Need advice on deck framing - Oval Pool

[Dirk]

Regarding my aluminum tents. That was all me. Not necessarily best practice. I was replacing deck on a landing and stairway. The joists under the shower were considerably more rotted than any of the others, so I know it was the extra water and sand and dirt. The flashing idea was born from that (flashing is, after all, used to deflect water). I won't know if it actually works until I replace again in another 25 years! But I figured even if moisture got in-between deck and metal, that would be better than two wet pieces of wood touching. And that the joist would likely be more protected either way.

 

[mgmercurio]

I have begun a few preliminary layout and markings with my laser level and stakes...pics attached

 

[mgmercurio]

View attachment 161180

Hi Dirk - I know it has been a while since my last post...but I have waited out the lumber price increase and it is finally back to normal in my area. I have begun constructing the deck and my plan has changed a bit.
1. I decided to do 6x6 posts with 2-ply 2x8 beams directly on top of posts.
2. I also changed the direction of my beams from parallel to perpendicular to my pool.
3. There is a 2x8 rim joist running around the interior and exterior of the deck.
4. Since the top rail of my pool is a 6 inch aluminum top rail that does not interfere with replacing the pool liner (it is a universal bead liner), I have decided to do a seamless look and set the elevation of my joists level with the top rail and then place the deck boards all the way to within a 1/2 inch from the edge of the pool-side edge of the aluminum top rail. Keep in mind, I ran the beams all the way within 1/2" from pool wall under top rail so I can place 4x4 posts from my beams all the way to underneath the top rails for support. Plus, I am either going to use stainless steal screws and screw the pool facing deck boards directly to the aluminum top rail, or I will drill through into the wood frame under top rail and use stainless steal bolts (recessed and filled with a gromet plug)
I have attached a few pics for your review.

With that said, how would you frame the curved sections of the deck to butt up against the edge of the pool? I know you said to cut 45 degree miters and use bolts to bolt additional beams under the curved pieces, but that was when you thought it was 4x6 beam running around the pool. With my new design, it will a 2x8 rim joist running around the pool...so is that still the method of choice or do you have another approach?

Thanks for your thoughts.
Matt

 

[Dirk]

Hey MG, I just popped into the forum for a quick response to someone else, and spotted your recent post. Can I offer some advice? I would strongly recommend you not sandwich two 2x8s together and instead use single 4x8s. That sandwich will wick water in between the joists, where it will remain for long periods of time. They will eventually rot out because of the constant moisture, from the inside out. I have direct experience with that phenomenon. The deck joists I replaced all showed evidence of that problem.

I replaced that framing, and facia, with that in mind, eliminating those types of "sandwich areas" wherever I could. Even the facia is nailed to spacers to allow air to circulate on both sides of the facia, to minimize wicking and maximize drying. And this for a deck that is only subjected to rainfall. A deck surrounding a pool, which will be subjected to both rainfall and pool water, will likely be wet most of the year. Rethink the 2-ply 2x8s...

 

[mgmercurio]

Hey MG, I just popped into the forum for a quick response to someone else, and spotted your recent post. Can I offer some advice? I would strongly recommend you not sandwich two 2x8s together and instead use single 4x8s. That sandwich will wick water in between the joists, where it will remain for long periods of time. They will eventually rot out because of the constant moisture, from the inside out. I have direct experience with that phenomenon. The deck joists I replaced all showed evidence of that problem.

I replaced that framing, and facia, with that in mind, eliminating those types of "sandwich areas" wherever I could. Even the facia is nailed to spacers to allow air to circulate on both sides of the facia, to minimize wicking and maximize drying. And this for a deck that is only subjected to rainfall. A deck surrounding a pool, which will be subjected to both rainfall and pool water, will likely be wet most of the year. Rethink the 2-ply 2x8s...

Hey Dirk...thanks for the advice. You are spot-on in your recommendations. My issue is this....
I already purchased the 2x8 lumber for the beams, before I found out about the wicking problem. Giving the large deck size, it would be a 3000.00 mistake to go back and replace them now. 1500.00 for the purchase of the exiting 2x8 lumber + 1500.00 for the purchase of the new 4x8 lumber.

