Deck Sagging and Rotting

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SFLman

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We have a deck which was constructed in 2009 and is 10" high. The planks are Trex. This is the view looking East.

2014-09-white-birds-2-1453.jpg


There are two unique areas which the deck covers. The first is cement pad which goes around the pool, and the second is that part of the deck which extends out over the yard. The sagging below shows where the cement is and where yard is. The higher part on the right is where the cement is.

pict0010_thumb-1446.jpg


You can see below that the joists which run East and West, and are perpendicular to the Trex planks are holding up pretty well. But the joists which run North and South, have really rotted.

There is landscaping fabric on the ground under the joists that go over the yard.

pict0001_thumb-1452.jpg


The Trex was not installed correctly, there is supposed to be a 1/4 inch gap between planks. I've communicated with the company on how to fix that. It involves using a circular saw to create a gap between the planks.

One of the joists which runs East West has significant damage.

pict0009_thumb-1447.jpg
 
I don't know what to make of these grey stains. The wood feels strong, so I think it's just dirt stains. But it may be the beginnings of rot. I just don't know wood. I've tried to clean these stains, and while some dirt comes off, the color is definitely in the wood.

pict0006_thumb-1448.jpg


Here is a picture of a wooden post siting on the concrete pad. It has a galvanized base:

pict0005_thumb-1449.jpg


There were 4 joists here. Three in particular are in really bad shape. What I can see of the one at the top looks good.

pict0004_thumb-1450.jpg


Other than dynamite, does anyone have any general ideas about what should be done?
 
The better looking joists my be treated lumber, if not they should be upgraded.
My guess is the the beam ended up 3" away from where the plans called for it and 2 untreated timbers were added to make the joists reach.
If the grey stains can be removed with a pressure washer without removing any wood, then you might think they are treated.
 
That last pic looks like that one support is sitting in the mud.
 
That last pic looks like that one support is sitting in the mud.

You are missing half of what you can see there.
There are 2 timbers in hangers on short posts.
2 more timbers nailed to the first 2.
We can see galvanized hangers and hanger nails.
But we also see some common or bright nails that have rusted.
We can also see the start of the problem when we look at the top boards there is a joint right above the timber that has almost rotted away, so water could get in but it had now where to go, so that timber never had a chance to dry out.
 
The gray streaks are just staining from the water coming off of the deck between the gaps in the TREX. I can see the same thing on the underside of my deck, though mine is all PT wood not TREX.

I'm not a fan of ground level decks. The 2x material used for the floor joists is most likely all PT wood but it is not rated for ground contact. A floor joist that is well off the ground will be able to dry out between rain storms. When it sits on the ground it will soak up water and rot prematurely even if pressure treated.

I would opt for either a paver patio or a stamped concrete patio instead of deck if I'm on grade. Higher cost but little to no maintenance over the years.
 
I'm with Sparky on this one.
A few other issues some of that older Trex had a recall because of all the failures.
http://topclassactions.com/lawsuit-...trex-decking-class-action-lawsuit-settlement/
Any composite decking needs air flow under it.
Joist spacing can not be more then 16".
There's been many post on this site and any DIY site showing all the damage to joist from ground level decks because of no air flow under them.
 
I don't know what to make of these grey stains. The wood feels strong, so I think it's just dirt stains. But it may be the beginnings of rot. I just don't know wood. I've tried to clean these stains, and while some dirt comes off, the color is definitely in the wood.

pict0006_thumb-1448.jpg


Here is a picture of a wooden post siting on the concrete pad. It has a galvanized base:

pict0005_thumb-1449.jpg


There were 4 joists here. Three in particular are in really bad shape. What I can see of the one at the top looks good.

pict0004_thumb-1450.jpg


Other than dynamite, does anyone have any general ideas about what should be done?

I think we all agree, it was built wrong, but there is lots of life left in much of the framing. And it is fixable if that is what you want to do.
 
That gray just looks like whatever they used to tint the composite is washing out.
One of the many issues with that old Trex.
 
Thanks for all the replies. Joe, I read about that mold and coloring class action lawsuit. Your comment about the grey coloring seems on target. I guess that the mold or algae is washing down onto the joists as well.

Anyway, to be more clear, here is a picture showing where the deck is resting on the ground:

pict0001-a_thumb-1454.jpg


You can see one area (under the 3rd red arrow) that is still up. I hired a guy to do a quick repair in the beginning of 2014. He lifted up that joist and put a stone under the joist. At the time, that was the lowest dip in the deck.

I'm almost for sure not going to do this repair by myself, but I want to have some good ideas before I get a carpenter over here.

I guess a complete repair would look like this:

1) Take up the planks over the four North South joists that run right at the edge of the concrete pad.

2) Tear out the rotten NS joists, and replace them. Reconnect the East West joists to the NS joists.

Put the planks back on and call it a day.

If I was going to do this myself, or if I hire someone, there would be a need to use some kind a jack. Maybe even several being operated at the same time, now that I think about it.

Am I thinking right here? I'm already trying to think of any short cuts!
 
