DarkMonohue
DarkMonohue GRM+ Memberand SuperDork
5/27/24 5:31 p.m.

The unnecessarily presumptious foreword: I posted a portion of this on another forum five years ago.  I'm a lot better at planner than at doing and even after five years have not taken action.  Coincidentally, Little Monohue will be five this summer.  Although my mental health and outlook are somehow a lot better now than before he came along, my spare time and budget have both suffered.  It looks like there may be room for improvement in the near-ish future.

The house: Mrs Monohue and I own a modest (almost embarrassingly so) little house.  It's our first house and we have now been here fifteen years without making any real changes.  It may be my last house based on the real estate market and how little interest either of us have in going through a move.  Home improvement isn't of great interest to either of us.  We are dull people with dull lives and do what we can to avoid obligation.  That said, we're also in dire need of storage space, and I would really like to be able to actually pull a car into the garage and possibly even swing a wrench or two.

The house was built in 1969 and boasts all of about a thousand square feet.  It's stick-built with 2x4 stud walls and a stick-built roof (no trusses).  Electrical service is 200A via an old GE split-bus panel in the garage and I added a Siemens 125A sub-panel in the next stud bay.  Power will not be a problem.

The garage: Attached, and technically a two-car garage, but only technically.  It's about 35' long but only 13'-7" wide on the inside, so walls are probably 14' apart on center.  Interior walls are sheathed with an attractive assortment of gyp on the east (house) side, OBS on the west (exterior wall) side, and some very 1970s wood paneling on the ends.  The floor is a concrete slab.  There's no ceiling.

The goals:

  • Build at least one storage loft in the garage to get junk off the floor
  • Add a standby generator, move most existing branch circuits serving the house from main to sub panel
  • Add at least nominal ventilation (attic fan), improve lighting, etc.
  • Re-purpose existing main panel to serve garage loads, pull new branch circuits as necessary
  • Bonus round: demolish the existing lean-to on the exterior wall of the garage and build a bigger one

The excuses: I'm poor, I'm broke, I'm too old for this E36 M3, I lack motivation, I'm easily discouraged, and I don't have any help.

This post is just to set the scene.  In the next exciting installment I will go over thoughts on the storage loft.

DarkMonohue
DarkMonohue GRM+ Memberand SuperDork
5/27/24 6:18 p.m.

Garage storage loft:  I would like to add a simple storage loft for storage of seasonal items, spare clothing, et cetera - nothing terribly heavy. 

As mentioned, my garage has no ceiling.  The roof is stick-built, so no prefab trusses, with a 4/12 pitch.  There are two sistered pairs of 2x12s that run east-west across the garage.  The northernmost one runs directly under the ridge line of the roof and the other runs parallel to it about 7' to the south (the north end of the garage faces the street).  Vertical clearance from the top of the sistered 2x12 beam to the bottom of the ridge beam is approximately 38".

I have this mocked up in Sketchup and took some screenshots to help illustrate.  The first image shows the basic structure as it sits today.  Again, the inside width of the garage is about 13'-7", so the walls are on 14' centers.  Walls are 2x4 construction.

 

If we take the rafters away, the second image shows those sistered beams sitting atop the walls of the garage.  There are three 2x6 rafter ties that run between the north beam and the north exterior wall of the garage.  They are nailed to the side of the rafters on top of the north wall, above the garage door, and are on 48" centers.  Length of those 2x6s is not quite 13' total, or 12'-6" measured from the sistered beam to inside edge of north wall.


In the third pic is an early layout.  The initial plan was to just tie some more 2x6s to the existing sistered 2x12 beams, throw some plywood on top, and claim victory.  I've discussed this with a few people and it turns out there is little consensus.  This may or may not be strong enough.  There has been much hand-wringing about snow loads (11.0 lb/sf here) and the entire house collapsing under the weight of the storage loft, never mind the things in it.  (This pic also shows an early design for  a platform between the big beams.  I would like to add a platform there but the first priority is the one on the forward/north side of the north beam.)


 

Another option (not pictured) is to sister another board on the north side of the north beam so that it spans the side walls of the garage, and use that to transfer load to the walls.  That would require cutting the existing rafter ties back enough to wiggle the new board in, and that means bracing the north wall so that it doesn't just bow out.  Not sure how to do that or whether it would even be necessary.

