Replies

1. 
   xMikeSmith | Aug 27, 2002 06:34am | #1

   don't know why they shifted.. i could guess though.. a 3' sonotube formed pier is unstable if a force is applied off center to it's top.. especially if the form was out of plumb to begin with.. the post acts like a pile driver. with every impact of people above on the deck

   but since they are adjustable.. cut the bolts..replumb the posts, dig new footings and repour.. ..maybe cut the top off the sonotube pier and use it as a sub-footing for the new pier top

   Mike Smith   Rhode Island : Design / Build / Repair / Restore

   
   

   ---

   Edited 8/26/2002 11:42:38 PM ET by Mike Smith

1. 
   user-6886775 | Aug 27, 2002 08:30am | #2

   I know that before and after the pour, the forms where plumb. But, I think that you are right about the offset load.

   I'm really trying to avoid trying to dig up the failing footings, because I can't realistically get any power equipment into the area anymore. And the footing is about 650 lbs of concrete.

   I keep wondering about a poured brace, like a wedge against the tilt, with the wedge rebarred into the side of the footing. It would have a limited distance to go because of the septic field and possible tree roots. Maybe this would keep it from further tilting. I could then just redrill the hole in the top of the failed footing. Maybe this is too much wishing....

   Thanks,

       johnbo----Cornelius, OR[email protected]http://www.johnbo.com

1. 
   Luka | Aug 27, 2002 07:48pm | #8

   johnbo,

   If the sides of the hole were simply straight up and down, instead of providing a wider footing in the bottom of the hole, as Shoeman has asked about...

   Then, yes, your idea is wishful thinking.

   Think about it. You essentialy have this straight as a pencil, concrete post, originaly standing straight up. It starts to lean. (Think, Tower of Piza) Now, you want to add more weight to the upper side of the concrete post.... on the side that it is leaning toward. Guess what's going to happen ?

   Yup, it'll lean faster.

   It will do so, and continue in the direction it is already going, no matter which side you put the 'wedge' on. I think it will just go slightly faster if you put it on the side that the post is already leaning toward.

   Quittin' Time

1. 
   user-6886775 | Aug 28, 2002 08:58am | #9

   This pretty much a reply to the last 3 or 4 posts. I think that I'm starting to see the errors of my ways. First, I had ASSUMED that a 18" pier (without a flare or bell at the bottom) was also a footing. In my original post, I had even occasionally swapped the terms for footing and pier.

   From one of the posts (Mike Smith, message #6), a solution was proposed, but I'm having some trouble understanding this. In his solution, he spoke (wrote) of a 12" (or 18") cube being placed with its base at 40" below grade. I assume that the new pier rests on top of this. If I've understood this correctly, it appears that the only difference between my existing (and flawed) solution and his, is the shape of the bottom 12" of the pier/footing object (ignoring my 36" depth vs. his 40"). I guess that I don't understand how this would be that much different, in that its really only the difference in the shape of the foot.  I wish that it was easier to show diagrams on this message board. But, my existing approach has an 18" diameter, his has a 18" square. Given that the horizontal extension of the footing in the axis of the thrust is the same, I can't see that this helps. Oh, unless its the little bit of extra surface area that a square would provide over a circle.

   I read the comment about the flared footing (using a Big Foot or equivalent), but it seems that the larger diameter is about the same as what I started with. Which doesn't seem to be the cause. My only exposure to the Big Foot devices was an 18" diameter for the large end and 12" for the small end. 

   So, is the real solution to get rid of the failed footings and replace them with a pier/footing combination as suggested, but more closely aligned to the center line of the load? In effect, not that it is possible, but basically shifting the existing pier so that it is properly in line with the load.

   I guess I can be glad that the loads on the other five piers are aligned properly.----Cornelius, OR[email protected]http://www.johnbo.com

2. 
   PhillGiles | Aug 27, 2002 08:59am | #3

   You didn't mention (or I missed) if the pier moved alone, or if the earth around it is moving with it. In any case, if the load was applied close to vertically, then that would be low on my list of suspects; shallow piers do have a reputation for floating around and drifting down-hill. In any case, I'm with Mike on this one that you need a new pier; preferably, IMHO, at least a 4' below grade

   .

