# How to replace posts before concrete is poured



## rosco (Dec 26, 2009)

the picture should explain everything. the four posts are holding up a porch. 

when i pour the concrete it will crack out from the four corners of the rotting posts. so replacing the posts before the concrete is poured will still result in cracks from the new inlaid posts.








HOW DO I SUPPORT THE PORCH, GET RID OF THE ROTTEN POSTS AND LAY CONCRETE? 

i have a manual post hole digger and don't want to spend lots of money on round steel posts.


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## rosco (Dec 26, 2009)

*another pic*

here is picture from a different view:


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## kwikfishron (Mar 11, 2010)

A picture of what the post are holding up would help but basically you need to temp. up the porch to the outside of your pour.


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## jomama45 (Nov 13, 2008)

I would replace the posts first if it was my own. I would also wrap the bottoms (below top of concrete) with I&W sheild & wrap 1 layer of foam expansion joint around the post to allow the concrete to move independently w/o binding. For the 2 posts in the middle of the pour, I would run a control joint right to the center of them. The 2 outer posts should be fine with just the expansion around them.


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## kwikfishron (Mar 11, 2010)

jomama45 said:


> I would replace the posts first if it was my own. I would also wrap the bottoms (below top of concrete) with I&W sheild & wrap 1 layer of foam expansion joint around the post to allow the concrete to move independently w/o binding. For the 2 posts in the middle of the pour, I would run a control joint right to the center of them. The 2 outer posts should be fine with just the expansion around them.


Why not post brackets?


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## jomama45 (Nov 13, 2008)

kwikfishron said:


> Why not post brackets?


 
Mostly because there is no mention to where in the world this may be. :whistling2:

If the patio were ever to heave, it would take the deck with it.

Post brackets would work IMO, but here's how I would do it then:

Extend the existing sonotubes to or above the top of the new patio elevation with tubes. Dowel a few small rebar chunks into existing sonos.

Wrap teh new tubes with the same expansion material. Fill inside of tube the same time as pouring patio. Set post anchors after concrete is hard.


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## kwikfishron (Mar 11, 2010)

jomama45 said:


> Mostly because there is no mention to where in the world this may be. :whistling2:
> 
> If the patio were ever to heave, it would take the deck with it.
> 
> ...


:whistling2:
I totally agree. If heave is a issue then dig, Anything than
entombing the post in mud.


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## tpolk (Nov 7, 2009)

jomama45 said:


> I would replace the posts first if it was my own. I would also wrap the bottoms (below top of concrete) with I&W sheild & wrap 1 layer of foam expansion joint around the post to allow the concrete to move independently w/o binding. For the 2 posts in the middle of the pour, I would run a control joint right to the center of them. The 2 outer posts should be fine with just the expansion around them.


i agree with all of this with the one question of whats under those posts now. footing?


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## kwikfishron (Mar 11, 2010)

I'll bet a 100 on nothing.


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## tpolk (Nov 7, 2009)

looks like concrete in the one pic unless its old slab


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## rosco (Dec 26, 2009)

*hmmm*



jomama45 said:


> ...
> 
> If the patio were ever to heave, it would take the deck with it.
> 
> ...


if the patio heaves it will take the porch with it? there is slight movement in the soil or settling, but no earthquakes. 

i'm curious if i could wrap this tape around the existing 4x4' and pour the concrete mix. once poured, i'd bracket in the old 4x4's. it seems unlikely that i could prop this porch up. it is a "home job" from about 30 years ago. and we have little interest in putting $ into it.


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## rosco (Dec 26, 2009)

tpolk said:


> i agree with all of this with the one question of whats under those posts now. footing?


contrete footing at bottom of posts. these posts were in dirt before i dug them out and broke off top three inches to lay cconrete (someone told me that was a good idea.

i've no idea how much is below it but i'll bet about 6" from just the way one of the post's foot was broken. it wiggled like a broken tooth. 

is there a way i could treat or fill in the rotten portion so it doesn't rot more? and then a way to wrap expansion tape around it to prevent thin cracks to from going out from the posts as the concrete slab is poured?



kwikfishron said:


> I'll bet a 100 on nothing.


who did you bet? i'll take the payout on that bet to fund this project! :laughing:


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## jomama45 (Nov 13, 2008)

tpolk said:


> looks like concrete in the one pic unless its old slab


Somehow, I caught that little part in the pic as well. I usually don't look at these pics long enough to catch these kind of things, but it looks like some kind of sonotube ot me.



rosco said:


> if the patio heaves it will take the porch with it? there is slight movement in the soil or settling, but no earthquakes.
> 
> i'm curious if i could wrap this tape around the existing 4x4' and pour the cement. once poured, i'd bracket in the old 4x4's. it seems unlikely that i could prop this porch up. it is a "home job" from about 30 years ago. and we have little interest in putting $ into it.


