Tell me he knows what he's doing

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Old 03-31-10, 10:11 AM
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No girder, weird spacing between boards and joists? Help!

I have a brother-in-law that's helping me install a 13x18 exterior composite deck (attached to the back of my house, partially over an old concrete slab and then some hangs over part of the yard). He used to install decks for a living. He's made the following statements/actions, which I would like to bounce off of you all and get your opinions:

-There are no girder beams: It's just a ledger joist, rim joists, posts in concrete (at the corners and two on each side attached to the rim joists). On the portion over the concrete slab, he's nailed some of the floor joists to vertical rail posts (cut off level with the joists). On the portion of the deck that hangs over the yard, there are no supports. The joists are just nailed into the ledger and rim joists. There are no ledger to joist metal brackets either. He says this should be all the support we need. Some of the deck has some give/bounce to it (we're almost done laying the floor).

-He says we don't need a gap between boards. We installed them in 70 degree weather, but I keep reading that you need a gap for water runoff. Now, there is a slight gap (maybe 1/16", but nothing we measured off or put nails down to gap with). Am I in for a flood?

-The joists range anywhere from 16.5" apart to more than 18.5" apart. I've read you need a maximum of 12" for composite decking. He seems to think it's OK and that there won't be any bending or breaking in our future.

Please let me know what you think. I really don't want an expensive project like this to be a disaster. Thanks guys.
 

Last edited by glutain33; 03-31-10 at 11:07 AM. Reason: To be more specific
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  #2  
Old 03-31-10, 11:11 AM
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A few questions:

Where are you located?
What is the brand of decking you are using?
What dimension is attached to the house? 13' or 18'?
 
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Old 03-31-10, 11:16 AM
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In Missouri

Hi, I'm not sure what brand it is (Is there a place to check on the board?). I got it from a reputable auction a few months ago. It's definitely not trex. It's very flexible and bends.

OK, so here's another part of this. It's 18' wide, but the planks are only 16' long. We're having to butt the ends together with cut 2' boards. So it's the "18'" end, but really it's a 16' and a 2'
 

Last edited by glutain33; 03-31-10 at 11:17 AM. Reason: forgot comment
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Old 03-31-10, 12:12 PM
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I'll keep you going with questions while we wait for Tolyn to return.
What size boards did he use for the deck 2x10's or 2x8's?

Composit boards don't shrink so they need the gap when built as it will not increase as things dry.

How did he mount the ledger board to the house and what did he do for flashing?

How high off of the ground and any steps and or hand rails?

Bud
 
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Old 03-31-10, 12:21 PM
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OK, so here's another part of this. It's 18' wide, but the planks are only 16' long. We're having to butt the ends together with cut 2' boards. So it's the "18'" end, but really it's a 16' and a 2'
Wrong. Joints should be staggered for appearance and strength. For example first row might be a 10" and an 8". Next might be a 14" and a 4". Third an 8" and a 10". Notice the position of the 8" and 10" are reversed from the first. row. 12" and 6" is another pair. I would not use a 2" at all if I could avoid it. With proper planning you will still have little or no scrap.
 
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Old 03-31-10, 01:21 PM
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Nothing against your brother-in-law, but this has been done wrong from the get-go!!

Installing over a slab (a very low level deck) takes a lot of planning to make it work, ESPECIALLY using a composite deck board. The decking can only span SO FAR -- most composites have a 16" max. span. They also have spacing requirements for the deck boards -- 1/4" to 3/16". DO NOT VIOLATE THAT!!

"He nailed some floor joists to vertical posts... NO -- You place the joists ON TOP OF THE POSTS for structural strength. You DO NOT rely on the #%#@ nails to provide that strength!! And he's relying on NAILS to hold the joists to the ledger and the rim joists?? NOT!! Simpson hangers are less that $1 each, and about 50 times stronger than nails!!

He has some of the deck boards spanning only 16.5" and others spanning 18.5" -- Let me guess where you are feeling the "springiness!!
 
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Old 03-31-10, 01:30 PM
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answers

Thanks Ray and bud.

I'm about 7 boards away from being done. Do you recommend I take them all up and start over with the different staggering, or will it be that big of a thing? I'm planning to build a bench and place it over the joints (weight and strength issue?).

In regard to your questions Bud, the joists I believe are 2x10.

He just drove nails into the house to attach the ledger board.

The deck floor is approx 2 feet off the ground. I plan to make 1-2 stairs.

I read on many sites that they do expand and contract. But since I put them in at 70 degrees it probably wouldn't expand much more (say in 100 degree heat) to the point that it would cause damage?
 
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Old 03-31-10, 01:35 PM
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Thanks for the reply Lefty,

But question: Why is the gap important? Because of expansion and contraction? Will it expand much more if I installed them at 70 degrees?
 