   Phill Giles

   The Unionville Woodwright

   Unionville, Ontario

1. 
   user-6886775 | Aug 27, 2002 10:32am | #4

   The pier or footing appears to be moving away from the soil. If I look at the back of the footing (away from the direction of travel) there does seem to be gap, roughly equivalent to the amount of travel. Hard to completely tell, as over time they get filled in with other stuff.

   Wow. 4' or deeper? The folks that I talked to when I built the deck, thought that I was nuts for going to 3', they thought that 18" (the frost line) would be way more than sufficient. In fact, the old deck footings (no longer in use) were set only 6" deep, sitting directly on the soil. That worked for about 15 years, until the deck above rotted away. If it helps, I'm located in the Pacific Northwest, where getting a snowfall of over an inch is quite an experience. Only once in 15 years has the top 2 inches of the soil frozen.

   Is a 3' pier really shallow? Or is it a function of the slope of the land. The slope where the footings are is at the most 2" drop over 24" or a 1 in 12 grade.

   Thanks,

       johnbo----Cornelius, OR[email protected]http://www.johnbo.com

1. 
   xMikeSmith | Aug 27, 2002 01:29pm | #5

   our design soil bearing is 2000 #/sf..  our frost depth is 40"..

   a footing for your deck would be 12x12x12  with the bottom of the footing at 40".. the post would extend all the way to the footing with no mechanical connection..

   if your soil (undisturbed for 7 years) will support it  (check local codes or do soil test ) dig a hole to 18" .. pour a 18x18x 12'High footing  ( or 12x12x12)  and reset the post..

    you can split off the top of the old pier and use it as a baseMike Smith   Rhode Island : Design / Build / Repair / Restore

2. 
   PhillGiles | Aug 27, 2002 06:08pm | #6

   Well, we could make lots of long-distance guesses because there are a lot a variables at work here, some might even be right. I gleaned that much of the soil all around the post has been disturbed (leach-field, septic, house); it may even be in a graded section itself. I also took a guess that if a 3' sonotube had been used to form the pier, that some of the 3' was above grade. I don't know if your pier is rolling over, sliding, or both, but we can guess that once it started to move that the load of the deck started to provide sideward thrust and is accelerating that movement. I do vaguely remember be told/taught once that the bigger the diameter of the pier/footing, the deeper it had to go to prevent hydraulic movement.

   I have no idea when or if that pier will stop moving nor do I know a way to stop it - where I live, deck piers (and fence-posts) occasionally move around: the deck/fence contractors generally shrug, pull it, dig a deeper hole, and pour a new one. Saving one requires real local expertise..

   Phill Giles

   The Unionville Woodwright

   Unionville, Ontario

3. 
   Shoeman | Aug 27, 2002 07:20pm | #7

   hadn't seen it mentioned here, and was curious, did you bell out the bottom of the original post hole providing a footing or was is just straight down on the sides?

4. 
   Piffin | Sep 02, 2002 06:33am | #10

   I feel for ya old man but one of the problems with the pencil pushing crowd is that in the time you've spent wondering, worrying, and figuring, not to mention cussing, discussing, and debating the issue while studying and researching an easier way out...well, I could've had a shovel in hand and dug new holes to place new forms and been almost done with the fix.

   Now git at it and have fun!

   and what the dickens did you mean by this comment? "Any thoughts? Other than I'm glad that is not my problem!"

   If you are the one who designed and installed it, your name is one the problem. Your DNA stains are all over it. Don't put the child in an orphanage!

   ;)

   Excellence is its own reward!
1. 
   UncleDunc | Sep 02, 2002 06:41am | #11

   I think John was suggesting that the readers would each have that thought, "... I'm glad that is not my problem!" and that if we had that thought we need not tell him about it.

1. 
   Piffin | Sep 02, 2002 07:18am | #12

   Ah! So! The light comes on now. Gotta brush up on my reading skills, Dunc and quit trying to be funny.Excellence is its own reward!

2. 
   user-6886775 | Sep 02, 2002 07:41am | #13

   I appreciate your comments, especially about the time wondering and worrying. The only thing that keeps me from grabbing the shovel, is that I want to understand what I need to do different to keep this from happening again. Probably the engineer in me.

