untreated deck joists

[Bigbartguy]

Our cabin has a large deck that the previous owners built with untreated decking and joists. Grrrrr.

The decking has rotted and we are replacing w/ composite decking.

Question about the untreated joists: These joists are 10 yrs old and most are in very structurally sound w/ no rot whatsoever. There are maybe 3 that are holding water and rotting, we are replacing these. This may be caused by the fact that owner butted all of his decking boards up to each other….no water could drain off the deck!

We're wondering the best way to preserve the remaining decent joists? We'd rather not replace them all right now. I've used some Thompsons Waterseal in the past with very poor results. We obviously would not pull decking off and retreat every year.. We're looking for any/all options to help seal the existing joists for as long as possible.

Some kind of pine tar product (like from old time boats, do they still even make this)?

Roofing tar (or would that stink every summer and expose kids to cancers?)

Tar paper over the tops of the joists?

Some of other kind of paper over tops of joists?

Absolute best sealant to use?

Thanks folks!

[crothmeier]

What i woould reccomend, and the product isnt specifically marketed for this purpose but it would work well is the Vycor window wrap tape. Its a black butyl product that you can get in 4", 6" or 9" wide rolls. Its self advesive and VERY sticky. its used over nailing flanges on windows before siding is applied.

Center the 6" or 9" tape on the joist and run the length of the joist folding the exess material down the sides of the joists. This will keep water off the top of the joist. You will be screwing your new decking down throught this tape, but it is a butyl and should seal around the screw once in.

A deck stain is another option but IMO that only lasts so long before the protection is gone. Thompsons Water Seal is no better than spraying water on your deck. A quality deck stain like pennofin, sikkens, superdeck, will give you much better results.

To do it the right way, replace them now and save the headache later! (budget allowing)

[Bigbartguy]

thanks Croth. I just checked prices on joists and they are getting replaced! I'm not fooling with this again in a couple of years. Wood prices have come down quite a bit from the last time I was buildling anything!

thanks again!

[MNice]

Very smart move!!

[crothmeier]

i agree. buy the green treated ones.