| Hi all, Here’s the deal: Some family friends have a deck that I’m concerned about. The pics tell the story…but my guess is that the concrete piers weren’t in line with the beam, and the beam had to be set in a certain position because of the door being right there. I think the fix would be to jack up the deck slightly on that end, rip out the old beam, and replace the posts (the outside one appears to have a crack from the stress of the situation). Question is: how would you all deal with the problem of the out-of-line concrete piers? dig them out and put in wider ones? I hope I’m making sense, let me know if I’m missing vital info here…one of those things that’s hard to describe in words I suppose. |
Justin Fink – FHB Editorial
Your Friendly Neighborhood Remodelerator
Replies
Justin,
I can't say anything about the beam, but those pressure treated posts will curve, twist, split, etc., just drying out. I've got two split ones right now holding up a shed roof that I put in last summer - very little load on them since I haven't even shingled the roof yet.
Justin, Justin, Justin....
Son
I know you know how to size photos properly to get The other half of your audience to be able to see them.
I guess I'll go make soup and a snadwich while I wait for them to download...
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
View ImageView Image
here's the experiment. Does the massive KB of the orignal pic in this cut and paste of the photos still take the excess time to download or not?
every court needs a jester
Edited 3/4/2007 6:22 pm ET by rez
hard to say so far. When I openned the thread again, Jason's first post is still there, so all five photo files were trying to open at the same time, and I think a couple were still alive in the internet temp folder, but two of the first were scrolling open gradually.Then i skipped his first by with re-engineering the URL and diret to your post, but then your second one was not displaying for me on screen - but in this reply page, it shows.I got them anyway while fixing dinner and resized on mine.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Last summer working out of state I was using a friends dialup machine for a while and was amazed on how slow it was downloading pics till I just gave up even trying to open them.
Ended up at the local library using the DSL.
If people ever experienced dialup they wouldn't even think of posting huge files.
be yet then again....snort
every court needs a jester
I am going to make a guess that Justin is over at the relatives house right there now having dinner. Some nice lasagna maybe. He had the camera, but not his laptop with him, so he shot the photos and posted from the hosts PC without benefit of his manipulation software since he didn't even turn the one right side up.So after desert, he will check again to see what we have cooked up and how hard a time we are giving him over this.Justin - look at all the tomatoe sauce on your nice new shirt!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I wonder if he's looking forward to going into work tomorrow?
be a little heehee in there
every court needs a jester
<<I know you know how to size photos properly to get The other half of your audience to be able to see them.>>
haha, I thought they were small enough. Sorry about that my man!Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Ha Ha yourself.I got to edit an editor
nanenanenah-nah!;)
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Hello from the great white north. I see from the snow on the ground that your problem arises( forgive the pun) from the ground itself.ADFREEZING. The concrete piers probably extend below the frost line and surely don`t have any footings beyond that. Ice crystals adhere to the concrete piers.The surrounding backfill freezes and adheres to the crystals ,forming a bond that allows the piers to rise and fall with the natural `heave`that occurs depending on the soil type used as backfill. The piers push the 4x4 up against the laminated beam causing it to twist and buckle.The pier will heave and then settle again with the thaw.The deck should rise and settle accordingly, but over the years the space under the pier will fill in and the deck will settle and rest higher and out of level.It is said that leaving the `cardboard`sonotube wrap on the concrete pier will stop the bond from forming.This is true, but how long before this material deteriorates and becomes usless.Stripping the tube material off and wrapping the concrete in plastic would have been the best thing. New 4x4 posts with 2x10`s lag bolted on either side would work well in this situation.As the years pass and the piers continue to lift,as they will, the bolts can be undone allowing the deck to drop alittle and then rebolted. Note that the three in-line piers will be affected at different rates. Salutations from Montreal.
Edited 3/4/2007 10:20 pm ET by McCliver
Justin,
The footings appear to be in line. IMHO, the reason for the failure is a poor beam-to-post connection. Jack it up slightly, like you said, and put in something more resistant to flopping over.
I think the best way to achieve this is to "sandwich" the posts with a pair of 2x10's or 2x12's, depending on the distance between posts.
Maybe this'll make it clearer.
