Deck Sagging and Rotting

[SFLman]

Not that it matters much, but I now know how the deck out in the yard is supported:

An 8" post supports two joists and sits on some kind of board.

But the real reason for my post tonight is that I've come up against a nasty problem which I have no idea of how to address. Some of the screws I'm trying to take out are snapping on me. I'm trying to get the planks up which are over the beam that needs to be replaced. Two different types of screws were used to fasten down the planks. One type has a larger head and has held up fairly well. But as I move South, I'm encountering another type of screw with a smaller head. Here is one of each kind:

These little-headed screws are mostly the type used from where I'm at going south. So far, I've snapped 1/3 of them. Then they just spin. 1/3 will come out, and the rest are frozen. I"m going to put more liquid wrench on the frozen ones, and they may snap once I start to get them up! I need to get about 230 screws up to get the 5 rows of planks up which are over the beam. Almost all of the screws are the weak small headed kind.

Any ideas?? If the bottom half of these screws are in the joist, I won't be able to put a new screw in that that hole. If they are snapping just under the head, I can twist them out with a pliers after lifting up the plank.

 

[nealtw]

I have broke those putting them in too.
I would leave that problem solving until after you have seen the wood, if you are changing beams out it won't matter as much.
New screw will just go down beside the old ones. Or maybe you can juggle some boards so the holes no longer line up.

 

[bud16415]

The reclaimed deck I took down to build mine 75% of the screws snapped off taking the old deck apart. I didn’t bother even trying to get them off I ether snapped them off flush or hammered them in flush. Like Neal said the new screws will run right in beside the old ones and hold fine. If you find a real problem one just angle it a smidgen when you start it. Much better than seeing open holes in the decking. Switching the boards is also a good idea of Neal’s.

 

[SFLman]

I have neglected these pages for the past two weeks, but for a good reason.

Remember the old newspaper comic "What's the Diff?"

I advertised the 20 year old hot tub on CL free to anyone who would pick it up. 18 people responded. After a number of near misses and complications, and people veering off on me (Hello? Hello? Do you still want this??) the hot tub is gone.

While we were moving it, much of the wooden framework broke up like mush. If it had not been for the insulation, we would not have been able to move it. I can barely believe that this tub was designed for outdoor use. The framework was clearly not pressure treated and had sucked up water like a sponge. Luckily, the guy still wanted the tub! We rolled it out on 4 4" pvc pipes with a 2X8 1/4 plywood sheet under the mushy part rolling over the pipes. After that dude was up on the trailer I was in such a good mood I gave each of the three guys twenny bucks!

I'm going to take a few days to regroup, coz that's how I roll, and then I'll be back asking more questions. Thanks!

 

[SFLman]

Over the past few days I have spent time cutting between the planks to create and increase the gaps. Trex calls this a Kerf cut, and they sent me a .pdf file on how to do this. To some degree, the reason the deck is rotting and sagging is because the person who installed the deck failed to leave gaps between the planks. My ability to fix this problem with the saw may dictate how I move forward with the entire fix of this deck.

In the picture below, you can see a dark spot on the deck. It rained here a two days ago, and there was a puddle there all the next day. Not good! This area of the deck is where the hot tub was.

The .pdf file says that you need to modify a rip fence to hold the saw in place while you push the saw along and make the gap cuts. I tried to make a few cuts without a fence, and it did not turn out well. Maybe you can see the uneven cuts between these two planks.

After ordering the Bosch WD7RIP fence, which has a wider "stem" than fences for other brands such as Dewalt, I could see that the modification suggested in the .pdf file was not possible. They want you to flatten out the blade of the fence, and I did not have the ability to either bend or grind down the curved bottom lip.

But I did come up with a fix, and I can testify that it works. I used a masonry bit to drill two holes.

I then cut and bent an ordinary piece of thin aluminum. I then tore out a hole with a pair of needle nose pliers and slid the aluminum "blade" onto the rip fence and attached it with bolts.

 

[SFLman]

Here is a view of the circular saw with the new fence. The original WD7RIP fence is upside down.

