Garage Proposal

[simple man]

I am talking to two builders concerning constructing a detached two car garage and I have a couple of questions regarding thier wall specs.


1. One builder is suggesting 2x6 on 24 inch centers and the other is 2x4 on 12 inch centers. Except for the ability to have more installation is the any structurial advantage between the two options?

2. Also, both builders are suggesting placing the pressure treated sill plate directly on the slab, with a vapor barrier. In previous construction I have seen the sill plate was attached to a concrete lip that was extended six or so inches above the slab. Is setting the sill plate directly on the slab adequate?

My concerns are based that previously I lived in Maryland and am now in North Carolina and am not sure how the building codes differ. My desire is to have a sound building not one that is built to minimum code.

Thanks for any comments including how you would spec the structure would be appreciated.

Rick

 

[jwhcars]

I prefer a stem wall. It puts the wood higher from the ground moisture , rain water & leaks less chance of wood rot and erosion. I like 2x6 on 12 inch center , may be over kill but it is a lot more stronger.

 

[RCman]

I too prefer a stem wall for the reasons above.
My new garage has 2x6s on 12"centers. It was just about $175 more for the 2x6 material than for 2x4s on 12" centers. No brainier.

How tall are your walls?

 

[rust buster]

I built mine with stem walls and 2x6s 16" OC. Just curious why you are suggesting 12 OC when it seems to me this would make insulation that much more difficult vs 16" OC. I don't argue that it would be stronger though.

 

[RCman]

I built mine with stem walls and 2x6s 16" OC. Just curious why you are suggesting 12 OC when it seems to me this would make insulation that much more difficult vs 16" OC. I don't argue that it would be stronger though.

In my case it was 10' walls with wind load. Also with my trusses on 24" centers I wanted each one to land on a stud below it. I wanted the strength, local code said I could have used 2x4s 24" on center. That was not going to happen.
Insy is easy, just get the 23" wide batts and split them down the middle.

 

[Cougar]

I built mine with stem walls and 2x6s 16" OC. Just curious why you are suggesting 12 OC when it seems to me this would make insulation that much more difficult vs 16" OC. I don't argue that it would be stronger though.

x2 on the 2 x 6 16" centers.

 

[simple man]

I too prefer a stem wall for the reasons above.
My new garage has 2x6s on 12"centers. It was just about $175 more for the 2x6 material than for 2x4s on 12" centers. No brainier.

How tall are your walls?

I should have mentioned this in my original post, the walls are 12'

Rick

 

[Falcon67]

I'd also vote 2x6 16" OC because of the difficulty finding insulation for 12" centers - and sometimes 24" OC. Almost all new construction is 16" OC with 8-9-10' walls common, so materials (OSB, insulation, dry wall, etc) are primary stock for those dimensions. Unless you spray it in (Big $$$$) insulation that is. You can do either a stem wall or plate on the slab - both work just fine. Stem wall just requires more foundation framing unless you use 8" block on a slab to build the wall base. If you do it on the slab, it's recommended that the slab be at least 6" above grade. If you were dry like we are here with maybe 20" rain/yr (if lucky) and have good drainage then you can get away with 4". I do walls on a slab because if I add a door or otherwise mod exterior walls without any foundation issues.

 

[kbs2244]

You can have a curb around the edge of a floating slab.
Most often 4 inch high.
It will cost more than a flat slab but will be less than a slab inside a wall.

 

[rsanter]

If your walls are 12' tall I would prefer to use the 2x6 construction.