View Image
The tenons are optional, but otherwise you're depending on the fastener to bear the load.
View ImageLive in the solution, not the problem.
IMO, the notching into posts are essential for load bearing. The bolts might handle the shear but the wood at the bolts will not. It will bruise in.Another suggestion for that method. If you use blocking to conect the twin beam two bys together, they will be much stronger and deflect less than they way you have it where they act independent of each other.But overall, great photos and good looking job
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I don't see anything that is likely to fall down - just some sloppy workmanship. That 32" cantilever of the beaam is way too much to expect it to do anything but try and move - especially without kickers.
The cheap way would be to just turn the beam loose from the joists and whack it over straight unless there is too much learned error in it, then add kickers to hold it straight and refasten. That means to get the post plumb, the beam would not be square and parrallel with the rest of the framing, but would that be noticeable?
The right way is as you hinted, to dig and re-pour the piers in the rioght locations and rebuild back again. I would not allow so much cantilever though and might use a triple 2x8 instead of double 2x10. Downsizing height of beam will help it resist that roll-over action.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
like so
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
What woudl be a more acceptable distance to the edge of teh deck? Maybe I could just pour some new footings over to the side, raise a new beam, then knock out the old? That might be an easier fix then jacking, removing old, then dealing with the old footings, no?
...also - which wins: triple 2x8s or double 2x10s split over a post?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
A 2 foot cantilever is pretty standard Justin. That would probably give you enough room to use what's existing as your temporary support. Live in the solution, not the problem.
two feet should handle the vertical load, BUT the long extend coupled with poor lumber is what is causing the twist/layover in part as the grain twists there, so he would be fine if he sidesaddles a post with bolts and notching, but if he still perches on top, I would not go more than the depth of the beam.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
not to revisit an old topic, but I'm curious from looking back at your pictures...why did you decide to run the deck joists parallel to the house and support them with cross beams underneath...as opposed to running joists perpendicular to the house and having a load-bearing outside rim joist?
Reason I ask, the way you built it is the way it's built on the project I was asking about. Seems like a strange way to make a deck, though I know it's done. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Couple of different reasons, depending on the situation. For one of my brother's decks, they wanted to be able to drive underneath to access the basement garage. A load bearing rim would have required post spacing which wouldn't have permitted that. By running the drop-girders perp. to the house, I could clear-span 14+ feet with the 2x10 joists, thus giving a very wide berth to the garage door.
On their screen porch, my logic (probably flawed), was simply to keep rafters and joists paralell to each other. Structurally, it may be moot, but we were always taught to stack framing members this way. Of course, when you stick a hip on the end, that thinking doesn't hold much water.
Fact is Justin, I just like the look of cantilevers on a deck; it breaks things up a bit. Plus, they're WAY easier to raise when working solo as I do.
Hope I've answered your questions.Live in the solution, not the problem.
<< Hope I've answered your questions. >>
You did, thanks. But you also inadvertently piqued my curiosity...
What is your technique for raising those drop girders on your own? cut and notch the posts, set them on the piers, then stand on scaffolding while you bolt them in place? pre-drill everything for bolts while on the ground? I work on my own too, so I always like to compare notes with other solo guys. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
I like to set the posts at rough height, backfill, and brace before I do much else. Then, I'll set up my builders level, shoot the ledger (bottom of ledger is top of girder), calculate any fall, then shoot the posts. I'll shoot only the corners if I can, then strike a chalkline to "connect the dots". Jerking around with a builder's level, tape rule, and a Quick-Clamp gets old fast and I don't want to perform that op any more than I have to.
With a drop girder, it's not the top of the post that's critical, but the top of the girder is. Does that make sense? What I'm saying is that the bottom of the notch can/will vary depending on the widths of your girder material. With wet PT, that variance can be considerable. Once the bottom of the girder notch is determined, I'll measure up within a 1/2" shy of the overall height and cut the top of the post off. For ex., if I've got 2x12 girder, I'll measure up from the seat of the notch about 11".
I do all the cutting off of whatever the height calls for. Could be anything from standing on terra-firma, to multiple scaffold bucks. Cut the faces of the post first (1.5" deep), then set saw to full depth and cut up the sides and across top. Small amount to clean with a chisel.