   The solution proposed seemed to focus on a wider foot. Unfortunately, the post that is failing already has that 'diameter' (slightly different than a square footing) at the base, that was recommended. At this point, I'm going to go make some careful measurements and see what happens over the next couple of months. If it is still moving, I'll have to deal with it this fall/winter, otherwise, I'll leave it until next summer. Still have a couple projects from this summer that are still being completed.

   And yes, as Uncle Dunc pointed out, the "I'm glad its not my problem" was my primitive attempt at putting words into my readers heads. Nope, this problem is all mine. I designed it, I dug the holes, I poured the concrete, I built the deck... Hard to pass the buck on this one.

   Thanks,

       johnbo----Cornelius, OR[email protected]http://www.johnbo.com

1. 
   Piffin | Sep 02, 2002 07:57am | #14

   I've dug out more than one of these tho' not as large in diameter. The ones that leaned more often than not did not have a flat base to them. They were dug down and maybe some dirt slid into the hole so the base of the concrete was angled allowing the loading to slice into the soil at an angle. I have a hard time seeing how one as wide as yours can do this but it is possible, I suppose. At 24"High by 18" wide you practically have a round ball that can roll in the soil easy. Mine are usually an 8" on a bigfoot at 60" or a precast 5' pier on tamped stone base. When I can use a backhoe digger, I like the later better, setting it with the buckeet and a chain. It has the threaded hole already installed.Excellence is its own reward!

2. 
   Luka | Sep 02, 2002 08:29am | #15

   John,

   It's not the diameter of the foot. It's the diameter of the foot in comparison to the rest of the post. Plus, it's the fact that you, in essence, have two posts and a pivot point between them.

   Ok, picture this.

   On flat ground, you pile up about a foot of pine boughs. A flat pad, uniform thickness all around. On top of that flat pad of pine boughs, you are going to sit two separate posts.

   One post is 12 inches wide, and is the very same width all the way up it's entire length.

   The other is 8 inches all the way along it's length, but at the bottom of it, you have a foot that is 16 inches wide, by maybe 10 inches high. (So in essence, the bottom 10 inches of the post is 16 inches wide.) Both posts are 4 feet tall.

   Now set those posts on the pine boughs. The boughs will compress enough that you will be able to balance both posts upright.

   Now, you get near the one with a foot, and your wife gets near the one without. Both of you push with one finger against the top of the post.

   Which post do you think is going to fall ? Your wife's will fall with little or no effort. You will have to push harder to tip your post.

   When those posts are in the ground, and the deck post is sitting on top of them, you have downward pressure from the deck, on the posts.

   UNTIL... one of those concrete posts starts to tilt a bit. (Maybe it begins to tilt because you set the deck post on it, a bit off-center....)

   Now, because the concrete post is separate from the deck post, a pivot point is created where the two meet.

   What you have, once this tilting process starts, is a case where the downward pressure from the deck becomes more and more, a sideways pressure in the direction of the tilt.

   I'll draw a pic of three diffeent ways of doing it. Two of those ways are the ways that you have been thinking. (Well, ok, I'll make it 4. with 3 being the ways that you have been thinking.) And one being the way that Mike Smith suggested. Have a look at the pic, and decide for yourself which way is the best.

   A is the way you have it. B is the way that you had thought to fix it. C is the way that you thought Mike said to fix it. D is the way that Mike actualy did say to fix it. The one on the far right is just to show how the point where your deck post meets your concrete, has started a pivot point, and there is no turning back now.

   ...

   1. Remove your sono concrete.

   2. In the bottom of the hole, pour the footing.

   3. Replace the entire deck post, with one that will go all the way down to the footing. (Treated, of course.) You want one single post from the deck to the footing. Don't mess up and just end up making another pivot point, by trying to keep your current deck post.

   4. Fill in the remainder of the hole with compacted gravel.

   Done.

   Quittin' Time

   
1. 
   user-6886775 | Sep 02, 2002 10:35am | #16

   This is starting to make some sense. From your picture, I was able to see what Mike Smith had meant.

   The bit that concerns me is planting the PT post into the soil. I know that its pressure treated and all that, but I can't say that I've ever seen one done this way. The idea makes lots of sense, but I'm a bit nervous about burying the post.

   The other thing that I've just realized (I think). Is that its not the heigth of the footing, but its the ratio of the heigth to the width, essentially the angle of a line from the pivot point to the bottom outer corner of the footing. Working from your diagram, my current situation (A/B), is many times higher than it is wide. Version D. although the footing is of a similar width, has a much shorter distance from the pivot point to the base of the foot.

