Joists rotting

[DanielP]

under composite decking. Foolish to have built an uncovered deck in upper Puna. Deck is only 7 years old. Joists don't dry out and apparently Hi-Bor doesn't help with this problem. Was going to "sister" some green board, but unavailable?

options: tear out deck or roof it, then replace rotten boards.

ideas?

[Carey]

We purchased the oil based "Copper Green" wood preservative from Ace for surface treating our replacement carport beam (termites decimated the 1st 2' & last 2' - so we had 16' of good wood & by the end posts, no good wood...never want to have to re-replace that beam, so we soaked the beam in the "Copper Green"!
Info link of the product from Ace (Keaau)
http://www.coppergreen.com/coppergreen.htm

[Obie]

You need to tear out the rotted wood,replace it and then use peel and seal flashing on top of the joists. Cut it in two inch strips.Stainless screws are a must too !


http://www.lowes.com/pd_154017-81326-PS6...Id=1018733

[bystander]

That flashing must be the one with the gooey tar like coating which actually sounds like a good idea. I built my deck using redwood joists 5 years ago without any flashing. It's holding up so far but I wish I had used some kind of flashing or painted the joists. I was under the impression that this kind of wood didn't need any coating.

[DanielP]

The rot is not just on the top of the joists. I am thinking buy new joists, dry them out and then immerse them in the Copper Green; then maybe flash the top of them. Wish I could get the real earth-to-wood contact pressure treat. The roof may happen too.

[kalakoa]

I've gotten the "real" copper-treated lumber at Argus; it's been a few years, not sure if they still carry it.

Trex is expensive, but it's also ... not wood, so it works really well in both fully-exposed and direct-contact applications.

[Carey]

Argus did not have "ground contact" pressure treated green beams (4x14's) when we got our carport beam from them this month - we did look at shipping the beam from the mainland, but the shipping cost was more than 2x the beam & 2-4 months time...(& our contractor thinks this will do, but "ground contact" was his first choice - he is a FLWright restoration specialist...so..oh, we really don't know)...

We did not check on other sizes, but it seemed like they do not have it anymore...so we made a trough & soaked the green into our beam....it does say it is a 'ground contact treatment' preservative....not that our beam will (hopefully) touch ground, but the drywood termites do not need ground contact to munch away at our wood...so we treat for them!

Oh, we also top coated with a clear coat & will stain this beam after a bit (wanna make sure everything that should off-gas does) hopefully by summer we will have a totally insect resistant beam.... overkill? probably, but wait until you get a quote for a carport beam replacement...you will want to overkill the replacement too!

[Obie]

The EPA has completed the re-registration of CCA lumber in December.It was banned because people were using it in the wrong applications.(picnic tables,playground equip)
They brought it back because it works so much better and it should be available soon.

ACQ is the next best and Argus carries that.I painted my joists before I used them.Portions of my deck are now 12 years old and still looking good.

Stainless fasteners are a must for the deck boards and hot dipped galvanized for the framing.

[Carey]

Argus has a mix of ACQ & ACA n-sized wood (looks spiked all over) in 2 by & a few 4 by dimensions& can order other sizes - these are not the "ground contact" preserved lumber, as the copper treatment is a water treatment & can, like borate treatments, leach out if exposed to water (rain, or ground, or...)

We have found that with ANY of the treated wood here, re-treat the surface of the wood, as you have absolutely no idea how it was shipped & stored, dip treat every cut & boring, use a top coat of non-leaching preservative & then coat again....but we have voracious drywood termites that have turned redwood homes of our neighbors into swiss cheese, so water based treatments that may have leached are a tasty treat for them!

[Rob Tucker]

.....or don't use wood.