Then it's simply a matter of humping up the girder mat. and setting it into the notches. A couple of beefy clamps ( C-clamps, not that Quick-Grip junk) are a safe move and very helpful. Double check the side-to-side plumb and drill & bolt. The in-and-out plumb can be adjusted by "spotting" a couple of joists at the middle and ends.Live in the solution, not the problem.
One more advantage of running the deck joists parrallel to the house is that the decking runs perpindicular to the hsoeu making it easier for rain water to run away from the house (assuming a drop was figured when setting the girders).
I can think of a couple of ways to set the girders solo since I work alone quite a bit too. I have some large vise grip C-clamps that are invaluable at times like these. Maybe tack a 2x onto the posts at the proper height & then set the girders and clamp in place. Maybe I'd have another idea if I was actully there doing it.
Running joists parallell to the house is the best way so the decking can shed the majority of rain water away from the house foundation
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
general rule of thumb for cantilevering is no more than the depth of the beam itself when carrying load above - say of wall and roof - and up to two feet over otherwise.for the other span engineering, I can't see the overall situation or size of this deck or know what your local live load requirements are.but for the twisting resistance Q - I'd go with 6x6 posts and notch in an inch on each side Your idea of how to replace by leaving existing there and doing new layout sounds good
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
<< I'd go with 6x6 posts and notch in an inch on each side >>
Time to start a new thread: What's your favorite method for notching a 6x6 post! haha!Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
I just set depth on my circular saw, make the first pass or three with a speed square at the end where it counts, then keep running the saw 'till I get it kerfed up and then knock away the chaff. might take five minutes per notch.I do it on a bench though - rarely after setting the posts.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Justin,
I have to agree with the other posters about your posts! There is some shrinkage in the posts or settling with the concrete piers (both normal) that is causing the beam to rotate. The beam appears to be adequately sized for a deck (assuming the deck doesn't extend up four stories outside of the frame of the pic!).
Jacking the deck up and replacing the posts is a good solution; it is definately removing the offending pieces of the assembly.
One cause of concern, and possible source for the rotation of the beam is the aparent absence of blocking between the beams. Since the joists are resting on top of the beam, the beam is subject to tortion and that is causing the rotation of the beam to occur.
I would consult with others, but my first reaction would be to provide a few "tie-backs" that could be sistered onto some of the joists that would fit between the two main suport beams, locking the entire assembly together.
Like I said, this makes sense to me, but check it out with others before you do all that work.
Good luck.
Justin,
I think you are on the right track, although not for the reason you think. I believe that replacing the post or posts is the right thing to do. It is not surprising that the outside post is the one that seems to be sinking. It is the one that is carrying the greatest load of the deck. Although the posts are not dead centre with the footing, I don't believe it is enough to cause the problem. My feeling is that the footing has simply settled overtime due to the wieght of the deck.
It would further fortify my feeling if you told me that the home was fairy new and the deck was built around the same time as the house. Before you go ahead with tearing out posts, 1. check the deck for level. How far out is? 2. Measure the length of each post, just to see if one was accidently cut a little short and giving the illusion that the deck is sinking (crazier things have happened).
After this has been done go pick up a "Screw Jack" (looks like a larger version of a jack post) from your local equipment rental place. There are cheaper methods (which I won't mention) but the screw jack is definately the safest. Put a chunk of 2 x 10 under it and nail the top to your support beam. Start screwing! The post I mean.
If settling appears to be the problem, you can jack the deck up a little bit past level. If there is any settling left to do this will help. If the footing continues to settle, you may want to consider pulling the footing and pouring a larger/deeper footing.
Best of luck
Dave
Justin
I guess it just depends on how much work you want to do.If it was me I would triple up 2 x 10 beam and bolt it together. I would add a decorative 2 x 4 to connect the beam and post so they stay in line, and bolt this on. I would bet if you poured another pier, and moved the 4 x 4 over, it would look the same as pictured in a couple a years.
I don't pretend to be an engineer, but it doesn't look settling or extrem weight issues. I would think it is just the pressure treated warping. I am surprised they didn't use 6 x 6. How long as this been up?