   I've put together a drawing that seems to bear this out. The first diagram is the current situation. It has an angle of about 76 degrees from horizontal. (An angle of 0 would be prefect, but would require a nearly infinite expanse of concrete.) The middle diagram is the "Mike Smith" design. Because of the close ratio to heigth to width of the footing (with an angle of 48 degrees) this appears to considerably more stable.

   The third diagram requires some explanation. When I was removing the old deck and its footings (in the wrong place for the new deck). I was really amazed to find that although the previous owner (the owner/builder of the place) had used the same diameter footing, it was barely 8" deep, some were 5". As near as I could tell, they had never moved, even as the soil settled during his construction work. I can know see that while certainly subject to a freeze up, they would be quite stable and very resistant to tilting.

   I think that I'm going to have to sleep on this. Because, it does seem to imply there might be a way to set up a grade level footing using the old footing (or its remains) as fill. Then pour a reasonably large footing right over the top of the compacted fill.

   Thoughts? Or did I get it wrong again?

   Thanks for your patience,

       johnbo

   ----Cornelius, OR[email protected]http://www.johnbo.com

   
1. 
   Luka | Sep 03, 2002 12:44am | #17

   I think you got it pretty much right.

   I have never seen a deck done the third way, that failed because of the footings rising and falling from freeze. It may just be circumstantial evidence. I may simply be lucky never to have seen one fail. But it remains that I have never seen one built like your third example... fail.

   But Mike's way is actualy the best way. Not only does it meet code, but the physics are better. I pointed out the pivot point. But there are other dynamics that all work together, as well. For instance, the longer the deck post itself is, and the better that it is set in the compacted gravel, the less likely the pivot point will ever be anywhere near pivoting.

   That 2 and a half feet or so of Mike's post, that is buried in the well compacted gravel, is going to anchor the bottom of the post. In the horizontal movement. If the bottom of the post is held in place like that, the only pressures exerted on the pivot point will be downward pressures. The point will not be allowed to become a pivot point.

   Look at your own picture. In the first and third example, the post can move horizontaly, at the pivot point. In the middle example, the bottom of that post cannot move horizontaly. (At least it can't, if it is really packed solid in there.) Take away that horizontal movement, and there is no more pivot point.

   Are those two posts cross braced ? I mean cross bracing right down to the bottom of the post. Not just a short cross brace up at the top of the post, where it can be hidden. I have been assuming the lesser cross bracing, because of looks. If that is the way it is set up, and looks don't matter at this point, lag bolt some new cross bracing to the post. This time, reaching all the way down to the bottom of the post. And make it a full 45° angle.

   You may still be wasting your time, trying to save yourself some work, though. Regardless of how well you cross brace it, SOME sideways movement at the bottom of that post is going to be allowed. Even if the whole deck has to go with it. It remains that the best way to anchor that post, and counteract the pivot, is to _solidly_ bury about 2 and a half feet of that post.

   ...

   If you do the job as the third example, you are either going to have to pull that sono crete post completely out, or you are going to have to break it up to at least the halfway mark. Then fill in the hole in between with very well compacted gravel. A foot of very well compacted gravel between what is left of the sono, and the bottom of your new 'footing, will probably do the job. And hey, do the job that way, and who is going to be able to tell the difference between your old footings and your new ones ?

   If you do it Mike's way, you'll have to break the sono up even further, or just pull it, and pour a new footing in the bottom of the hole.

   As for burying the PT post... 1.) They are specificaly made for direct contact with the ground. They were invented for this purpose. When you buy the posts, you should be able to get information from the lumberyard, about how long the lumber is expected to last if buried. You may be quite surprised.

   2.) It will not actualy be buried directly contacting the soil. It will have compacted gravel around it. That gravel will allow for drainage of water away from the post. That will prolong the life of the post as well.

