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Old 05-18-2019, 01:33 PM   #31
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Quote:
Originally Posted by Nealtw View Post
.... he said he was going to talk to an engineer
Your right, kind of.

You suggested the 2x6's on post #2

I mentioned checking the deck capacity on post #8 & 11

Then tgm1024 mentioned an engineer on post #12

Folks need to be reminded to stop and ensure the structure is sound before suggesting recommending any changes be made.
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Old 05-18-2019, 01:55 PM   #32
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Well, I don't mean to overstep by chiming in with the big dogs (no insult!), but one of the things to (please) keep in mind is that regardless of the span, it's the same span that the 2x10's on the floors below are experiencing. This means that I'm losing the rough 2" height but with dramatically less load.

IOW, is this really that likely:

1. Span X of 10" joists ok for both floors of living space (30 lbs per sq ft. (?))
2. That same span X of 8" joists not ok for attic storage (1/3rd the weight requirement per sq ft.)

I believe that's what's driving the default posture of "it really ought to be nothing to worry about". Thus far it seems sensible, but I'm not the one to judge: All of you are.
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Last edited by tgm1024; 05-18-2019 at 02:02 PM.
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Old 05-18-2019, 03:20 PM   #33
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Ok, I went up there and did some measuring.


Outside of the width of 2x4 stud and beam width considerations...

The interior of the house from front to back is 28'.

1. I'll check the lumber markings, but I remember the framers saying that it was Douglas Fir. From this website, looking at their "horizontal roof rafter span" (same thing??) https://www.engineeringtoolbox.com/h...an-d_1484.html, the worst quality #2 would allow for a 16 foot span of a 2x8 with 20 lbs/sqft capacity.



2. Two floor house, colonial, with attic.

3. The beam structure of the house is not a center spine as I originally reported, but from the basement on up they're beams running along 2' to the right of the center line stopping (seeing diagram) and another beam continuing from there to the left of the center by 2'. The upstairs hallway has a jog in it as it goes from the left side of one beam to the right side of it.

4. There is a 3rd beam structure in the house running perpendicular to all of this to accommodate a corner master bedroom upstairs and family room below it.

Attic ceiling thus roughly looks like this (and looks like every floor, ignoring other walls which may be curtain)

| Joists (including -), all 16oc, count not accurate
# Perimeter & Support structure

...#####
###-----#############################

#----------#|||||| ^ |||||||| ^ ||||#
#----------#|||||| | ||||||||12'||||#
#<--14'--->#||||||16'|||||||| | ||||#
#----------#|||||| | |||||||| V ||||#
#----------#|||||| V |||||###########
##########################||| ^ ||||#
#||||||||||||||||| ^ |||||||| | ||||#
#|||||||||||||||||12'||||||||16'||||#
#||||||||||||||||| | |||||||| | ||||#
#||||||||||||||||| V |||||||| V ||||#
#####################################

Does this help?

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Attic flooring: Ok to flush cut joist hangers that are sticking up?-spans.png  
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Last edited by tgm1024; 05-18-2019 at 03:32 PM.
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Old 05-18-2019, 03:51 PM   #34
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Thanks for taking the time to post the data.

There's a lot going on with this structure.

Upon further review, it seems strange that there are beam structures in the attic unless it was planned to have some inherent light duty storage above and beyond merely supporting the ceiling below.

Any chance you could post a photo of the attic space?

The 8" beams.. are they sistered 2x material (if so how many) or are they steel?

And the roof structure.. rafters or trusses? I'm assuming rafters if you're wanting to use this space for storage.. but we all know the old story about "assume".


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Old 05-18-2019, 05:26 PM   #35
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Well, this may be a terminology collision, because I always thought that joists hung on a multiple boards meant that those multiple boards are called "beams".

I think they're 3 2x8's sandwiched together, like the 2x10's are in the basement, but they might be just 2 of them....part of it is difficult to assess because it's running underneath an air conduit.

