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WALL DIMENSIONING

127

This tread makes me smile. :) 

Feb 21, 18 5:27 pm  · 
 · 
GeoffL

Some things just get better - including, of course, the age-old builder vs. architect "playful" disagreements.  Master-builders (Architects) used to work shoulder-to-shoulder with the builders - and created very fine work. 

If we walk a mile in each others' shoes, and focus on the project, we'll have a little more fun and make more friends.  We ALL make mistakes once in a while. 

Mar 28, 18 4:26 pm  · 
 · 
BulgarBlogger

I don't get why you just don't measure to the actual wall substrate - ex. sheetrock? If you have your wall types setup correctly and have different wall types for different stud sizes (say your standard is wall type H and H1 is similar except you use 2 1/2" studs instead of 3 5/8") then measuring to the outside of the wall is perfectly ok. If you have a tile finish then that would be inboard of the dimension you give... 

Jun 6, 18 12:21 pm  · 
 · 
GeoffL

Every firm has their own special sauce they like to keep special. 

The only thing useful I would add is: if you don't dimension to the CL, then only dimension to one-side of the wall.  Save Life-Safety or ADA critical dims for the detail plans.

Jun 6, 18 1:23 pm  · 
 · 
OneLostArchitect

our office dims to finish faces.

Jun 7, 18 12:59 am  · 
 ·  1
apscoradiales

including face of ceramic tile on the wall?!!!

 · 
Wood Guy

Coincidentally, in an online builder's forum they are having the same discussion right now, and the prevailing opinion is that walls should be dimensioned to the face of stud, and that any architect who doesn't know that or understand why it would be important is an idiot. (With plenty of strong dissenting opinions, of course.) And on another online architects' forum, a similar discussion is going on, with the same range of opinions as here.

I may have already said this, but since the purpose of the plans is for the builder to be able to build, in the absence of a universal standard, shouldn't the builders' preference rule? As a designer and builder, I find dimensioning to the face of stud to be the best for new construction--when you're trying to frame in the mud and rain, having to also do math at every point increases the risk of a mistake. 

Jun 7, 18 6:47 am  · 
 · 
tintt

Got links? This all feels kinda petty but interesting.

 · 
Non Sequitur

Our office standard has always been C/L of stud with no complaints from GCs. They lay it out on the slab and get to work... but I don't do wood frame construction. Perhaps that's key? Also, it's always metric.

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SneakyPete

"the purpose of the plans is for the builder to be able to build"

I have worked with Architects who believe that the purpose of the plans is to illustrate a Design intent, not an instruction manual. This is why those Architects dimension to finish faces.

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Wood Guy

SneakyPete, in some cases I suppose I would agree. When doing a very detailed interior, for example. My experience is all wood-framed residential, so that's my frame of reference. When framing a house, a carpenter wants to know where to snap lines. Making them add or subtract 1 3/4" or 2 3/4" at every single wall is a PIA, in my experience. Even if it's easier for the person drawing, or if it makes the drawings look cleaner.

1  · 
Wood Guy

tintt, they are closed groups on Facebook, but you can ask to join. It was either Construction Pros or Contractor Lounge. I believe it was the first.

There are also older threads in The Entre Architect Community on FB, which I highly recommend if you're an architect. I got special approval (I'm a designer/builder) but generally they only let in architects, and it's a very positive and supportive group.

 · 
GeoffL

face of stud is the most logical and useful in the field.  But designers pulling a string in CAD are just selecting one side of PTN.  How do you resolve this with CAD / BIM?

Jun 7, 18 7:46 am  · 
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Non Sequitur

C/L of stud is the most logical.

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Almosthip7

How do you put a tape measure on the C/L of stud?

1  · 
Non Sequitur

I get the point behind face of stud, but my contractors always chalk up the C/L of wall track on the slab first. Been doing that for over 10y now. I won't dimension, for example, a counter lenght or exterior wall to C/L of stud. That's just silly.

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Wood Guy

As a former and still occasional carpenter, I strongly dislike centerline measurements. Why make me do math? Why is centerline more logical? Centerline looks cleaner on a drawing, that is the only reason architects like it, IMO.

