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Recommend decking for Chicago rooftop deck

Posted by esk8mw (My Page) on
Fri, Jul 8, 11 at 19:27

We just bought our first place and it has a 1000 sqf 6th floor private rooftop deck. The pressure treated pine deck that is up there now (11 years old) is in pretty bad shape - the 2x4 stringers directly below the 2x6s are badly rotted and the deck board are dried out, popping up, snapping in half, etc. I seem to put my foot through another board every day.

Long story short, we need a new deck and I'm not sure which way to go. As you can see in the pics below, ventilation is really poor for the deck - the walls are solid on each of the 3 sides and a bedroom takes up the 4th wall. Since it's a condo of course I can't mess with the structure that much.

Any recommendations?


Follow-Up Postings:

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RE: Recommend decking for Chicago rooftop deck

John Hyatt or any other experts, are you out there? Was really hoping for your input on this one. I'd like to consider ipe or some other premium wood but I'm worried the 3" or so of clearance from the rooftop and the lack of ventilation would make it a big waste of money. I talked to the condo board and they said they would re-do the roof under the deck before I lay a new one down so that's a plus as far as not having to worry that my new deck would have to be ripped up in a few years to fix the roof.

The existing deck is getting worse every day. I can stick a knife in each of the stringers (joists?) about an inch deep from the rot and I'm putting my foot through a new deck board every other day it seems. The pressure treated wood up there now isn't cutting it. Am I stuck with having to do stone pavers or some other non-wood product to have a usable rooftop deck?


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RE: Recommend decking for Chicago rooftop deck

ESK,, Pretty nice view.. in the window.

I am out there but latley its an invite only for me so thanks for that.

First off find a rooftop Deck Builder in your area. Check Him out, go look at his jobs.

There are all sorts of ways to get cross ventilation going on with your project dont panic over that. Chill.

The new roof is a major plus.

Ipe,Garapa,Masenranduba can all be installed. If done corectley Your Project will only be done one time in the time span of hmmmmmmm 50 years or so. There are some little things I know about that will help inform you but First find a Contrator, Let me know what he has to say. Also be sure to come up to your local permit store requirments.
Dont stick your knife in anything anymore.

JonMon www.deckmastersllc.com


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RE: Recommend decking for Chicago rooftop deck

Thanks John, appreciate the input.

A family member will be putting down the deck with my help. He's a retired GC (commercial, not residential) but was a carpenter for 25 years prior and has built dozens of decks, houses, furniture etc. He's very skilled but hasn't worked with SA lumber so I'm on here taking notes on all your old posts.

From what I understand our best bet is pressure-treated 2x4 joists (on pressure-treated 2x4 sleepers to avoid roof damage?), 1x6 ipe, face screwed with brown headcote screws into pre-drilled holes (into the ipe only) 1/2" from the ipe board edges, 16" on center joists, makita impact driver, forstner bits for drilling, bowrench, carbide blades, wood from East Teak, no anchorseal, finish with multiple TWP 116 coats when good weather hits. Miss anything?

He hasn't had a chance to come to the new place to check out ideas for ventilation, though, which is my concern I was hoping you had some ideas on. I've seen you recommend skirt vents but in my case the "skirt" is a rooftop wall + brick exterior that I obviously cant cut into on 3 sides and the building itself on the 4th side I can't mess with either.

Hopefully the new roof will provide better drainage since moisture obviously caused the PT joists in there now to rot away to nothing. Should I look into other sleeper systems besides PT wood?

If you want to see pictures of anything else on the deck let me know and I'll snap some more pics.


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RE: Recommend decking for Chicago rooftop deck

Thats a big project,you guys take care and work safe.

With a new roof the demo will be done,your working on fresh material. Get the best pt lumber you can find the stamp on the end should say Ground Contact. I am not knowing how old your structure is but the kind of rot your talking is rare,the warping is not,they might have not used pt lumber on the frame. Find Jasco Termin-8 paint stores will be able to order it. Retreat the stringers on all four sides with it be very carefull doing this the stuff is nasty but stops rot and bugs completley.

