Experience would have told you that span is going to be bouncy. You should always do blocking it helps keep the boards in line. The deck is going to look like an ocean unless you use a treated 2x6 plank.

 

Did you crown?

 

Floor Joist sizing.

First of all I always do 12" oc. For 16' it is only 4 more joists. This could be one issue. As far as the sag did you put every joist crown up. This could cause i to sag as well.

 

yea they were all crown up

 

I come up with 14'4" at L/480 40/10
This us fir thou
I would never go 16 ft with a 2x10. I dont go over 12 with 2x10, everything over 12 gets another beam. I like my decks to be as solid as my floors if not more so. People congregate on decks in groups and a little over building makes it not feel like a trampoline when 8 adults are siting/ standing in a 7 ft circle.

 

Crown would not help this at all.

 

What kind of PT are you using.

 

The quality of wood we get around here, crown makes a big difference. :laughing::sad:

 

Bluebird, you are all over this board with plumbing, roofing, carpentry & framing questions.

I admire that you are ambitious....but learn a trade & learn it well.:thumbsup:

Become a real pro. I believe you recently had a flashing question.

To succeed you must rise above the norm...acquire a reputation as a top drawer all first class kind of guy. No BS with reusing flashings or what ever...All top notch first class stuff. When you acquire that rep you will have people that demand & want that type of guy. It takes experience & knowledge, but you have to start to get there.

 

All wood is not created equally. Take morningwood for example...

The span chart is probably for fir/larch/hemlock. Your pressure treated stuff is probably southern yellow pine.

12" spacing is a good thing. It will help. Same with solid blocking. Don't forget you can cantilever over the beam by 3x the joist width. This will help also.

Griz is right about the quality work. Hopefully you will still be able to walk by the time it pays off.

 

Southern pine.

Griz... I'm headed to the masonry forum next... but i might stop off in flooring first...

 

Just because a span is allowed, does not mean it won't sag, it probably just won't break.

Span tables are the max..

I would have either put another beam in or used 2x12's with blocking midspan.

 

You have to use a span table with a deflection table. This will tell you what kind of deflection your going to get.

 

Mark is correct.
If you get closer to the limit of your span it will start to bounce.
Depending on the wood type looks like you are very close to that.
Add a beam in the center and it will be solid.
Clemens
www.finedecks.com

 

Error on my behalf...in '93 if I remember correct.

9 1/2" TJI15, continuous span, 15'-6" both sides of bearing wall, 24" o.c., 5/8" T&G OSB...met span tables of the day...worst floor I ever did.

I gave the customer a 5/8" drywall ceiling in the basement to reduce the bouncing effect, but never again would I follow that table to the max. spans allowed.

We are all here to learn from each other.

Perhaps as a good measure you go back and install another joist between, 8" o.c. or get a beam running down the center.

 

My deck has a 14' span and I built it with double 2"x10" on 12" centers. I also have triple blocking course (solid).

The deck is topped with 5/8" sheathing and will get another 1/2" layer, 1/4" Hardiboard then Noble Companies Noble Deck.

The deflection rating of my deck is L/1120 or something like that plus what ever gain I get from the 1/2" ply and blocking.

Some jobs here in Vancouver I jump on and the bounce factor is insane. When I can bounce it with so much ease and the builder doesn't want to upgrade - we go bye bye. :no:

JW

 

Anyone who builds decks should get the free download of DCA6-09, from www.awc.org, also known as the prescriptive wood deck construction guide. According to the span tables contained in it, 2x10 at 16" o.c. is allowed a span of 13'7". It would appear that you are a bit overextended at 16'. And midspan blocking is always a good idea. Adding a beam in the center, as someone suggested, is probably your best best.

 

This is L/180 at 40/10
I think my daughters trampoline has less bounce then your deck.

The Maximum Horizontal Span is:
14 ft. 4 in.
with a minimum bearing length of 0.84 in.
required at each end of the member.
Property Value
Species Southern Pine
Grade No. 2
Size 2x10
Modulus of Elasticity (E) 1368000 psi
Bending Strength (Fb) 966 psi
Bearing Strength (Fcp) 378.55 psi
Shear Strength (Fv) 135.8 psi

 

I like the morning Wood thing :shifty:

The span charts are rated right next to falure -.2 percent.


I am not understanding " I did not install bridging blocking because I wanted to eliminate the sqeak factor " If anything the close cut blocking would have helped.

A 16 ' span with 2x 10s installed outside exposed to the weather on a deck is going to bounse and fail. Your project is ill fated.

JonMon www.deckmastersllc.com

 

Well I checked the span table for local code. I guess that is what I am getting at because it said 16' max span was allowable. I will just never trust it again. The American wood council calculator I checked after the fact and it allows 2x10 pine to span 16'1'' but that is a 360. All in all it is very nice, and the homeowner is thrilled. Next time I make sure I get a 480 which I thought I was getting when I followed the table. It is not really bouncy I just noticed a bit of a sag which got me to wondering if preasure treated lumber was more deflective than kiln dried. Also I put a roof over it so it is not exposed to the elements. Anyways, I am done rambling and will post some pics maybe thursday when I go back to finish. Thanks to all for their input!:clap:

 

We use pressure treated douglas fir here.

I'm very conservative with my spans and I have a easy rule that I follow for deck joists. This actually is from back when I framed a 24" on center, so I allow a little bit longer when I frame at 16" O.C.

6" joists span 6'
8" joists span 8'
10" joists span 10'
12" joists span 12'

These numbers always give me a little wiggle room.

 

I'm with you on that. I will sometimes give a bit more but not much. Passing code sometimes just isn't enough.

 

What span tables is the local building department using? 1933 version?

http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

You can get this in a Iphone app too.

14' 4" is the typical span for a 2x10 span of most common lumber. That will give L/360

Unless you used Select Structural lumber. Which is what is required to allow 16' span 16' 5" to be exact. Or No.1 You may have failed with your structural calculation. No.2 or better is not a option at this span.

 

The thing that you guys need to understand is that the span table give you the maximum allowable span for a given load. That does not mean that the joist will not sag or flex, it will.

Be conservative or expect it to move, sag or flex. If you want a stiff floor, do not max out your spans.

 

Yes this is true. But I don't think bluebird read the tables right or at all and was basing in second hand knowledge with. The calculation of the dead load is what is screwing him along with not using the right grade of lumber. Also incised lumber has a lower span.

I have a feeling this is a combination of several factors than just maxing out a span table with proper procedures and material.

 

As stupid as this sounds...

If you can't put a beam down the center, fasten 2x4's with 6" screws to the underside of your framing. You'll be surprised how much this works.

It's not the best solution but hey it's something else to consider

 

That sounds like a good idea

Also to bluebird- the original poster... if the sagging span is a concern, putting a temporary beam with a bottle jack to raise the sag back up and adding blocks in between the joists will add strength to the span... :thumbsup:

 

Also, here you can't even use 2x6 joists for a deck. Basically a deck needs to be constructed to the same specs as a house.

 

Also, here you can't even use 2x6 joists for a deck. Basically a deck needs to be constructed to the same specs as a house.

I haven't done a deck in probably a decade (no pun intended) but I thought decks were more strict then the house. I remember one that fell of just north of Barrie and it involved a kid and a senior citizen...two things you don't want but it changed the whole landscape on decks

 

very little