My new house has a back porch. The roof is held up by a couple of 4 x
4 treated posts. Both posts were green when installed. Now, after 6 months, both posts are warping. There is as much as a 1" deflection from the top(or bottom) to the middle. Is there anything I can do about it? These posts have not been stained or sealed.
Probably means they were treated way before they were cured, then finally dried out and warped after installation. Bad lumber. Short of replacing them, the bend is pretty hard to cure, but other than being cosmetically unappealing, probably not yet a worry, structurally.
I cant see the porch but deflected wood usualy means to much weight is on it, and both deflect!
According to the lumber yard where we got the posts, they would have been dried before being treated. However, they were not dried after being treated. Do you think I could force them back straight if I put an I beam on the bowed in side and used a clamp to pull in the center?
Dubious. It might work, but I don't think it would stick. Once you pulled it back into place and removed the brace it would drift back. You're fighting the natural inclination (grain) of the wood. Once the lumber is cut out of the log, all of those nice round sections (with opposing forces that pretty much cancel each other out) disappear. You're left with a piece of wood that wants to relieve stress. This is a major problem with treated wood since, as you've discovered, most of the stuff is sent out from the lumberyard soaking wet. One of the reasons that some people use posts that are built up from a couple (or more) pieces of lumber.
R
Deflection does indeed imply stress. I don't read this as exceeding the posts capacity, but more of cheap, wet treated lumber trying to "straighten" itself out by bowing. I'd be surprised if there wasn't some twist in there as well.
To the OP - how tall is the post?
RBut we can see what the 4x4 is holding up.
Treated lumber is notorious for bending and twisting. Pressure treating forces water into the wood. Even is the wood is dry, it's once again wettened during the processing. When it drys, it warps. I had a 10' 4x4. It was straight when I bought it. A couple weeks later I go to use it on a shed and find its so twisted that the bottom of the post faces north and the top faces east. I was not in a position to go buy another one and wanted to finish my project. I put the bottom in the ground and started nailing the lower boards to it, using ringed spikes. Each board when driven securely straightened the post a little. By the time I go to the top, it was only off by 1/2 inch. Close enough for what I was building. A couple weeks later I added a few more spikes and got it even straighter. It's stayed that way since. Of course I have a wall mounted to it, not just posts in the middle of something.
The easiest way tot "fix" the posts is to replace them.
Go to a real lumber yard (if you've got one available) & try to buy some treated 4x4's that are already dry. If dry / treated posts not available, go for the driest you can find (if you or they have a moisture meter available, even better)
Ideally you want to buy posts under 19% moisture content, closer to 10% would be better. I have purrchased treated sills (Hem-Fir) that actually dripped liquid when crushed in a vise.
Also when selecting the posts, look at the ends. AVOID posts cut from the very center of the tree. Try to get posts with the end grain with a little curvature as possible. Less curve means cut further from tree center. This grain pattern will tend to dry with less cracking, twisting & warping.
Another possibilty (but a lot of work) is to "fixture" new wet posts to restrain them while they dry.
cheers Bob
That dripping stuff freaks me out. Sometimes you shoot a nail in and the wood bleeds. It's disgusting - like pus. I like my wood dead, just like nature intended.
R
ROFL I hope you never cut your finger when you are working......
Why would you expect a different answer when you're asking the exact same question? It's time to move on to plan B, or at least question B.
R
I was just having this conversation yesterday with a plumber. I always wear gloves now, have a several pair of different types in various stages of decomposition that I cycle through depending on the job at hand. We were working on replacing a 70 year old one-pipe steam heating system return line, and I wasn't really planning on doing his work, but you know how it goes. I got three nicks on my knuckles in a couple of hours of work because I wasn't wearing my gloves. That would normally be my tally for a month of working with my gloves.
It's not that I hate blood, or even my blood, it's just that I'm old-fashioned and like to try and keep the blood in the original container.
RAre the posts only bowed in one principal axis?
that means, when viewed while facing one side it looks straight, when viewed from 90 degrees off the first view , it looks bowed
if only bowed about one principal axis (like a bowed yard stick) you COULD straighten it but IMO it would less time, effort & material cost to replace them
Do you have an appropriate steel member to use as a strongback? and a bunch of clamps?
a better question is why are they bowed? are they over loaded?
cheers Bob
I'd change COULD to MIGHT, and use a bigger font so you'd know that it was an extremely remote possibility. Once they're straightened - if it can be done without cracking them - what is holding them in place? Memory? Their memory of being bowed is a lot more urgent than their memory of being straightened. Without bracing or leaving the straightening mechanism clamped on for a _long_ time the chances are nil.
The OP mentioned these posts were supporting the roof. Why would you assume that the designer undersized the posts?
R
Is there any twist in the post?
A 9' tall 4"x4" post is not a great idea. Too slender. Some people clad them in 1x for appearances and to help keep them straight. Other people would use a larger post, or a treated LVL.
R-
I think you answered your question to me........
""Why would you assume that the designer undersized the posts? "
I didn't necessarily assume the designer undersized the posts......
designers & engineers make mistakes and contractors do sometimes cut corners. Rather than just telling him how to straighten or replace the posts I thought it prudent to dg a little deeper as to why they're bowed.
I haven't seen that many bowed posts in my experience, so w/o seeing this installation (or pictures) it seemed reasonable to ask if they were maybe overloaded.
It could have been a boot legged install
(I know he said "my new house, maybe new to him but not new)
Also I've seen new houses (custom design & engineered) with grossly undermized members & major deflection issues, so it does happen.
wrt to my use of COULD, I really meant "he possibly could".
I know I could (definitely) straighten them, if for no other reason but to prove it could be done.
but in his situation I'd make sure the member was correctly sized & then replace the bowed posts with straight one........
quickest & cheapest way
cheers Bob
Hmmm, seems we have a horse race! Too bad we can't have two identical post installations and see who's "right". I have my hunches. ;)
Not having seen the situation, I can't say for sure, but you may very well be right. As long as the post is a simple installation with a post cap and base, it would be pretty trivial. If the installation is more complex with a deck wrapping around the post and/or beams let into the sides, it would obviously be much more complex to swap out.
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