No big suprise! :laughing:

Yes, the patio could heave IF you are in a cold climate, but I guess no one here will ever know if that's the case. :whistling2:

You can wrap the existing posts, but if they touch any earth or concrete, they will continue to wick moisture into themselves & rot out. Now would be a good oppurtunity to rectify that situation.


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## cocobolo (Dec 16, 2008)

We are lacking some information here. It might be very handy to know what these posts are holding up, and what the weight may be.

In any event, I think you might be barking up the wrong tree here. Don't entomb your posts in your new pour.

Take the weight off the posts, one at a time if necessary, dig a hole and construct a proper footing under the location of the posts. If you could make the top of your footing slightly above the finished concrete floor - about 3 or 4 inches, that would be good. You could set your saddle in the correct place and the problem of future rotting wood is solved.

If there is some old concrete under there, I would get it out.


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## rosco (Dec 26, 2009)

What are you talking about? read two or three replies above the last jomama45 reply and you'll see i wrote the posts have concrete feet. i don't know how deep they are. i'll guess 6". 

"barking up the wrong tree"? do you mean that i have the wrong approach or that i'm asking the wrong people? 

jomama45 - the owner of the house, not me, is wanting to save money and knows these posts are rotting. she can see them. if i could wrap it in expansion tape there wouldn't be cracks shooting off around the posts. the posts would be bracketed to the concrete so when they do rot, she should be able to see more of it before the porch collapses. are you kinda following me? it is likely i won't be here to catch blame for not putting in steel poles and replacing much of the rotting wood above in the actual porch. someone else will get to deal with that.


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## cocobolo (Dec 16, 2008)

Apparently there was some kind of problem before to cause the rot.

Maybe it is just old age, I don't know.

I would remove any old concrete that is there and make a proper new footing. 

If you intend to use the same posts, surely it would be best to cut back to sound wood. Make the center part of the new footing up to that elevation.

I got the impression that these posts were still going to be surrounded by the new concrete pour. I don't think that's a good idea. That's all.


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## rosco (Dec 26, 2009)

yeah, i hate doing it this way (pouring concrete around rotten wood. i'll probably just get some 4'x4' and put up a temporary brace. maybe i can find some cheap steel posts around town.

wood has rotted in all concrete footings that i've seen. water soaks into the wood and settles to the bottom over time where it can't really escape. wet wood rots. Exposed wood here deteriorates quickly with the high winds and low humidity (desert almost).


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## tpolk (Nov 7, 2009)

box out 12-16" around posts, do new pour, let concrete cure a few days, temp walls, pour boxed areas high strength, set new posts


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## cocobolo (Dec 16, 2008)

rosco said:


> yeah, i hate doing it this way (pouring concrete around rotten wood. i'll probably just get some 4'x4' and put up a temporary brace. maybe i can find some cheap steel posts around town.
> 
> wood has rotted in all concrete footings that i've seen. water soaks into the wood and settles to the bottom over time where it can't really escape. wet wood rots. Exposed wood here deteriorates quickly with the high winds and low humidity (desert almost).


There's absolutely no doubt you are right about that.

I wonder what sort of wood the posts are now. Do you know by chance?

Something like black locust would last a long time if it's available where you are, or alternatively, pressure treated wood. It all depends on what you can get I suppose.


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## rosco (Dec 26, 2009)

the posts are ~30+ years old. i've no idea if they are pressure treated. 

i saw some guy with about 5 metal steel posts laying against his house down the street. ~5:30PM i'll swing by and see if he wants to sell them.


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## rosco (Dec 26, 2009)

*Going to Try One post (the rotten one)*



jomama45 said:


> I would replace the posts first if it was my own. I would also wrap the bottoms (below top of concrete) with I&W sheild & wrap 1 layer of foam expansion joint around the post to allow the concrete to move independently w/o binding. For the 2 posts in the middle of the pour, I would run a control joint right to the center of them. The 2 outer posts should be fine with just the expansion around them.


see scanned image and my questions are there but you can't read them: 
1) What should the diameter of the sonotube be (ID)? 
2) Sonotube should be level with the Future Slab?
3) How far below the bottom of the "pit" (dug for the future concrete slab) should the "feet" be made?
4) Did Someone say rebar dowels should be put into the "feet" of the posts when laying the slab of concrete around these posts? 
5) i'll have to do this one at a time. "she" might stop me after this post is put in. it would be much safer for me if i set these posts one by one. this means i'll pour the "feet" of these posts first. i'll wrap them in the expansion stuff before pouring. coool? 
6) can i use two screws on each side to affix the Braces? i'll post photo in a sec.


