# building deck beams



## RETALS (Sep 27, 2016)

Looking for some advice on building triple 2x10 beams. I've seen a lot of info when using double, but not finding good info on triple. What do you recommend for fasteners, bolts, spacing, glue? Should each nail or screw touch all three pieces or should the two outer pieces only tie to the inner?


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## Marklifedo (Jun 12, 2017)

Timberlocs, or GRK screw fasterners from both sides of the beam will do the trick. You use and alternating pattern, and a screw length that does not come through the beam. You can also nail from both sides the same way you put two together.


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## MTN REMODEL LLC (Sep 11, 2010)

I'm interested what everyone does.....

I gun nail the lamination with standard 131 framing nails, staggered patter, and I glue them up also with liquid nails or PL premium adhesive... if damp/wet lumber I'll drop in a few screws figuring they will tend to minimize cupping/warping.


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## RETALS (Sep 27, 2016)

Marklifedo said:


> Timberlocs, or GRK screw fasterners from both sides of the beam will do the trick. You use and alternating pattern, and a screw length that does not come through the beam. You can also nail from both sides the same way you put two together.


How many would you use for a 2x10x12? Those things are $$$.


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## red92s (Nov 14, 2012)

A big part of the answer depends on how your beams and joists are connected:


A) Joists resting on *top* of the beams. This is a pretty typical arrangement for most decks.
B) Joists *flush *with the beams, with joist hangers connecting the two. This is more common on very low freestanding decks where you don't have enough height to stack the joists over the beams.
In situation A, some construction adhesive and generous nailing from both sides is usually sufficient. All the loads from the joists are transferred straight down vertically into the beams.


In situation B, you are side-loading the beams through the hangers. Heavy loads will want to twist and pull the individual beam plys apart from each other. In this situation, you want fasteners with more resistance to withdrawal, like structural screws or though bolts, to keep the "sandwich" nice and tight. When using something like structural screws in this situation, it pays to consider which side (or both) of the beams is having hangers installed. A bit more info:
http://www.grkfasteners.com/Portals/0/documents/Techbulletinx3_new.pdf


The GRK RSS screws in a 5/16" X 4" size are a fairly reasonable cost, and will hit all 3 plys in a triple-2X beam without penetrating the other side. I would look at some tables and recommendations for attaching ledger boards to the house for spacings and quantities and use that as a guide, since your beams are acting in a similar fashion.


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## ktmrider (Apr 3, 2017)

you don't need the timberlock screws, your not holding the beam up just together, just use 16d nails and nail from both sides


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## XSleeper (Sep 23, 2007)

ACQ framing nails. 4 every 16".


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## carpdad (Oct 11, 2010)

I would use just enough nails to hold them together, straighten and tops even, then use 1/2" double dipped bolt, washers, and nuts every 16". Build them on the posts and use post to beam metal connectors. Separate the metals from treated lumber with flashing. Expect about where your joists will fall and space the bolts in between. Timberlocks are thin and I don't know if I trust the engineers enough to depend on their numbers. Timberlocks also need impact screw driver.


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## carpdad (Oct 11, 2010)

BTW, if the chimney is near the top, chance to use it for venting.


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## NotyeruncleBob (Mar 9, 2017)

One of the failure points I've been running into lately is outdoor beams nailed and glued together that rot from water pooling in that seam. I'm wondering if applying a strip of peel and stick membrane like Grace ice and water shield for roofs would be worth it?


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## MTN REMODEL LLC (Sep 11, 2010)

NotyeruncleBob said:


> One of the failure points I've been running into lately is outdoor beams nailed and glued together that rot from water pooling in that seam. I'm wondering if applying a strip of peel and stick membrane like Grace ice and water shield for roofs would be worth it?


I'll bet so in a moist /rainey/ humid area.


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## Nealtw (Jun 22, 2017)

NotyeruncleBob said:


> One of the failure points I've been running into lately is outdoor beams nailed and glued together that rot from water pooling in that seam. I'm wondering if applying a strip of peel and stick membrane like Grace ice and water shield for roofs would be worth it?


Protecting the top of beams and joists no that they have changed the treatment is a good idea.

2x10 beams need 3 3' nails every 16 inches, 3 ply just nail both sides into the center. 