I would have absolutely gone down the 4x8 route if I hadn't already purchased the lumber.

But....

I have done more research and I have come up with a solution that I think will fix the issue.
I actually ran a bead of caulk that is safe for wood down each of the "sandwich seams." (LOTS AND LOTS of caulking)
After that, I ran joist tape on top of the seam on all the beams. My goal is to waterproof the seams. I am hoping this helps the wicking issue.

Thanks for your advice...I appreciate it and know you are right.
-mgm

 

[PieterS]

Didn't ready anything in detail - but just want to add that be aware of using posts that are too SHORT - I believe they are more prone to cracking and splitting. Look into it - I may be way off base but I thought that's what I understood at one point in time... Good luck - sounds like a neat project!

 

[Dirk]

Hey Dirk...thanks for the advice. You are spot-on in your recommendations. My issue is this....
I already purchased the 2x8 lumber for the beams, before I found out about the wicking problem. Giving the large deck size, it would be a 3000.00 mistake to go back and replace them now. 1500.00 for the purchase of the exiting 2x8 lumber + 1500.00 for the purchase of the new 4x8 lumber.

I would have absolutely gone down the 4x8 route if I hadn't already purchased the lumber.

But....

I have done more research and I have come up with a solution that I think will fix the issue.
I actually ran a bead of caulk that is safe for wood down each of the "sandwich seams." (LOTS AND LOTS of caulking)
After that, I ran joist tape on top of the seam on all the beams. My goal is to waterproof the seams. I am hoping this helps the wicking issue.

Thanks for your advice...I appreciate it and know you are right.
-mgm

If this work is already done, then "it is what it is." If the caulk is successful, then that might help. But it might also help to trap the moisture even more. What I mean is: if the caulk keeps every bit of water out, then that's good. But if it fails some day (like from age, or sun, or movement, whatever, which it will) then it will allow water in, but work to keep it from evaporating out, actually exacerbating the problem.

If you haven't done the work (or even if you have), you might consider an alternative. I would add 1/2" spacers between the 2x8, creating a channel through which air can circulate. I don't know the engineering involved, but I would guess that nailing or bolting the 2x8s together does not significantly increase their load-bearing capacity all that much, if any: they're going to hold what the hold whether they are bolted together or separate. In fact, your deck would have a more solid feel if the the 2x8s were spaced evenly apart. So, for example, a deck with single 2x8s on 2' centers will feel more solid than one with two 2x8 sandwiches on 4' centers.

So that's a couple ways you can still use the wood you own but end up with a longer lasting frame...

 

[PieterS]

If you haven't done the work (or even if you have), you might consider an alternative. I would add 1/2" spacers between the 2x8, creating a channel through which air can circulate. I don't know the engineering involved, but I would

That's exactly what I did when building my deck many years ago. If I recall directly - it was more to fit the standard ties that you place on top of 4x4 posts - they are made to support a 3.5" wide beam for some reason - so that's exactly (2) 2x8s in my case plus a 1/2" spacer. This keeps the 2x8s spaced a bit to allow moisture to not get trapped.

All that said - sounds like the OP is doing his research, what he came up with I think is a perfectly doable plan and will last many many years!

 

[Newdude]

+2 on the spacers. Around here we just use scrap 2X’s. The half inchers clog too easy with pollen and whatnot.

 

[Dirk]

That's exactly what I did when building my deck many years ago. If I recall directly - it was more to fit the standard ties that you place on top of 4x4 posts - they are made to support a 3.5" wide beam for some reason - so that's exactly (2) 2x8s in my case plus a 1/2" spacer. This keeps the 2x8s spaced a bit to allow moisture to not get trapped.

All that said - sounds like the OP is doing his research, what he came up with I think is a perfectly doable plan and will last many many years!

Yep, that's where I got 1/2", so that the 2x8s plus spacer will sit nicely on a 4x4 post... I haven't had any issues with the 1/2" space filling up with crud, but I suppose that depends on what kind of crud falls on the deck...