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Non Sequitur

Wood Guy, yes, it makes drawings much cleaner since more than basic constructions notes often crowd the page, however, my GCs have no issues with it for general wall layouts. I would not dimensions from C/L for a door jamb for example. As a tangential point, using C/L of walls when laying out several units/offices, esp with revit, makes changing wall types easier during the CD phase.

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SneakyPete

Metal runners can be aligned to centerlines on the floor. No math required.

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atelier nobody

I prefer face of stud, too, for the same reason carpenters like it: tape, snap line, no math. On the other hand, I've never met a carpenter who can't add or subtract 1-3/4" in his head almost without conscious thought. The big exception to face of stud is where room square footages need to be broken out accurately (e.g. BOMA leasing requirements) - I've done projects where we dimensioned to face of stud for the CDs but I had to go in and add partition centerlines on a non-plotting layer to produce a required report to the CA Department of Education.

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Non Sequitur

not sure why this was necro'ed up, but I've recently completed my first ever set of construction docs with face of stud dimensions. In unrelated news, I've also just recently completed my first ever set of constructions docs using wood studs. Coincidence? Maybe. (editor: the 2nd part of the above claim is incorrect and the original story was modified to suit the intended narrative).

 · 
chigurh

face of stud, center line of steel, face of concrete walls, face of cmu walls, center line of concrete/cmu columns - occasionally that doesn't work so note accordingly where you shifted and why.  

Jun 7, 18 9:40 am  · 
 · 
apscoradiales

"...Wood Guy

As a former and still occasional carpenter, I strongly dislike centerline measurements. Why make me do math? Why is centerline more logical? Centerline looks cleaner on a drawing, that is the only reason architects like it, IMO...."

Centreline dims come from stud spacing, eg. 16", 24" o/c. Framers like centreline dims; they're used to that. If you change it, that fookes them up.

Jan 13, 21 4:12 pm  · 
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Wood Guy

What makes you think I wouldn't understand what a centerline measurement is??? The carpenters I know and have talked with, which includes being active on construction forums for over 20 years, tend to prefer measurements to the side of walls and not the center. It's not a big deal for anyone but having framed many houses and additions in cold, snow and rain, I try to make it easy on everyone, including myself.

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SneakyPete

WG, it does make things more complex when the juniors doing the dimensioning don't understand that, while dimensioning to face of (whatever), one needs to be consistent. I trust framers to know their shit, so I use face of finish when CLR is important and centerline otherwise, since then there's no chance architecty person #1 uses the right side and person #2 uses the left side and nobody at the PA or PM level checks it because who the fuck has time for redlines when the client slashed your budget and won't pay you add services to help them strip 10% of the cost out of the project you designed according to their original cost requirements?

Anyhow, it's not simple, just like everything. 

TL;DR: Be consistent and, if you have the time or whatever, make it easy on the contractor.

2  · 
Wood Guy

All good points. Also, I draft in ACAD LT which means dimensioning to centerlines requires an extra step. If it was automatic I'd be tempted to try it; I like clean drawings and know the builders will adapt. But for projects I build I don't care how the drawings look and I'll dimension to the face ;-)

1  · 
apscoradiales

"...Almosthip7

How do you put a tape measure on the C/L of stud?..."

Watch how framers do it. They lay the bottom plate on the floor, measure off and mark lines 16" o/c or 24" o/c on it, as the case may be, then they draw a X, then nail the studs on the X.

After that, they put the double plates for the top of the wall, nail them to the studs, and finally lift the wall into place. It actually makes sense.

They don't nail the bottom plate, and the top double plates, then fit the vertical studs between the two.

There could be a Youtube video around showing you how they do it.

Jan 13, 21 4:19 pm  · 
 · 
atelier nobody

Most prefer to snap their line to the face of stud, rather than the center, because the line can still be seen when the wall is lifted into place, so they can be certain the alignment is correct. So, when we dimension to the centerlines, they have to adjust where they snap their line by 1-3/4" (assuming 2x4 studs). They only have to make the adjustment for the first one in each direction, then they can just follow the dimensions for the rest, so it's not really too onerous as long as they're dealing with wood studs. It becomes a bigger problem with 3.625 steel studs or masonry walls, since the 1/2 measurement comes out to 16ths and not all tape measures on the market have 1/16 marks.

