Attic in Garage

[MJBaldwin]

I just moved into a new construction home and trying to get my garage cleaned up and storage ideas. That being said I was planning on adding about 2 sheets of plywood or OSB onto the roof trusses with a ladder in order to create a little storage up there for misc things. Kids misc things, Christmas items, hockey bag, golf clubs, etc etc. Not looking at a huge weight in my opinion. I am reading since they are roof trusses I shouldn't do this. Although I had a 1928 home and did this with no issues? Just wondering your thoughts on the whole topic again not going to be weights/steel/etc just some simple storage.


This would be above the 3rd stall being I could get some insulation around the perimeter of it but would have to use batt under the storage... thoughts? Plan on insulating and finish rocking at some point.


What type of wood would you use for this? I know i used OSB at my old place and probably only 1/2 if I remember as I had the same thoughts as when I was installing that just to get items up off the ground.

 

[pattenp]

If those are standard truss, not actually attic truss, they are designed to handle the load of insulation and drywall. You can add plywood for storage but you need to be very mindful to not put to much weight up there. If the truss are on 2' centers I'd use plywood instead of OSB.

 

[Kaizen]

And if I was standing in it I’d do 3/4 inch ply. I am not an engineer or truss designer
If it were me I’d put some 2x from the bottom truss up to the top truss for some extra strength. Theoretically it will take some of the load off the deck and put it out to the walls.


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[finn]

Use the lightest plywood available, 7/16 or half inch.

All 3/4" does is add dead weight to what already is a marginal structural situation.

 

[Richard Cranium]

Welcome to our group, Congrats on the new home and garage
Please update your profile to include your city or at least your state.

 

[nolimits76]

Guess I've been lucky in the fact builders in my area utilize 2x materials or wood I-joists for ceiling joists instead of pre-fabricated roof rafters. But most the structures are stick built on-site as well.

I've owned about 5 different places, and all them had joists running 12" to 16" apart, depending on specifics. At almost every place I've placed 3/4" T&G plywood decking above the garage and used the space for light storage as you noted. On the place I had with wood I-joists, the space above the garage remained for storage but other parts above downstairs living spaces were converted to an upstairs game room (I designed and custom built the house to add this on later as money allowed).

I'd be more concerned about having live loads up there then dead loads from minor storage items. At the least, you could probably get a structural engineer to come look at the structure and give a professional opinion for a few hundred bucks. Probably many framers (that you trust) could do the same thing, but wouldn't have the engineer stamp or design calculations to support their field experience.

FYI, the PO of the last house I lived in installed 3/8" or 1/2" OSB above the garage for storage. While I'm sure it saved him $100 at the time, it was garbage. I intentionally walked on the joists as I didn't like the way unsupported it bowed/moved on me. If you're a smaller guy maybe it's fine but honestly I like to build stuff so I don't have to rethink it later.

 

[Stuart in MN]

For the lightweight items you mention it should be okay. The problem is if people decide to put heavy items up there in the future, so be mindful of that.

 

[MJBaldwin]

Thanks all for the replies. My father in-law has worked in construction for quite a few years he said I should be fine just thought I would turn to you guys in order to get another opinion. I am not sure what style they are they are roof trusses that are made out of 2x4's that being said I know they were not made on site.

Really dont want to hire anyone if its not needed. I would be willing to add extra supports if needed.

That being said would you use OSB or plywood at that 1/2" mark?

Maybe I will try and post a picture once I get home to give a better idea. This area isnt going to be large maybe (2) 4x8 sheets with a access ladder...

As far as weight goes I guess everyone has a different opinion on this. I dont plan to put much up there but get the fact if i sell it might be different for the next guy...

 

[MJBaldwin]

Not the best pictures but will give you guys at least an idea.

 

[nolimits76]

Not the best pictures but will give you guys at least an idea.

Are you still in the framing stage of the project? And what centers are your current rafters on -- appears to possibly 24" centers?