The roof itself are what look like precisely the same 2x8's as the joists. No triangulation trussing involved that I know of except for a few boards connecting one roof to the other. I was told by the builder that the roof was pitched "10 and 12" ("10 in 12"?), well basically 40, fairly steep.
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Old 05-20-2019, 07:29 AM   #36
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Back to an earlier question related to expansion and gaps between panels. I used T&G subflooring and sealed any tiny residual gapping with sealants, then sanded, then painted. Two summers worth of heat and no paint bubbling, peeling, or cracking. I left 1/4" gap at the ends of the flooring runs around the floor perimeter.
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Old 05-20-2019, 11:07 AM   #37
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Which area did you want to add the floor
...#####
###-----#############################

#----------#|||||| ^ |||||||| ^ ||||#
#----------#|||||| | ||||||||12'||||#
#<--14'--->#||||||16'|||||||| | ||||#
#----------#|||||| | |||||||| V ||||#
#----------#|||||| V |||||###########
##########################||| ^ ||||#
#||||||||||||||||| ^ |||||||| | ||||#
#|||||||||||||||||12'||||||||16'||||#
#||||||||||||||||| | |||||||| | ||||#
#||||||||||||||||| V |||||||| V ||||#
#####################################
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Old 05-20-2019, 01:18 PM   #38
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Quote:
Originally Posted by F250 View Post
I used T&G subflooring and sealed any tiny residual gapping with sealants...
Uh, I wouldn't recommend doing that. I'm glad it's working out for you, but those gaps are there for a reason. Swelling from moisture is the main issue. Without the gap if the moisture level gets high enough for the edge to swell it will have nowhere to go but up.
I think you'll probably be ok in your specific application (unless they get really wet) since the caulk and painting might be controlling the moisture at the edge, but it's a risky move taking off the "safety valve". If moisture enters from underneath where there is no paint on the edge it's likely to swell.
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Old 05-20-2019, 04:32 PM   #39
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


OK, NotYerUncleBob2... let me explain my layout in a tiny bit more detail... I do not, however, want to detract from the OP's thread, so I'll offer up my details via PM directly to you.
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Old 05-20-2019, 09:28 PM   #40
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Quote:
Originally Posted by F250 View Post
OK, NotYerUncleBob2... let me explain my layout in a tiny bit more detail... I do not, however, want to detract from the OP's thread, so I'll offer up my details via PM directly to you.
Like I said, you should be fine in your specific application, but it's not advice I'd be giving out in general because for most people who butt them that tight and then caulk the expansion gap it can very likely lead to issues.
No offense intended to your usage and not knocking your work. Just want to point out that yours is more of a unique case (already enclosed attic with finished ceiling below) and not the standard way to install tongue and groove subfloor where it can and typically does either see rain during the build or get varying levels of moisture from the basement or crawl below.
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Old 05-21-2019, 08:53 AM   #41
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


You're right, and your points are well-made. My installation is very atypical. The only reason I even brought it up was because the OP's situation is quite similar, and he stated an explicit desire to avoid gaps and cracks between panels. I do not recommend my approach when constructing in exposed conditions or in any situation where moisture exposure is a possibility - that would be irresponsible and a very bad idea!

Also, in my case, I was very specific and intentional with my approach because I know that it adds significant "curb appeal" as an easy and low cost "conversion" to a living space as an office, play room, or bedroom when we sell the home. In the meantime, we are really enjoying the super-easy-access and well-appointed attic space for our own stuff.
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Old 05-21-2019, 12:34 PM   #42
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Quote:
Originally Posted by tgm1024 View Post
Well, this may be a terminology collision, because I always thought that joists hung on a multiple boards meant that those multiple boards are called "beams".

I think they're 3 2x8's sandwiched together, like the 2x10's are in the basement, but they might be just 2 of them....part of it is difficult to assess because it's running underneath an air conduit.