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Old 03-31-10, 01:42 PM
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glutain33,

If you installed the decking at 70 degrees, use a 1/4" gap between the boards. A composite reacts to temperature (wood reacts to moisture) and 70 degrees is right in the middle. At 110 degrees, the boards will swell, due to the temp. The gap will shrink to about 1/8". In the cold of winter, the gap will grow to 5/16" or MAYBE 3/8". A 1/4" at a 70 degree temp., you're fine
 
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Old 03-31-10, 01:46 PM
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Thanks Lefty,

So if the gap is only about 1/16" now, then when they expand they will what? Crack and break?
 
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Old 03-31-10, 02:36 PM
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"He just drove nails into the house to attach the ledger board."

Tear the ENTIRE mess out and get a contractor that knows what he's doing.

"He just drove nails into the house to attach the ledger board" is just a lawsuit waiting to happen.
 
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Old 03-31-10, 06:06 PM
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I agree with Lefty. Unfortunately, this whole thing is a train wreck waiting to happen. Where I'm from decks need a permit, and therefore, inspection. There is no way this would pass inspection in any township, borough, or city. I can smell the irony from here (your brother having been a deck inspector).

Ledgers should be attached to the house with Lag bolts, spaced and staggered into structure (studs) behind. Not to mention the use of flashing and weatherproofing.

If you don't space those boards, they will in the least buckle. Not having the joists supported by anything else other than nails into the posts will eventually lead to failure. 2 ft. off the ground won't hurt anyone most likely but will certainly crush your wallet.

Seems as if (and I'm just spit balling here) that your brother in law is doing this for free and may be looking for a quick and easy way out.

For your peace of mind, the responsibility you have to those who will be on that deck, and for the sake of the value of your home, get it done right. It's well worth the extra money now than the issues you will have down the line.

The advice you have gotten so far from BIL is negligent to put it mildly.
 
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Old 03-31-10, 09:01 PM
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what I'll do

Spoke with a clerk at Home Depot who also used to install decks for a living. He says that until a few years ago nails were all that was required to install a deck. He says the lag screws and simpson brackets are a part of new code, but that they aren't always necessary. He also says that at 1/16" spacing installed at 70 degrees isn't likely to break or buckle, even if it gets to be 110 degrees or more.

However, I may install the lag screws and brackets (I will only have to tear out a few boards) just for peace of mind. I'm also adding concrete blocks and a 4x4 board underneath to act as a girder. As far as the ledger board goes, it was secured with MANY nails (the type with the ribs on the end). I'm confident the new girder, brackets, and lag screws will help. I'll keep a close eye on the expansion this summer and if need be, I'll take them all up and re-install them. Thanks for all your help guys.
 
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Old 04-01-10, 07:18 AM
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Rhino deck

Come to find out what i have is Rhino deck, which does need at least 1/4" like you all said. I am going to take it all out and start over with the gapping. At least I'll have plenty or room to do the lag bolt, bracket, and girder work. Thanks again guys.
 
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Old 04-01-10, 03:15 PM
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Lag bolting the ledger to the wall is fine, but make sure that you get it properly flashed as well. You don't want water or moisture to get between the ledger and the wall or you will have MAJOR problems.
 
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Old 04-02-10, 08:57 AM
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Hi again lefty,

Yes, that is something I will address. I found an article at Installing Deck Flashing After Deck Built that talks about putting it in after the ledger board and joists are already installed. The deck floor planks are still up, so I don't have to worry about that part. This is how I understand it: I cut a portion of the siding just above the ledger board and insert a piece of flashing (spanning the length of the ledger board) underneath. The flashing channel or lip will come down and cover the top of the ledger board so as to direct water away.

But here's my questions: After I do this, how do I secure the siding back down? Nails and screws with silicone caulk (or heavy construction adhesive) around the screw/nail heads or just the adhesive? Also It will be murder (and possibly destruction) of the ledger board and joists to take it all back out and flash behind the ledger board. OK to just apply sealant/silicone around the lag screw heads and the bottom of the ledger board and just have the flashing above the board? Any advice would be greatly helpful.
 
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Old 04-02-10, 10:45 AM
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You don't want the flashing BEHIND the ledrer, you want it slip behind the siding at a point above the ledger, and then have it fold down over the top of the ledger.
 
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Old 04-02-10, 12:47 PM
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Think of it as an umbrella for the ledger board. The purpose is to keep water (weather) from seeping BEHIND the ledger board. Or more importantly, BETWEEN the ledger board and HOUSE.

You don't have to do anything to the ledger board. As Lefty says, slide it up the siding (just over the ledger) and have it come down over the ledger itself.
 
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Old 04-02-10, 01:07 PM
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The thing is you don't want to cut the siding ABOVE where the flashing tucks in behind it -- so there's no siding that will have to be reattached.

The biggest problem that you'll face will be getting the siding cut in such a way that you CAN get the flashing slid behind it. Having the ledger in the way IS going to complicate things.