   Quittin' Time

   Edited 9/2/2002 5:49:07 PM ET by Luka

2. 
   user-6886775 | Sep 03, 2002 08:26am | #19

   As far as cross bracing is concerned, I have all but 2 of the 7 posts (6 bays) cross braced from the beam (directly above the adjacent post) all the way down to the bottom (well, 6" shy) of the post. Used 2x6 PT (lag bolted) as the braces.  Had a rather serious wobble before that. I tried the half length cross bracing on one set of posts and got to observe some real time deflection in the 4x4 PT posts at the brace anchor point. The only two bays that aren't cross braced is to permit access to my woodshop (need a straight line to unload sheet goods into the storage racks) and the access to the slider for the rest of the basement (needed that when I huffed about 30 bundles of sheetrock into the basement a couple of months ago).

   The only hitch in this discussion about cross bracing is that all of the bracing has prevented movement from side to side, but the current failure is prependicular to that, i.e. away from the house.

   I thought about this a bunch last night, I think that I'm going to go with the third approach, but a bit deeper on the footing. I'll see if I can rent a jack hammer or the equivalent and grind up the bad footing down to the base of the new footing. Like you said, this should make for a nice bit of compacted fill.

   The only trick remainding is to figure out how to shore up the deck when I pull the post out during all of this, and allow some room to work. So far the best that I can think of is a another beam placed under the deck joists and lifted up with some lally (spelling?) columns. I've toyed with a fork lift type setup, but can't figure out how to control it carefully enough, not to crack the glass in the railing above.

   Unfortunately, through just bad luck, both of the posts that need to be replaced are at the splice point between the support beams (4X12 PT). So, I think that I really do need to support this point during this operation. I thought about a plate of 1/4 steel with lots of holes for lag bolts to splice the beam together better for this operation. Seems like overkill, but I've never had to lift something of this size before. I've moved doorways in load bearing walls and know how to set up the temporary braces, but I've never had to worry too much about the clearance to the area directly underneath.

   Thanks again for your advice.

       johnbo

   ----Cornelius, OR[email protected]http://www.johnbo.com

3. 
   Luka | Sep 03, 2002 10:14am | #21

   How about a couple photos, John ?

   At the post... Do the joists run toward the house, or parallel to the house ?

   The fact that you were getting a lot of movement is a good indication of why it has done this pivot point thing even though you cross braced. You could go back and cross brace toward the house as well, but I don't think it'll make that much difference. Your deck is too flexible for it to make that much difference.

   As for how much to cut down the existing sono... Here's a pic...

   If you are going to go with number 3, then you still need to cut the existing sono down by at least a foot and a half. You need compacted gravel in there. If you knock off the top of the sono, and then pour again, right on top of it, what is the difference ? You have just recreated the old sono.

   I have also included something to show the difference in the horizontal movement.

   Quittin' Time

   
4. 
   user-6886775 | Sep 06, 2002 09:54am | #23

   Hi, sorry about the delay, I had to fly down to Southern California for a couple of meetings.

   I'll attach a couple of pictures to this reply as well. To answer some of the other questions, the joists are running away from the house, and rest on a large beam that is parallel to the house. The beam transfers the load down to the 4x4 posts.

   On the amount to cut down the existing sono footing. I would do something pretty similar to what you are describing. I will probably widen the hole and tamp in more gravel (or the sono rubble) around the remains of the footing and then bring the level up far enough to give myself a foot at least of compacted gravel between the new and old footings.

   I've been poking around my area trying to see an example of a PT post buried as you've (and Mike Smith) have been suggesting. I haven't found any yet, but I'm still looking. I did mention it to the pest control person that was by today (they come monthly), and he was not thrilled. I don't know if its an old wives (or old carpenters) tale, but around here having any sort of wood path between the soil and the house is a bad news because of carpenter ants. A lot of attention is paid to making sure that even the posts in the crawl space don't have wood sitting on the concrete. Oh course, this is also because people don't typically use PT for the crawlspace posts here. Personally, I can't see why it would make any difference to an ant whether it had to cross 4" of steel, vs 4" of PT wood. They seem to be able to hang onto anything, even upside down.

   If it appears that the footings are moving rapidly, I may take the suggestion that was made here to tie them back to the far side of the deck (next to the house), just to hold them in place until I can address the problem.

   I've attached three pictures. One of the full back side of the deck, to get a feeling for what it looks like. The second is the structure underneath the deck (and no, my house is not painted like a zebra, it is the sunlight coming through the deck boards above). The final one is a side view of the footing that is in the most trouble.