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Almosthip

Thanks aps....but I was being facetious

1  · 
apscoradiales

atelier nobody,

haven't seen it done that way, but anything is possible. Your wood studs are 1 3/4"? Ours are 1 1/2"...3 1/2", 5 1/2", 7 1/2", 9 1/2", 11 1/2".

Seen studs in older houses that are 1 5/8"...I think they changed the size a while back. Checked out lumber at Bauhaus (Europe's answer to Home Depot) in Europe that came from Canada - studs  are 50mm x 100mm!!! And they're straight as an arrow - not like here.

Jan 13, 21 5:32 pm  · 
 · 
atelier nobody

No, the studs are 3-1/2", half of which is 1-3/4" to get from the centerline to the face.

 · 
citizen

At the higher end, dimensions are 9-1/4" and 11-1/4". More fun variations to take into account.

 · 
curtkram

working on a project with a handfull of FR T 2x10s. the framer says he can't buy them. nobody has them in stock.

 · 
Wood Guy

In the US, 2x8s are 7 1/4". I have seen a lot of architects thinking they are 7 1/2".

2  · 
Non Sequitur

38x89mm solves this dilemma.

1  · 
citizen

I was in that group, WG. Is that change fairly recent? Or has that long been the case?

 · 
Wood Guy

Citizen, it's been the case since I started building things around 1990. It's not a commonly used size for platform framing so I have not seen a lot of older examples of 2x8s that aren't rough sawn. There could be regional variations as well.

1  · 
SneakyPete

I remember how hard it was to remember that it drops to 1/4" at 8x when I first learned it. I think that's why I remember it... I've NEVER understood why we don't just upsize green lumber so it kiln dries to real inches... (I also have never looked into it)

1  · 
atelier nobody

I'm pretty sure 7¼" goes back at least to the 50s.

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SneakyPete

Lotta things go back to the 50s that are better off leaving there. ;)

1  · 
atelier nobody

You mean like Boomers?

1  · 
Wood Guy

It's funny to me how much the nominal size varying from actual size bothers some people. Maybe because I've often worked with rough-sawn lumber that is close to the nominal dimension, it just makes sense to me that you would cut it at the nominal size and plane it to the dressed size.

 · 
SneakyPete

I was always told the kiln drying caused the shrinkage

 · 
Almosthip

I was in the pool!

3  · 
Wood Guy

They shrink a little from kiln drying but not that much. Freshly cut trees are around 50% water by weight, and they're kiln dried to about 20%. (They actually dry the boards more than that, then add moisture back so they don't get overly case hardened and warp.) But framing lumber species don't expand above the fiber saturation point, about 28%. Using a shrinkage formula, an 8" doug fir board going from saturation at 28% to "KD" at 20% will shrink 0.17" (or about half that across the grain, "quartersawn"). Eventually it will reach equilibrium moisture content, about 12% where I am. In that case the 8" board will shrink 0.34" from its fully saturated state. But they only dry the boards enough to slow fungal growth and mainly to reduce shipping costs.

1  · 
SneakyPete

Then FFS make it make sense with something other than 1/2" GWB! :D

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apscoradiales

"...curtkram

working on a project with a handfull of FR T 2x10s. the framer says he can't buy them. nobody has them in stock..."

Yeah, because they don't exist, unless you have them custom cut at a lumber place. He could probably get 1.5" x 9.5" or some variation thereof.

Jan 14, 21 2:55 pm  · 
 · 
apscoradiales

"...Non Sequitur

38x89mm solves this dilemma..."

In a way yes, but still stupid numbers harking back to 2"x4"'s.

Why not 50mm x 100mm like they do in Europe? What's even more contentious is the stud spacing; is it 16" o/c or 400mm or 405mm or 24" or 610mm or 600mm...hmmm!

BTW, the correct answer is 405mm and 610mm.