One way to do it would be to make the flashing 2 pieces -- an upper and a lower. (It's called counter-flashing.) Remove the first deck board along the wall and, using the top of the ledger as a guide, set a Skil Saw to the depth of the siding and make that horizontal cut. Then set a 2X4 on edge on top of the ledger and make another cut parallel to the first one. Remove the strip of siding between the two. Bend (or buy one pre-bent) a flashing that will slide up behind the siding, have a horizontal bend as thick as the siding is and then bend down about 2". Install that then reinstall the strip of siding that you cut out. You can nail the strip of siding back into place. Take a second piece of flashing that is an "L" tall enough to slip behind the upper piece and rest on the ledger and extend out far enough to cover the top of the ledger. Paint it to match the color of the house, then reinstall the deck board, which will hold the lower flashing in place.
 
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Old 04-02-10, 04:42 PM
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Thanks again lefty and riggstad,

I was with you until that very last post lefty--You said I shouldn't cut a portion of siding out above the ledger, but then your "upper and lower" piece idea has me confused (surprised?). What if I cut a horizontal line just above the ledger. The cut will span the length of the ledger and just past it (the ledger is interrupted by a high-efficiency furnace PVC exhaust pipe that sticks out of the wall). So, if I cut the horizontal, then cut one vertical (height of the flashing--about 2-3 inches) on one end, then can't i slide the flashing underneath. I would then nail the siding back in (the nail won't go through the flashing b/c the horizontal cut goes out past the end of the ledger board. Let's see if I can illustrate:




horizontal cut just above ledger about 2 in. l (vertical cut here "l")
------------------------------------------l
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
ledger itself
<--flashing slides in

What do you think?
 
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Old 04-03-10, 07:43 AM
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Reread my last post CAREFULLY. I said that you don't want to cut the siding above where the FLASHING slips into it.

You're going to find that you cannot slip the siding into just a saw kerf -- you'll need to remove a strip of siding in order to get the flashing behind the siding.
 
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Old 04-03-10, 09:44 AM
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I take it your saying that the siding doesn't separate itself from what's behind it, so I would try to slide it in and stall out an inch or two in. My "Z" flashing is about 1" tall (the part that goes behind the siding). So I will make one cut at the level of the ledger, then another cut about 1/2" to 3/4" up, then take the strip off the wall completely (because I can't slide it in with the horizontal and vertical cut at one end), slip the flashing behind the siding above the cut area, then nail the strip back over the flashing (I assume I'll need to silicone the cracks after I put it back on). Then I'll also need to add another nailer joist so I don't put a nail through the flashing on the ledger. Correct? Thanks again lefty.
 
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Old 04-03-10, 05:24 PM
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Check the maker's web site for air space under so as not to mold. http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf

Be safe, Gary
 
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Old 04-03-10, 06:15 PM
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The Upper flashing is a "Z" bar -- the upper portion slips behind the siding above your saw cut. The strip of siding that you'll have to remove in order to get the flashing in then goes back on just like it was -- it will be BEHIND the lower leg of the "Z" bar so that it's cut edge isn't exposed. Once that is in place, you will slip the second piece of flashing -- the "L" -- under the exposed lip of the "Z" bar and the fold will rest on top of the ledger, totally in front of the strip of siding that you removed and reinstalled.

The only reason that I'm saying that you'll need to cut a strip of siding out is so that you can get the upper flashing slipped behind the siding. You won't be able to do that with JUST a saw kerf. You'll need more space below the siding in order to get the upper leg of the "Z" bar flat against the framing of the wall so that you can push it straight up.
 
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Old 04-03-10, 06:40 PM
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I think a note I need to add here is that I have OSB siding (yes, I know it's prone to rot and water damage).

I still don't understand why I can't make a horizontal cut in it, then a short vertical cut on the end and slide the z flashing in there. There are nails in the siding, but no nails in the area I'd be sliding into. Lefty, what exactly will happen when I try to slide the flashing in? Thanks again.

If you want to see something almost identical to what I'm doing, check out the picture link. Assuming I would have to cut out the piece with the dotted line, after I attach it won't I need to caulk the cut gaps?
 

Last edited by glutain33; 04-03-10 at 07:05 PM.
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Old 04-03-10, 08:20 PM
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You saw kerf is horzontal and only 1/8" wide. The siding is 1/2" thick. (Probably 7/16", but, still -- that's close to 1/2".) Without pulling the siding away from the wall, it will be virtually impossible to get the 1" leg of the flashing to bend within the 1/8" thick saw kerf and go up the wall like you want it and need it to.

You need the clearance created by removing the stip of siding below the upper saw kerf so you can LAY the top flashing directly on the studs (or whatever is behind the siding) and push the flashing straight up.

You can TRY getting it to bend inside the saw kerf, but I don't see it happening.
 
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