As long as the foundation level is sufficient above ground level then you can put the walls direct onto the slab. However if you may want to ever wash out you garage you will want the walls on a stem wall to avoid the moisture issue

Bob

 

[bczygan]

Get the bid itemized with alternate prices for different options.
Use a sill seal and sealant under the treated sill plate. Put that on top a single course of decorative concrete block as a perimeter knee wall under your wood framed wall of 2x6's at 16"o.c.. Leave rebar sticking out of the slab to tie the knee wall into the slab (Or form and pour the knee wall. Use anchor bolts to anchor the sill plate to the knee wall.
A knee or stem wall keeps your wood structure above grade by 8" min. Good in snow areas and to keep water out. Another critical thing to watch is where they set finish floor level compared to surrounding finish grade. I like the slab to be 4 to 6" above finish grade minimum. And then I like that finish grade to slope down and away from the foundation sharply to get water quickly away from the structure. Builders like to save money here and leave the slab low because building the pad up to accomplish this costs more money.

 

[simple man]

Thanks for all the comments and suggestions.

Based on the comments I will probably go with the 2x6 on 16 inch centers.

I will have to talk to the builder about the stem wall.

However, my concern is that both of the builder seem to be inclined to build to the minimum standard, ie the minimum that code requires. When I mentioned the stem wall to the builders previously their response was why would I want to spend the extra money.

Rick

 

[Dick in Wisconsin]

When I mentioned the stem wall to the builders previously their response was why would I want to spend the extra money.

Your answer should be simple: Because its my money that is paying for it. Not yours. Not the government's. Mine.

I am always open to ideas and suggestions, especially from builders/contractors who do this all the time. But in the end ... its my money and I might have done a ton more thinking and reading on the GJF than the builder!

 

[rburke65]

I vote for the 2x6" 16" OC with your 12' walls. I just did the same thing this past summer.

 

[NUTTSGT]

I'd be building it with 2x6 walls 16" OC and that wouold be sitting on a concrete stem wall or 1 course of block.

 

[Zeke]

Like the others said above, the stem wall is a way to elevate the sole plate above the grade. You are able to wash out your garage without getting the lower walls wet. And, you don't have to build up the driveway to meet the slab. Because if the builder does place the sole plate directly on the slab, he essentially needs to place the slab 6-8" ABOVE the grade. Stem walls keep the framing high and dry.

 

[volaredon]

mine is 10' walls 2X4 construction 16" OC and right on the slab. If I were to do it again though I have had no probs with it as is I think if I were to change 1 thing it would have been 2X6 walls instead of 2X4 if I were to change 2 things it would have been to put in floor heat.
Everyone who has seen my garage tells me it is "over built" as it is now...
I see alot of garages that are only 24" OC.... stupid!
you say that one builder suggested 12" OC... yet you say that both want to go to "minimum standard" that, I would say is what you would have with 24" OC construction..
One thing that my help complained about, but I am glad I stuck with, is being 100% stick built no pre made trusses for me.. among other things even "storage trusses" take away way too much available storage space

 

[BillK]

Rick,
Where are you at in NC ? I have a customer/friend that retired and moved down there and he has a BEAUTIFUL garage. If he is close to you, you might want to talk with his builder just for another opinion.

 

[1921runabout]

I agree that 16" OC is common design. Most building material is designed to fit the 16" OC.

Orlando

 

[The Frisco Kid]

2x6 16" OC would be adequate IMO, but I'm not looking at what you have above the garage or wind loads.

 

[wedge40]

At a minimum, stem wall. This will help with varmints.

 

[Falcon67]

I'd put it flat on the slab with a sill seal or caulk. If I has sheetrock walls and washed mine out a lot - and I don't - I'd put in a baseboard with a bead of caulk on the bottom. Lots cheaper than a stem wall. And varmints get in a lot of places that aren't any where near the sole plate

PS - I do mop once in a while and have OSB walls unpainted. Doesn't bother them a bit.

 

[68 Bird]

Thanks for all the comments and suggestions.

Based on the comments I will probably go with the 2x6 on 16 inch centers.

I will have to talk to the builder about the stem wall.

However, my concern is that both of the builder seem to be inclined to build to the minimum standard, ie the minimum that code requires. When I mentioned the stem wall to the builders previously their response was why would I want to spend the extra money.