This leads to a further issue; is gwb 4'x8' or is it 1220mm x 2440 or is really 1200mm x 2400mm or 1000mm x 2000mm or 500mm x 1000mm as can be found in Europe or Middle East. Same with batt, and rigid insulations...what size are they really?!

The problem is the Americans - they need to abandon stupid "feet-and-inches" system (they hate calling it "Imperial", as far as they're concerned that was decided back in 1776), and move to a far more civilised metric system...;))))...! Not holding my breath, though. Perhaps now that Trump is gone, maybe they will go metric!!!!

Funny stuff, most bricklayers used to be European - metric system, but when they came to Canada they went to Imperial, so if you told them you wanted something 3 meters x 6 meters, they would look at you cross-eyed - you could see their brain trying to figure out how many feet-and-inches that is.

Jan 14, 21 3:10 pm  · 
 · 
Non Sequitur

is it not 1219x2438mm tho?

Just think it's too much to re-tool and retrain just to make things convenient by +\- 2mm.  I get more upset at staff drawing/writing out decimal mm (ie. 15.9mm) than them rounding up 2438 to 2440 but the important is always to draw design intent clearly, which means using intelligent numbers instead of just snapping the dims and going home.

We've currently in the process of banning our drafting staff from showing studs in the 1:10 details because no one knows how to show the correct studs in a corner, or a bulkhead, or a header, etc.



 · 
apscoradiales

Good question!

1  · 
Non Sequitur

Aps, see my edit. Cheers

1  · 
apscoradiales

Wood Frame Construction handbook shows corner conditions plus all the other things you find in frame construction, including span tables. It's put out by either CMHC or NRC or someone like that. Probably can google it.

No matter what we show on our drawings, guys on the site know it better, and will do it properly. They just laugh at our drawings, "wtf is this?".

 · 
Non Sequitur

Yes, I know those docs, but not everyone who touches the drawings do. The intent here is to minimize that reaction from the GC on site so I don't look like a fool when I show up for a review. Sure, they now how a corner goes in order to support the gyp, but we're also doing the same thing for membrane sequencing and firestop. On those last two, the guys and galls on site definitively don't all know how to do it.

1  · 
apscoradiales

"...On those last two, the guys and galls on site definitively don't all know how to do it...". VERY true! That's were inspections come in handy.

 · 
Non Sequitur

inspectors... as in city inspectors or independent 3rd party consultants? The city is getting better with the firestop stuff, but they are definitively not reviewing membranes.

2  · 
apscoradiales

Not the city inspectors. The architect, and the consultants; that's who I'm talking about. Never seen a city guy flag down badly installed air barrier, for example. Manufacturer reps many times do an excellent job in inspecting, and teaching the site guys as well as people in the office.

 · 
Non Sequitur

Got it. Yeah, I’m that site guy and I don’t like it when I’m on site reviewing something I did not draw or take part in documentation. I do set ground rules with the trades early on so they know to expect comments when they fuck up.

 · 
natematt

"No matter what we show on our drawings, guys on the site know it better, and will do it properly. They just laugh at our drawings, "wtf is this?"."

Disagree haha.... Framing is an example where this is often true. But not always. So many other trades are wildly inconsistent about this though. 

 · 
apscoradiales

that is true when it comes to residential construction (I'm thinking sub-division residential, not the high end custom homes) where practically anyone who can use a hammer is hired. Other construction sectors - commercial or institutional, for example, the work crew are an entirely different cup of tea. Remember, here you are dealing with many sub-trades who are trained to work in their own field. You will not find a waterproofing contractor there do the plumbing or install kitchen cabinets or do suspended t-bar ceilings, but you will see that kind of stuff in residential. Many of those subs are very good at what they do, and, as architects, we need to learn from them.

 · 
apscoradiales

Non Sequitur,

being laughed on the site is nothing really bad - we've all been through it. But, when you get a brick thrown at you, that's a whole different ball game. Never had it happen to me, but have heard about it.

Jan 14, 21 4:10 pm  · 
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Almosthip

I know a mechanical engineer that got kicked in the balls. He didnt even fall down. We call him "Ole Iron Nuts" now

1  · 
Almosthip

oh i forget to mention they were steel toed boots that connect with Ole Iron Nuts

 · 

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