Drafting Measurements in AutoCAD

This must be the most dumbest question that is probably asked on the forum, but I do need the answer to it. As school is not providing me the answer.

Say I am drawing a deck. Low deck, less then 2ft in height. Using 2x8 lumber for structure. 2x6 for floor boards, 4x4`s for posts, etc..

What size on the drawing would I draw the 2x8 for example? Would I use the actual 2x8 measurement or would I use the actual size of a 2x8 (2 1/2" x 7 1/4")?

Again its a little dumb of a question, but like I said school is not provding the answer. School is just saying "here is assingment, draw what is asked (either your own creation or reproduce an drawing) and hand it in". I would really like to know the asnwer for two reasons. (1) Clearity (2) I'm actually submitting drawing to my municipality to get a building permit for a deck and I would like to sumbit it done proper, I don't want the paper to come back with a bunch of red lines and one line being your measurements for your lumber are wrong.

Draw the actual size of the object and always 1:1 scale.

KC

I always use 1:1 scale.

To get this correct, if I am drawing a 2X8, I would draw it the exact measurement 1 1/2" x 7 1/4" x length?

I always use 1:1 scale.

 

To get this correct, if I am drawing a 2X8, I would draw it the exact measurement 2 1/2" x 7 1/4" x length?

Yes, however, I believe it's 1-1/2...

KC

Draw it at 1:1, exactly how it would be when it's finished. Bear in mind who the end user is and what they are looking for from your drawing. If you give you deck drawing to a carpenter and he assumes that all your timber planed (Beacuse this is what you want), but youv'e drawn it as sawn lumber, he will cut all the parts to your drawing dimensions, and then find they don't fit...

The place to show sawn and planed dimensions is in a cutting ticket, much as Kencaz has shown above.

And when you dimension the structure, show centre to centre measurements. That way the actual sizes are not significant.

Draw the lumber based on the actual sizes as you see them in the chart provided by kencaz. However, you call out the lumber just as you indicated i.e. - 2x8, 2x6, 4x4, etc.

Note: 2x6 = nominal or rough size. 1 1/2x 5 1/2 would be the "dressed" size (after material is removed via planing process).

I will just say what I say to everyone, be consequent and be clear. If you choose the nominal sizes, use them all over, and be clear that that is the dimensions that you are using.

Better be overly clear and have the builder say Doh! at you, than him building your house wrong.

Thanks guys for the posts.

I will be using the actual sizes for when I do my drawings from no on.

I will just say what I say to everyone, be consequent and be clear. If you choose the nominal sizes, use them all over, and be clear that that is the dimensions that you are using.

 

Better be overly clear and have the builder say Doh! at you, than him building your house wrong.

I agree with Tiger... If you work with a 100 different Architects, You will see 100 different ways to draw, dimension Etc... and everyone of them will tell you they are doing it the "CORRECT" way

...and if you ask the builder, nearly all of them will be wrong!

...and if you ask the builder, nearly all of them will be wrong!

Aint dat the truth

Thanks guys for the posts.

 

I will be using the actual sizes for when I do my drawings from no on.

I have drawn house plans for some of the major home builders in my area since 1971, and I have always drawn framing plans at actual lumber sizes and never had any architect expect any different. The walls are always dimensioned stud face to stud face as well. Only the framing carpenter cares where the studs and joists are. Everyone else just works with what they find to hack them full of wire, pipe, and duct passages, and hang sheetrock on them.

When you draw your deck, start the joist spacing at the first outside face of joist, dimension over to the nearest face of the second joist using the center line modulus, minus half the thickness of one joist. For example, at 16" o.c. your first dimension will be 15 1/4", and all the rest will be 16" from same face to same face. Lumber does not come with center lines and a framing carpenter will not use your dimensions if you dimension to the centers of joists. He or she will lay it out correctly, he will just igonore your numbers.

This stuff must fit together out in the field. Worry about the framing carpenters and not the architect, and please, do some research on proper framing techniques and requirements so you won't have to take a jar of vaseline with you to the permit office.

This stuff must fit together out in the field. Worry about the framing carpenters and not the architect, and please, do some research on proper framing techniques and requirements so you won't have to take a jar of vaseline with you to the permit office.

!! LOL !!

I think most of us agreed that lumber is drawn at actual and not nominal size. As for 16" same face to same face isn't that just like saying center to center? The measurement will be the same. Maybe the proper place to change our perspective is in the classroom where most architectural design/drafting courses teach center to center dimensioning.

Building requirements for some things, such as decks, can sometimes be found right at the local building department. If you're building a house you better know what code your state follows.

I think most of us agreed that lumber is drawn at actual and not nominal size. As for 16" same face to same face isn't that just like saying center to center? The measurement will be the same. Maybe the proper place to change our perspective is in the classroom where most architectural design/drafting courses teach center to center dimensioning.

 

Building requirements for some things, such as decks, can sometimes be found right at the local building department. If you're building a house you better know what code your state follows.

That's the whole point, for the measurement to be the same. But once again, framing lumber does not come with center line markings on them and given the quality of today's lumber, that is a good thing. You can also google up most county code requirements.

The framing carpenter will start at one outside surface, usualy the right front corner, and lay out the joists face to face no matter what you put on a drawing because he does not have a center line to use. In my first drafting class, in 1970, I was not taught how to dimension framing plans, and I was taught that walls were 4" thick. One year later at my first real world drafting job, I discovered what realy goes on out there.

Sucks having to live in the real world. Virtual reality is so much less confining.

...and if you ask the builder, nearly all of them will be wrong!

I've worked at Habitat for Humanity quite a bit, and as a mechanical engineer, I'm always out there trying to figure out why the pitch of the roof is what it is, and how to get that darn speed square to work. The lead guy there sees me thinking, trying to figure it out and says "you're an engineer, aren't you?" I admit to it, and he says "carpenters build it, engineers spend all day thinking about how to build it". And then when I cut the corner vinyl siding piece at the wrong angle where it went up to the soffit, we had another laugh... and then I spent the rest of the day thinking about why the angle didn't line up... I still don't know why that didn't work:lol:

I've worked at Habitat for Humanity quite a bit, and as a mechanical engineer, I'm always out there trying to figure out why the pitch of the roof is what it is, and how to get that darn speed square to work. The lead guy there sees me thinking, trying to figure it out and says "you're an engineer, aren't you?" I admit to it, and he says "carpenters build it, engineers spend all day thinking about how to build it". And then when I cut the corner vinyl siding piece at the wrong angle where it went up to the soffit, we had another laugh... and then I spent the rest of the day thinking about why the angle didn't line up... I still don't know why that didn't work:lol:

Well said... Had a similar experience try to cut stair stringers with a speed square! Nothing speedy about it when I'm using it.

My motto is: Measure twelve times and cut three. Am I doing it wrong?