Covered Deck: Pressure treated joists?

[midrover170]

Hi all -

I may be running into my first big  moment...

My design has a 9' deep x 16' wide covered deck. All corners of the structure are covered. I got into a lumber ordering frenzy a week ago and ordered everything as normal, kiln dried lumber. My thought was that since the framing will be out of the elements, that I could get by with this material.

Was that too hasty of a decision? Should it be PT regardless? My clearances are big - about 3 feet from the ground. Thoughts? Most deck guides don't address a covered deck scenario, and most building codes just recommend normal clearances (12").

Thanks,
~D

[Redoverfarm]

I like to think that any surface exposed to the elements should be pressure treated.  If you choose to go w/ white wood I would at least put a protective coat or two of something that will preserve it.

My porch is covered by a roof but still exposed so I went with PT.  A deck w/o a roof is a deck but a deck w/ roof moves it into being a porch.   

[midrover170]

Thanks, Redoverfarm.

I'm thinking of grabbing some pressure treated for:
- Rim joists
- The 6-8 joists at the two edges of the deck, and
- Ledger Board

Applying a water sealant to everything else. I may put some flashing over the beam even to keep it as dry as possible.

[Redoverfarm]

Thanks, Redoverfarm.

I'm thinking of grabbing some pressure treated for:
- Rim joists
- The 6-8 joists at the two edges of the deck, and
- Ledger Board

Applying a water sealant to everything else. I may put some flashing over the beam even to keep it as dry as possible.

You need to put a barrier between the flashing and the PT lumber.  A chemical reaction takes place between steel or aluminum and PT lumber.  I just use # 15 or #30 felt.  I have also used "ice or storm guard" membrane.  Down the road regular flashing will corrode and be of little value for it's intended purpose.  They also say you can use copper flashing w/o a barrier but that is only if you have deep pockets.