Manmade runners of any kind will not hold the fasteners any place close to real wood, forstner bit is for pluging,bowrench will not be used with 2x4 stringers laying flat google up tiger jaw installation tool <<< Very Nice Tool with a job like that well worth the Money <<<

Ventilation....Floor vents, ya know like inside a house, installed in the decking. These can be as simple as homecheppo $12 special with the works removed and painted black to solid brass supper fancy.

Again thats a big job to take on like your doing. Major bucks can be saved as long as No Mistakes are made.

JonMon www.deckmastersllc.com


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RE: Recommend decking for Chicago rooftop deck

Thanks again for all the knowledge - furiously taking notes over here.

The building is just 11 years old so I'm assuming the deck is the same age. I took more pictures below. The wood is so light and rotten now maybe it wasn't PT after all.

Floor vents sound like a good idea - how many and where should they be located? Just around the edges or throughout the deck? Should I do anything else to increase ventilation like increase the gaps from 1/8", give a bigger gap all around the edges rather than decking out to up against the edges of the roof, etc?

Now what should the stringers be sitting on? Looks like right now there's little 2x4 squares sitting on the roofing that the stringers are laying on (maybe with extra roofing material under the little 2x4 pads? hard to tell).

Do I need 5/4 ipe? Cupping is the obvious concern so I know you've said face screwing is the best way to prevent that. Any other little tricks I should know about working so close to a rooftop? I think we'll do alright as long as we can keep our patience and we have all the best info from the ipe pros. Thanks a million.


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RE: Recommend decking for Chicago rooftop deck

That is one Funky deck MW !!

Another reason to at least get a Contractor to bid your job..you will find out how the local Boys do it over there. Find the Best couple Contractors around,tell them what your plan is,Pay them a few hundred for their time. I think this well be money Very Well spent.

Local is everything I can tell you how we do it here but a Deck Contractor in your area would be a big help I am thinking. If you have any say so on what kind of roof is going back on do not install a hot mop roof go with a torch down modified or TPO.

We lay the stringers in the direction of the flow(with a strip of roofing under them ) so they dont stop the water from geting to the drains or the roof edge. Usually they are pt 2x4 s laying flat yours might have to have little blocks under them for clearance of several things like air vents or the drains themself. If it was my job I would figure out how to just lay them flat and let the vents/drains show or build a bench/planter box over them.

The floor vents will be placed depending on the flow of the water most of the time I place them around the edges. A biger gap wont hurt but not so big some little Girls ring could fall thru it,dont laugh this has happened more than one time, same with the space between the decking and the edges of the building.

Again, hiring a local Contractor / Adviser would be a good idea. Anyway if you do the whole thing your self do not ... drop a runing saw into the roof, drop the sharp edge of a 2x4 into the roof, stomp a hole in the roof with the heel of your boot, run a stainless steel screw into the roof or drive one in by steping on it , Keep you knife in you pocket, Dont hurt the Roof at All!!!!

Most all of my South American Jobs are done with 3/4 x 6 '' material, 5/4'' will cup less. While your talking to George at East Teak ask about 5/4 x 6 '' masenranduba it might suprise you but if you decide to get it dont buy yours before I finish my next job. Just Kidding !!!

JonMon www.deckmastersllc.com


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RE: Recommend decking for Chicago rooftop deck

I will probably solicit some bids from local contractors and pick their brains a bit; that's a solid idea if I can find the time. It's looking more and more like a next year project since everything has to go through the condo board and scheduling re-roofing and all that.

The 2x4 stringers right now are laying flat on 2x4 pads also laying flat all over the roof - I think it's done this way because my deck actually runs right into the neighbors decks (where you see the fences in the pics) and the condo board probably mandates that the decks all be the same height all the way around. That means I'll need at least 3"-4" or so clearance under the decking to achieve that height so I can't just lay 2x4s flat on the roof. Should I get 4x4s instead? Or stick with the 2x4 flat + 2x4 pad laying flat? I would think the pad method would be a better way to get airflow through and under the decking but what the hell do I know.

Plus the deck is shaped very irregularly and there's at least 3 drains on my deck alone so drainage could be in multiple directions - can't really tell what's going on until we rip out the junk that's in there now.

I'll be sure to check out the Massenranduba but for now it's all yours. Already dreading carrying 1000 square feet of decking by hand up an elevator to the 6th floor and up another 20 steps to roof level. That will suck.