The roof itself are what look like precisely the same 2x8's as the joists. No triangulation trussing involved that I know of except for a few boards connecting one roof to the other. I was told by the builder that the roof was pitched "10 and 12" ("10 in 12"?), well basically 40, fairly steep.
Notice how quiet it got in here after you posted your diagram

For me, there's just to much going on here to feel comfortable in agreeing that this is a good structurally adequate space to use for storage.

The capacity of the deck is dependent upon the sistered 2x8 "beams" and what supports them. That support would come from the type and location of walls on the 2nd floor, and walls on the 1st floor that support the 2nd floor.

It all ties together. Make sense?

Last edited by HenryMac; 05-21-2019 at 12:41 PM.
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Old 05-21-2019, 05:44 PM   #43
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Quote:
Originally Posted by Nealtw View Post
Which area did you want to add the floor
...#####
###-----#############################

#----------#|||||| ^ |||||||| ^ ||||#
#----------#|||||| | ||||||||12'||||#
#<--14'--->#||||||16'|||||||| | ||||#
#----------#|||||| | |||||||| V ||||#
#----------#|||||| V |||||###########
##########################||| ^ ||||#
#||||||||||||||||| ^ |||||||| | ||||#
#|||||||||||||||||12'||||||||16'||||#
#||||||||||||||||| | |||||||| | ||||#
#||||||||||||||||| V |||||||| V ||||#
#####################################

Roughly here, which is directly over the support walls on the 2nd and 1st floors, which sits directly on that beam in the basement (which is in the same configuration on all 3 floors).

...#####
###-----#############################

#----------#|||||| ^ |||||||| ^ ||||#
#----------#|||||| | ||||||||12'||||#
#<--14'--->#|━━━━━━━━━|| | ||||#
#----------#||||| | ||||||| V ||||#
#----------#||||| V |||||##########
#########################|| ^ ||||#
#|||||||||||||||| ^ ||||||| | ||||#
#||||||||||||||||12'|||||||16'||||#
#||||||||||||━━|| | ||||#
#||||||||||||||||| V |||||||| V ||||#
#####################################


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Old 05-21-2019, 05:56 PM   #44
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Quote:
Originally Posted by tgm1024 View Post
Roughly here, which is directly over the support walls on the 2nd and 1st floors, which sits directly on that beam in the basement (which is in the same configuration on all 3 floors).

...#####
###-----#############################

#----------#|||||| ^ |||||||| ^ ||||#
#----------#|||||| | ||||||||12'||||#
#<--14'--->#|━━━━━━━━━|| | ||||#
#----------#||||| | ||||||| V ||||#
#----------#||||| V |||||##########
#########################|| ^ ||||#
#|||||||||||||||| ^ ||||||| | ||||#
#||||||||||||||||12'|||||||16'||||#
#||||||||||||━━|| | ||||#
#||||||||||||||||| V |||||||| V ||||#
#####################################


I would put 2 ply 2x10 beams between the joist from the outside wall to the center bearing wall then build the 2x6 deck sitting on those. moving it all or most of it over to the 12' side would be better.
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Old 05-21-2019, 06:04 PM   #45
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Re: Attic flooring: Ok to flush cut joist hangers that are sticking up?


Oh, and the attic door opening (boxed off) is 4'x2' and roughly here (obscuring the beam # notation):

...#####
###-----#############################

#----------#|||||| ^ |||||||| ^ ||||#
#----------#|||||| | ||||||||12'||||#
#<--14'--->#|━━━━━━━━━|| | ||||#
#----------#||||| | ||||||| V ||||#
#----------#|||||||||##########
#####################|| ^ ||||#
#|||||||||||||||| ^ ||||||| | ||||#
#||||||||||||||||12'|||||||16'||||#
#||||||||||||━━|| | ||||#
#||||||||||||||||| V |||||||| V ||||#
#####################################
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