Also, what is the span length of them? It appears the area you want to put the storage is running the length of the 3rd car bay; however, it looks like part of the 3rd car bay is covered by other rafters. That may work to your advantage as running a 20' unsupported distance is rough without upsizing lumber.

Once you get some data, you can plug it into this span calculator and it will tell you based on the type of lumber, size of lumber, spacing, etc what span it can hold. For instance 2x12 SPF on 12" centers can span 19'11".

http://www.awc.org/codes-standards/calculators-software/spancalc

 

[MJBaldwin]

nolimits -

what do you mean framing stage of the project? The house is built and we are moved in. Yes 24" centers.

I think the span would be roughly 22' give or take. The original documents for the house says 20'4" although I added to the garage to make it larger although I dont remember exactly which way we went.

 

[nolimits76]

To me, the "framing stage" is when your wood framing is still accessible and modifications can easily be made. Since your moved in, I would assume your garage has drywall on the ceilings and walls making it harder to change framing structure. However, that may be an incorrect assumption as I know not all areas finish out their attached garages.

Again, I could be wrong here, but in my head this is how I envisioned your garage layout (where the red represent the rafter alignments). To me it appeared you were trying to put the storage space in an area that was less than the 20'+/- distance.

 

[MJBaldwin]

You are right although I think the dimension is 20' from where the structure changes. That is an additional 10'x10' work area I added. I will have to verify the exact dimension though I could be wrong. Whats your thoughts on how to add support. You are correct at the location I plan on putting the storage basically just in between the roof webs is what I was thinking.

 

[MJBaldwin]

And to add from your previous comments they sheet rocked that back corner due to firewall although didnt insulate it that being said all that sheet rock is coming down for me to add insulation. The area is fully accessible with no sheet rock on the ceiling where I plan on adding this.

 

[MJBaldwin]

Alright attached are a few better pics sorry for the mess been to cold to get any other storage things done. Space is about 7’x9’ garage array is about 22’x12’...

Having issues uploading pics from phone? Any help?

 

[MJBaldwin]

I guess they posted?

 

[finn]

Looking at the pictures, I'll stand by the suggestion that you put the lightest sheeting you can find if you plan on storing light objects in the rafters.
And don't plan on walking up there. The bottom cord isn't strong enough to reliably support much weight on those trusses.

 

[Vintage Veloce]

I'd venture that that truss isn't designed for any "attic weight" at all. Looks like a 22' span with a 2x4 that is jointed in the middle. You may get away with a thin sheet of plywood (1/4 in) to store very lightweight things, like empty cardboard boxes. Really, not much weight at all. Certainly not your body weight. Maybe 1 pound per square foot.

If you want to store real stuff up there, consult with an engineer who designs trusses. For a couple hundred he may be able to give you a great solution. I recommend this guy:
Aaron M. Reed, PE, MBA
DEADLINES ENGINEERING
601 Morro Bay Blvd, Suite F
Morro Bay, CA 93442
805-771-9649 (P)
Fixmytruss.com
Fixmyjoist.com

 

[Lelandwelds]

Funny how stuff has changed. I have lived mostly in older non stamped buildings. If something sagged or needs changed, the PO jumped right in with steel fish plates, sistered 2x, or added plywood webs.

Now, the automatic response is probably "better not". Not judging. Just observing.

(But all the wife's favorite shows rip walls and stuff out willy nilly and make it seem cheap and easy. I hate home improvement shows.)

 

[GMCGarage]

Funny how stuff has changed. I have lived mostly in older non stamped buildings. If something sagged or needs changed, the PO jumped right in with steel fish plates, sistered 2x, or added plywood webs.

Now, the automatic response is probably "better not". Not judging. Just observing.

(But all the wife's favorite shows rip walls and stuff out willy nilly and make it seem cheap and easy. I hate home improvement shows.)

Engineering has changed so much that with design software it can be engineered right up to the design minimum loads. Not always alot of additional capacity left in members.

