Deck Sagging and Rotting

Well, as usual you've made a comment which has caused me to do more digging. (It's good for me!)

Over the concrete, the EW joists are propped up with metal feet. The feet are not only screwed to the wood, they are screwed into the concrete. Here are two different EW joists. The camera is pointed toward the house in both pictures.



In the picture below, the joist terminates at the East side of the pool.



Also, I believe that those EW joists which go all the way to the house, in other words, do not terminate into the side of the pool, were cut to rest on the concrete.

It's really the first bit of carpentry that I've seen which I really admire. Near the skimmer below, the there's an EW joist just to the left of a light grey line.



I took a picture holding the camera over the skimmer lid aiming toward the house, and the joist is cut to rest on the ground, plus it has a metal bracket screwed into it, which is also screwed into the concrete.



The joist you see on the left in the picture also rests on the ground, and makes the west wall of a box that goes around the skimmer.

With this new information would you now think that the "One 2 joist beam" design with I drew above would be adequate?

Well that is a neat trick that I never thought of.
If these are the same joists that you intend to stretch I would think yes, you could even use that trick to stiffen things up.
My only other question is, did they give any special arrangement to get the water out from under there. If there is a slope on the old concrete deck it should be running right to where your beams are may be a little trench to let it flow out?

While I was doing the kerf cutting a while ago down at the south end of the deck near the house, I could see sunlight reflected in a small amount of water. I took it to mean that the planks are so tightly placed along side each other that evaporation is slow.

As for drainage in the West area of the deck between the house and the pool, maybe there is a way for the water to drain down onto the lip of the pool.

I have thought it over, and I'm going to hire this fix out. But at least I have a plan and a good understanding of the main problem. I will post pics of the repair as it progresses. Thanks again!

You would really like water to go someplace not just sit there but you can't do much about it now.
Each contractor may have a different approach to the fix but you have enough what ifs to ask to get what you want.

Well, I tried to find a company to fix the deck, but it did not work out, so I'm doing it myself. This is much, much easier than I thought it would be. Additionally it has occurred to me that I can fix the deck in 10 foot sections, and the southernmost twenty feet can even be fixed next year since it is in pretty good shape.

Here is how things look with the most rotten part removed, and a new 2 joist beam put in. I'm using the GC (ground contact) wood from HD. I was told that they are phasing out their Weathershield wood entirely. It is still on the shelves but not for long at the store I was in.



The new hangers aren't holding hardly any weight at all. The metal feet drilled into the concrete supporting the joists support the weight. Even so, of course, I put in hangers and connected the East West joists over the cement part to the new beam.



But I do have a question now that I'm in the middle of it.

The part of the deck that is over the yard has sunk quite a little. I could do it, but I don't want to jack the East West joists over the yard up any higher. Instead, I'd like to "cheat" the sister joists as shown below:



The piece of wood shown clamped to the original joist in the picture above is a 2X4, and that is not what I will actually use. I will actually use a 2X6, but all of my 2X6's were too long to fit in there to photograph.

I will run a 2X4 between the original joist and the new beam for the plank screws to bite into. I intend to screw it into the new sister joint. Would I need to cut a wooden pad for the plank screws? Something like the photo below?

Your sisters should match the originals, 2x8 or 2x10 ?
Cut a bunch of tappers and wedge the joists back up the straight.
I am not understanding the Vs cut out of the beam, that really does weaken it.
Your taper to level the joist in the last picture works if you are replacing missing wood.
http://www.deckmagazine.com/engineering/rules-for-drilling-and-notching-deck-framing_o.aspx

I don't know where I got the idea that 2X6's were sufficient for sister joists. If I were to use the original size joist, I guess I'd have to notch it to clear the cement pad. I've got maybe thirty bucks worth of cut 2X6's which can't be returned. I suppose I could take it to the re-store and start over. On a scale of 0 to 10 how essential would you say it is to use the same size joist?