Not that this has anything to do with beam issue, but how is deck flashed at house?
Greg In Connecticut
It could be photo distortion but it looks to me like the outside post is a good 2" off plumb. He might be able to rebuild the beam that way and by using a 6x6 get things plumbed up and still setting on the sonotube, but I think not.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Hi Greg,
You could be right, may just be warping of the PT lumber - it's hard to tell in this situation - it's like trying to reconstruct a crime or something!
I'm not sure of the age of the deck, it was tehre when they moved in. I would guess least 15 years though. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Some people just get ate up with using this, that and the other Simpson bracket for anywhere they will fit. Sometimes they don't work out. If I hadda been building that structure I woulda just scabbed some 2x4 pieces on there and the issue wouldn't be occurring. BTW - are the posts plumb?
Also BTW - I'd say that the beam cantilever over the end of the outboard post is almost certainly too much.
Are the posts plumb?
Well, I didn't have my level with me at the time, but I stood back and viewed them in line with the door jambs in the background - the outer post is pretty off-kilter - that ain't photo distortion. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Maybe I'm in the minority here but I see this as a potentially serious condition possibly leading to deck failure. The beam is overturning, possibly due to the fact that there is no cross-bracing under the deck. Under a heavy loading condition (decks should carry 100 psf comfortably) with moving loads I think they could have a real problem. Footings seem small and could be heaving up and down (like pistons) with frost as noted.
Jeff
Get rid of the 4x4's as well, they aren't good for anything but landscaping. They twist and split way too easy.
Go with 4x6's, notch them like David Hawks posted pictures of. THen put a 2x12 in each notch. Assemble with Ledger Loks or through carraige bolts.
We usually dig holes to frost depth 48", pour some pads with 4,000 psi concrete, and put our posts on top of the pads. Fill and compact with dirt. I really don't like the pier idea in frost areas.
When people don't know what you're about, They put you down and shut you out.
I agree, also dig a new footing so there is not so much cantilever. Or notch the 6x6 and keep the old header, through bolt it so the header is more resistant to rolling. Diagonal brace the underside of the deck to square it up first.
It only looks like 2' of cantalever to me, that not alot. Thats what I typically do.
The hangers on the cantalever are overkill, I would probably use hurricane straps to attach the joists to the beams. Simpson 2.5's or something along those lines.
Did Justin say if the deck/ledger looked like it was pulling away from the house? When people don't know what you're about, They put you down and shut you out.
Looked like more to me, but you are probably right. I dont think it's pulling away, but it could be getting out of square.
<< Did Justin say if the deck/ledger looked like it was pulling away from the house? >>
I didn't look at the ledger - but I might as well give the whole deck a onec-over at this point. The other posts/beams don't look spectacular either, but this outer section was the worst of the bunch. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
So, How was the lasagne?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Actually, I believe we had fajitas that night...though chicken provolone was on the talbe last night. mmmm!
I didn't get over there last night until after dark, so I couldn't check out the ledger connections - but I will. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
I think the beam is leaning because there's nothing to hold it upright. There should be some angle braces from the bottom of the beam back up to the deck, or some scabs alongside the posts that extend up over he beam.
Man should forget his anger before he lies down to sleep. [Gandhi]
The way to keep the posts from leaning (due to deck racking) is to attach a diagonal brace to the bottom of the deck, across as long a length as possible between beams. Far better than knee braces, and less obnoxious looking.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Edited 3/5/2007 4:51 pm by DanH
Well, I think I'm more inclined to find a solution that doesn't include angle braces at this point. I think notching a 6x6 and letting in 2x10's or x12's would do the trick - no?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
The reason I figured it is 32" is because of a quick look lining up post location with joist and assuming 16" OC, but taking a closer look, it seems the post is just barely to the outside of the joist and the outer joist space is slightly less than the typical for this deck, so probably 28" is more accurate. That is unless they laid it out with black diamondsCompromise?;)
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
You think it needs to go up to 2x12's? belt and suspenders?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
It may cost you a little extra but a beam thats holding up a deck is not a place to save a few bucks. When people don't know what you're about, They put you down and shut you out.
hey Stilletto, How about back filling w/ 3/4" crushed stone instead of dirt? It helps w/drainage are the deck post(or concrete pier) and helps break the freezing/bonding cycle of dirt backfill. You can fill with dirt(loam) for grass for the last 2" or so.....also use a landscrapers fabric to prevent silt/fines from filtering through stone...or just finish w/ stone.