 

[bugnut]

So l'll be the smart azz. My traditional 2 story home built in 76 looks just like your images. Pull down stairs with attic storage over the garage. Osb and plywood in the 11/32 variety, long strip thru the middle as the back side of the attic is shared with the family room. Been here 25 years, using it for Christmas, camping and general storage. Got several boxes of old magazines stacked up. Drywall below. So it hasn't collapsed, doesn't show signs of sagging, easy to retrieve stuff when needed. I go better than 225 and haven't fallen thru. The flooring material bows when I walk on it but I assume if is spreading out the load. Do what you think is right. If you thinking of stacking up gold bullion or cement blocks probably ought not..... ymmv

 

[MJBaldwin]

Engineering has changed so much that with design software it can be engineered right up to the design minimum loads. Not always alot of additional capacity left in members.

I would disagree that engineering is done the the minimum of what it needs. Are there engineers out there who do this absolutely but everyone wants things to work and last. Although I will say it comes down to money.. this builder builds quite a few homes and I guess I didn’t think of asking before hand. Should I ask who the truss designer was or who did the framing and see what can be accomplished.

From that calculator it appears I can span roughly 11’ with a 2x6. Do I span the east west direction and rest on the wall and then that other piece? I wouldn’t even hardly be touching the world trusses the. I would be up on that wall and then a double roof truss that is supported on beams? I don’t know maybe over thinking this. Although I would agree with some other comments I lived in an old home it was single hip or pyramid hip roof. Didn’t have trusses or anything had 2 supports down the side that was all. I had 2 4x8 sheets filled with camping etc, along with that I had my portable fish house. Not saying it was right but I didn’t have any issues. My concern now is that I want to Sheetrock and insulate this so I’m not looking for issues later on...

 

[lakeroadster]

I'm one of the guys here who always says "Don't store anything on the truss lower chord unless the trusses are rated for it."

My response to the OP in this thread is, it is new construction, get a copy of the plans and see what the truss lower chord is designed for, and proceed based on that information. It's not a mystery at all, due dilligence will answer your question.

The trusses are designed for combined loading conditions such as environmental loads (wind, rain, snow, etc.) If you stack weight on the lower chord in excess of it's design capacity you may never know it's an issue until there is, for example, a snow storm that is accompanied by high winds.. that's when you'll find if it's an issue. Not on the nice sunny calm day when you load the stuff into the attic.
___________________________________

That being said when we bought our current home (a 1978 built ranch) one of the first things I did was remove 4 bundles of shingles, including a couple partial bundles, that were stacked in one area spanning two truss lower chords.

That was about 300 lbs.of localized weight or about 50 psf
___________________________________

The pictures below outline what to look for on the truss drawings...

A bottom chord dead load of 5 psf is what is typical for a ceiling and insulation... the truss shown below has 15 psf which is good for light storage.

 

[MJBaldwin]

Where could one go for truss drawings?

 

[Vintage Veloce]

Find the building plans. Ask the builder.
Some manufacturers stamp the trusses with the specs, look for stamps.

 

[NUTTSGT]

It's hard to tell from the pictures but it looks like those trusses are built with 2x3s and 2x4s for the bottom chord. I'm no engineer but I would have a hard time putting something up there myself.

 

[lakeroadster]

It's hard to tell from the pictures but it looks like those trusses are built with 2x3s and 2x4s for the bottom chord. I'm no engineer but I would have a hard time putting something up there myself.

And that's what is truly scary about folks advising "It's ok for light storage".

Pretty much everything today is being designed as minimal as possible and without the "robust" qualities of the past.

 

[Jlbc212]

Each individual element of a truss, such as a chord or splice, and each truss are essential elements of a truss assembly, such as an entire floor or roof. The failure of even a single element can trigger a complete and total failure. While such occurrences are most often seen with events such as a heavy snow, a flooded roof (because of a blocked drain) or a fire, be aware that any overloading can cause a failure.