Some inspectors, engineers may ask for more depending on load.


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## NotyeruncleBob (Mar 9, 2017)

MTN REMODEL LLC said:


> I'll bet so in a moist /rainey/ humid area.


Pacific Northwest, so yeah...near constant drizzle for half the year. 
I'm going to be starting a house build in a literal rain forest later this year. Those little water management details will make or break that project.


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## RETALS (Sep 27, 2016)

Thanks for all the suggestions everyone. I think I'm going to go with liquid nails and 16d nails every 16".


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## RETALS (Sep 27, 2016)

So I built two of my beams today. I was wondering how you deal with varying degrees of crowing among your boards. We tried to compensate as best we could, but neither beam has 3 plys that are perfectly level. One had a board that is up a good 1/16th. Do you sand or plane them somehow? I have to assume that if they aren't good and level then you don't get the structural integrity of having 3 plys.


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## jlhaslip (Dec 31, 2009)

Looks like more than a sixteenth there. I would plane it down to flush with the others.

When I build a double or triple beam, I crown one layer up and one layer down. Work them as you nail them together from one end to the other so they are flush all the way along. Toe nailing the edges works to pull them flush. By the time you finish, voila!,a straight beam.
Do the same thing for additional layers, starting at either end and work the top flush. Usually I go crown up for the third layer. Old fashioned me uses a nailing pattern of 1 nail per 2 inches of material, so a 2 x 10 gets 5 nails and a 2 x 12 gets 6 every 16 inches. The opposite side gets the lines offset by 8 inches. Nail the first two layers from both sides, and the third layer from one side only, using a similar offset.
Does it cost more? Yes, a little bit, but nails are cheap.

And also add a strip of membrane to the top edges.


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## Daniel Holzman (Mar 10, 2009)

The reason for nailing the boards together is to generate sufficient horizontal shear strength so the three boards work together as a unit. It is not necessary to glue the boards, so long as you use sufficient nails, although the glue does no harm. The nails need not penetrate through all three boards, so long as you nail from both sides, so typically people use 16 penny 3 inch long nails spaced about 6 inches apart, staggered, both sides. And you alter the nailing pattern so the nails from one side are between the nails from the other side.

If you use enough nails, it makes no structural difference if the tops of the boards are not precisely even, however it does make a difference to the deck boards (cosmetic), so it is certainly a good idea to build the beam, then plane it flat on top.

When I built my deck, I used Ice and Water Shield on top of the joists and the beams. I have seen enough videos about decks where the joists have rotted because of water pooling on top of them so I wanted to avoid it. The deck has been in place about six years, no damage so far.


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## ront02769 (Nov 28, 2008)

To steal a quote from a long forgotten book titled something like "tricks of an old time carpenter", you're building a house , not a piano. Any joist should cross over the entire beam anyway. There is no framing crew in my area that is going to plane the top of a built up beam to level it off.


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## RETALS (Sep 27, 2016)

What's the best way to plane it down? Belt sander?


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## RETALS (Sep 27, 2016)

Daniel Holzman said:


> The reason for nailing the boards together is to generate sufficient horizontal shear strength so the three boards work together as a unit. It is not necessary to glue the boards, so long as you use sufficient nails, although the glue does no harm. The nails need not penetrate through all three boards, so long as you nail from both sides, so typically people use 16 penny 3 inch long nails spaced about 6 inches apart, staggered, both sides. And you alter the nailing pattern so the nails from one side are between the nails from the other side.
> 
> If you use enough nails, it makes no structural difference if the tops of the boards are not precisely even, however it does make a difference to the deck boards (cosmetic), so it is certainly a good idea to build the beam, then plane it flat on top.
> 
> When I built my deck, I used Ice and Water Shield on top of the joists and the beams. I have seen enough videos about decks where the joists have rotted because of water pooling on top of them so I wanted to avoid it. The deck has been in place about six years, no damage so far.



