Rafter Slits ??? Probably not dangerous..

zman22

OK, so I was in the attic today to begin running a kitchen exhaust duct as my kitchen renovation continues. The roof rafters are 2X12 #1 Hem Fur rafters. That sounds good. However, I noticed today that many have quite a bit of knots in them. They also must have sat in water for a while as most have a blackish residue or mold look on them that has since dried. More important I noticed that a few have mutliple horizontal "slits" that run near the mid span as if a very sharp knife made multiple gauges in the wood]. Should this be a future concern? Or is this somewhat normal to see. The slits run about 2 feet or so. The gauges in the wood look like they only go in about 1/8 of an inch.

Thanks

oh'mike

What you are describing sounds like 'heart checking'

These splits do not substantially weaken a joist. Not a concern.

Splits that actually reach the edge of the board are a different issue.


Sounds normal and expected. If you are still worried --crawl back up there and take a picture.

Good luck--Mike--

zman22

Thanks a lot Mike for the responce. I'll climb up to the attic and post some pics tomorrow just to be sure.

zman22

Here are 4 pics to prove whether or not I am crazy to be concerned about this.
I'm really not too worried, but I may NOT want to go over the existing roofing asphalt tiles with these joists. I need a new roof soon. What do you think?
Thanks

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Ron6519

The pictures of the check/gouges are typical wood issues I wouldn't concern myself with.
In any case, I would not throw another layer of roof over an existing one. This is purely a personal preference. Many locales allow 2 or 3 layers. I like to see the sheathing condition before it's covered up for another 20+ years.
Ron

zman22

Thanks for the reply Ron. I will probably have the entire roof stripped down before adding a new one. This also reduces the weight on the rafters as well I guess even though I will probably want a heavier 50 year roof. I'm probably a year or two away from needing a new roof.

oh'mike

Ron has a good suggestion about avoiding a "roof over"--A roof will look better,and last a bit longer when laid on a clean surface. This also gives you the chance to add ice and water shield where needed.

About your rafters--heart checking---not to worry about,look normal. Wood is a vegetable--we use it as a building material--the engineers take into account for the natural flaws that sometimes happen.


---Have fun----Mike---There is a PM (personal message) feature on this site,If you have a business question,PM the question--We like to keep anything that might look self serving out of our posts.
The contractors that are helping here do it for fun . --Thanks--Mike--

zman22

Thanks Mike for the heads up about the rules of DIY. This newbie didnt know the rules. I am getting addicted to this site and certainly want to abide by the laws here.

As for the rafters, you guys really know your stuff. I googled heart checking and indeed it appears to be a common issue with these "vegetables" that we use to build our houses. There is nothing comforting about seeing cracks in the sticks that hold my roof up, but you make a great point that the engineers account for these flaws. The 2X12s were a bit of overkill anyway. Now back to finishing the stove venting. I promise not to get side tracked again.

oh'mike

ZMAN---I really enjoy my time on this site--I've learned a lot here,and have fun solving the puzzles that appear in the posts.

What amazes me most is the depth of knowledge that is available--if a question is asked clearly or a good picture is provided.
Eventually a fine solution comes up.

Keep on posting--Thanks--Mike--