1 Remove enough of the decking to work on full length of beam.
2.Remove the hangers from the joists on the rotted side of the beam.
3 remove the two rotted members.
4 Inspect the other beam members replace if needed.
5 Cut the ends of the joists to allow for 3 plys of beam.
6 paint all cut ends and any wood with signs of rot or everything you can see with copper treatment.
7 build an new "two"ply beam with underground rated wood. "underground rated wood looks just like regular but has hundreds of knife cuts so the treatment gets deeper in the wood".
8 add 8" blocks to one side of the new 2 ply beam. "each end and in the middle"
9 Bolt the new beam to the old beam with HDG 5/8 thru bolts and washers at the area of the blocks.
10. Replace the hangers with HDG nails.
If two men can't lift and block the joist back in position for working on them an old bumper jack will work fine.
I put the blocks in between for two reason 1 cut away rotted ends. 2 allow water to drain between the 2 beams.
If the ends are worse that that, cut off the rot and sister on new as long as you can 5-6 ft.
11 before we had treated wood we put strips of tar paper on top of joists so water did not sit on the top of the joists and I think I would do that here. 3" for singles 5" for doubles
 
This is just the sort of suggestion I'm looking for :)


Of course, I have a couple ?uestions:

1) If I'm going to chop off the ends of the East West joists, I wouldn't have to remove the hangers (your step #2 above) which are attached to a rotted member of the old 4 ply North West beam. I'll just cut off the ends of the EW joists and toss the hangers in the trash.

Do I have that right?

2) I get the whole concept of creating a new North South beam (in addition to repairing the old one). I'm just not sure if the new 8" blocks will be, according to your plan, sitting on the yard or sitting on the concrete.

FYI, only one member of the 4 ply North South beam is good. In the photo below, it looks like two of them are still good, but only the top two inches of the second joist dpwn is good, and it has rotted the rest of the way downward. I think the topmost member in the photo is still good, but once all three bad plys are taken out, it might reveal that there's some damage.

pict0002_thumb-1451.jpg
 
This is just the sort of suggestion I'm looking for :)


Of course, I have a couple ?uestions:

1) If I'm going to chop off the ends of the East West joists, I wouldn't have to remove the hangers (your step #2 above) which are attached to a rotted member of the old 4 ply North West beam. I'll just cut off the ends of the EW joists and toss the hangers in the trash.

Do I have that right?

2) I get the whole concept of creating a new North South beam (in addition to repairing the old one). I'm just not sure if the new 8" blocks will be, according to your plan, sitting on the yard or sitting on the concrete.

FYI, only one member of the 4 ply North South beam is good. In the photo below, it looks like two of them are still good, but only the top two inches of the second joist dpwn is good, and it has rotted the rest of the way downward. I think the topmost member in the photo is still good, but once all three bad plys are taken out, it might reveal that there's some damage.

pict0002_thumb-1451.jpg

1) The bottom of the hangers are 3" deep, so if you don't want to cut them, you will need to remove them.
2) You are removing 2 rotten plys and replacing them and bolting them to the other 2 ply beam with blocks for spacers between the 2 beams.
So just like the old set up where everything was nailed together except now water will be able to run between the old beam and the new one.
We can see one joint in the top decking was right over the second timber and the water had no where to go.
As far as more damage goes, just keep digging until you have it all and replace.
If one ply of the other beam has to be removed you can sawsall the nails that hold them together or just pull the hanger nails on that side and change them both.
http://www.homedepot.com/p/Estwing-12-in-Pro-Claw-Nail-Puller-PC300G/202033613

You will be cutting only 1 1/2 to 1 5/8" off the joists.

What you have now is 4 timbers nailed together, I am suggesting 2 2 ply beams bolted together with a 1 1/2" space between them
 
I think I've got your idea.

In the drawing below, the old North South beam is shown in gray with a gray post. The purple area is empty, to allow water to flow down. The orange shows a post, and a new 2 ply green beam, with one ply nailed to the other ply.

Do I have the location of the the bolt correct?


position-of-the-bolt--1455.jpg
 
Almost, the block will just be 1 1/2 thick so both green beams in your picture go thru and will be the same length as the old one
When we bolt the ledger to the house we put a bolt about every 32" so maybe more bolts and blocks than I said before.
If there is a footing below those posts and below this second beam you could block up under the new beam too.

The picture is incised lumber and it should be tagged for below ground use.
Hot dipped galvanized nails, hangers, bolts, nuts washers. The treatment will eat untreated steal

incised.jpg
 
From what I'm reading here and other threads, you might consider raising the section of the deck that's over the dirt. A two-level deck has disadvantages but it might hold up better with some circulation below it....just a thought.
 
From what I'm reading here and other threads, you might consider raising the section of the deck that's over the dirt. A two-level deck has disadvantages but it might hold up better with some circulation below it....just a thought.

This is a big expensive deck, I think he can get another ten or fifteen years out of it, with a good repair. Other issues may show up in time but most anything can be fixed cheaper than replacing.
 
The cement pad lines up with the 2nd ply:

cement-1_thumb-1456.jpg



1st ply is definitely damaged :mad:!

cement-2_thumb-1457.jpg


In the next few days, I will get more planks up so I can see how the deck is supported out in the yard. I've never been able to see that because there's a North South Beam which blocks my view. Also, not every East West joist is on the ground. I need to put pavers underneath of them.
 
Where you have the blade stuck in there, change them both, there is no sense in leaving cancer in there when you are this close.
Where you put the red line, it looks like there is one on top the other, or??
On the pool end you would expect to see a beam below the joists with the joists cantilevered over it to pool edge.
If you haven't got enough scrape laying around just cut a bunch of untreated 2x4 blocks to hold stuff up while you work on it.
Since you have fabric down there I would get a shop vac and clean the leaves out of the area
 

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