Looking to add flooring to attic for storage. Any structural engineers/architects here?

[EngineerJet 191]

Measured yesterday. The 2x6 spans 20.5 feet and has a wall support right in the middle.

[remixer 1,645]

6 minutes ago, EngineerJet said:

Measured yesterday. The 2x6 spans 20.5 feet and has a wall support right in the middle.

a 2 X 6 depending on the species of wood usually has a max span of 10'-0 - 12'-0" or so.. you right at that point...

how much weight are you planning to put up there and how many sheets of 4 x 8?

 

[EngineerJet 191]

oops

[EngineerJet 191]

2 minutes ago, EngineerJet said:

I'll mainly be loading towards the center with the wall support and avoiding the ends. from center id say i want a storage area to span maybe 12-14 feet. Mostly christmas decorations and other boxes that tend to weigh less than 4 pounds. All the boxes with the exception of one are all super light my wife can one hand them. The heaviest single box is around  30+ pounds. Everything else we can kick around the floor.

 

[Zeke 5,504]

27 minutes ago, EngineerJet said:

 

Kicking Christmas boxes = broken ornaments 

True story 

[Sniper 6,372]

3 hours ago, AVB-AMG said:

What is reckless and potentially dangerous is for you as a lay-person, who does not know how and where the variables of structural loads are determined, carried and dispersed, is stating to the O.P., with apparent absolute certainty, that you know that his existing situation will work for his intention.  Of course, who cares if you are wrong.....   you are just some guy giving his silly uneducated, as well as unlicensed opinion on something you know nothing about.  

@AVB-AMG

Let's start off, you can go stuff it where the sun don't shine. First, you have no idea what I know about construction, but in your usual "I'm smarter than every one else" attitude you spew here regularly, you feel the need to spew your crap. Here's a hint, you AIN'T the sharpest knife in the drawer here, even though you think so. I really don't know what your fu*kin problem is? I'm certainly NOT a "lay-person" in this field.

Try some reading comprehension for once. I stated there were variables the OP needed to consider in how his existing structure is built and supported. Without seeing his situation, everyone here is just speculating. I gave some general information based on normal conditions, he's not building a 50 floor office building in NY... geez...

3 hours ago, EngineerJet said:

Mostly christmas decorations and other boxes that tend to weigh less than 4 pounds. All the boxes with the exception of one are all super light my wife can one hand them. The heaviest single box is around  30+ pounds. Everything else we can kick around the floor.

@AVB-AMG

Oh look, what is he storing? Christmas decorations and light weight boxes. Hey AVB, he needs to double up all his 2x6's with 2x12's, add steel "I" beams, then put down 1-1/2" tongue and groove plywood, right, because after all, he's needs total structural safety in that attic.

4 hours ago, AVB-AMG said:

We Architects and Structural Engineers have studied theses issues and are tested and licensed by both state and national registration organizations for a reason.  Unlike you, we have an obligation to gain an education from both formal schooling, apprenticeship to other licensed professionals and from our work experience.

Thank GOD we have such educated and morally superior people on this forum, like yourself, to protect us peons from major structural collapse. Can you imagine what it would be like to have your Christmas decorations crash down on you while sleeping on your bed? Talk about a national disaster.

4 hours ago, remixer said:

IMO If 20lbs over a span 32 sf makes it a danger or less safe then you might other structural issues.

1/2 plywood might be strong enough but when you are walking on a floor carrying items for storage it makes it very uncomfortable mentally that the floor is flexing..

He has a bunch of variables we don't know. Can he get full 4x8 sheets up there, or will they have to be cut to get them up there. Spreading that 20 lbs over 32 sq ft covering at least 4 joists (depending which way he lays the sheets) would be a non-issue. The flexing while walking on it can be un-nerving, might be time to cut back on the extra Twinkees.

[remixer 1,645]

32 minutes ago, Sniper said:

 

The flexing while walking on it can be un-nerving, might be time to cut back on the extra Twinkees.

Twinkees are fucking delicious.

