Decks, Patios, Porches and Docks - Deck Reconstruction

I am in the process of rebuilding a 12' x 16' 15 to 20 year old deck. The framing seems to be in good shape, but the decking and railings have not been maintained and are shot. I am going to use composite decking.

The issue that I see is that even though the framing seems to be in good shape, the tops of the joints have nail holes in them and there is splitting along the tops only. The splits do not visibly extend into the meat of the 8" joists. I plan to seal the joist with primer and stain, and then to cover the tops of the joists with a rubber membrane. Will this last, or am I better off replacing the joists as well? Obviously, I would prefer not to have to replace the joists.

Any suggestions would be appreciated.

For the few dollars that new joists would cost, I wouldn't even THINK about reusing the ones that are there!!

My reasoning -- The joists are the part of a deck that is most suseptible to damage due to debris and water. The ones that you have, besides being 15 to 20 years old with all of these splits and other seak spots, are probably spaced too far apart for a composite decking. MOST composites call for the maximum joist spacing being 16" O.C., so you would be adding an additional joist between each of the existing ones.

If your joists run in the 12' direction and are 24" O.C., you have9 of them. You will be adding 8 new ones. If you remove the existing and install new ones throughout, that's a total of 13 joists -- only 5 more than you are going to be adding anyway.

And composites have at least a 20 year warranty -- you are going to put that on a 15 to 20 year old frame??

Thanks, Lefty. You have a good point about the age of the deck. The spacing isn't an issue, as the joists are 16" on center. However, replacing the joists may raise other issues about which I could use some direction.

First, the deck is attached to the house and there may be aluminum flashing on the old ledger board. I can't remove the aluminum, as a patio door rests on it. How would I address the incompatibility between new pressure treated lumber and aluminum? Would covering the new pressure treated lumber with rubber membrane do the trick?

Second, no joist hangers are used with the existing framing. Are the new joist hangers compatible with old lumber, particularly the ledger board, and, if not, how do I get around this?

Assuming that the flashing is aluminum, then covering the new joist tops with Grace Vycor to seperate the aluminum from the ACQ will work fine. (I cover all of my joist tops with Vycor, just to prolong the life of the joists.)

Simpson Z-Max hangers and hardware do fine with ACQ. That's why Simpson went to the Z-Maz line -- it has a heavier galvanized coating.

Sight unseen and just thoughts -- if whoever built the deck originally didn't use joist hangers, I wonder how the ledger is attached? And did they indeed use a flashing? You can see it, so you know. But my experience has been that when one corner was cut, I can usually find at least 3 or 4 others as well.

So far, I've only managed to rip out only half of the decking (original guy used nails, most of which are rusted and either do not come out or break). However, I was able to see under the deck; he used hangers on the ledger board, but not on the other side. I won't be able to confirm whether there is flashing until the rest of the decking is ripped out.

Another thought occurred to me - if I am replacing all of the joists, might I be better off in spacing the joists 12" apart, instead of 16"? The old deck felt a bit bouncy at 16".

By the way, when applying the Grace membrane, how much do I overlap on each side of the joist? I was planning on 2" per side.

Thanks.

Oh yeah -- old nails, and probably screw nails or ring shanks. Even galvie's hang on like nobody's business. I know what you're fighting!

The Vycor, at least what my supplier carries, is either 4" or 9" wide. I use the 4" for joist tops -- that leaves a little over an inch hanging off of each side, and that's fine.

Joist spacing -- it depends a lot on the composite that you will be using. Most call for 16" max., and I usually cut that down to about 14". That's two extra joists in a 16' wide deck. Adding four extra would put you about 12" O.C. Let's see -- 12' X 16' -- that's 192 sq. ft. That's about 425 linear feet of 1X6 decking. At $2.50/ft., that's $1100. At $3.00/ft., that's $1300. You're there, you're doing it. An extra $100 for 4 extra joists and you don't have to worry about the 'bounce' -- sounds like a 'no-brainer' to me.

I have a supply of the 9" Vycor, so I'll cut it in half for the top of the joists. As for the joist spacing, I'll go with 12" oc. The extra cost is worth it for a solid deck.

Since you've been so helpful, what are your thoughts about railing posts? I'm planning to use cedar posts mounted to the outside of the skirt board on two sides, and two feet on each end of the long side of the deck (the center of the long side will be open to accommodate a new free-standing 12' x 12' deck which will be a stop lower than the existing deck. My wife does not want to give up 4" on each side of the deck for railings, therefore I have to mount the posts on the outside of the deck and am worried about stability.

Any thoughts about this?

I set my railing posts INSIDE of the rim joists. You can gain 1-1/2" by notching the posts so that the outside of the post is flush with the outside of the rim joist. But DON'T hang them on the outside.

I have used Simpson HDU's to secure the rim joist to the butt ends of my deck joists and then hung the railing posts on the outside (notched 1-1/2" deep so that they sit on the rim joist), but that is a lot of work and a lot of expense to pick up a couple inches of deck.

I look at everything in a cost/benefit analysis. A few hundred dollars in a $10K deck to use ACQ rather than plain Doug Fir or even borate treated framing lumber for the framing -- I don't give my customer a choice. I use the ACQ. An extra couple hundred for the Vycor -- again, no choice. A little extra to add a few joists to reduce the span of the deck boards, eliminating the 'bounce' -- it's figured into the bid. I'm going to walk away and leave my customer with a 'bouncy' deck. But a few hundred dollars for the HDU's in order to gain a couple of INCHES of deck in each direction -- the option is there, and if the customer wants to pay for it, I'll do it. But that is getting into the area of 'upsell'. Certainly I 'upsell'!! Lights, outdoor kitchens, fireplaces, spas, ... But I also realize that almost none of my customers have an unlimited budget to work with. Those that DO have the budget know what they want, and they realize that all the 'beels and whistles' are going to add to the cost. But that's what they want, and they know it's less expensive to do it now rather than to add those things later.

You convinced me against placing posts on the outside of the deck. However, in terms of materials for posts, the ACQ around here is pretty bad - bowed, cracked, wet, etc. What do you do in those situations?

You are dealing with the same thing I am. ACQ simply isn't a finished product.

I use post sleeves -- either vinyl or one from a composite deck mfgr. Given that, the wood 4X4 post doesn't have to be ACQ. It wont be exposed to the elements. The sleeve covers the sides, and a post cap prevents water from getting to the top of it.

Folks on the right coast use PT for deck boards. That's all well and good -- they have PT boards that will WORK for deck boards. I've seen pictures of PT decks from the right coast, and the PT SYP looks good! On the left coast, we simply can't get anything like that. (Well, we can, but the cost to us will be about the same as a right coaster trying to get redwood!!)

Again, it's a situation where you'll pay a few extra $$ and get the look you want. If you choose not to pay the few extra $$, what you'll get will look like... well, the suits in this forum won't let me complete that thought, and, all in all, I'm OK with that!!!

Sorry for the delay in responding, but I've been out of town for the last week.

What I decided to do is rebuild the framing with ACQ lumber, 12" on center. For posts I decided to use composite posts which match the decking. This is cheaper than using wood posts and putting sleeves on them. Besides, the sleeves around here are really unattractive. And, the composite posts have a hollow center which will allow me to run wiring through them for lighting. For railing I intend to use ACQ lumber and stain it to match the decking and posts. For the rail cap I will use composite material, as I was fortunate to find several 12' pieces which match the decking and posts for 70 cents each on clearance at Lowe's.

Thanks for the help and suggestions, as I am sure to have a better product now than I would have had before.

Check your ledger fasteners: http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf
Be safe, Gary