Geoff
Depending on all the other soil and water factors, that can be bad.If the soil under is clay or otherwise non-permeable (good chance ion Connecticut) then it can lead water to the bottom of the hole where it is trapped.If ware drainage issues overall are right, it can llow more water to freeze to one side of the sonotube than the other, causing a tilt over time.Simply leaving the cardboard on and or wrapping with plastic breaks the ice crystals from locking soil to the pier.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
piffin, good point, I tend to forget where I live now, only been here a few years, home was Ma./N.H. for 40 yrs. plus, so I tend to talk from that viewpoint, if you know what I mean. I in fact was quite surprised at the high clay content in this neck of the woods, although it does tend to vary from town to town, or what side of the mountain your on.
Geoff
>> How about back filling w/ 3/4" crushed stone instead of dirt? <<
That works good with some soil types. Here, our soil type is predominantly red clay. Using that method just holds water up against the post &/or footer, since the surrounding soil doesn't drain. To explain a bit more, let's say you dig some footer holes in this red clay. It rains and partially fills the footer holes with water. You come back a week later, there has been no more rain, but the holes still have most of the water in them! So, what is adding gravel gonna do for drainage? Nothing. It's like having a bucket of water with gravel in it - it actually makes drainage worse.
If the surrounding soil will drain or "perk" well, filling with gravel will help it dry faster, but personally, I don't think there is a distinct advantage to it, since granular soil drains and dries rater quickly anyway.
Personally I think it's more important that the post not be in direct contact with concrete, since concrete that outside and is in ground contact is inherently damp. I use post bases in all situations. Also, I always put a uncut end of the post down - since a cut end will not have as much treating.
Working with PT posts is different on the west coast is different, since they have that wood that doesn't absorb the PT chemicals very well. They "incise" it to try to get it to absorb the chemicals better, but IMO the results are still marginal.
We used to do the crushed stone as fill. Not allowed to anymore for the reasons that the other posters pointed out. We have alot of clay in this area as well.
When people don't know what you're about, They put you down and shut you out.
You could run new longer posts to the left of the beam, on hangers. Would keep the beam from canting, and likely wouldn't require new footings.
That's what I meant about the 6x6s
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Justin,
There are a number of issues with that structure that simply boil down to poor practices in the original construction.
The best method is to use 6x6 posts for columns instead of 4x4, imo. With these, you can notch the tops to receive the beam.
The beam should be comprised of 2 ea 2x? (depends on span between columns), HOWEVER, the beam should NOT be built so that the two member touch each other as is the case in the pics youve posted. My reason is that water and debris will become trapped in the space between the two side-by-side beams and this will cause rot over time. That will lead to a weakened beam and a potential collapse.
Also, the beam should be bolted together through the column tenons top and bottom. That means two through bolts, 5/8" diameter, per connection point. I use carriage bolts with a washer and nut on the threaded end.
I'll attach a pic but I don't know how well you can tell what I've done. I hadn't yet drilled and fitted my bolts in this picture.
In your situation, I assume that the foundation piers are set in the wrong place and the builder in trying to line things up had to move posts to the outside edge of the footing. The footings should have been wider in the first place. Good rule of thumb might be to use a pier that is double the dimension of your column to be set upon it.
Also, for the column to footing connection, you really should avoid the cups that were used in your example deck. The far better method is to set an anchor pin into the concrete when poured and then to bore the post and set atop. Those cups are ugly and trap debris that will eventiually aid rotting of both the column and cup.
I will also attach a pic of a footing detail from one of my plans.
I would suggest for your problem, to increase column dimensions and rebuild beam as I've instructed. That will give you a more sound structure.
Furthermore, clean the deck and seal. All that mossy growth is bad for it too.
When you're this good, EVERYONE wants a crack at you!
http://www.petedraganic.com/
Good info Pete, thanks.
