Construction question

[brendaninnh]

I'm hoping to be able to put up a garage before winter. Plans are for a 24x24, attached to the house with a 10x12 breezeway. The garage is cape style, 12 pitch and there will be space to finish off a room up there eventually. I got my first quote a couple days ago. It was very reasonable, but noticed that the specs called for 2x6 construction, 24" on center (rafters were also 24"OC)

I talked to a couple friends who are or have been builders -- one said he wouldn't frame it 24 OC, other said it was totally fine. The one who said not to, said it'd be better to do 2x4, but 16OC, than 2x6 at 24OC. Just wanted to get some more opinions -- is 24 OC ok for 2x6 construction?

I can't imagine it would add much to the cost to go 16 -- it's only a few extra studs at $3 a piece. This is in NH, by the way.

 

[FunfDreisig]

For most wall heights, 2x6 24OC and 2x4 16OC are roughly the same structurally.

The 2x6 24OC is considered more "green" since it uses less total board feet of lumber, nails, etc. Particularly if the rafters/trusses can be aligned directly above the king studs. That way you can use a single top plate and often reduce or eliminate headers over windows etc. where they can be aligned with the king studs/rafters. But more importantly 2x6 24OC allows for better insulation due to the wall cavity thickness and the width between studs.

Funf Dreisig

 

[heavytlc]

2x6 24oc meets code. I built my shop office/apartment 2x6 16oc. 2x6 will give more room for insulation. 24oc makes for a better insulated building, studs do not insulate very well.

 

[logical]

2x4 @ 16 oc and 2x6 @ 24 OC may be considered structurally equal but if the walls exceed 10 feet tall, most likely you will need to go to 2x6 @ 16 OC to meet code.

Also, keep in mind any time you go 24 OC, you have probably forced yourself into 5/8 instead of 1/2 drywall if you want to avoid seasickness looking at the walls. The real over-riding reason to go 2x6 in any circumstance is to allow a larger cavity for insulation.

In a garage, I'd go 2x6 @ 16 OC and be done with it. Closer studd spacing for hanging cabinets and more insulation possibilities if nothing else.

 

[Kevin54]

I'd go with 2x6 @ 16" OC for the walls. More structural integrity. Almost all trusses are 24" on center unless you are in an area wihere you have high snow loads. On a 24' wall, you are only looking at 6 more studs per wall. The reason I would go with 2x6 would be for the added width for insulation.

 

[Sundowner]

For most wall heights, 2x6 24OC and 2x4 16OC are roughly the same structurally.

The 2x6 24OC is considered more "green" since it uses less total board feet of lumber, nails, etc. Particularly if the rafters/trusses can be aligned directly above the king studs. That way you can use a single top plate and often reduce or eliminate headers over windows etc. where they can be aligned with the king studs/rafters. But more importantly 2x6 24OC allows for better insulation due to the wall cavity thickness and the width between studs.

Funf Dreisig

I agree with what 35 said. My 2nd floor addition starts in 2 weeks and the roof is framed at 24". I do reccomend up-sizing the sheet goods to stiffen up the structure. 5/8" exterior ply is only a little more than 1/2" (I'd spec 3/4, but that's me). I can't speak to the sheetrock.

 

[FunfDreisig]

Here's a little 2x6 @ 16OC framing story...

The rear wall of our cabin has row of 24"X42" windows and the rafters are exposed twinned 2x8" 48" OC with the rafters aligned to fit exactly between the row of windows. Think "clear story" with minimal gaps between the windows

In my innocence, I let the framing crew "do their thing" on the rear wall. So they went with their "standard" 2x6 @ 16 OC framing with solid window headers (a sandwich of 3- 2x8s with 2- 1/2" plywood fillers) - DUH!

A high percentage of the dimensional lumber in this wall was not needed. And worse yet, it reduced the insulation efficiency of this north wall quite a bit. For example,
* NONE of the headers were needed - they rafters bear only on the king studs - so now I have massive "blocks of wood" 5 1/2" thick, 7 1/2 " high and 4 ft long where I could have had insulation in all but 1 1/2" of this area (i.e. a 2X6 on edge) .
* the 16"OC framing was laid out such that king studs between the windows did not exactly align with the 16"OC center studs - so they added several extra cripples/jack studs under the window sills which are so close to the king studs they were nearly impossible to insulate well.

So now you know why I am framing my new garage myself - I am no longer innocent.

Funf Dreisig

 

[GSSFC]

I was a builder in NH. I would go 16 oc. For a 24 foot span you are talking 6 extra studs on each wall and 6 extra rafters on each side. With a 12 pitch and the last winter we had I would not go with 24 oc on the roof. Also unless you plan to insulate, the 2x4 or 2x6 makes no difference. If you plan to insulate use spray foam! I just finished framing my shop addition. 2x4 walls 16 oc. 2x10 rafters 16oc with 3/4" osb sheathing. Pretty solid. 100% ice and water shield. With last years winter any indication of what might lie ahead I see no need to take chances. You only get one shot to do it right. You get to try over if you do it wrong!


Tim