Timber Framers Guild Forums General General Forum Questions Post checking

7 1/2" square post in timberframe home (RF/V kd red oak) is undergoing some substantial checking. Frame was raised 6 months ago in midwest. This is the most heavily loaded post in the home under a splined joint of 8x12 beams (rafter plates) plus supports top ends of pair of valley beams. Checking is to the heart with widest point about 1/2-3/4" spread and runs vertically 6'. It is a 16' post with 2nd level floor girt tenoned into it with shoulder. My immediate fix is to band it with 1/4" steel plate "bracket" that can serve to attach balcony/stair railing fairly inconspicuously.

Thoughts??? Thanks in advance.

Will,

Oak is very likely to check, the bigger timber the wider checks and 16" post is pretty massive one. I've seen splits over 1.5" wide so you could fit your hand in. Over time the check will progress and you'll see more of them all over the posts and beams. Those shall be located on sides close to the centre line.

Bending strap as you described is fine, but might not be necessary. Take a closer look at post/beam joint to see what happened to bearing face. Was housing deep enough to allow for movement? I presume housing should be at least 2" deep for this size of oak post and loaded beam.

I'm afraid we need to see some pictures to provide proper advice in this particular case. Can you upload some?

Michal
TFDesign.cz

I'm a newbie myself, but I am wondering...was the oak post green when you cut and fit the joints? I also have a few oak posts that have some decent size checking to them, but not as bad as what you describe. They are seasoned now and should not check any further. I wonder if there is a way to slow the drying of green oak to reduce checking? I wonder if anchor seal applied to the exposed end grains would have helped? There must be a way to control checking to some degree. Maybe mills have a technique? I'd love to hear anyone with knowledge on this.

7 1/2" square post 16' long. It was radio frequency/vac kiln dried red oak. Milled after kiln drying.

As I look at this post checking, it seems to me the tenon of the beam it supports (Hundegger machined) might be acting as a wedge into the mortise. The check or split is centered right up the mortise side of the post above and below the mortise. The shoulder for the beam is not very much over 1" deep. A handcut square tenon could rest in a square mortise without causing a splitting force, but a rounded machine cut tenon unless undersized on the bottom, could act as a wedge, it seems to admittedly non-expert me. Thoughts?

Again, a picture is worth a thousand words... If you don't know how to post pics, let us know and we can tell you how. It's an immensely useful tool when you can show people what you are talking about.

A square cornered mortise probably has more reason to initiate a check out of the sharp corners than the round cornered mortise IMHO.

Hope these pics help and hope the consensus is I worry too much. Again, this is a 7-1/2"x7-1/2" post that is about 16' high supporting part of a balcony and also supporting roof plate that includes top ends of two valley beams. Red oak radio frequency vacuum kiln dried. House standing < 6 months.

This long check goes to the heart on mortise side. Top check to the tenon is opening up in last few days about an inch to right of the long check. Pic shows 2x4 collar to support temp 2x4 railing. These are full res images so they're big files.

http://www.wcctonline.org/House 074.jpg
http://www.wcctonline.org/House 073.jpg
http://www.wcctonline.org/House 072.jpg

Thanks

Linky no Worky.

cut and paste the entire line. The space in the link broke the link.