   Thanks,

       johnbo----Cornelius, OR[email protected]http://www.johnbo.com

   
5. 
   Luka | Sep 06, 2002 10:02am | #24

   Uff Da !!

   Thank you John. The pictures are perfect, and make all the difference when trying to figure out by long distance, what the problem is.

   Mike Smith... you tell him. I need to sit out for a bit.

   : )Quittin' Time

6. 
   ProDek | Sep 06, 2002 10:30am | #25

   johnbo- that footing really is shifting. I'm thinking it was poured on top of a rotten log or unstable surface like that. I would take two 4x4's an set them on some wide blocking on each side of this post. Cut the post out and replace it with a longer post set plumb on the back side of the same footing. If you have a rotohammer drill a 1/2" hole and put a 1/2" striker bolt through an ab44 post base. Can you give us a shot looking down the beam run?Bob

   "Rather be a hammer than a nail"

7. 
   Luka | Sep 06, 2002 11:37am | #26

   John,

   The best advice you will ever get on decks and deck footings... you'll get from Pro-Dek.

   None better.Quittin' Time

8. 
   user-6886775 | Sep 07, 2002 08:14am | #35

   Hi Bob,

   When I drilled the holes for the footings, the bottom of the holes looked good. Of course, a rotten log could have been an inch farther down.

   On your suggestion, do you think that the footing has stopped moving? I can certainly redrill the hole for the saddle at a plumb position, but I'm worried that this might cause it to tip farther.

   I like the support method. Do you just drive the temporary posts in to take the load off the existing post or do you use bottle jacks (or similar)?

   Can you be more specific about the picture "down the beam run"? If you are asking if the main beam is straight, it is pretty close. It was when I put it up there, I don't think that it has warped more than a 1/2" total. I sorted through about 4 dozen beams looking for these.

   Thanks for the great ideas.

       johnbo----Cornelius, OR[email protected]http://www.johnbo.com

9. 
   ProDek | Sep 07, 2002 09:27am | #38

   Johnbo- just take 2-8' 4x4 posts and wedge them between the exiisting beam and a 2x8 laying flat on the ground, pound the foot of each post till it takes weight off of the post on your footing. (IMPORTANT) take out the teco's from the saddle so the post will lift out of the saddle.You can use jacks if this method doesn't work.

   The best type of saddle is one that adjusts that way if there is any settling you can crank the saddle up , and yes I think you will be safe moving the saddle to the back side of you footing, if anything the footing will go back to its original posistion.

   I'll dig up a picture and post it.

   Heck we're neighbors, I live just North of you in a town called SeattleBob

   "Rather be a hammer than a nail"

10. 
    ProDek | Sep 06, 2002 07:00pm | #27

    Thanks Luka, I'm just trying to save johnbo ALOT of work digging up that footing because it looks substantial.

    I would recommend you lose those ugly 2x6 knee braces after you install some 36" to the long point of a 45 degree 4x4 knee braces. Knee braces are required for any post over 4' high. If you nail 2x4's diagonally from the ledger to the beam that will take out all the sway of the deck.Bob

    "Rather be a hammer than a nail"

    
11. 
    Luka | Sep 06, 2002 08:03pm | #28

    Bob,

    It looks like your posts go into the ground there. Can you explain to John, why that is ? And what concerns there might be, or might not be, about part of that post being buried ?

    : )

    I still say that I simply would not put that sort of post, in that architectural situation... on top of the ground... attached to concrete or not.

    ...

    Unless.

    Unless the concrete were part of a larger foundation, or slab, etc. Anything like a pillar block, or even this sono tube sort of setup is prone to movement.

    ...

    Ok, here is where I go out on a limb. I think the best solution he could ask for, since he doesn't want to bury the foot of those posts... is to brace up the deck in place. Remove the posts. Cut the sonos down by at least a foot to a foot and a half. And pour a slab from the house, out to a point past the foot of the posts. He can possibly use the sono rubble for filler on the slab.

    He would still do well to use your advice on the bracing, even with the slab. But the slab would take care of the bottom part of the equation.

    There would also have to be extra 'footing' in the slab at the points where the posts will be. But any good contractor can tell him that.

    Quittin' Time

12. 
    ProDek | Sep 06, 2002 09:07pm | #29

    Luka , I only bury arbor posts , deck posts should always be above ground because of the weight they support. The slab idea is ok but that would cost quite a bit. He has a very substantial looking footing but I would sure want to know why it moved so much.

