Deck Over Living Space Question

NK8892

Im currently building a deck over a living space are and have 2 2x12 pressure treated joists as the deck support, but they must rest on a 5 1/4" x 11 7/8" LVL. My question is whether or not they all need to be pressure treated ( I am assuming they are because they are under the EPDM membrane, plywood and deck boards, and is there a certain way I need to attach the PT wood to the regular wood of an LVL? Thanks


Nick

John Hyatt

Wtf j.

DecksEtc

My thoughts exactly John.

I'm struggling trying to picture a deck with only 2 joists

NK8892

I guess I didn't explain it well enough, its not just 2 joists i accidentally put that additional 2 into there sorry guys.

But the point of my question is whether or not these joists (size is 2x12's) supporting the deck need to be pressure treated or whether they can be regular wood ( because the deck above the living area ( where the joists would be) will have membrane, so cant the joists be non-pressure treated?)

If it does have to be treated wood, would it attach to the LVL regularly or is there some special procedure to attach pressure treated wood to LVL's made from non pressure treated wood.

the layout is pretty much Joists covered with Plywood then EPDM membrane, sleepers, and deck boards ( which will of course must be pressure treated).

thanks , sorry for the mix-up, gotta explain it in more detail next time

BreyerConstruct

This honestly sounds like a recipe for future disaster.
Nothing special between PT & LVL.

I'd be concerned about moisture hitting that LVL though... and don't trust the roofing to work forever...

~Matt

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genecarp

What does your carpentry crew recommend?

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NK8892

I am just currently looking at what I need for this to be started ( only on concrete part of this walkout basement/ deck) but The structural engineer said it needed to be PT joists and that you coudnt attach PT wood to LVL's regularly..I was looking to see if that's the case with what you guys have done before and whether you used PT joists or regular wood joists

maceycon

I think you may be better off if the structural engineer builds it. Or maybe anyone else!

KennMacMoragh

So you are building a balcony? That's what I assume when you say "deck over living space". If everything is enclosed then no they shouldn't have to be treated. I've framed lots of outdoor decks with a solid plywood subfloor and water proof membrane on top. And all of those joists had to be treated, but they were all exposed to the outside air.

As far as I know, anything totally enclosed isn't required to be treated unless it's touching concrete or if they are floor joists less than 18" from the dirt. Unless there's some weird local code of yours saying they have to be treated. Some things are optional, skylight curbs is one of them, those don't have to be treated, but I've seen a lot of people use treated. It's just a personal preference, I would not use treated on a skylight, because to me if it ever leaks then you're going to be ripping it up and fixing it before it has time to rot.

And if you're worried about your deck leaking and causing wood rot. Then wouldn't the homeowner know it was leaking and contact you about it? You said it's over living space, so if it leaks, they will know about it. With my experience fixing wood rot, it's always been in the walls. It's when water leaks into the walls is when nobody is aware of it, then it leaks long enough to completely rot out the studs. If it's in a roof or balcony, then the homeowner will notice it right away and have it fixed before there is any wood rot.

I've never had to fix wood rot from a roof, except once, but that was in some apartments where the part of the roof that leaked was outside of the living space, so no one knew about it for a long time. And are these joists part of the ceiling too? So will there be sheet rock attached to them? If there is, then that's another reason I wouldn't use treated. Attaching sheet rock to treated wood isn't a good idea, you get more shrinkage in treated, and it will cause problems for your drywall.

DecksEtc

So, you've got a structural engineer telling you how to do something and you've come here to see if anyone here (who has no more specifics than what you've provided) will contradict it?

You're sounding more and more like a DIY'er to me

John Hyatt

WTF. Joist into beam, get the money, get on the Harley, forget about it.

ghesssssssssssss be a big boy figure out the job your very own self. Build the roof with no leaks and frame the whole thing out of pt .40 lumber. It dont matter if the direct rain dosent get to it all the rest of the Weather will. Use .40 pt lumber on all outside Projects. J.

MartyCD

Is this a deck over a garage? Just wondering what that glulam is spanning. In any case, I would almost look at it in two pieces, making a secure roof and putting a deck over that space. For me I like PT joists, which the SE may be requiring because it is stronger wood; and even PT or marine plywood. I know EPDM is done right is as good as it gets but for the small upcharge why not have the cheap insurance? Also, your SE may just be referring to what are now fairly standard ACQ compatible joist hangers.
Remember to make the deck removable or in pieces, so that the roof can be fixed. And remember to water-test the roof before putting the decking on to test your work. And for God's sake use CorrectDeck CX instead of PT decking! Marty

AutumnWood Inc.

I will second that Correct Deck CX - RULES! We heard so many great things here about it (especially from Robert CDF) that we started recommending it first, over the last year and half. And we like even more now than when we started using it. The only draw back has been, only one lumber yard in our area carries it and we are worried they might be closing up. Thank You, for all the help with getting us samples and display's
Your local rep is great guy (Dale Sternard)

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MartyCD

Thanks! I will get right on it, and get an attaboy to Dale. Marty

seifconst

Annnnnd how do you "regularly" attach any two pieces of wood together?

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AutumnWood Inc.

Two quick things, Marty I heard you guy's are discontinuing the Sand color. I would like to say we used that color on almost every deck we built this year, alot of customers like that color and the sand color goes real well with Pebble, Merlot, and Mahogany. We really like to use the border's in different colors.

Also hope Correct Deck will get all their colors into Deck Tools deck design program

Thank You
Hope you have a
Blessed new year

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Goldenboy

You do not need PT joists over a living space. You must vent the joist cavity or use that spray ploy insulated foam directly to the underside of the plywood, to get your R-rating, if you can not vent. The plywood that excepts the membrane is not treated, right? Once water gets through the deck membrane your screwed anyway. Also, I have built outside solid decks for 20 years and never used PT joist. How many eaves are built out of treated lumber. I am assuming you do not live in the tropics. That would be a different deal. I will add that I only use Doug Fir joists material for roof decks.

Mc...

Good Luck!

greg24k

You should change the Trade name you listed from General to Private

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