I have to take exception to your post-to-footing connection, though. You really feel that a naked PT post can sit directly on a concrete footing without troubles? I would think that's a scary thing, especially if you're using incised doug fir posts (I assume that's what you have in your area) - once you cut that post, you've just opened the door to untreated wood.
No stand-offs? No ice & water wrap? Nothing?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
In my post-to-footing connection, the benefit is that there is nothing to trap the water in the post. The concrete rises above grade, keeping the post from sitting in wet soil and with no additional hardware, the post can breath rather freely, keeping it from retaining water. It is FAR superior to burying posts and IMO better than any hardware that cups the base of the post, potentially allowing moisture to remain trapped.
When you're this good, EVERYONE wants a crack at you!
http://www.petedraganic.com/
Pete,
Curious what prevents "up lift" with your post base connection?
Just the embedded depth of the anchor bolt into the post?
In my application the threaded rod is inserted into a tightly fit bore. There becomes a friction hold. You can also endeavor to slightly align the rod out of plumb so that the post, when plumbed, will bind more positively against the rod. Also, an adhesive could be used although, per my design, it is merely an application of post over rod that has not been a problem with any of my area building departments.... and has been applauded by some, with rotting being the primary concern of failure in my area.
If we were tornado or hurricane prone, there would be just cause for modifications to my design.
I'm in Ohio.
When you're this good, EVERYONE wants a crack at you!
http://www.petedraganic.com/
Edited 3/8/2007 1:39 pm ET by PeteDraganic
Pete, Thank You for the input. I was just curious.
I have used "Knife Plates" embeeded in the concrete and then bolted thru the post for a silimiliar application. BTW.. I grew up in Lakewood, family still back in that area.
Another thing that I just noticed.
Those joist hangers are absolutley worthless in this application. If anything, they are a detriment to this structure as another place to trap debris that holds moisture and facilitates rot.
They do not support any load in the way they are installed.
Make sure that thye rim joist is fastened well into each joist end. 4 screws/nails per location.
And another thing I meant to mention in my last post... The rule for cantilevering is a set standard being 25% of the joist length, IIRC. Don't forget to still comply with applicable joist dimesions.
When you're this good, EVERYONE wants a crack at you!
http://www.petedraganic.com/
"The rule for cantilevering is a set standard being 25% of the joist length, IIRC. "Sorry Pete. I gotta call you on that and raise you one "please quote where that rule exists, of you don't mind"
I believe what you are thinking of is the rule of thumb that you can cantilaever out one unit for each two units back into the structurre when cantilevering floor joists with no load above.But this is a beam, and considering snow and such, there can be considerable load.on the debris trap - I have taken apart PT lumber up to about 15 YO in situations like this and never seen any rot starting.
You guys on the left coast use incised fir for your PT which is not quite as penetrated with treatment as the SYP PT here on the east coast. I would not worry about rot there.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Edited 3/5/2007 4:49 pm ET by Piffin
The JLC Field Guide has a chart titled "Cantilever Rules of Thumb" on page 121. Their numbers for the max length of the cantilever are: L/8 for 'supports only roof load with clear span of less than 28 feet'. L/4 for 'supports only non-loadbearing wall'. L/3 for 'supports only floor load'. (L is the supported length of the floor joist)
Based on my inspection experience and knowledge of commercial and residential building codes I would suggest the following:
Temporarly support the decking and floor joist system and remove the the 4"x4" posts and footings.
Enlarge the footings and set new 6"x6" post.
Replace the twisted (2) 2x10 girder with new material of the same size if spans permit (Verify for your jurisdiction)
Either sandwich the new 6"x6" post with one 2x10 on either side and through bolt with (2) 5/8" diameter carriage bolts per post or notch 6"x6" post and bear the new girder on top of each 6"x6"post and bolt the girder to the remaing post material with (1) 5/8" dia. carriage bolt for good measure.
Then add 4"x4" knee braces (at 45 deg. angle) extending 1/3 the post height. Through bolt each knee brace to 6"x6" post and 2x10 girder with 5/8" dia. carriage bolt at both bearing points.
Reference material: IRC with North Carolina Amendments Appendix "M" Decks