The V's cut in the bottom allow for drainage. As I said above, for the time being, it's just not bearing hardly any weight. The metal feet screwed into the concrete are holding up the EW joists over the concrete. Are you advising me to take it out and start over? The V's are 3 inches wide. More that three times the limit in the chart you linked.

The East West Joists which go over the yard terminate in an unknown way into a North South joist which sits on the ground in the yard. I can't see how they are fastened together. I'm afraid if I elevate the EW joists which go over the yard much more, something is going to snap. Here are two photos to show what I'm talking about. This is the view East away from the house.




This is the view West toward the house.



To review, I am not talking about the joist termination at the edge of the deck. That looks like this:

To be clear the notches they talked about in that article would not get past an engineer, they just say no.
That being said , you are so close to the concrete I would just put a treated shim under each side of the V cut.
The photos you have under the joist are showing blocking.
When joist are more than 7 feet long they have solid blocking between them to stop any roll over with warp or twisting.
Your deck originally went over the concrete, so there should be no reason you can't get it back to where it was.
So if you set up to shim them back up, you set them up and wedge all at the same time, tap one just a little then the next and the next and back and forth until you have them all back up.
Lay a chunk of wood under each joist and cut a wedge that fits between the joist and that chunk of wood.

Understanding the floor joist.
A joist gets it's strength by the compression of the fibers on the top 1" and the tension of the fibers in the bottom 1".
To gather more strength for a longer span or a heavier load we want more distance between the top and bottom.
So with that we can see the notch in the bottom is a problem for strength and a change to a 2x6 will be just like a notch and would provide a weak spot.

As you already are against the eight ball with so many sisters in close area anything else that weakens the structure is just bad news.

I'm thinking the pictures were unclear.

Only two feet of the ten foot beam I've installed is off the cement. I cut a GC 4X4 post to go under that part in addition to putting in a hanger.



The other eight feet is sitting on the concrete.





The cement has pebbles in it, so I probably didn't need to cut any damn triangles anyway.

Check the picture of the knife cuts in post#15 and make sure you are not being lied to about underground treatment, check with other lumber yards.
Having the beam sitting on the concrete isn't the best, I would have cut it down by a have inch so it could be raised giving space below but as is it will likely last the better part of 10 years
I see you used bolts on the beam, when you sister go with nails and lots of them like 4 every 6".

Your using the wrong sized hanger on that beam, and it's one of the most important connections.
That spacer you put in there is useless for anything but a temporary block to hold it in place.
With the end grain exposed at the top and the bottom going to be sitting on top of that concrete unable dry out it will fail.

Nealtw - little by little I have wedged up the joists so that the sister joists will not have to be "cheated" up. You certainly stopped me from getting creative in a bad way!

Regarding how to connect sister joists, as best as I can tell there's continued vigorous debate as to whether one should use nails, screws, carriage or hex bolts. If you have a link to a source I will read it.


Joe - I will look at replacing the hanger on there. I thought the label said the hanger I bought was for 2X6's and 2X8's. When I google the big number on the receipt 044315271908 I keep coming up with a taller 6.75 inch double hanger. The one I have is 5 inches tall.

Regarding the pad, I will cut a new one going with the grain. That's a good thing for me to learn. I should have something reliable at that spot in case the structure sags in the future.

All little blocks shown in my pics will be removed, they are temporary.

If anyone knows how many feet I should overlap on my sister joists I'd appreciate hearing. I'm still debating whether to use my 2X6's, or, as Neal has advised, to sister with 2X8's to match what is there. I still can't remember who told me 2X6's were acceptable to use as sisters! I know I did not play lone horseman on that point.

Screws do not have the same shear as the nails, you can find charts for that, so even more if you want to go that way.
You read the bit about notching, in effect you would be notching out 2' x what ever length you have cut away.