Rick

Good call on the 2x6 16" centers. Plenty strong. Your second comment is part of reason why I hire out as little as possible.

 

[matouse3]

If you are wanting a 12ft wall, have you tried pricing out having a stem wall installed, 2-3 bricks high? This would reduce your dimensional lumber costs for the 2x6's as you wouldn't need to purchase 12 footers and could get away with 10 or less depending on how high you went with the stem wall. Could save you a few bucks that you could put toward that stem wall.
Also, how are you going to finish the outside? A stem wall makes is much easier to terminate the siding and gives you some room above the dirt for protection from weed whackers, mowers, kids, etc. and damage to your siding.
I went with 3 rows of block, vapor barrier, treated lumber, standard lumber (double sill plate). I chose 6 inch wide block so that my inside wall wouldn't have that worthless 2 in ledge.

 

[Spudland_Dave]

Stem Wall...IMO Depends on a few things, for me, waste was a factor...both of my money and materials...
-My Money because Stem walls add alot to the price of the concrete AND I know of more floating slabs around then stem walled garages. Seems like Stem walled garages are for A) attached garages and B) where required by code.
-Materials...I wanted a 10' sidewall...that means either going with a 24" high stem wall with 8' Lumber on it which seemed kinda high and odd looking from the exterior or B, 12" Stem wall and 10' lumber cut to 9' long...whole lotta wasted wood. Same applies when it comes time to sheath it. With your 12' wall sitting on a floating slab, your looking at exactly 3 sheets high of sheathing...no cutting except for length...No wasted materials or wasted time.

16" OC for sure...the whole world is built around 16 OC. Things are easy to get & find...for example, you wont be able to flush mount a breaker panel in a 12" OC wall....if you were doing a house, I'd use the medicine cabinet as an example.

 

[RCman]

Stem Wall...IMO Depends on a few things, for me, waste was a factor...both of my money and materials...
-My Money because Stem walls add alot to the price of the concrete AND I know of more floating slabs around then stem walled garages. Seems like Stem walled garages are for A) attached garages and B) where required by code.
-Materials...I wanted a 10' sidewall...that means either going with a 24" high stem wall with 8' Lumber on it which seemed kinda high and odd looking from the exterior or B, 12" Stem wall and 10' lumber cut to 9' long...whole lotta wasted wood. Same applies when it comes time to sheath it. With your 12' wall sitting on a floating slab, your looking at exactly 3 sheets high of sheathing...no cutting except for length...No wasted materials or wasted time.

16" OC for sure...the whole world is built around 16 OC. Things are easy to get & find...for example, you wont be able to flush mount a breaker panel in a 12" OC wall....if you were doing a house, I'd use the medicine cabinet as an example.

Or just make your walls taller. I did this with my walls. A 8" stem wall, plus the sill, plus the 10' studs (which are just shy of 10' cause dimensional lumber this days is never on target), plus the top plate and that gives me just about an 11' wall. Add in my vaulted ceiling and I've got a 14'5" finish.

I like the 12" OC simply because when doing the rafters/trusses 24" OC every one lands on top a stud. Why can't you just box out the panel like you would a window or door and add a header? That's what I did, worked out really well. One does the same for a medicine cabinet during rough.

 

[Pudmunkie]

mine is 10' walls 2X4 construction 16" OC and right on the slab. If I were to do it again though I have had no probs with it as is I think if I were to change 1 thing it would have been 2X6 walls instead of 2X4 if I were to change 2 things it would have been to put in floor heat.
Everyone who has seen my garage tells me it is "over built" as it is now...
I see alot of garages that are only 24" OC.... stupid!
you say that one builder suggested 12" OC... yet you say that both want to go to "minimum standard" that, I would say is what you would have with 24" OC construction..
One thing that my help complained about, but I am glad I stuck with, is being 100% stick built no pre made trusses for me.. among other things even "storage trusses" take away way too much available storage space

My old 70s era home is 24 oc... I hate it!