hi
last year i purchased 7 oak posts for a pergola project, now i have noticed huge splits in the posts running vertically the length of the post, at about an inch deep in some parts.
Now, should i be worried at all ? these splits are big and visible and am a little concerned, is this normal ?
Thanks
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Replies
Last year like 4 months ago or last year like a year ago? Purchased green and stored improperly ,yah ,thats pretty normal. Those boards are split, most likely still somewhat green and likely to split more. Try again ...either purchase dry 4x4s or if green is all you can get or afford -wax the ends and store them covered and stickered and next year or maybe two, three would be better, they will be ready to use. The other alternative of course is to use them as they are for that derelict farm look, some people like that!
Oops...are those set in concrete?
hi and thanks for your reply, yes they are set in concrete. i purchased them 9 months ago to be precise.
If you used red oak, yes, I'd be worried. It's going to rot and the structure will be at risk. White oak is suitable for outdoor use (and a few other oaks that are not easily obtained). Red oak is not.
If this was a project that required a permit and code inspection, it would have failed probably even if you used white oak. Code inspectors are looking for grade stamps and certifications.... for a reason.
Where I live, anything built in your backyard that can fall over and kill somebody requires a permit and an inspection.
100% normal. These are not 'huge splits' but 'normal checking'. What is happening is the timber is drying and this drying is forcing these checks to relieve pressure from uneven drying. This is very normal for oak (and most wood) and not a problem. It will not have any impact on the structure. Go over to England and see 700 year old timbers with this checking as evidence.
Now with this said, Charlie is 100% correct. If this is red oak, this is going to rot. Hopefully its white oak.
Also, no oak is suitable wood for 'ground contact.' If its touching the ground, especially dirt, in such a way that it can't dry out, you are going to get rot there, even white oak. It looks like the timbers are standing on stone pavers which will probably be ok but that is a weak point in any timber frame structure.
Agree with jbailey, normal drying cracks. Most 4x4s have the pith in there and shrinkage around a center point produces cracks. If you can add plastic or metal feet you'll reduce moisture uptake. Simpson strong tie makes a couple different ones, T-connectors are pricier but also prettier.
Thank you guys,
just want clarify a couple of points. these are 6x6 and its white Oak, they are set in concrete and the bottom of the post is wraped in postwrap to prevent it from rot.
Those look like some beautiful white oak timbers! I can't tell from the pictures, but the timbers look to have "boxed hearts" (i.e. pith generally in middle of the timber), which makes sense with the checking observed. Nice work on those tenons as well.
Should have left them unpainted. It accentuates the cracks (by contrast) and not in a good way IMO. Penofin or something like would have been better. I suspect they were a little green, too, so they needed some weathering time if the paint had to happen.