    It looks like ALOT of water has passed buy that yard.Bob

    "Rather be a hammer than a nail"

13. 
    jonblakemore | Sep 06, 2002 10:51pm | #31

    "Deck posts should always be above ground because of the weight they support."

    What do you mean by this?  Is it a structural concern or a longevity concern?Jon Blakemore

14. 
    ProDek | Sep 07, 2002 12:00am | #33

    Both- Jon- Longevity because it keeps the post away from ground and surface moisture which eliminates wood rot, structural because a wide footing supports more weight, depending on thickness,than sticking a post in the dirt and expecting the post width to be all that is needed to support the weight of a deck.Bob

    "Rather be a hammer than a nail"

15. 
    Piffin | Sep 07, 2002 04:32am | #34

    Here's what I'm seeing from the photos, Johnbo.

    I might be wrong because they come through a little dark to me but it looks like the top of the concrete sticks above the dirt maybe four inches. Then it looks like the ground is mounded up around it about eight inches. So if we draw a line where I assume the original plane of the ground is, you only have half the 24" concrete in the ground, really. That means you have a footer almost on top of the ground, not below frost and maybe not deep enough to be into solid, undisturbed soils.

    If I'm right, you have no choice but to dig it out and dig deeper.

    As high as this porch is, there will be no problem supporting it. Angling from the post at top away to the ground only 15° will get the temporary support out of the way enough to work.Excellence is its own reward!

16. 
    Luka | Sep 06, 2002 11:48pm | #32

    Thank you Bob.

    : )Quittin' Time

17. 
    user-6886775 | Sep 07, 2002 08:40am | #37

    We do get a fair amount of rain, but not too bad. I'm located in the Portland, OR area and I think that we get about 30-40" of rain per year. Although, according to my weather station (http://www.johnbo.com/Weather_Text.htm) we've only seen about 16" since January.

    My other interpretation of your comment about the water, is that everything is very dry right now. We have a very minimal producing water well and really can't water anything but the plants, sparingly. The lawn has to fend for itself.

    The septic drain field starts about 8 feet downhill of the footings. I saw some of the other posts about the soil levels and to be honest I can't tell. I'm sure that some soil was spread around after the foundation was dug, but the general slope of the land matches the surrounding area that I know has never been touched.

    Even so, the spoils from the construction of the house have been undistrubed for the last 25 years. When I dug the holes (one by hand, the rest with a Bobcat with an 18" auger), the soil was firm (not clay) and consistent once I got past the first 2 or 3".

    The sono tubes were cut at about 30" and driven into the hole. I tried to leave a couple of extra inches at the bottom. The main intent was to have a common reveal at ground level. I would guess that this would add another inch or two to the length. I poured concrete directly into the hole, no gravel. I did wet the bottom of the hole to keep the concrete from setting too fast. As I was mixing in 2-3 bag batches, I'm pretty sure that I didn't trap a big bubble in there.

    Later,

         johnbo----Cornelius, OR[email protected]http://www.johnbo.com

18. 
    ProDek | Sep 07, 2002 10:08am | #39

    Here is a shot of that adjustable saddle.

    If you decide to break up this footing and pour a new one please double nail  diagonal 2x4 bracing from the ledger to the beam, and leave those 2x6 cross braces on till your done. Bolt a 2x to both sides of your beam splice to keep them together .

    Yes the knee braces are lagged to the post and the beam with 1/2" lags.  Bob

    "Rather be a hammer than a nail"

19. 
    ProDek | Sep 07, 2002 10:09am | #40

    Picture of adjustable saddleBob

    "Rather be a hammer than a nail"

20. 
    user-6886775 | Sep 07, 2002 07:14pm | #41

    Hi Neighbor,

    Yup, I looked at the 'profile' for you and saw the Seattle location. Nice town, but a bit busy for my tastes. Of course, Portland isn't much better, thats why I live out in the sticks.

    You can't tell from my pictures, but I'm using the same adjustable saddle on all of the posts. This was part of my original plan to avoid doing precision concrete work. I don't know if you caught it in my original posting, but the two footings that are failing (or falling...) were placed about 3" off the ideal line. So the holes for the saddles were drilled where they needed to be, which ended up 3" off center on the footings. Does this change your opinion on simply redrilling the holes for the saddles?