[PK90 3,570]

On 4/9/2019 at 6:29 AM, EngineerJet said:

My attic does not have flooring and I'm looking to use it for some light storage. The joists are 16" on center and are 2x6. Can I just add some 1/2 inch plywood and call it a day? Not concerned about insulation.

Soooo, where is your insulation? Between roof rafters? Hammock type? Sprayed on roof? Rigid above rafters? Do you not have at least 9" between joists?

[remixer 1,645]

1 minute ago, PK90 said:

Soooo, where is your insulation? Between roof rafters? Hammock type? Sprayed on roof? Rigid above rafters? Do you not have at least 9" between joists?

The joists are 16" on center 

 Keep up man!

 

[EngineerJet 191]

well that escalated quickly. Either way, thanks for the insight. I'll probably build a 2x4 riser spanning the storage area just so I have the options of adding insulation if i need it down the road. The fact that it will have a wall in the center will allow me to sleep at night.(Literally, since my bedroom will be directly under)

[EngineerJet 191]

9 minutes ago, PK90 said:

Soooo, where is your insulation? Between roof rafters? Hammock type? Sprayed on roof? Rigid above rafters? Do you not have at least 9" between joists?

We made it through the winter with virtually no insulation. We just bought this house in the fall and there was about an inch of super old fiberglass insulation for the whole attic. Our heating bill wasnt that bad, so we recently added cellulose up to the top of the joists, giving us total of 6 inches. It should be good enough for now, but I like to keep my options open, thus the riser.

[PK90 3,570]

20 minutes ago, remixer said:

The joists are 16" on center 

 Keep up man!

So. What does that have to do with the insulation thickness? Stupido!!

7 minutes ago, EngineerJet said:

We made it through the winter with virtually no insulation. We just bought this house in the fall and there was about an inch of super old fiberglass insulation for the whole attic. Our heating bill wasnt that bad, so we recently added cellulose up to the top of the joists, giving us total of 6 inches. It should be good enough for now, but I like to keep my options open, thus the riser.

Really? You should have at least R30 in the attic. This site recommend R49. Did you buy without an inspection?

[remixer 1,645]

1 minute ago, PK90 said:

So. What does that have to do with the insulation thickness? Stupido!! 

 

He already mentioned he had 16" on center joists.

 

[PK90 3,570]

2 minutes ago, remixer said:

He already mentioned he had 16" on center joists.

16" centers has nothing to do with the insulation.

[EngineerJet 191]

3 minutes ago, PK90 said:

So. What does that have to do with the insulation thickness? Stupido!!

Really? You should have at least R30 in the attic. Did you buy without an inspection?

We did an inspection but we were fine with it at the time. With the cellulose we have about R20 now. Again, our heating bill wasnt even that bad without the insulation so we are fine with R20 for now. Later down the line I can always increase it.

[remixer 1,645]

1 minute ago, PK90 said:

Not sure why your Facepalming... you replied to him asking if he had at least 9" between joists when he said he has 16" center joists.

[PK90 3,570]

1 minute ago, remixer said:

Not sure why your Facepalming... you replied to him asking if he had at least 9" between joists when he said he has 16" center joists.

Still  with a  added.

[BobA 1,235]

Testosterone here!  Get your testosterone!

[10X 3,296]

3 hours ago, PK90 said:

16" centers has nothing to do with the insulation.

Sure it does.  It tells us that standard precut batts are the right width!

[EngineerJet 191]

1 hour ago, BobA said:

Testosterone here!  Get your testosterone!

butt scratchaaa

[10X 3,296]

1 hour ago, BobA said:

Testosterone here!  Get your testosterone!

Yep.  Who'd have thought that a thread asking for an architect's opinion--right there in the thread title--would get so heated when an architect's opinion was provided.

[remixer 1,645]

Correct. As much as it bothers me avb is right.  If u can’t trust an architect and an ffl confiming his finding who can u trust

[Zeke 5,504]

Me

[Malsua 1,422]

The only thing I was going to add was that if it's spongy, sister some 2x6s in there.   Cross as much of the span as possible, add some glue, lag or better yet, bolt it tight.  If the joist is going to fail, it will fail in the middle 3rd all other things equal.

