hoping someone can answer this.
i have a few 2x10 joists that have horizontal cracks.
each joist has only one crack.
they all appear to originate from where the nails went in to secure the joist to the joist hanger.
these joists also have bridging in the center span.
my question is, if these cracks are stable over years and have not grown in length. is it safe to presume they were from the original construction, and not from being stressed ? (ie. heavy loads on top).
the other question is, if the crack originates from the end, where it's resting on the hanger, wouldn't a load on top, tend to compress the crack together ? (since the hanger is providing some resistance from the bottom of the joist).
and thirdly, what does "sistering" the joist actually do ? it would seem to be futile, since the sistered joist, would need to be in a hanger too to support the weight wouldn't it ? (i don't see how just lag bolting another 2x8, 2x10 next to an existing joist is going to help that joist bear any loads that are vertical - since the sister joist isn't resting on anything - just lag bolts - and the forces are still transmitted to the existing joist hanger of the existing joist).
thanks in advance for any responses.
basically i'm wondering if i should worry about those cracks or not - they are stable, and have not changed in size. the joists in question are also sorrounded by doubled up 2x10 joists, 16" away.