    Given the problems in trying to place a auger with small tolerances, how do you handle this? Oh, wait a minute, you said that you were using a boxed footing (2'x2'xsomething). This is probably what I should have done in the first place, and is probably a lot easier to position correctly.

    Thanks,

        johnbo

    ----Cornelius, OR[email protected]http://www.johnbo.com

21. 
    ProDek | Sep 06, 2002 10:00pm | #30

    Here is a shot of my footings. There is a bank in front of them which made the posts look like they went into the ground. Most of our footings around here only require a 2'x2'x1'deep hole filled with concrete and an elevated saddle.Bob

    "Rather be a hammer than a nail"

    
22. 
    user-6886775 | Sep 07, 2002 08:24am | #36

    Are you using lag bolts to put those knee braces in? From the picture, it appears that the knee braces themselves are the only ones with 45 degree cuts, in other words, they are not notched (let?) into the post or the beam.

    Also, the 2x4s on the underside of the deck to reduce sway. I considered that, but was worried about debris and moisture collecting on the flat surface (on the top of the brace). I used a stainless wire rope, but its not a particulary good solution as it works only in tension.

    The deck that I replaced was built with beautiful wood, 20' clear fir 2x6's (stamped standard and better), but they were spaced about 1/8" apart and the fir needles filled the gaps (most of the damage had been done before I bought the place). The winter before I tore down the old deck, we had 6' diameter puddles on top of the deck after a rain.

    When I built this one, I used Trex (2x6) and spaced everything at a 6" pitch (0.5" gap). I just worry about the debris collection potential of the flat 2x4. Still, it would certainly help the sway. I really don't like the cross braces, but the motion on the deck was "interesting" before.

    Thanks,

        johnbo

    ----Cornelius, OR[email protected]http://www.johnbo.com

23. 
    TommH | Sep 03, 2002 10:32pm | #22

    I had the exact problem in the spring of 1994 after a very bad snowload winter. My deck is also on an incline and the 4 6x6 posts and the corresponding  concrete piers (42" deep sonatube))"KICKED OUT"  in the downhill direction, with the same type of pivot point where the two meet. To make matters worse, there was no connecting hardware; only the weight of the deck was holding the posts on the piers. My simpleminded dyi fix was to straighten them out, one at a time and the eliminate the "hinge" action at the pivot point by bracing each post with a 2x4, angled at about 45 degress back toward the house(uphill). These were carriage bolted at the post and the floor joists. If the brace fell between two joists, I boxed in a length of joist board between the joists and bolted the brace to it. I straightened the posts and piers by relieving the weight with a jack and removing soil behind the contrete pier, enough to bang it back into plumb and then repacking the soil. My thinking was that if the post was firmly held plumb by the brace, it would eliminate any downhill force and,hopefully, tha pier would also stay put. Not a perfect solution, but no further problems after 8 years. (My posts are shorter, only 4-5 ")

24. 
    TommyB12 | Sep 11, 2002 04:34am | #42

    As others have alluded to, about the best place for ptyp underground.  Maybe someone can provide a link but I saw a study years ago in one of the trades that rated all species, in the air, in the soil, and in water.  Treated submerged outlasts all others.

    Drying cycles and u.v. are hard on any wood.  I like to pour a big fat footing, with rebar if necessary, set the post on it and backfill.  You'll do more damaged to the exposed lumber with your weedeater, than what the soil will do.Tom

25. 
    user-6886775 | Sep 03, 2002 08:32am | #20

    Just had a another comment as I posted the previous reply.

    In your discussion about the buried post resisting horizontal movement. I'm not completely convinced on that. Granted, my current situation was caused by some poor decisions on my part, but what I'm seeing as a failure is an entire 18" footing being driven through soil that has been undisturbed for at least 25 years and potentially much longer. Admittedly, compacted rock is not exactly a fluid, but I'm not sure that its that much stronger in that dimension than the soil, especially given the differences in the surface area of the object being pushed.

    Thanks,

        johnbo----Cornelius, OR[email protected]http://www.johnbo.com

26. 
    rez | Sep 03, 2002 01:45am | #18

    and make sure your pressure treated post is rated for 'ground contact'.Half of good living is staying out of bad situations.