As I explained earlier about joists the top is under compression and the bottom is in tension so that big notch moves that tension from the bottom of the 2x8 to the 2x6, at some point of loading the 2x8 will split length ways starting at the notch.
Same with using bolts, you are moving the compression and tension to the center of the wood in the joist, either could split on the drill hole.
As for length, as long as you can get in there and still be able to nail it.
Might be a good time to rent a nail gun.
After all that is said the better plan would be to put in new footers and a beam to carry those joists and short blocks in between the beams.

And good job lifting them.

And I now remember who it was who told me I could sister 2X6's onto the 2X8's.

I went to HD and asked to speak with someone experienced in deck construction. I explained that I wanted to create a new North South beam of 2X6's which would sit on top of several 4X4 inch pads. So, the 2X6 inch sisters would connect up to my new beam of two 2X6 inch joists. The person who I talked to said that would be fine.

A day later I got to measuring here and there and I discovered that I could just use 2X8's, sitting on the ground. I learned about "ground contact" wood and decided to create the new beam with two 2X8's sitting on the ground. It seemed to me more stable than 2X6's sitting on 4X4 pads. I then got concerned about drainage, and that's when I cut the triangles.

Neal, I have read in many places that if you are going to sister on a joist, you need 3 feet of overlap. You don't agree with that in this case?

I'm strongly considering removing the two 2X8 inch beams with the triangles I've installed.

Yes if you have one broken joist you would sister on a 6 ft piece giving you 3 ft of overlap.
As you have a multitude of joins, I would go all the way back as far as I could, just think of doing it again in a year or two, this is a time for over kill.
The one you have that is really short I would cut that square and install one between the two longer ones and then hang shorty off that and then a short up to the beam.
If you change out that beam, rip 1/2" off them so they will not sit on the concrete, you should be able to find plastic shims in the door dept and then just shim them to the concrete.
I do not believe that wood is treated for underground use.
You could use that beam for filler pieces after you have sistered to replace what was cut away.

That souinds like a good idea for dealing with that short one. I have drawn the fix you suggested as I understand it. The original joists are in yellow, the new sisters in orange, and the fix you've suggested to deal with the really short one in green. (The sisters will in reality overlap more going further back.)

Wouldn't I need two 2X8's going perpendicular to the short one?



I don't know if you can have two hangers on opposite sides of a single 2X8, so I've drawn two.

Yes a double is required but then the joist on each side should be doubled too, which you can't do. I should have said that.

I've taken up planks down at the South end. I won't be replacing the beam in this area since it has not yet rotted. I suppose I could put some tar paper on it to help it survive longer than it otherwise would. I will replace the beam when it deteriorates more some future year.

I now know what the original carpenter did when he constructed the beam. The bottom three joists of the beam are 2X6's. The bottom two are in a double hanger, and go into the 4X4 inch posts. Then, the next 2X6 up is toenailed onto those. Then he toenailed a 2X8 onto the 3rd joist. The 2X8 extends down to just below the concrete pad.



So the East West 2X8's over the yard are hung onto that 2X8 inch beam joist.



If the 4X4 inch posts had been just a little taller, he could have just hung the EW 2X8 inch joists onto the bottom two joists. That beam would not have been 4 joists wide, and then it probably would not have rotted. I'll never know what he was thinking. It's tempting to believe that I'm seeing something that was improvised due to some sort of disorganization or miscalculation.

He could have hung the 2x8 joist off the 2x6 beam, but he would have had to notch the joists for the concrete, I suspect he was afraid the 2x6 beam would sag and wanted the height of the 2x8 for strength and get away from the concrete below.

What he did just seems improvised. From my viewpoint, I need to replace 20 feet of his handy work!

BTW: as I have taken out plank screws, quite a few of them would not come up because they would just spin. When I finally got the plank up, I would see that the wood around the screw had rotted or split. These are screw holes in joists that I will be keeping! There have also been plenty of stubborn screws which I got out by using the crow bar, so there's more screw holes which are compromised.

I'm tempted to fill the cracks and screw holes with a glue or something. Good idea? Not worth it?