Author Topic: House Deck Rot Damage Control  (Read 3523 times)

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Offline Adam Roby

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House Deck Rot Damage Control
« on: May 24, 2014, 09:56:02 AM »
When I moved into this "new to us" house last year the deck posts had a fresh coat of paint on them.  I slowly noticed it degrade over the past year and it appears the previous owner filled the rotted parts with some kind of cement filled and painted over it in order to sell.  There wasn't much of an inspection done to the outside deck since it appeared at least at a glance that it was in good shape.

The deck is 16 feet wide, and extends 12 feet out from the house.  There is a shingled roof over top with 4 cornder posts.  We started noticing some rot on the bottom of the roof post where I found all the cement filler hiding the original damage.  Here is a picture of what it looks like right now.  (There is a plate of metal there temporarily to discourage the dog from chewing the rotted wood).



My first thought was to simply replace the 3 or 4 2x6 beams that compose the post, but on further inspection the floor boards under that post are also rotted.  In addition, the tops of these posts have some pretty elaborate bracing that I am a bit weary to disasseble.  Here is a pic of the top of that same beam.



Looking at the side of the deck, I noticed the end cap was starting to disintegrate as well.



So I took off a couple of deck boards to inspect further... and was pretty shocked at what I saw.
The tops of the 2x8 end caps are completely rotted away.  There is another beam right on the side of this one but for some reason is only a 2x6.



so it appears as though the last joist was removed, and they added a 2x6 with no joist hanger, and just nailed to the rotten end beam.



And to make things worse, the other end does not even go all the way to the end of the deck, instead they cut the joist in 1/2 and they did this.



So what all of this actually means is that the roof is not being held up by very much... possibly just the deck boards lending some support from the other joists.  I need to either replace all 4 posts (all are rotten on the bottom 3-4 inches) or cut and add some pieces there to avoid removing all of the decorated parts.  Before I do that however, I need to fix the joist problem, so I can properly put a temporary support for the roof so I can cut or remove the posts.



This is the side split view from the floor boards I removed.  My idea is to add a new 2x8 from girder to house ledge using joist hangers, and place them on the left side of that roof post (left side 2x6).  Then it should be strong enough to remove the 2x6 and end rotted end beam.  Once they are out of the way, add a second 2x8 with hangers on the edge under the right 2x6 roof post.

Once that is squared away, I can put some temporary 2x4's to support the roof and cut away at the post, and replace the deck board underneath the post (post is just sitting on the deck board - maybe I should change that?).  I was thinking to cut away for example 8" of the bottom of that post, add new pressure treated wood to replace that section, then put some decorative cap over the cut ends, like a floor board kind of idea that may also offer some lateral stability. 

I know this is not a cabin, but figured your combined knowledge would help me a lot with this.  I do not want to lose the deck, and am not in any condition to remove and replace it all (back is pretty bad lately).  I am willing to replace as much as I can, with the first priority to make it as safe as possible.  Then I may treat the entire thing with some deck resurfacing product.

Note:  The house side has a beam lag bolted to the house and seems strong.  The opposite side is cement piers into the ground, with a cement beam running the wide of the deck.  There is another beam lag bolted to this concrete mass.  This appears to also be in tact.
« Last Edit: July 10, 2019, 08:47:41 AM by Adam Roby »

Offline Don_P

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Re: House Deck Rot Damage Control
« Reply #1 on: May 24, 2014, 11:07:45 AM »
Plan and do what you can when you're down and move forward when you can. I'm sort of damaged goods today myself. A deck with a roof, is a porch. Back up and take a pic. The first shot in troubleshooting by email or over the net needs to help the viewer get the overall scene to orient himself.

I'm not certain that there isn't a treated timber underneath the rotted wood... are we looking at just a post wrap? I'm wondering the same with the end rim joist. Are these untreated "trim" boards?

The shot of the ledger end and the joist hanger don't look too promising. The crack in the foundation corner should be looked at as well. Is this a crawlspace or basement? Looking at the deck surface in that last pic in relation to the brick joint it looks like the end has dropped a bit. A point load like a roof support post should really not bear on a ledger but should be carried down to a foundation so I'm not liking the repair idea yet, I think it'll just weaken a compromised situation. Not much help yet, just sort of bouncing some thoughts around.
« Last Edit: May 24, 2014, 11:25:24 AM by Don_P »

Offline Adam Roby

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Re: House Deck Rot Damage Control
« Reply #2 on: May 24, 2014, 01:12:17 PM »
Sorry for the lack of perspective.  This is the entire structure, and the post in those pictures above is the one against the house on the right hand side, behind the BBQ.



Until I cut into the post, I have no idea if this is just a post wrap or the actual post.  It appears to be void, unless they have one more 2x in there. 
All the wood is painted in opaque paint, so I have no way to know if it was originally treated or not.  My feeling is that it was not treated, simply because it is so rotten.  The ledger against the house appears to taper off at the ends to become 8", where in the center it might be a 10".  I am having a hard time to get under there, there is skirting screwed around the perimeter and the previous owner piled a bunch of garbage underneath the deck, old blocks, old wood, all kinds of stuff.  It all needs to come out, but again the back is limiting me.  I never noticed that drop... and now I see the same drop on the other side.  Now I am really scared.  Can you believe I actually stored my 600 lb motorcycle on this deck over the winter?  :o

The only thing holding up that entire side (house side) is that ledger.  There is no post or beam support at all.  It is possible the posts against the brick wall are lagged down, but a brick wall offers no support either.  The crack in the basement (it is a full livable 8' basement) might just be the parging, then again the opposite corner of the house had a similar crack and after taking a hammer to it a chunk about 6" cube came off the corner, luckily above grade.  I repaired that last summer... might have to do the same here. 