The ice and water shield product appears to only come in 36" rolls. Would this be the same idea? 

http://www.homedepot.com/p/Grace-Vy...Roll-Fully-Adhered-Flashing-5003106/203057406


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## red92s (Nov 14, 2012)

RETALS said:


> The ice and water shield product appears to only come in 36" rolls. Would this be the same idea?
> 
> http://www.homedepot.com/p/Grace-Vy...Roll-Fully-Adhered-Flashing-5003106/203057406


Yes. The Grace Vycor is good stuff and comes in several widths. It's often used on the tops of joists and beams during deck construction.


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## RETALS (Sep 27, 2016)

ront02769 said:


> To steal a quote from a long forgotten book titled something like "tricks of an old time carpenter", you're building a house , not a piano. Any joist should cross over the entire beam anyway. There is no framing crew in my area that is going to plane the top of a built up beam to level it off.


The joists will cross, but if you think about it, if the joists are only resting on 1 of the 3 plys, then there really wasn't a point in making a built up beam, right? Structurally the 2 untouched plys are just sitting there unutilized. Unless I'm missing some concept?


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## red92s (Nov 14, 2012)

RETALS said:


> The joists will cross, but if you think about it, if the joists are only resting on 1 of the 3 plys, then there really wasn't a point in making a built up beam, right? Structurally the 2 untouched plys are just sitting there unutilized. Unless I'm missing some concept?


With enough fasteners holding them together, the beam plys start to approach acting as a single piece of timber. That's _why_ they are sandwiched together and not build with big gaps between them.

If it bothers you, use a hand plane or a power plane to knock down the high spots. It's more important to have them nice and flat with flushed deck beams where the decking will lay right over it.


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## Daniel Holzman (Mar 10, 2009)

red92S explains the concept of joining the three beams together. The idea is that by nailing the three beams to each other (or bolting or gluing), the three beams act like a single beam for resisting bending, which is the main failure mechanism on long prismatic elements like a rectangular beam. If one ply sticks up, you load only the top ply in direct compression, however 1-1/2 inches is plenty of width to handle direct compression. The three plys still act like a single beam in bending and in shear, which is what counts.

So structurally it makes no real difference if you flatten the top of the three ply beam. If one ply sticks up a long way, say 1/2 inch, the top of your decking may not be level, in which case you may want to plane down. I use a hand plane, much faster than a belt sander on PT lumber, and you don't want to be breathing PT lumber dust.


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## RETALS (Sep 27, 2016)

Daniel Holzman said:


> red92S explains the concept of joining the three beams together. The idea is that by nailing the three beams to each other (or bolting or gluing), the three beams act like a single beam for resisting bending, which is the main failure mechanism on long prismatic elements like a rectangular beam. If one ply sticks up, you load only the top ply in direct compression, however 1-1/2 inches is plenty of width to handle direct compression. The three plys still act like a single beam in bending and in shear, which is what counts.
> 
> So structurally it makes no real difference if you flatten the top of the three ply beam. If one ply sticks up a long way, say 1/2 inch, the top of your decking may not be level, in which case you may want to plane down. I use a hand plane, much faster than a belt sander on PT lumber, and you don't want to be breathing PT lumber dust.


Thanks for the explanation! Yeah I agree. I'll use a hand planer to touch it up.


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## ktmrider (Apr 3, 2017)

RETALS said:


> What's the best way to plane it down? Belt sander?


 I would use sand paper


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## RETALS (Sep 27, 2016)

Got my beams finished and planed this weekend. They came out pretty good. I had a bunch of liquid nails left over so I used it to fill the seams all the way around the top, bottom, and ends of each beam. I have them sitting atop the posts for now but nothing is secured. Tomorrow I'm going to tighten down the post bases, attach the posts and caps, and then it will be time to start framing. 

Anyone have any idea how tight the post base bolts should be? They're 5/8 x 10" L bolts. I wouldn't think it should require much torque at all since there will be a ton of weight on top. Anyway...here's a couple pics of the finished beams and where I'm at so far.


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## carpdad (Oct 11, 2010)

For me it was as tight as I can push the open end wrench with one finger. They didn't feel like I could torque it down.
Before you begin the framing, make sure the beams are in one plane and pitch down away from the house. Could be the photo but 2nd beam looks lower against the siding.


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## red92s (Nov 14, 2012)

They don't need to be super tight. Stick a wrench through the side of the bracket with the post in place and get them "good n' snug".


