Garage contruction - Attic build possible?

[shamoo]

I'm in the process of remodeling/setting up cabinetry in my gf's garage. Epoxying the floor is one part of it (http://www.garagejournal.com/forum/showthread.php?t=224315), so if any of you have any more advice in that thread, it would be greatly appreciated.

As you can see the garage space is very cluttered with boxes and other family items over the past 30 or so years. We already got rid of about 50% of the clutter here so this picture is a couple of weeks old.

Goal - Cabinets and track wall (for hanging things) for right side and rear wall.

Left side and ceiling to be determined. This is currently only limited by budget.

Problem #1

The space above the garage (attic) is open, and has a truss style attic similar to the below. Queen style truss?

It does NOT have a knee wall, and I don't intend to make this space into a livable loft. It will be for STORAGE ONLY for non-heavy items. As you can see from the following pictures, the truss beams are only 2x4 and aren't made to support any
significant amount of weight. If I wanted to make a storage area that you can walk on (only to move boxes up there), I assume I would need at least a 2x8 or 2x10 similar to a normal ceiling joist?

Here are the current beams going across.

If I were to install some 2x8s or 2x10s, I think I could support them on these sides here, right?

As you can see, the slope of the roofline will likely hit the corner of the 2x8 or 2x10. Is it okay to cut the corner of the joists like this?

The garage width is ~22". Aren't ceiling joists not supposed to go more than 12' without another support beam going perpendicular (or a support column/loading bearing wall)? Currently these 2x4s are going all the way across.

Problem #2

Venting. I feel this garage was completed in a weird way. The right side of the garage has no drywall. Only the portions attached to the house are finished (I guess to comply with code). If I seal off the attic, the roof has no venting. Then it could be a breeding ground for mold/moisture. I don't have the skill to make my own roof venting. Should I just "seal off" half of the ceiling?

The right wall of the garage has this, leading right to the side yard. What gives? Is this the "half assed" venting that the builders included for venting the entire garage? Can I cover this area up? What if I drywall over it? Most garages don't have venting inside the car park area. It's vented enough with the garage door opening and closing.

Any advice is greatly appreciated.

 

[shamoo]

Wanted to bump this up.

After some more research here and online, it appears that roof trusses aren't supposed to support any additional weight at all, and are meant to support the main roof structure. Drywalling may work, but may crack over time, etc.

That being said....how about drop ceiling? It seems to be very cheap and light.

I will also drywall the sides of the walls (until the vents). I already have a ton of Gladiator Garageworks cabinetry on it's way.

 

[paranoid56]

In Sothern california we see that kind of venting in every garage made from the 60s till today. very common. also my trusses are built exactly like that one too. I beefed up both ends of my attic so i could store items up there. i sisterd a full lenght 2x6 (and notched the corners like you showed) then installed plywood over it. I still try not to store to much up there, but its much better then the spliced 2x4s

 

[mark5767]

After some more research here and online, it appears that roof trusses aren't supposed to support any additional weight at all, and are meant to support the main roof structure. Drywalling may work, but may crack over time, etc.

While I respect the engineering precautions expressed in the area of bottom chord load restrictions, there must be millions of garages around the country and globe where people are storing items on the bottom chord of the garage roof trusses.

So even though it's a no-no from an engineering perspective, where are the horror stories of garage roof collapses? If I search for garage ceiling failures I don't come up with much of anything.

Has anyone heard of some failures related to overstressing the bottom chord they can share?

If as a practical matter the bottom chord survives improper loading in most cases maybe it's not such a big deal to store a few things up there after all.

 

[MackMan]

regarding that ground level vent, my parents built their house in Florida in 2007 and had to add vents like that to comply with code. They were told (I'm not a code expert) that a ground-level vent was required as an escape for potential flood water, as they are on the waterfront and only 7' or so above the water table. They were originally planning to air-condition the garage, but decided not to when they had to add 2 huge holes at floor level.

