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cbzdel 09-28-2012 12:10 PM

bad lumber for deck issue
 
I went to a quality lumber yard, not a big box store, probably the biggest on in my area, they do HUGE volume of materials here. Dnd got all of my PT 2x8s for my 10'x20' deck. Hung the ledger perfectly level, snapped a line for all of my hangers, installed the beam and all the joists perfectly level. All was perfect, level and square.

I go and get my 5/4 decking and lay it down on the deck, its not flush! So I string a line across the top of the joists, nothing is level. So I start to measure the joists and NONE of them are the same size, they range from 7-1/8" to 7-1/2".

What do I go at this point. I spent a whole weekend framing this thing, and have already invested close to $1000 in materials just for the frame alone. The summer is not going to last much longer in my area so I want to get this thing done ASAP before the rain comes back.

Side note, we are just building this sell the house next spring, so we are not looking for perfect, we are just look for meets code and is safe and looks respectable.

Can I shim the decking? I really dont want to rip it all back down and get all boards that are the same size...

md2lgyk 09-28-2012 12:25 PM

Let me guess: You installed the joist hangers and then the joists. Big mistake, for obvious reasons. PT lumber in particular is subject to a lot of shrinkage. The yard doing a huge volume virtually guarantees their PT lumber is new and still pretty wet. Unless you're lucky, you're never going to find some that's all exactly the same size. Pull it all out and try again.

Daniel Holzman 09-28-2012 12:30 PM

That is really unfortunate about the joists being different sizes. I have never seen dimensional lumber from the same manufacturer vary that much. There are several options for you, none of them appealing, but so far as I can see here they are:

1. Remove the hangers from the ledger and the opposite beam. This will require pulling all the nails that hold the hangers to the beam and ledger (I assume you used manufacturer supplied galvanized nails). Reinstall the hangers (with the joists attached) so the top of the joists are all level. You can leave hangers that are within 1/8 inch or so of proper position in place, should not affect the deck boards much. The advantage of this approach is you do not remove the nails that hold the hangers to the joists, only the nails that hold the hangers to the beam and ledger. Some of the hangers are going to be OK, so this does not affect all the hangers.

2. You leave the hangers in place, and pull the nails holding the joists which are too low. You then shim the joists at the hanger by the appropriate amount, and install new nails to hold the joists in the proper position. This is probably more work than 1, since typically some of the nails that hold the joists are diagonal, and should be longer than the face nails that hold the hangers to the ledger and beam.

3. You shim the top of the joists which are low using PT lumber you cut to size. You may want to tack glue the shims in place. This has the advantage of not requiring you to remove any hangers or joists, and will be invisible after the deck boards are installed. You may need to predrill for the deck boards, or you are likely to crack the shims when you install screws to hold the deck boards. This assumes you are face screwing the deck boards in, if you are using deck board clips this does not apply, or if you are using a jig like the Kreg jig to install deck screws diagonally this does not apply. I had to shim a few of my deck joists in a few places, it was no problem, and came out fine.

cbzdel 09-28-2012 12:35 PM

regardless of if the hangers are put up first or not have nothing to do with it.. stick a 7-1/8" board next to a 7-1/2 and show me how adjusting one end of it will make them the same.

plus the engineer spec'ed out concealed joists hangers, due to the better connection at from the hanger to joist, show me how to attach one of those while the joist is already nailed off in place :)

allthumbsdiy 09-28-2012 12:50 PM

That's about 3/8" difference in height.

Unless you are using Trex or something like that, I would just use composite shims under that pressure treated decking and not worry about it.

Good luck

drtbk4ever 09-28-2012 01:05 PM

Quote:

Originally Posted by cbzdel (Post 1019266)
regardless of if the hangers are put up first or not have nothing to do with it.. stick a 7-1/8" board next to a 7-1/2 and show me how adjusting one end of it will make them the same.

plus the engineer spec'ed out concealed joists hangers, due to the better connection at from the hanger to joist, show me how to attach one of those while the joist is already nailed off in place

You definitely don't have many options when using those hangers. Typically, my joist hanger isn't nailed to the beam/ledger until after I have leveled the joist and ensured it is flush with my other joists.

I would try Daniel's #2 method first to see how it goes. I would leave the joist hangers fastened and just shim it. It that proves to be too time consuming, then try shimming the decking material.