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## rosco (Dec 26, 2009)

*photos*

Question
7) is this brace going to work? i plan on putting a similar one where the cinder blocks are stacked. 
8) how many pieces of rebar in one footing (if there is supposed to be rebar dowells in the [see ? 4) above]
(the pink 4'x4' is the brace)













​


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## Scuba_Dave (Jan 16, 2009)

You usually put the bracing out side of the area where you are pouring cement
Bracing it at an angle


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## tpolk (Nov 7, 2009)

you're just holding up a roof? put some temp bracing to outside of pour, lose the post, thicken slab at new post position to 12" thick and be done with it


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## kwikfishron (Mar 11, 2010)

Sonotube, get the post out of the ground. No more rot. Cardboard peels off.


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## jogr (Jul 24, 2007)

You confuse me when you say you know there is a concrete footing but you don't know how deep they are. Do you know the diameter of the footing? The Load on the posts?

Based on the load you can calc the needed footing size. If the current footings are adequate then you can prop up the structure above, cut off the posts above the rot, attach a bracket designed for concrete embedment and use a sonotube and rebar to pour a 12" concrete column on top of the footings up to the bracket.

If the footings are undersize, remove them and use appropriate bigfoot and sonotube to pour footing and column in one step.


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## tpolk (Nov 7, 2009)

i guess a 12" thickened slab with brackets at post locations wont cut it? mymy


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## rosco (Dec 26, 2009)

*inside or on top of sonotube???*



kwikfishron said:


> Sonotube, get the post out of the ground. No more rot. Cardboard peels off.


so, should i bring sonotube all the way to the top, then bracket the post on? OR, should i put post down into to footing, inside the sonotube?


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## rosco (Dec 26, 2009)

jogr said:


> You confuse me when you say you know there is a concrete footing but you don't know how deep they are. Do you know the diameter of the footing? The Load on the posts?
> 
> Based on the load you can calc the needed footing size. If the current footings are adequate then you can prop up the structure above, cut off the posts above the rot, attach a bracket designed for concrete embedment and use a sonotube and rebar to pour a 12" concrete column on top of the footings up to the bracket.
> 
> If the footings are undersize, remove them and use appropriate bigfoot and sonotube to pour footing and column in one step.


I don't know the load, give a damn how it is calculated and the porch is very old and not built properly. the old post and footing will be removed.


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## jomama45 (Nov 13, 2008)

rosco said:


> see scanned image and my questions are there but you can't read them:
> 1) What should the diameter of the sonotube be (ID)?
> 
> How big is the current footing these posts are resting on? I think 12" dia. is more than enough.
> ...





rosco said:


> Question
> 7) is this brace going to work? i plan on putting a similar one where the cinder blocks are stacked.
> 
> Not for sure, as I can only see the underside. If there is a porch above this, I assume the stell roofing is meant to keep the patio dry if it rains?
> ...





kwikfishron said:


> Sonotube, get the post out of the ground. No more rot. Cardboard peels off.


A pic is worth a 1000 words! :thumbup: Do this right here, but IMO you don't need to keep the sono tube high, just flush. Make sure you use a post anchor/bracket that holds the post off the crete a little so water can weep out.



rosco said:


> so, should i bring sonotube all the way to the top, then bracket the post on?
> 
> Yes, probably the best situation.
> 
> OR, should i put post down into to footing, inside the sonotube?


Only if you wrap the wood column with I&W shield, or something similar. BUT, we have no idea where you are and if you have to deal with an uplift scenario do to storms.



rosco said:


> I don't know the load, give a damn how it is calculated and the porch is very old and not built properly. the old post and footing will be removed.


:thumbup::thumbup::laughing::laughing:

AWESOME POST!!! If the footing has indeed been in place successfully for 30+ years, there's no reason to replace it. I think this thread has been way too over-done, and understand why you're somewhat confused.


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## jomama45 (Nov 13, 2008)

I just looked at those pics again. If by "porch" you're refering to the porch under the roof, there's next to no load there at all. If all you have is that little framing & steel roof, nothign more above it, you could damn near hold that roof up temporarily by hand. :thumbsup:


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## rosco (Dec 26, 2009)

*pic's this time -*

Jomamba45 - 
The pic's will best describe the current status the two posts (pink and new cedar are braces for this part of the porch, although this particular post doesn't seem to be supporting any weight it probably helped hold it down in the sometimes violent updrafts adn gusts of wind). 

I"m just doing one post right now. using a 24" long sonotube and 8" wide. 
the old "feet" were 8" wide and i've no idea how deep. they were cracked/crumbled.


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