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## RETALS (Sep 27, 2016)

carpdad said:


> For me it was as tight as I can push the open end wrench with one finger. They didn't feel like I could torque it down.
> Before you begin the framing, make sure the beams are in one plane and pitch down away from the house. Could be the photo but 2nd beam looks lower against the siding.


It's just the pic or that piece of siding. They're all spot on. It's level and not really pitched down, but I plan to have some spacing between my deck boards. Is that a big deal?


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## red92s (Nov 14, 2012)

RETALS said:


> It's just the pic or that piece of siding. They're all spot on. It's level and not really pitched down, but I plan to have some spacing between my deck boards. Is that a big deal?


You'll be fine with everything built level. Because it's a free standing deck with no penetrations through the siding it's less critical to build slope into the structure. Just install the board nearest the house with ~1/2" or so gap off the siding so that it does not become a "trap" for leaf litter and other gunk that might collect against the house with a tighter gap.


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## RETALS (Sep 27, 2016)

red92s said:


> You'll be fine with everything built level. Because it's a free standing deck with no penetrations through the siding it's less critical to build slope into the structure. Just install the board nearest the house with ~1/2" or so gap off the siding so that it does not become a "trap" for leaf litter and other gunk that might collect against the house with a tighter gap.


I actually factored in a 1" gap between the decking and the house. Do you think that's too much? Nothing is set yet so I could always bring it in closer. 

I'm also going to put flashing tape on top of the posts and beams, but not the joists...would this be a mistake?


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## Nealtw (Jun 22, 2017)

I would protect the top of the joists too.


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## red92s (Nov 14, 2012)

RETALS said:


> I actually factored in a 1" gap between the decking and the house. Do you think that's too much? Nothing is set yet so I could always bring it in closer.
> 
> I'm also going to put flashing tape on top of the posts and beams, but not the joists...would this be a mistake?


1" sounds a little wide from a purely aesthetic standpoint, but I doubt it would be problematic. 

If I was going to do joists OR beams, I'd do the beams. Water and gunk has a tendency to build up between the beam plys and deteriorate them faster. You've sealed them up with liquid nails, but moisture can easily wick past that. 

Honestly though, it's what . . .another $50 or so to do the joists as well (guessing 2 rolls @ $25/ea) on a project that where you are probably spending $2k or more by the time it's all done? That's not exactly going to bust the budget and will let you sleep a bit better.


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## RETALS (Sep 27, 2016)

Yeah you're right. I'm already at $1,300 in materials so I might as well spend a little more for the extra protection.


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## RETALS (Sep 27, 2016)

Running into a slight issue. The L bolts that I bought are 5/8" and the accompanying nut is 15/16". Well a 15/16" wrench is too large to be able to engage the nut from the side of those bases. The ABA66Z states to use a 5/8" anchor so I'm not sure what I missed here. Any suggestions?


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## red92s (Nov 14, 2012)

RETALS said:


> Running into a slight issue. The L bolts that I bought are 5/8" and the accompanying nut is 15/16". Well a 15/16" wrench is too large to be able to engage the nut from the side of those bases. The ABA66Z states to use a 5/8" anchor so I'm not sure what I missed here. Any suggestions?


If you haven't already nailed/screwed the posts to the bases, it might be easiest to just trace around the perimeter of the bases to give yourself a good reference, remove the beams/posts, and use a 15/16" socket on the nuts from the top side.

Beyond that . . . buy a cheap wrench from the auto parts store, break out the grinder to thin down the sides. Or call Simpson and solicit their input.


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## RETALS (Sep 27, 2016)

Thanks for all the help everyone. Today I got the piers, posts, and beams tied. Which doesn't sound like a huge task but damn it was a ton of nailing. Simpson doesn't skimp on the number of recommended fasteners. Each cap alone called for 18 nails. Not sure why the SD screws were approved for the bases but not the caps. 

Anyway...about the asphalt flashing tape....is it ok to put it on now? It could be exposed for a while until I get my lumber for the joists. I didn't know if being in the heat and sun would cause it to peel up or have any issues. I did put some over my posts and it went on real well. Seems to be good stuff.


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## Nealtw (Jun 22, 2017)

I used some to cover holes in the roof of an old van it was still there when we junked the van 6 years later.


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