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RE: Recommend decking for Chicago rooftop deck

Come on Man, if you get a Contractor over there tell him you plan to do it yourself and Pay the Dude for his time. That's only fair.

John


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RE: Recommend decking for Chicago rooftop deck

Maybe I worded it wrong but I planned on being upfront with any contractors - more of a consulting role and paying them. You don't have to worry about me screwing over a guy in the construction field - I may be a lawyer now but I spent several years working for a family construction business before law school, dad's a GC, 3 uncles that are contractors/carpenters and just about everyone else in my family is in the industry. I have a lot of respect for the construction trade. Plus, my family would disown me.

Any ideas on my stringer question up above re: 2x4 pads or 4x4s or something else to get that 3-4" clearance? Appreciate all your help so far; you have no idea how much trouble you've saved us already.


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RE: Recommend decking for Chicago rooftop deck

Good to know that, You just moved up several levals.

I have only done one like that,what a pain takes twice as long. Laying the stringers flat spreads the weight along in an even nature.

First thing find grade. An optical maser,laser leval,would come in handy. Mark it all around the outside walls. Tap con small blocks at important points to hold strings maping out the height for your layout. Check the spans with the leval for sag. Temp up all the strings. You now have deck grade.

Find the grade for the drains with a good 4'/ 6' leval mark them with spray paint in long lines. That is find all the dips that end in the drains conect them with the paint lines. You now have roof grade.

Now comes the tricky part and why the good Roof top Deck builders get the big bucks. Using 2x6 joists the span should be no more than 7 ' 6' is better. My way of going from this point might be different than the Local Boys. Decide what direction you want the decking to go,lay out strings every 6' on center I call these primaries or think of them as grade beams they will need to have support every 6 ' you can get away with 7 ' but I try not to.

With the primaries in place joist in on 16'' centers. This way the only long 2x6 will be used on the primaries the rest could be 6' or 12' makes for a better elevator ride.
Little trick I pulled off one time>>> pay the building mang and the elevator guy even tho the fraight elevator is usually bigger that wont help a lot. Either take the celing out or lower the elevator so you both can get on top of it. They can operate the thing from up there. You can hold up hmmmmm 3/4 18 ' 2x6 at one time mabey more. I lifted up a book case set spaning 30 ' made up in 3' sections 6' high doing this. Very cool ride. <<<

The 6' 2x6 you can handle in the regular way. Placing the primarie's 2x4 plates landing on the roof with little 2x6 posts is going to be intersting. Use 3' or so lenghts placed in a way that will somewhat not restrict the water flow sometimes this will be easy just put them right under the beam sometimes your going to have to angle them. Whatever figure out the flow and place them the best you can to let the water find the drain.

Doing it this way should work all though it might be a litte higher than some Folks want but not by much.

JonMon www.deckmastersllc.com


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RE: Recommend decking for Chicago rooftop deck

Nice, got this one printed out and ready to go for next year. All the grade stuff makes sense but the primaries/joists stuff has me a little confused.

Let me see if I have this right - I lay 2x4 PT stringers flat directly on the roof every 6 feet in the same direction as the deckboards will be. I then lay PT 2x6s flat running the opposite direction every 16" on center. Then screw the decking to the flat 2x6s.

Is this right? Sound like it's going to be a pain to get level. I took some measurements and the clearance under the decking ranges from about 2.5" to 4.5". I wonder if bison deck supports or some other pedestal system would work better for getting the deck level and avoiding rot since only plastic would be touching the roof. Or are those junk?


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RE: Recommend decking for Chicago rooftop deck

What I was decribing is an actuall Frame.

The 2x6 primaries and joist system would look like a normal deck frame with small 2x6 posts under the primaries landing on 3' or so 2x4 plates that lay flat on the roof.

The 3' plates will spread the weight. The cleats are placed on the joint of the primarie and its post.

The Termin-8 ( copper Naphthenate ) will stop rot and bugs. Again take care with this real nasty stuff.

The Bison pedesal system would not spread out the weight of the deck enough. Remember all the weight of the deck has dead bearing on the posts. Working off a soft roof is total different than soil or creet.

John


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RE: Recommend decking for Chicago rooftop deck

Perfect, makes sense now. Looking around at my neighbors to see what they are doing since 2 are building decks right now. One is running 2x4 stringers flat sitting on little pink foam pads and the other is setting crazy thick stone tiles on bison deck supports. Your way sounds the most solid, though.

