How wide should my pad/framing actually be?

[VietGnome]

Hey all,

Planning a 30x40 stick build in Eastern Canada (DIY). When I originally designed my floor plan I made the walls 6.5" thick (2x6 frame, 1/2" sheathing , and 1/2" interior). When I finished my floor plan I did a layer of joists in SketchUp, so I knew the exact joist layout, could layout doors, etc.

Have a 2D floorplan, turning it into a 3D model, finished building 3D trusses, went to plop them ontop of the structure, and realized the 30' span overhangs 1/2" on both sides..

Due to my planning, the outer edges of my framing without sheathing dimensions are 29' 11" x 39' 11". Now I'm having the dilemma of how do I proceed?

Should I continue as is, on a 30x40 pad, and have the sheathing meet the edge of the pad and have it be flush for a 30x40 exterior measurement? Or should I have the stud to stud measurements be 30x40, on a 30x40 pad, have the framing flush with the edge of the pad, and the sheathing will stick out over the edge of the pad?

 

[NUTTSGT]

Personally, I would want a short stem wall, whether it's a poured wall incorporated into the slab or at least a course of block.

I would want my sheathing over that seam between the walls and foundation.

 

[BillK]

For what its worth my 24 x 24 has the framing at the edge of the pad and the sheathing and siding sticks out past it. Been that way for almost 40 years and has worked fine.

 

[VietGnome]

Personally, I would want a short stem wall, whether it's a poured wall incorporated into the slab or at least a course of block.

I would want my sheathing over that seam between the walls and foundation.

I've been somewhat debating this as well.

It's going to be a floating pad, I looked into a raised concrete edge, but I figured that's going to probsbly raise the price a fair amount on an already expensive pad.

I assume the cinderblocks would be cheaper, is there any risk/downside of using them over just a concrete edge?

Admittedly I was planning on just building on a flat pad, but if it's REALLY worth it to build a stem wall ill definitely consider it.

Edit: I assume you want the sheathing to overhang to mitigate moisture getting to the sill?

 

[OccupantRJ]

Milder climate here, but I would never place a wood building on a slab without some sort of stem wall or block of at least one course.
In fact here requirements last I added on are sidings 8 inches above ground, then I used pressure treated for the sill plate. The shop I have now was built on top of one row of 4” thick block before I came here. Before I covered interior walls I drilled through the sill plate into the pad and added extended wedge anchors every 3 feet or so for more stability and anchoring. On the 10x26 room I built on I anchored with threaded rod all the way from the pad up through the top plate every 4 feet, and added hurricane ties from the top plate to all the trusses. There are sometimes those light winds called hurricanes that like to tease us around here.

 

[NUTTSGT]

Like RJ mentioned, I would never place my stick right at slab level. Sure many do, but I wouldn't... Get the ground moisture, whether melting snow or dripping rain splashing away from the sill and sheathing.


I've done a course of block right at edge with no issue. I'd pin the block to the slab and core fill the block...mine, I would probably core fill every block. In the grand scheme of everything in the long run, it's not that much of an extra cost till fill all... especially if you have access to a concrete mixer.

 

[VietGnome]

Like RJ mentioned, I would never place my stick right at slab level. Sure many do, but I wouldn't... Get the ground moisture, whether melting snow or dripping rain splashing away from the sill and sheathing.


I've done a course of block right at edge with no issue. I'd pin the block to the slab and core fill the block...mine, I would probably core fill every block. In the grand scheme of everything in the long run, it's not that much of an extra cost till fill all... especially if you have access to a concrete mixer.

Thanks. You're kinda swaying me. With the amount of concrete I need for a 30x40 pad I think the extra to fill every block is negligible..

Now time to melt my mind in sketchup fixing the stud plan

 

[carcruse]

A layer of block (often called a stem wall or pony wall) is not strictly required by all building codes for a garage wall, but it is highly recommended and standard practice. A 1-course block foundation provides a sturdy base, elevates wood framing above ground moisture, and creates a durable, rot-resistant ledge for the slab to rest against.

