Dimensions to sheathing

[SH_Canada]

hi,

 

I noticed that CA dimensions to the stud. In order to get the same dimensions for the foundation and the main floor CA offsets the sheathing such that it is proud of the foundation. (If you "build foundation" and then set the reference plan and zoom in you can see the sheathing is not on top of the foundation)

 

I realize it can also dimension to the finished wall, which would be the siding, but no one around here offsets the studs by both the sheathing and the siding

 

Framers around here align the sheathing to the outside of the foundation. So what this means is if the dimensions on the plan are stud to stud and match the foundation dimensions, then the framer has to "take out" 3/8" times 2 on an outside wall, and they need to take it from somewhere. I would assume they would take this out of the nearest room, or maybe at the end when they realize the dimensions do not match. This would be all fine and dandy as long as they did not take it out of a 5 by 8 bathroom, where the tub requires 60" to the framed wall. So is the framer knowledgeable enough to know, hey I need to take this 3/4" out of some other room?

 

Is this one of those things that no one actually states anywhere, but occurs everywhere, and framers are just cursing the designers, but not curse too much as they measure from the stud when they frame the wall? i.e. it would be easier for them to frame to whole inches for the most part, and simply leave the last room as it ends up being (assuming there is no bathroom problem)

 

I was thinking I have never seen plans where outside dimensions to the first inside wall are down to the 3/8". If people were to start dimensioning to the sheathing, it would then cause some pretty ugly dimensions

 

Thanks

 

 

 

[SNestor]

Modify your wall definition...

[SH_Canada]

thanks, is that what everyone(i.e. yourselves) does? because if everyone did, then at lease one room dimension would be into the eights to account for it. take the simple case of wanting the first room to be 10' stud to stud (9'11") finished.

 

would your outside dimension to the first stud show 3/8+5-1/2+10', which is 10'5-7/8"?

 

 

 

[joey_martin]

I have one builder that does their slabs to the outside of the sheathing. My wall set up for them is 3-1/2" stud, 7/16" OSB. 1/16" Houswrap, set the foundation to build to the housewrap. Exterior of a 50'w home is 49'-11". slab is automatically set for me to 50'-0". Easy as that. Don't get all wrapped up in all the 1/8" stuff.

[joey_martin]

1 hour ago, jasonN said:

So is the framer knowledgeable enough to know, hey I need to take this 3/4" out of some other room?

Not my concern. My dimensions are QC checked before getting to the framers. If the framer is scratching his head, he is the problem, not the plans.

[GeneDavis]

Foundations built to eighths and sixteenths are never gonna happen.

 

I know there are local practices, and this one's pretty dumb.

 

I want whole inches for outside dimensions, and framing to those building lines.

 

Describe the feature or benefit if aligning sheathing to foundation (which is always gonna be off line somewhere) and why you cannot do what's done most everywhere.

[SH_Canada]

8 minutes ago, GeneDavis said:

Foundations built to eighths and sixteenths are never gonna happen.

 

The foundation is typically to the foot or inch here

 

It is the framer which would have to do the math when he frames if one gives stud to stud dimensions which matched the foundation wall. as he would have to take out the 3/8s for each side when he frames the wall, if he aligns the sheathing to the foundation

 

Joey has the explicit solution which lines up nicely because he is using 7/16 sheathing:

"I have one builder that does their slabs to the outside of the sheathing. My wall set up for them is 3-1/2" stud, 7/16" OSB. 1/16" Houswrap, set the foundation to build to the housewrap. Exterior of a 50'w home is 49'-11"

 

we use 3/8s here. I suppose I could put the housewrap at an eight instead of a 16th and that would get me to the 1" overall reduction

 

So my next question is, does everyone specify this detail in their comments or via a CAD detail. i.e. how does the framer know for a 50' foundation if the main floor sheathing is proud or not proud of the foundation? and if you do show a CAD detail with it in alignment, are your dimensions matching this detail?