BTW: I'm using a rather thick blade in the circular saw, and it's working out better than the thin blade which came with the saw. Trex does make a blade and I bought one for $30.00 or so, but I have not yet used it. They advertise that the blade they make will prevent melting the Trex. The blade I'm using is made for plywood. I got two bundled together at HD for 8 bucks. The company advises against using a thick blade like the one I'm using. So far I've encountered no problems.

I plan on doing the Kerf cuts for a few more days, and then finally get back to figuring out what is the ultimate solution to this whole mess.

 

[nealtw]

https://www.jccayer.com/Dewalt-DW35.../p/7848/gmc/?gclid=CK3Fl7zI4csCFRVsfgodeHAPwQ

All the tool brands make blades like this pretty much all purpose.

 

[SFLman]

Here's a floor jack which starts out at 3.5 inches. I will need one of these, unless anyone has a better suggestion. Kinda pricey at $51.00 but I will be glad to have it.

http://www.sears.com/craftsman-2-1-2-ton-floor-jack-low-profile/p-00950165000P

Next question: should I worry about trying to match the screws that were used in 2009 ? I think these are them:

http://www.homedepot.com/p/Grip-Rite-9-x-2-1-2-in-Coarse-Gray-Internal-Square-Torque-Drive-Composite-Deck-Screw-5-lb-Pack-N212CSG5/202755197

I guess the question is, will it be noticeable if I use a different style of screw?

The last issue: instead of using the kerf cut I'm toying with the idea of removing a row or two of planks, and then shifting the other rows to create gaps. I could use this shifting technique on the rows that don't go around the pool. Would this work ?

After all this I've finally learned what the Kerf of a blade is. They make some blades awfully wide. I won't be buying one of these:

http://www.infinitytools.com/8-Flat-Top-Blade-24T-5_8-Arbor-250-Kerf/productinfo/080-250/

 

[nealtw]

Do a little digging in grandpas garage, and old car jack or a pick will work for a lot of weight.
If you rework the deck for proper spacing, you may end up with water landing on beams again with no where to go.
I am not sure it was a spacing problem it was just that the water was on the beam with nowhere to get out.

 

[slownsteady]

I'll bet no one is going to look at the screw heads on your deck except for you and anybody (family friends and neighbors) who are familiar with your deck saga (well, maybe us too; but we're prolly not coming by to visit). But you, on the other hand, will probably notice the difference every time you step onto it. match them if you can, but don't make yourself crazy...and don't match them to the ones that are breaking.

 

[nealtw]

Because you want to use the same holes and some screws pulled thru I would just use the green or beige deck screws.

 

[SFLman]

Thanks for the advice on the screws. Neal, do you remember who makes the ones you recommend?

Here is the plan I have come up with to fix the deck, I'd appreciate hearing your opinions.

The first picture below is to review. This is a drawing of what we currently have going on under the planks, which did not last. The red numbers 1 2 3 4 are on the North South beam which is composed of four joists. The purple squares are 4 X 4 inch posts. The yellow East West joists are 16 inches apart. The drawing is not to scale. In real life, the posts are 6 feet apart along the beam.

The first step in the repair will be to cut off any East West joists over the yard which have rot, and to remove North South joists 1 & 2. The newly cut EW joists will have to be temporarily propped up at the correct height.

The next step will be to remove the remaining half of the beam, and cut back the EW joists which are over the cement. Some of these have a little rot right at the edge where they were fastened to the beam. These will be cut the same. I don't know how much of these joists I'm going to cut off, but I'm guessing maybe 1 foot. As these joists are cut, they will be propped up as well.

Whereas before we had 1 beam made of 4 joists, now two separate beams will be constructed, with both sitting on the concrete. These narrow beams won't hold water like the old bigger one did. Additionally, these beams will have roofing paper tacked on them.

 

[SFLman]

For the next step, short EW joists will be fastened between the two new beams.

Then Sister joists, shown in orange below, will be fastened to the EW joists over the yard. In the drawing the three original cut joists over the yard are the same length. When I really do this, they will be cut according how much rot is on that particular joist, so they will be different lengths. More board will be run to continue the original joist so that the plank screws will have something to bite into. The completed new structure as I envision it is shown below:

Here is a picture of the new structure with one gray 5 inch wide Trex plank on it.