GBrackins 09-28-2012 03:09 PM

Quote:

Originally Posted by cbzdel (Post 1019266)
regardless of if the hangers are put up first or not have nothing to do with it.. stick a 7-1/8" board next to a 7-1/2 and show me how adjusting one end of it will make them the same.

plus the engineer spec'ed out concealed joists hangers, due to the better connection at from the hanger to joist, show me how to attach one of those while the joist is already nailed off in place :)

in your original post you did not state they were concealed hangers .....

with that said I would suggest leaving the shorter joists (7-1/8") in place and remove the taller ones. once they were removed I would strike a level line against the house for the top of these joists. then I'd measure down from the line down to the seat of the hanger. subtract this measurement from the depth of the joist going into that hanger and notch out the extra material (1/8" to 3/8"). do the same on the other end.

someone may have a quicker way, but this should work.

code allows you to notch floor joists adjacent to their support no more than 1/4 the depth of the joists. See this link for code requirement http://publicecodes.cyberregs.com/ic...9_5_par030.htm

Good luck!

mae-ling 09-28-2012 05:16 PM

shim them up, or notch them down, really your only 2 options.

robertcdf 09-28-2012 06:12 PM

Quote:

Originally Posted by Daniel Holzman (Post 1019263)
That is really unfortunate about the joists being different sizes. I have never seen dimensional lumber from the same manufacturer vary that much.

No offense Dan but you must not ever look at PT lumber then, this is VERY typical for PT lumber, this is one of MANY reasons I've gone to exclusively steel for all framework.

OP this is VERY common for PT lumber, I've seen over 1/2" variations many times before, PT lumber is garbage material. If your 10x20 frame pack cost you $1,000 you've got some expensive lumber there. I can buy a steel frame pack for that same size for less than $1,000 and that material is all perfectly consistent, flat, level, and cut to my length spec.

mae-ling 09-28-2012 06:15 PM

Must be a location thing, I have never seen it vary more than 1/8"

cbzdel 09-28-2012 06:21 PM

Quote:

Originally Posted by robertcdf (Post 1019487)
If your 10x20 frame pack cost you $1,000 you've got some expensive lumber there.

Not just the lumber, that was everythign up to this point, concrete, rebar, nails, connectors, bolts, lumber ect.. Everything but the decking and handrail.

I actually just talked to a local framer that I know and he tells me that when he builds decks he runs all the joists though a table saw to make them the exact same size and then paints them with the end cut solution, and then puts this cut end down so it is it does not get as wet when it rains..

robertcdf 09-28-2012 06:31 PM

Quote:

Originally Posted by cbzdel (Post 1019255)
I
What do I go at this point. I spent a whole weekend framing this thing, and have already invested close to $1000 in materials just for the frame alone. [

That's where my confusion came in... :whistling2:

That's why I won't touch PT lumber again, it's a total waste of money and time, the lumber itself is also of terrible quality, it's grown too fast and therefore is considerably less stable.

mae-ling 09-28-2012 06:37 PM

Quote:

Originally Posted by cbzdel (Post 1019500)
Not just the lumber, that was everythign up to this point, concrete, rebar, nails, connectors, bolts, lumber ect.. Everything but the decking and handrail.

I actually just talked to a local framer that I know and he tells me that when he builds decks he runs all the joists though a table saw to make them the exact same size and then paints them with the end cut solution, and then puts this cut end down so it is it does not get as wet when it rains..

So are they being cut uneven or drying uneven?
If it is in the drying then even though he cuts them even as they dry more they will become uneven.

Knucklez 09-28-2012 06:40 PM

ya i had the same problem but only over small portch.

i put the joist into place first and then added the hanger so at both ends it was flush with the rim joist.. but still not level in the middle due to bow in the wood. after i screwed everthing together and .. added hurricane ties .. it all stiffened up nicely and can't notice any wrongs at all.

same problem when forming two 2x for a beam .. they are not flush across the top (or bottom) over entire length so the joists really only sits on half the beam.

knucklez

woodworkbykirk 09-28-2012 06:52 PM

we allow for the variation in pt.. for the beam we pick out the straighest materail and make sure its all hte same dimension soo its flush on top and sits evenly on the posts.. the joists are set flush to the top of the ledger or if we do a kickboard ledger the tops are set to a chalk line.

lvl is extremely bad for variation. we use it all the time for reno's and new home construction for our beams and large window headers. we have to rip down prob 90% of them to be the same width especially for the tops of windows to be all at the same height as we set them via laser level. it creates a much nicer finish when the siding goes on along with interior trim having window sills and tops all at the same height


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