Thoughts are welcome.  Mostly.

Kendall Frederick
Kendall Frederick GRM+ Memberand Reader
5/27/24 6:35 p.m.

Just frame it in as in your 3rd sketch and start stuffing things up there.  Use joist hangers where the 2x6s meet the 2x12s, put hangers on the existing ones if they don't already have them, and sheet it.   It'll be fine for any load you can put up there in the (not very tall) space you mention.

Antihero
Antihero GRM+ Memberand PowerDork
5/27/24 7:32 p.m.
Kendall Frederick said:

Just frame it in as in your 3rd sketch and start stuffing things up there.  Use joist hangers where the 2x6s meet the 2x12s, put hangers on the existing ones if they don't already have them, and sheet it.   It'll be fine for any load you can put up there in the (not very tall) space you mention.

From what I understand from the sketchup, I agree with this.

DarkMonohue
DarkMonohue GRM+ Memberand SuperDork
5/27/24 8:29 p.m.

In reply to Kendall Frederick and Antihero :

That's what I thought at first, but there had been so much hand-wringing that I lost all confidence. My gut said I'd be adding strength by tying the beam to the front wall that much more securely, and not adding or storing enough weight to warrant any concern at all. But my gut is not a structural engineer.

Sistering anything onto the north side of that north beam, in order to transfer load to the east and west walls of the garage, would be fairly invasive. That's the bad news. The good news - and this just occurred to me - is that there's no native structure between those two sistered beams. It  would actually be really easy to add whatever I want in there. We could run anything we wanted crosswise, wall to wall. Maybe that's where the heavy stuff goes, and the light stuff gets thrown onto the north side.

I took some terrible pics to further muddy the situation. First is looking toward the north from the east/house side:

Second pic is looking at the north wall where the rafters and rafter ties join:

Third pic is looking south from the north end, showing the north beam as well as the gap between north and south beams. Disregard the 2x4 between those beams in the pic. I added that to give me a place to hang a light fixture. The existing plywood on top of the rafter ties is 1/4" or so and just strong enough to hold up a couple rolls of fiberglass insulation. 

AWSX1686 (Forum Supporter)
AWSX1686 (Forum Supporter) GRM+ Memberand UberDork
5/30/24 2:20 p.m.

Commenting to come back to this later. 

golfduke
golfduke Dork
5/30/24 2:58 p.m.

Are the sistered 2x12's properly supported with jackstuds/columns/something?  If so, I'd have a VERY hard time believing you can put enough load in a sloping 38" loft to make any lot of difference, assuming you frame it 16"ish OC and tied in with sheathing, blocking, and hangers as in your sketchup.  Those 2x12s are going to carry the vast majority of the load, and with a 14' span, sistered pairs seems to me more than adequate for basically storage items. 

 

Full disclosure- I am not a structural engineer. 

 

DarkMonohue
DarkMonohue GRM+ Memberand SuperDork
5/30/24 3:25 p.m.
golfduke said:

Are the sistered 2x12's properly supported with jackstuds/columns/something?  If so, I'd have a VERY hard time believing you can put enough load in a sloping 38" loft to make any lot of difference, assuming you frame it 16"ish OC and tied in with sheathing, blocking, and hangers as in your sketchup.  Those 2x12s are going to carry the vast majority of the load, and with a 14' span, sistered pairs seems to me more than adequate for basically storage items. 

 

Full disclosure- I am not a structural engineer. 

I have not yet opened the walls to see what's below the sistered beams. This is a cheap little old tract house so I expect to find some doubled up 2x4 studs under each beam, probably not 4x4s. Ironically, I can't hardly get to a wall to open it up without getting some garbage off the floor. A list would be so handy for that.

The plan was to add 2x6s on 24" O.C. on the north side of the main beam because that's the spacing of the existing  rafters.  Even at 24", with blocks and hangers, it seems like it would be strong enough to support itself and some Christmas decorations.

For the space between the beams, I'd also go with 24" O.C. (though maybe 2x8s, and oriented east-west) in order to accommodate an attic ladder. Or maybe the ladder could go on the north side, oriented north-south...

It'll all gel at some point, and everything will make sense.

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