight, add a roof diaphragm, and give an opportunity for a water barrier.
RE: Ever see this type of splitting in a ridge board?
Have never heard the word 'brash' used in this context. What does it mean?
RE: Ever see this type of splitting in a ridge board?
From the link:
"...brash wood breaks suddenly and completely across the grain with brittleness in fracture and with a comparatively small deflection. Consequently it absorbs relatively little energy in bending. Wood that is characterized as tough, on the other hand, breaks gradually, with continued splintering, and only after comparatively large deflection in bending has occurred."
RE: Ever see this type of splitting in a ridge board?
Dik
RE: Ever see this type of splitting in a ridge board?
Mike McCann, PE, SE (WA)
RE: Ever see this type of splitting in a ridge board?
RE: Ever see this type of splitting in a ridge board?
Dik
RE: Ever see this type of splitting in a ridge board?
Thanks for the definition. From that description, which says that "brash wood breaks...across the grain", that doesn't seem to be the issue here, as this broke with the grain.
RE: Ever see this type of splitting in a ridge board?
RE: Ever see this type of splitting in a ridge board?
I agree that that the timber did not break across the grain which is the usual definition of brashness, however Brash lumber can be harder and less flexible than the good timber adjacent to it The only way to tell would be to pull the piece down and try to break it.This timber appears to have split on a growth ring very cleanly , and from the straightness of the split it appears to be a nice piece of wood, sometimes a failure of this type will show up when the lumber is felled. Starting off as an end shake that nobody spotted when the lumber was sawn. If that split does not travel any deeper into the ridge timber than it has , I would not mess with it.
B.E.
You are judged not by what you know, but by what you can do.
RE: Ever see this type of splitting in a ridge board?
Could the brashness be caused by a very dry year followed by a very wet one, causing a weak plane in the growth rings, existing the splitting we see here?
Mike McCann, PE, SE (WA)
RE: Ever see this type of splitting in a ridge board?
Mike McCann, PE, SE (WA)