 

 

[Zeke 5,504]

@AVB-AMG make attics great again!

 

Oh that’s gonna leave a mark 

[AVB-AMG 530]

On 4/10/2019 at 4:20 PM, Malsua said:

The only thing I was going to add was that if it's spongy, sister some 2x6s in there.   Cross as much of the span as possible, add some glue, lag or better yet, bolt it tight.  If the joist is going to fail, it will fail in the middle 3rd all other things equal.

@Malsua:

That is a very sensible option.  If the O.P. is going to go to the trouble of augmenting the existing 2x6 wood joists in the attic, I agree that instead of using 2x4 members, to use 2x6 lumber, and then stagger them in section by two inches (2") which would add both stiffness and load bearing capacity to the joists.  When I have done this in the past I recommend using  3/8" x 2 1/2" stainless steel hex head screws staggered at 16 O.C. to gain the desired stiffness and bearing properties. 

On 4/10/2019 at 12:34 PM, EngineerJet said:

well that escalated quickly. Either way, thanks for the insight. I'll probably build a 2x4 riser spanning the storage area just so I have the options of adding insulation if i need it down the road. The fact that it will have a wall in the center will allow me to sleep at night.(Literally, since my bedroom will be directly under)

@EngineerJet:  See my comment and suggestion above.....  Also, by doing it this way, you will be able to add more insulation to achieve a higher R-Value and can also add a vapor barrier as part of it, typically available with some fiberglass batt insulation blankets.  Keep in mind that when one compresses fiberglass batt insulation, the R-Value per inch goes up, but the overall R-Value goes down because you have less thickness of insulation.

On 4/10/2019 at 12:52 PM, remixer said:

Not sure why your Facepalming... you replied to him asking if he had at least 9" between joists when he said he has 16" center joists.

@remixer:  I assume by now you understand that @PK90 was referring to a depth (thickness) of the fiberglass batt insulation of nine inches (9") and not the horizontal o.c. spacing of the rafters, hence the facepalm.  While I am often criticized here for my lengthy and wordy posts, one benefit is to hopefully reduce any ambiguity or confusion by not making certain assumptions.

On 4/10/2019 at 12:54 PM, PK90 said:

Still  with a  added.

@PK90:  At least you can find the humor in all of this...   It is rather comical...!

On 4/10/2019 at 4:00 PM, 10X said:

Yep.  Who'd have thought that a thread asking for an architect's opinion--right there in the thread title--would get so heated when an architect's opinion was provided.

@10X:  Thank you for your overall perspective observation and backdoor compliment....    Some folks who post here seem to like to offer their opinions when they would be better off just reading and listening to others who are more informed than they are on the topic being discussed.  I have learned much about firearms from many posters on this forum, gaining an invaluable education and did not pretend to know more than I did at that time.  I am amazed that some people seem to be "know-it-all's" on just about every thread topic.  It says quite a bit about those people.....

On 4/10/2019 at 4:12 PM, remixer said:

Correct. As much as it bothers me avb is right.  If u can’t trust an architect and an ffl confiming his finding who can u trust

@remixer:  While we do not agree on most of our politics, we do seem to be in sync on this topic, in our attempts to help the O.P.  Thank you for the 

AVB-AMG

[AVB-AMG 530]

30 minutes ago, Zeke said:

@AVB-AMG make attics great again!

Oh that’s gonna leave a mark 

@Zeke:

Now that was funny.....!

AVB-AMG

[Zeke 5,504]

Best bet

 

[Ray Ray 3,566]

I still say 1/4 inch will do.

[remixer 1,645]

24 minutes ago, AVB-AMG said:

@Zeke:

Now that was funny.....!

AVB-AMG

Does that mean you will wear that hat?

6 minutes ago, Ray Ray said:

I still say 1/4 inch will do.

Lol

and yes I realized Pk mistakenly said space between joists instead of depth of joists. He is forgiven