[olson2334]

Hello,

I have posted a few times on this. Hope this is ok to create threads for different questions.

Essentially my posts are rotted and I have to replace them. I am trying to determine the quickest simplest but correct way of replacing them.

Below is an image of the ruff measurements. The red lines are where the beams are today. The blue would be where I place the new beams. my plan would be to shorten the longest span and lengthen the one furthest from the house but I think they are still within range? These are 2x8's. I can also attach some pictures of the effort.

What is the furthest I can span a 2x8 without support? The deck is at most 3' off the ground.

Thanks for the help.

 

[chandler48]

See also Deck Repair as well as Deck Repair adding Pergola or Sunroom
Best to tag new information on the old post so we don't have to go around the equator.

 

[jim_bee]

Prescriptive Residential Wood Deck Construction Guide see page four

 

[carpdad]

Maybe possible if you can find post bases that can sit on existing piers, though they have old posts in them. You may have to custom order post bases that spans most of the top area of the piers. How about? Grind the top of the piers flat, slip 1/4" metal plate and add existing post base and weld the two? Plan on such and cut existing posts to correct dimensions? Just an idea.
Another idea. Live with it. If posts are rotting but only at the base, how much could it sink and how long would it take? Since your deck is not high, such "floating" deck is not a terrible idea. You can add cross braces so the deck doesn't rack too much.

 

[olson2334]

@chandler48 to be sure i understand as I don't want to break any rules. Are you saying to continue to ask question on one of the other topics i created or create a new question but link the original question to it?

Thanks also for the replies. @carpdad I have already dug into this project to leave it at this point. All the deck boards are off. I plan on creating concrete bases for the new posts to sit on. @Nealtw had some thoughts on leaving the beam where it was. Now that i have the deck boards off i thought I could give a bit more clarity to the effort and where this idea was hatched to just move the whole beam one direction or the other. Maybe that is easier but it does increase the span but it seems within range.

@jim_bee thanks for sharing this. I would be using treated pine so at 16" oc I can go nearly 12' which this would be.

Also once i got some of these deckboards off it looks like some of the 2x8's seem to be still structurally sound. Would you guys just replace all of them new or save some money and try and reuse some of these original boards?

Last, the ledger is exposed and I thought it was supposed to be wrapped to keep it water tight? Most of it seems structurally ok but some of it was not flashed for some reason. Most was. The siding goes right down to the ledger.

 

[carpdad]

I think you should replace the whole thing. I forget if this is your home or selling. As long as selling, you can do some cosmetic. But if to keep, then its life span is important to you. ALL of the materials are outside grade and will be under weather. That means you want ALL of the parts to have the same life span. Ledger too. Pressure treated lumber needs specific fasteners also. All metal must be separated from lumber with peel and stick membrane or spec'd for the lumber. Coated to resist copper or hot dip. Zinc coated is no good.

 

[jim_bee]

Also once i got some of these deckboards off it looks like some of the 2x8's seem to be still structurally sound. Would you guys just replace all of them new or save some money and try and reuse some of these original boards?

If it's not too much work to salvage them and they are really in good condition, then I'd re-use them. Any sign of rot, fungus or insect infestation, I'd discard them or use them someplace where they would be easy to replace. You're putting a lot of effort and money into the repairs and you wouldn't want to take a chance on "iffy" lumber.

 

[chandler48]

It's just easier for us to keep one train of thought, with addendums, than it is to jump all over the place and reconstruct each one from the other threads. Not a violation or anything, just keeps old minds from wandering

 

[olson2334]

Sadly it seems to many are not in good condition so I am going to replace them all as you guys suggested.

When I replace the ledger and beam(doubled) in addition to posts, joists and rim how do I ensure they are protected from rot going forward?
I can see with the ledger there was some metal flashing that went over the top of it (is that called z flashing? ) which I would replace it it wasn't fully flashed for some reason. It was slid under the siding. Is this still the proper method?

 

[chandler48]

See post #3. That Prescriptive advice will cover everything from flashing, to post bases, to how attach your beam to the posts. To directly answer your question, z bar flashing is not accepted on a deck. It has a particular purpose and it doesn't apply to decking.

 

[olson2334]

Thanks I didn't realize that was in there. If i am understanding this right it looks like i would need a piece of flashing that inserts into the siding (not sure minimum so lets at least an inch) that is caulked and extends some distance past the ledger board. It looks like it must be at least 6" since in the image it looks to extend past the first piece of decking. Am i understanding that right? I am looking at page 14: https://awc.org/wp-content/uploads/2022/02/AWC-DCA62015-DeckGuide-1804.pdf

 

[chandler48]

That is correct. I would fasten my last piece of decking only on the edge away from the house so as not to penetrate the flashing. After all, what good is a perforated flashing material? If that presents a problem, over flash the part on the joist and rim with self healing sticky flashing tape.

 

[olson2334]

That is correct. I would fasten my last piece of decking only on the edge away from the house so as not to penetrate the flashing. After all, what good is a perforated flashing material? If that presents a problem, over flash the part on the joist and rim with self healing sticky flashing tape.

Great. I can also place the joist tape down first and then place this metal flashing over top of that? Doing that I imagine then then joist and ledger are all now protected from moisture.

 

[chandler48]

I would flash first, then use the tape, but there may not be a problem with having the tape under the flashing. The main thing you want to do is stop water infiltration. Stopping it before it gets to the metal flashing may be a better thing.

 

[olson2334]

I would flash first, then use the tape, but there may not be a problem with having the tape under the flashing. The main thing you want to do is stop water infiltration. Stopping it before it gets to the metal flashing may be a better thing.

To be sure I understand, you would first place the metal flashing and then put the joist tape right over the top of that continuing down the joist?

 

[chandler48]

I would, yes.

 

[olson2334]

I have another issue while working through this. I am trying to get the post out but this(the only freakin one they put concrete in it seems and the one i really need to get out) one has concrete at the base of it. I cannot get it out of the hole. you can see there are steps there as well that make it really hard to get the jack i have over the top of it to try and pull it straight up and out.

One thought I had was to try and cut it off as far in the hole as possible and just put the concrete pier around it. Any other thoughts? If the cut off idea would work does anyone have any thoughts on a saw to get in this small hole to cut it off? It is nearly 4 feet down the hole to give perspective.

I need this new concrete pier to hold the new post in place exactly where this one sits. none of the other posts have had concrete but this one seems to.

The crack in the dirt next to the post is the concrete.

 

[Nealtw]

Re design so you don't need the new one to be right in that spot?

 

[olson2334]

I was thinking on how to do that but I don't currently have a good solution. This is a corner post which lines with a ledger board coming off the house. Plus my wife wants to keep these giant steps.

 

[Nealtw]

I was thinking on how to do that but I don't currently have a good solution. This is a corner post which lines with a ledger board coming off the house. Plus my wife wants to keep these giant steps.

A post can be a foot or 18" from the end of the beam, Cantilever rules apply . distance between posts divided by 4 = max cantilever. But never see more than 2 ft.