 

And if you do have the plans  as proud of the foundation, do you know if it actually gets framed that way? I suppose in theory it should not matter to the designer as it would not be executing per design, but if everyone is framing with the sheathing in alignment, I would almost think at some point the drawing dimensions would change to follow the framing convention. or maybe no one want to see the eights or dimensions different from foundation so everyone just "knows"

 

I'm curious to know what framers/designers do in different areas

 

[SNestor]

I don't see the problem really...

 

[SH_Canada]

sorry getting used to the notification bell and messages up top.

 

This is X6

[parkwest]

2 hours ago, jasonN said:

hi,

 

I noticed that CA dimensions to the stud. In order to get the same dimensions for the foundation and the main floor CA offsets the sheathing such that it is proud of the foundation. (If you "build foundation" and then set the reference plan and zoom in you can see the sheathing is not on top of the foundation)

 

I realize it can also dimension to the finished wall, which would be the siding, but no one around here offsets the studs by both the sheathing and the siding

 

Framers around here align the sheathing to the outside of the foundation. So what this means is if the dimensions on the plan are stud to stud and match the foundation dimensions, then the framer has to "take out" 3/8" times 2 on an outside wall, and they need to take it from somewhere. I would assume they would take this out of the nearest room, or maybe at the end when they realize the dimensions do not match. This would be all fine and dandy as long as they did not take it out of a 5 by 8 bathroom, where the tub requires 60" to the framed wall. So is the framer knowledgeable enough to know, hey I need to take this 3/4" out of some other room?

 

Is this one of those things that no one actually states anywhere, but occurs everywhere, and framers are just cursing the designers, but not curse too much as they measure from the stud when they frame the wall? i.e. it would be easier for them to frame to whole inches for the most part, and simply leave the last room as it ends up being (assuming there is no bathroom problem)

 

I was thinking I have never seen plans where outside dimensions to the first inside wall are down to the 3/8". If people were to start dimensioning to the sheathing, it would then cause some pretty ugly dimensions

 

Thanks

 

 

 

How do you isolate your sheathing from being in contact with the concrete foundation?  What keeps the sheathing from absorbing moisture from the concrete and eventually rotting?

[SH_Canada]

Sosnestor:

 

Your two "Adjustment" rooms show as 7-5-1/8 and 4-5-1/8. 

 

I'm wondering, is this what everyone does on their plans?

 

Thanks

 

 

 

[SH_Canada]

3 minutes ago, parkwest said:

How do you isolate your sheathing from being in contact with the concrete foundation?  What keeps the sheathing from absorbing moisture from the concrete and eventually rotting?

They run "ladders" below the bottom plate here. Rather ingenious idea to get a flat concrete wall

 

Ladders are comprised of 2x6 on edge which are put into the concrete forms for basement walls. for 8" concrete wall, actual concete for last 5.5" is only 5" wide. think of it as ICF as the last block, but wood

 

But in thinking about it, even if there were not ladders,  I think they keep the sheeting off the bottom so the 8' sheathing will cover more of the top top plate as typically here a 8' wall is studded to 97-1/8

[parkwest]

Just now, jasonN said:

They run "ladders" below the bottom plate here. Rather ingenious idea to get a flat concrete wall

Can you post that wall detail, please?

[SH_Canada]

15 minutes ago, parkwest said:

Can you post that wall detail, please?

here is a picture of my garage wall looking down, where I have about 15" of the concrete wall coming out of the ground. you can see the 2x6 on edge

 

As well here they put a membrane beneath the sill plate for moisture

[GeneDavis]

Is this the "ladder," i.e. embedded pressure treated 2x6s?  Lotta lumber.

 

Where is finished grade?  

[SH_Canada]

11 minutes ago, GeneDavis said:

Is this the "ladder," i.e. embedded pressure treated 2x6s?  Lotta lumber.

close instead of side by side one is inside, one is outside. 5" of concrete in the middle

 

Its also not pressure treated, just regular 2x6. Which is interesting when you think about it. Apparently it is an "Alberta" thing. A cribber from Ontario told me they dont do it like that there.