I'm leaving out quite a few details, but this is generally what I think should be done.

Is there a much better solution? Cheaper? Faster? Am I doing too much? Or do I pretty much have it?

 

[nealtw]

Just a few thoughts to go with that. The space between beams 2 and 3 should have the odd block between them just to hold everything together, we wouldn't want to separate decks moving independently.
Hopefully the east west joists will only need to be cut back enough the get the new beam in. If some do have to be cut back more, I would do a long sister for lots of strength. Something around three feet of overlap and the fill in the missing space so the screw holes in the decking will still work..

 

[slownsteady]

You mentioned that the new beams will be sitting on the concrete. I hope that is just a quick way to explain it and that those beams will not be in any contact with concrete. make sure you have drainage (and air) underneath those boards.
How are you fastening down the (purple) posts?

 

[SFLman]

Posts will not be sitting right on the concrete.

Do you know the specific names of the hardware pictured?

I will be imitating the work that was done before, except that there will be two main beams instead of one.

I'm guessing I shouldn't try to re-use any of the galvanized hangers?

 

[nealtw]

For the next step, short EW joists will be fastened between the two new beams.

Then Sister joists, shown in orange below, will be fastened to the EW joists over the yard. In the drawing the three original cut joists over the yard are the same length. When I really do this, they will be cut according how much rot is on that particular joist, so they will be different lengths. More board will be run to continue the original joist so that the plank screws will have something to bite into. The completed new structure as I envision it is shown below:

Here is a picture of the new structure with one gray 5 inch wide Trex plank on it.

I'm leaving out quite a few details, but this is generally what I think should be done.

Is there a much better solution? Cheaper? Faster? Am I doing too much? Or do I pretty much have it?

Green a beige deck screws a available where you buy treated lumber

Don't forget some end cut treatment for any cuts you make in treated lumber.

Two points.
1. the blocks between beams 2 & 3 just nail a 2x4 on flat to #3 every 3 or 4 ft and then nail the next to that and then the next. It will be one with a space between.
2 The old beams were hung on the the post, if it is easier you can just place a short block under the beam, no real need for the hanger.

But yes I think you have it. When we sister to a joist we expect the next joist to do some of the work so if you are doing a bunch in a row, add to the length of the sisters and lots of nails or screws

 

[SFLman]

Your suggestion #2 is really sharp and you just made the project considerably easier. Thank you. :beer:


I don't follow suggestion #1. Considering how good suggestion #2 was, I want to be sure to understand

the blocks between beams 2 & 3 just nail a 2x4 on flat to #3 every 3 or 4 ft and then nail the next to that and then the next. It will be one with a space between.

I think your saying that I should drop the idea of having EW joists drawn in yellow above between beams 12 and 34. Instead I should just have a 1.5 inch space. In the drawing below I've put two green 2X4s. They would be nailed into joist 2. Joist 3, the left half of beam 34. would be nailed to the 2X4s, and joist 4 would be nailed to joist 3. Beam 34 would still rest on short blocks as you suggested the beams should.

Below is a rodent's eye view of joist 2 in yellow with a green 2X4 nailed to it, and the joist sitting on a small purple 4X4 post :

The screw holes in the planks are fully 3 inches apart, so there will be one row of planks covering over the 1.5 inch gap. Do I have your idea right?

 

[SFLman]

Well, this would be even easier.

Here I cut off just a few inches off of the EW joists over the cement, and then create 1 beam just 2 joists wide which sits on 4X4 purple posts. Then I extend the EW joists over the yard to the new beam.

What say you?

 

[nealtw]

Your picture with the green 2x4 between the beams is what I had in mind.
In your first photo in post #1 it is clear that the gap in boards was over the beam and the space provided by the 2x4s will allow water to drain thru.

I am not sure that just the one double beam will be strong enough to carry the weight from both sides. I would hate to have you do all this and find the deck sagging under it's own weight.