OK... so there is no way I can dig 4' to the front line under an existing deck.  If I were to at least place some temporary patio blocks under there with 2x supporting the floor joists... daing, don't think that would be enough.  The person that designed and built this thing really was not thinking.  All of the weight of the roof is on the corner of the floor board.  The end joist is not even using a joist hanger... here is the left hand side support.



As you can see, the last joist hanger is 16" in from the end, the trim boards are just toenailed in, the floorboards are the only think supporting the roof. 

This is the front left view of the deck, away from the house and opposite the BBQ.



Now I am not even sure about how well that was done.

I think I will need to somehow underpin the house side.  I can not dig down 4' for sure... maybe I can dig 1' down, 18"x18" and fill with cement then add a post up to the deck to give it a bit more support.  I will throw down some temporary 2x's with those old blocks until I can figure out the next step.  I still need to replace the end joists and posts... what do I tackle first is the question?

 
« Last Edit: July 10, 2019, 08:39:13 AM by Adam Roby »

Offline Adam Roby

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Re: House Deck Rot Damage Control
« Reply #3 on: May 24, 2014, 01:39:02 PM »
Ok this is a terrible drawing, but what if I put a vertical board lagged to the concrete foundation, then add some angled support braces to the two end joists?  I will line those joists up with the posts...




« Last Edit: July 10, 2019, 08:35:52 AM by Adam Roby »

Offline Don_P

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Re: House Deck Rot Damage Control
« Reply #4 on: May 24, 2014, 05:01:56 PM »
I guess let me pick it apart first so we can see just how bad it might be. Is anything under there treated? The ledger and joists in the pics look like weathered untreated wood. The ledger to house lags look like they have no washers and are in a line up high across the ledger. If that is the case, at a minimum you need to put some lags down low ~2" above the bottom edge so that the hangers aren't hanging from just a narrow strip of ledger above the lags.

A small drill bit into the post would tell you if there is just void behind the wrap.

Some solid cap blocks for a temp footing and posts from the ground up might not be able to keep it from sinking if the load went to them but they would go a long ways to keep it from collapsing if the ledger or rims let go of the house.

Right now my gut feeling is that it's all untreated, the rotted rim is probably the worst and the rest are somewhere in between. I think you're probably looking at temporarily supporting the roof on angled posts just outside of the deck, keeping the roof and replacing the posts and deck.

Since that is very major, another thought if the interior joists are good. Hire a kid to dig holes alongside the foundation at each end of the ledger (with the crack there I'm leery of trusting something bolted to it for support). Support the inboard end of the roof and pour piers to grade with embedded post bases.  Support the rim joist and cut the end off for a 6x6 or whatever the post above is. Remove the center ply of the built up post, maybe up to the diagonal braces leaving the 2 side casing pieces intact to as close to the floor as possible. A flat bar and sawzall should be allow you to clip nails and carefully get rid of that center section. Drop the solid post down thru to the pier between the 2 side pieces of the built up posts and fasten those sides to the new post. Notch the new posts to support a horizontal ledger that runs under the joists supporting them in case the house ledger fails. Use inturned double joist hangers on that new horizontal beam to carry the rim joists. Repair/replace the side post casings at the bottom by making a decorative base  to replace the bottom rot.

Offline Adam Roby

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Re: House Deck Rot Damage Control
« Reply #5 on: May 24, 2014, 07:01:43 PM »
Hi Don,

Firstly, thanks for taking the time to have a look at this.  If I were younger and had the physical ability I would consider tearing this thing down and starting over.  Hopefully I can make it safe, if not pretty.

I wish I have Sketch Up to do this rendering, all I have at home is the laptop and it is a pain to use with no mouse.  I used Paint to do the drawing below so hopefully it makes some sense.  This is a 2d view from the side, more to understand how the pier would look.  Since normally you would do a round hole with a sonotube, the post bases would not have enough meat on them to support the existing ledger.  I guess this would need to be a square pier, flush against the house's foundation.  In my drawing, I am using laminated 2"x6" pressure treated lumber rather than a 6"x"6 post with notches.  Since my main beam is using the 2x6 through the center anyways, this should fit with the "look" of the existing post.



So there would be a 2x6 from the pier to the bottom of the existing ledger to help support it.
The next laminated piece would run all the way up to the roof.
The next laminated piece would support a new 2x? ledger board that would run from pier to pier, parallel to the existing ledger but runing underneath the existing joists, giving them a bit more support.  (The tallest PT 16' long piece they sell at the local box store is a 2x10x16').  Since that is more of an additional support, would 1 be enough?
PT 2x6 is added to all other sections to form the rest of the post. 

Is this in line with your suggestion?
« Last Edit: July 10, 2019, 08:32:55 AM by Adam Roby »

Offline Don_P

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Re: House Deck Rot Damage Control
« Reply #6 on: May 25, 2014, 07:10:50 AM »
That's along the lines of what I was thinking. Rather than 4' deep, go until you hit undisturbed ground.
To act as a stand alone girder it would take a 4 ply 2x12 as the "new ledger". If there is a mid support a 2 ply 2x12 would work. You could run another short 2x6 post from the piers up to the underside of additional plies. I doubt there is frost heave in the middle of the girder under the porch roof. A shimmable or screw type support on a surface footing would avoid digging in that area.

 

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