 

[GMCGarage]

I would disagree that engineering is done the the minimum of what it needs. Are there engineers out there who do this absolutely but everyone wants things to work and last. Although I will say it comes down to money.. this builder builds quite a few homes and I guess I didn’t think of asking before hand. Should I ask who the truss designer was or who did the framing and see what can be accomplished.

From that calculator it appears I can span roughly 11’ with a 2x6. Do I span the east west direction and rest on the wall and then that other piece? I wouldn’t even hardly be touching the world trusses the. I would be up on that wall and then a double roof truss that is supported on beams? I don’t know maybe over thinking this. Although I would agree with some other comments I lived in an old home it was single hip or pyramid hip roof. Didn’t have trusses or anything had 2 supports down the side that was all. I had 2 4x8 sheets filled with camping etc, along with that I had my portable fish house. Not saying it was right but I didn’t have any issues. My concern now is that I want to Sheetrock and insulate this so I’m not looking for issues later on...

I get grief all the time if my designs are too conservative. Truss mfg are known for sophisticated programs to minimize materials used. Same with the manufactured buiilding companies. Why have more materials in them thats needed??

If you have contact info, ask them what you can store up there. Worst they can tell you is nothing, then you have to decide if its worth it or not.

 

[MJBaldwin]

What would be your suggestions then? In reality if I would have thought about it while building it would have been designed that way. Although there were a lot of other favors in our move including a new job and moving 300+ miles away.

What would you do? How would you add street or make it a place to store items?

 

[terabitdan]

You can always build a separate support structure just for the storage.

For example, 9 1/2” or 11 1/4” I joists 12” OC between the trusses spanning from to back. Then build an attic floor over that. Don’t tie it into the existing trusses at all.

It looks like you have plenty of height in that area, so taller I joists would work as well.

20’ I joists are about $30 at menards around here.


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[GMCGarage]

What would be your suggestions then? In reality if I would have thought about it while building it would have been designed that way. Although there were a lot of other favors in our move including a new job and moving 300+ miles away.

What would you do? How would you add street or make it a place to store items?

Since very new, track down the builder, ask him for the truss drawings, and see what they can hold. Have to start somewhere.

 

[lakeroadster]

..My response to the OP in this thread is, it is new construction, get a copy of the plans and see what the truss lower chord is designed for, and proceed based on that information. ...

Find the building plans. Ask the builder.
Some manufacturers stamp the trusses with the specs, look for stamps.

I...If you have contact info, ask them what you can store up there. Worst they can tell you is nothing, then you have to decide if its worth it or not.

Since very new, track down the builder, ask him for the truss drawings, and see what they can hold. Have to start somewhere.

.........

 

[MJBaldwin]

Thanks for the information you guys, I have contacted the builder and they are going to try and get me some information. Everything is do-able all depends on how much money I want to throw into a little storage. The thing I worry about is the height. This isn't a large area if I add a floor joist at 9.5 or 11.25" this will take up quite a few inches of height although I like the thoughts.

 

[lakeroadster]

How about a storage shed outside? Then you can keep other stuff out there too that would otherwise clutter up your new garage.

Much more convenient. Some of them have half attic storage too.

 

[MJBaldwin]

How about a storage shed outside? Then you can keep other stuff out there too that would otherwise clutter up your new garage.

Much more convenient. Some of them have half attic storage too.

Yes, I agree although I figured 2 sheets of plywood and an attic ladder I got for free from CL is much more economical than a shed. I do plan to add a shed at some point. Although there are bigger things we need.

 

[Falcon67]

I'd stand a 2x4 on end next to that 2x4 or 6 that lays flat, nail the 2x to the existing to create an "L" and lay the sheets next to that. 7/16 OSB weighs about 48~50 lbs/sheet - that's 1.56 lbs sq/ft. Big deal.

 

[nolimits76]

Thanks for the information you guys, I have contacted the builder and they are going to try and get me some information. Everything is do-able all depends on how much money I want to throw into a little storage. The thing I worry about is the height. This isn't a large area if I add a floor joist at 9.5 or 11.25" this will take up quite a few inches of height although I like the thoughts.

