I plan to replace my pool decking. The 16×32 pool is inground, boardered by a concrete apron, which is in turn bordered by a PT approximately 4′ wide deck. The decking surface is 2×6’s nailed to 2×6 joists, set on edge, buried in 5 inches of #2 stone. All the decking and joists need replacement. This is an upstate NY installation (much snow and cold). The ground surrounding the pool slopes away from the area.
My plan is to remove all the decking and joists then reset new PT 2×6 joists in the existing stone bed and replace the decking with something like TREKS.
I’m not particularly confortable with resetting the new joists in the stone bed but I don’t have any better ideas. I’m looking for suggestions and opinions about other approaches.
Tom
I
Replies
Foundation grade joists.
Another option would be black locust. You'd probably have to source it from a sawmill, and use it green, but it will hold up.
You considered pavers? They would solve all your problems and probably cost less than a new wood deck.
first...
I would want to know how long did deck #1 last?
trex andwood require 18" of
trex andwood require 18" of venting under the deck to last any usefu l time
Free Draining
If you have enough gravels under and around the pressure treated "joists", that the installation is free draining you should be okay. The critical issue is to avoid having water stand against the wood, leaving it saturated and vulnerable to attack by molds and fungii. I'm not sure that the #2 gravel is appropriate. Typically that is road base and is what Engineers refor to as well graded, meaning that there is a good blend of sizes to minimizes voids. In this type of installation you want gaps to allow air circulation, and water drainage.
That is essentially how railroads are built. The ties that secure / support the rails are bedded in a deep course of roughly 1-1/2-inch gravels. The gravel provides drainage for any water, while providing a firm bedding and lateral support to the ties. Around the turn of the last centry they started treating the ties with creosote to double thier life. And, now they use concrete or plastic ties. But, on your pool deck I wouldn't expect to see the kind of high impact repetitive loadings that are seen with rail roads.
So, just be sure your gravel is at least a couple of inches deeper than the bottom of your "joists", (grade beams would be a better description), and the water that gets in has somewhere to drain to. Also, I'm not sure you need the 2X6s. Since all the grade beams will be doing is holding the Trex in place.
I could show you a trex over PT on 12" good drainig stone here that is about 5-6 years old, with mushrooms growing out of the bottom of the trex. I hink they call them mushrooms because they make it get mushy.
check with the manufacturer and they will say clear venting, not just drainage
Treated Lumber
There are a few different stipulations in the specs. for treated lumber regarding the definition of "ground contact." As Dan mentioned, treated lumber generally called "foundation grade" is treated to the maximum for the most severe rot inducing condtions. Is it used for wood foundations, and for all practical purposes, it never rots. It lasts forever.
It is somewhat confusing because at performance levels less than "foundation grade," there are all sorts of grades, species, and treatment specs. Some of those will rot in the application you have around your pool.
I am not sure about the rot resistance of TREKS. But one detail that would help reduce rot inducing conditions would be to make sure the subgrade below your rock bed is well sloped away from the pool, so any water that falls on the rock bed can drain out underneath it.
Another thing to consider is how absorbant the soil under the rock bed is. If that soil is holding a lot of moisture, it will encourage rotting in any decking material that is not 100% rot-proof. I would consider removing the rock, tamping the soil (making sure there is drainage slope), laying down 6 mil polyethylene, laying down woven geo textile fabric, re-laying the rock bed, and then setting the deck joists. That way, the soil underlying the rock will never get wet.