For screws, do I need to go with 1 5/8" SS screws? I'd like to use the brown headcotes because the smartbit looks pretty idiotproof for a guy like me, but I understand that these are only in 2 1/2" lengths? I'm worried about screwing into the roof with the 2 1/2" screws at the lower spots. Then again I'm worried that the 1 5/8" might not be long enough if I end up going with 5/4 ipe (plus I'd have to use 2 bits for the drill/countersink unless theres some other tool out there). 2" seems like it would be perfect but I've never seen the pros on here discussing any 2" SS screws. Any recommendations? I don't want to plug, just facescrew flush with colored screw heads to blend in.


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RE: Recommend decking for Chicago rooftop deck

Brown Headcote screws come in 1 5/8" lengths, as well as 2 1/4" (which I recommend). They don't come in 2".

steve
www.urbanexteriors.biz


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RE: Recommend decking for Chicago rooftop deck

Thanks Steve. So do you recommend 2 1/4" if I go with 5/4x6 ipe and 1 5/8" if I do 1x6? My main concern is that the bottom of the screw could be poking through the bottom of the bottom of the flat 2x4 stringers if the screws are too long (or does this not matter, structurally?). Also, I remember reading somewhere that the smartbit penetrates the PT to some degree if using 1x6 ipe so that is a concern as well.

I was hoping you'd chime in at some point since you have probably done a ton urban applications like mine. Any other advice/tricks to add to John's excellent advice?


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RE: Recommend decking for Chicago rooftop deck

Mk your going to have to tell me your Name,we cant go on meeting like this.

These Guys >> Fasco Fastener << can not be bested in price or quality when using Stanless Steel screws. They have all sorts of color heads and can do custom colors. They have a site but its complex better to call them 1 866 327 2633. Tell them I sent you and they will charge you twice. Example 7x 2 1/4 '' SS trim head torx drive #1 3000 count delivered $ 159.90 They pay the shiping over $75.Two inch drivers .52 cents. Been doing business with them for a lot of years and big A +.

Steve uses the smartbit but it is too slow and cloges up too fast for me.

JonMon www.deckmastersllc.com


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RE: Recommend decking for Chicago rooftop deck

Obviously, you don't want your screws poking into the roof.
If you use 5/4 Ipe and 2x4 acq on the flat, you can use 2 1/4". I never use 5/4x6 Ipe anymore. Too expensive, heavy, harder to cut, and drill thru...and unnecessary.
I don't set my joists (nailers, stringers...whatever you want to call the boards that you screw into)on the flat. 2x material is much stronger on edge, and will require less support below. Besides, if you are going to frame your substructure, you can't screw flat 2x4's together (securely).
I design my roof deck projects in a different way.

Back to screws...I use the longest screw that I can (up to 2.5", and don't worry about the smartbit piercing the joist by 1/4".

Buy a couple of board bosses (I don't use the bowrench anymore, as the board boss is a better method, IMHO.
I have a lot of tricks/tips that I have developed over the years, but if I tell you, I'll have to kill you :-)

steve


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RE: Recommend decking for Chicago rooftop deck

John <<<< geting Major Yucks.


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RE: Recommend decking for Chicago rooftop deck

Thanks guys. Might as well get all my questions out in one spot here!

What finish do you recommend? I just found out I can't get TWP 116 here in Illinois. John, I know I've seen you say OK things about the TWP 1500 series and storm shield. Steve, I think you are a fan of Penofin, right?

For me, the darker the better, as long as the grain is clearly visible. I'd prefer more of a dark brown than a redder tint, but obviously performance of the stain >>> color. I don't mind putting in the work to maintain the deck so the build coat characteristics of TWP sound nice but I wonder how that opinion will change after laying 1000 sqf of ipe...


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RE: Recommend decking for Chicago rooftop deck

Yeah, I'm a penofin guy.
There is no...I repeat...NO product that you can seal Ipe with, on a Chicago rooftop, that will last very long. The same holds true for Brooklyn rooftops, or back yards. I use penofin because it's easy, and looks good...for a few months.
If I had an Ipe deck, I'd just let it age naturally.

steve


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