 

but it does make for a nice even finish when the cribbers are done

 

 

 

 

[SH_Canada]

sill plate "gasket" for moisture:

https://www.rona.ca/en/sill-plate-gasket-5-1-2-x-75-white-35475079

[SH_Canada]

9 minutes ago, GeneDavis said:

Where is finished grade?  

finished grade is typically at least one foot below the bottom of the 2x6.

 

The basement top of concrete wall is typically then at least 17" above grade. The reason is snow here. We try and keep snow away form the wood.

 

So if you are doing some math, we typically always have at least three risers here for front steps

 

[kMoquin]

The convention here (northeast US) is to align framing and foundation with the sheathing and siding overhanging.

[robdyck]

2 hours ago, jasonN said:

So my next question is, does everyone specify this detail in their comments or via a CAD detail. i.e. how does the framer know for a 50' foundation if the main floor sheathing is proud or not proud of the foundation? and if you do show a CAD detail with it in alignment, are your dimensions matching this detail?

This is best to note near the beginning of a plan set in your general notes. In Medicine Hat for example, no one frames to the sheathing, but go an hour north, and no one seems to have ever heard of measuring to the stud. So, when I know the regional preference, I make sure to note this in my General Notes.

[SH_Canada]

33 minutes ago, kMoquin said:

The convention here (northeast US) is to align framing and foundation with the sheathing and siding overhanging.

that from what I can tell is the cleanest solution. I actually went around and checked here, and was surprised to see they were not overlapping. Which is why I started thinking about it. Not that I have seen a lot of other plans, but I've never seen dimensions on plans to the eight for the first or last wall in the room that I can remember. So I'm pretty sure the framer "just knows" to take it off "a" room, just not a bathroom

[SH_Canada]

23 minutes ago, robdyck said:

This is best to note near the beginning of a plan set in your general notes. In Medicine Hat for example, no one frames to the sheathing, but go an hour north, and no one seems to have ever heard of measuring to the stud. So, when I know the regional preference, I make sure to note this in my General Notes.

 

I assume then you are dimensioning to the stud for both,   and the stud dimensions equal the foundation, so that the dimensions are cleaner, then in your general notes you indicate it is to the stud? I'm curious do you also note that if they are aligning the sheathing to the foundation, that the framer should take it out of any room but the bathroom?

 

Or do you actually change your dimensioning and general notes between the two scenarios?

 

 

[GeneDavis]

Somebody tell us why the sheathing should sit on and have its face flush to a foundation.  This does not seem like a good practice, particularly in this current age of rainscreen walls.

[LevisL]

40 minutes ago, robdyck said:

This is best to note near the beginning of a plan set in your general notes. In Medicine Hat for example, no one frames to the sheathing, but go an hour north, and no one seems to have ever heard of measuring to the stud. So, when I know the regional preference, I make sure to note this in my General Notes.

 

I do the same. General note. When I worked in Edmonton, it was very common to frame with the sheathing flush to the foundation, but up here in the Peace Country, it varies. I always dimension to the studs and let the framers figure it out. Hopefully they're smart enough to know not to take the 3/8" out of a bathroom (if they choose to frame that way)!

 

The one thing I found you have to watch for... the truss designers will sometimes assume the sheathing will be flush and they subtract 3/4" from the truss span...

[robdyck]

Just now, LevisL said:

Hopefully they're smart enough to know not to take the 3/8" out of a bathroom!

 

The one thing I found you have to watch for... the truss designers will sometimes assume the sheathing will be flush and they subtract 3/4" from the truss span..

These are the 2 main areas that become affected. I grew up building in a region where everything was dimensioned to the sheathing, but then spent 20 years framing in a region where it was always to the stud. 

The long & short of it is this....If you switched from sheathing to stud, you'd wonder how you could have been so stupid in the past. If you switched from stud to sheathing, you'd wonder why you're doing something so stupid now.