 

[shamoo]

regarding that ground level vent, my parents built their house in Florida in 2007 and had to add vents like that to comply with code. They were told (I'm not a code expert) that a ground-level vent was required as an escape for potential flood water, as they are on the waterfront and only 7' or so above the water table. They were originally planning to air-condition the garage, but decided not to when they had to add 2 huge holes at floor level.

Interesting, although I'm not sure this would be for flood water escape. The driveway slopes up quite steep until the garage. And if waters got to the level of the vent, it would already be 3-4 inches in the house.

I'll probably dywall around the vent and make it look good.

 

[Krash Kadillak]

What you've got is basically a standard garage for southern California. I lived in the City of Orange for 25+ years (2 houses) and my garages were basically the same as yours - only 'finished' on the inside walls. I never has any problem storing stuff up in the rafters. I laid up lightweight paneling or other material on top of the rafters, then stored my stuff. Heaviest stuff I kept away from the center. Most of the stuff was fairly light weight - Christmas stuff, extra suitcases, fans (in colder months), miscellaneous bric-a-brack, long pieces of pipe or wood (not much), etc. I never did any reinforcing up there. If I had seen it sag, I would have either reduced the weight or sistered some additional supports in.

My garage here in Oregon is a bit better constructed. Completely finished (including the ceiling), I installed a drop-down ladder, and 5/8" plywood in about 50% of the attic space. Using the same guidelines, I've been able to store an amazing amount of stuff up there.

The vent you've shown is standard for the area. It should be enough. Don't block it.

 

[shamoo]

Okay, so it would be okay for a drop/suspended ceiling installation? I didn't want to drywall it because the trusses are 24" OC.

 

[Modern Jess]

In Sothern california we see that kind of venting in every garage made from the 60s till today. very common. also my trusses are built exactly like that one too. I beefed up both ends of my attic so i could store items up there. i sisterd a full lenght 2x6 (and notched the corners like you showed) then installed plywood over it. I still try not to store to much up there, but its much better then the spliced 2x4s

I'm in Northern California, and have the same vents on the side of my garage. They're put there (as I understand it) to (a) let carbon monoxide out of the garage, and (b) to give your water heater the oxygen it needs for combustion.

I wouldn't drywall over it.

 

[Krash Kadillak]

Okay, so it would be okay for a drop/suspended ceiling installation? I didn't want to drywall it because the trusses are 24" OC.

A suspended ceiling would be OK. I think you could also get away with a paneling product or perhaps 3/8ths drywall if you can find it. 1/2" might even be OK.

 

[67carl]

I'm going through the same thing as you are, only a little bit further along. I've got a puny little 1 car garage and am in desperate need of more storage. As you can see in the pics below my garage was open to the roof and there were only a few, widely spaced sagging horizontal 2x4's. My truss structure is different than yours but I don't see why you couldn't do something like what I did. There isn't a whole lot of space up there now but it's more than I had and worth the effort.

I set my 2x8's on the top plate of the wall rather than attaching them to the side as I wanted more vertical space in the garage. I also spaced them closer together than necessary (about 16" OC vs. approx. 20" OC recommended by my contractor), because it was only a little more for the lumber and I felt better about parking my baby under it. Definite overkill. I see you also have a "finished" wall (drywall) on one side of the garage. In order to set the joists on the top plate I had to cut into the drywall so I could maneuver the 2x8 into position. You could sister the new lumber against the old and add more in the spaces between, then block them off.

I stapled twine across the joists and then stuffed un-faced R30 insulation. This was far cheaper than using faced... I also hoisted up sheets of OSB into the attic prior to finishing the framing to use as a floor. I also added an attic ladder in a location that allows me access without moving the car.

For venting there was already a ridge vent and a gable fan with a thermostat, so I just added a soffit vent. I just finished wiring and am ready for drywall, then cabinets (bought used kitchen cabinets off craigslist).

Anyway, sorry for the long post but I just saw you were doing something similar and thought maybe my examples would be helpful. Good luck!