 

[Stuart in MN]

A layer of block (often called a stem wall or pony wall) is not strictly required by all building codes for a garage wall, but it is highly recommended and standard practice. A 1-course block foundation provides a sturdy base, elevates wood framing above ground moisture, and creates a durable, rot-resistant ledge for the slab to rest against.

That's how my garage was built ~30 years ago.

 

[Codyboy]

Weird that different parts of the country have different building standards.
Ive never seen a course of block or raised concrete edge on a structure around here.
Slabs are typically built about 6 inches above grade. Meaning typically when it is formed up a 2x6 or 2x8 is used for the forms.

As far as the slab dimensions it depends. I would allow for the sheathing to overhang the slab.

 

[PCustoms]

Weird that different parts of the country have different building standards.
Ive never seen a course of block or raised concrete edge on a structure around here.

I'm guessing S.E. Texas doesn't deal with a lot of snow or wet ground...

 

[Codyboy]

I'm guessing S.E. Texas doesn't deal with a lot of snow or wet ground...

Yeah no snow but we have a lot of rain.
Splash or puddling is minimal if the grade is right and at least 12 inches of overhang/soffits.

ETA. Not sure where op is as no location is given.

 

[VietGnome]

Yeah no snow but we have a lot of rain.
Splash or puddling is minimal if the grade is right and at least 12 inches of overhang/soffits.

ETA. Not sure where op is as no location is given.

I said E. Canada.

I would think a bigger issue here is snow piling around the foundation?

 

[Codyboy]

I said E. Canada.

I would think a bigger issue here is snow piling around the foundation?

Ah, skipped right past that part.
How are other structures in the area constructed?
I would follow suit.

 

[VietGnome]

Ah, skipped right past that part.
How are other structures in the area constructed?
I would follow suit.

I live semi rural, so it's kind of all over the place. Lot's of old garages, permit-less builds, additions to old garages, etc. I don't think I've seen a garage around here on a course of CMU, but I haven't specifically been looking out for it. I've only seen my FILs on a stem wall, but I believe his is on a frost wall foundation. But if the difference is $500 in materials and some sweat on a $20k pad, then I won't question it lol

 

[OccupantRJ]

My brother in law is a masonry contractor. When he built a 24x24 materials storage behind his house he poured a footer, then laid a row of block, then another row of header block to act as a form for the concrete pour. After that set he laid a course of block as a stem wall for his building to sit on. It was quick for him to do that, saved form materials, and screeding the concrete was easy to level with the top of the block. It also tied the floor to the foundation. Frost line here is around 12”.

 

[BillK]

Weird that different parts of the country have different building standards.
Ive never seen a course of block or raised concrete edge on a structure around here.
Slabs are typically built about 6 inches above grade. Meaning typically when it is formed up a 2x6 or 2x8 is used for the forms.

As far as the slab dimensions it depends. I would allow for the sheathing to overhang the slab.

Same here and I am in Maryland. My slab is about 6" above ground level all the way around and the sill plate is right on the slab. No issues.

 

[NUTTSGT]

Since you are trying to learn and in the planning stage, let me throw this advice out there:

Don't make your slab bigger than what you need, thinking you'll incorporate a sidewalk, porch or apron into a single pour. I don't care what snake oil your contractor tries to sell you, you will get water intrusion under the wall. It might not happen right away but probably about the time any warranty (if given) expires.

 

[VietGnome]

Since you are trying to learn and in the planning stage, let me throw this advice out there:

Don't make your slab bigger than what you need, thinking you'll incorporate a sidewalk, porch or apron into a single pour. I don't care what snake oil your contractor tries to sell you, you will get water intrusion under the wall. It might not happen right away but probably about the time any warranty (if given) expires.

I appreciate it

I'm definitely not planning anything bigger than the slab. Driveway is gravel so I can grade up to the entrance with left overs from the base.
Side door will come onto the lawn, but that's fine by me until I figure out what I want to do about that next year.