Getting the truss drawings and discussing your options with the truss manufacturer is a good idea. They might be able to offer some more economical solutions/ideas. Looking at the big picture, a traditional 2x12 joist has a span of 20' unsupported. The truss manufacturer has apparently managed to achieve the same thing using 2x4's. I'm not saying their design is bunk, but that is a feat by itself and not something I would personally want to push any further without some reassurance.

Attached is a sketch of what I had in mind. The red lines indicate where I would install 2x12's to span the entire 20' length. I'd place them on 12" centers personally and then add your plywood above it. Basically you are just adding new joists in a larger size to span the distance. Yes, you will lose a few inches of height. I am not sure how much height clearance you have now, but I'd rather have something structural secure than a few more inches of height myself.

We do know a 2x4 is 3.5" tall and a 2x12 is 11.5" tall, so assuming you install 2x12's then you would lose an additional 8" of height.

If you try to beef up a smaller area you need to run some horizontal bracing (blue line) to tie off your joists. The problem is you can probably land one side on your main structure wall and the load will transfer down. But the area between the 2 car and 1 car garage needs supported, and the load transferred. Perhaps putting in a 2x12 along that 20' span and then tying in the horizontal bracing would work. Otherwise, you'd probably need a support to transfer the load down (green line).

Yes, I agree although I figured 2 sheets of plywood and an attic ladder I got for free from CL is much more economical than a shed. I do plan to add a shed at some point. Although there are bigger things we need.

Unless the truss manufacturer comes back and confirms you have some capacity left, I think it's much more than plywood and an attic ladder. If you have the space and no HOA restrictions that allow an outbuilding it may be a really great solution.

Having used attic space at all my houses for storage, I can testify they are usually a pain in the ***. Your free ladder will likely be the culprit of many cussings. I hate the standard ladders designed for a max 225# capacity. It makes getting stuff up in the attic a pain and usually with your weight and the stuff you are carrying you are at max capacity. At the least I prefer to get the oversized ladders with more width and weight capacity. So while I find attic space incredibly handy, personally I'd rather have a set of real stairs or one of the fancy attic storage lifts. Instead I complain and save the money and space.

But an outbuilding would allow for maybe the best of all worlds. The downside being the cost. But in your case, I don't think you have a super easy solution either and the final bill will be more than a few sheets of plywood, a free attic ladder and a case of beer to aide in install.

 

[LifeLongWNYer]

Ah, I'm glad I found this thread. So, I am in the initial stages of planning a garage and want to store "light" things in the attic. I am working with a lumber yard which is preparing a price for a package of "everything" that I will need, including the trusses.

I would like to know what to tell them that I want, so that I get space for light storage, but NOT something designed ( and priced ) for engine blocks, which I don't intend to store up there. The firm that I'm dealing with is an old firm, and reputable, so I trust them, but I don't think I know enough about trusses to know what questions to ask them.

While I am on the subject, I am in my local volunteer fire department, and at drill last night, a local carpenter rattled on for quite a while about "gang nailed" trusses. He advocated trusses assembled with rectangles of plywood on each side of the truss, at all the places where 2x4's meet. So, when I talk with the firm building ( pricing ) my trusses, do I tell them "no gang nail plates"? My thinking is that there are millions of trusses assembled with them, and I don't hear about a lot of them collapsing, therefore, are gang nail plates okay, or not? I don't want to get the "Yugo" of trusses, OR the "Cadillac", but I'd like the Chevy" of the mix.



.

 

[MJBaldwin]

I am still waiting to hear back from the builder although I did a little digging on my end. I believe its a 5/12 roof. Also its the same for 20'/22'. I attached a picture from the good ol' Menards website it appears they design everything to 62 lb per sq/ft. Appears they do not have a life load but the Dead load for btm cord is 10..

Thoughts? (I am not saying these are my trusses Although image looks close and stats look close)