How do I draw professional quality floorplans of houses?

January 24, 2017 8:07 PM

I'd like to learn how to draw professional quality scale floorplans of existing buildings. For example, the previous owners of our house had an addition made, and as part of that they had drawings of the entire house (not just the addition) done. I would like to learn how to do that myself.

In the past, I have somewhat successfully drawn plans like this through trial and error, lots of measuring, re-measuring, a few guesses, and some swearing. I run into conundrums like, "how do I measure/deal with this weird angle?" or "how thick is this wall that I can't directly measure because there's no exposed end?". Sometimes I'll be almost done and realize that some key measurement is off and nothing fits together right. And beyond all that, I'm absolutely sure that there are more accurate and more efficient ways to do it than I know. So I'd really like to learn how a pro does this.

But I don't even know what terms to use to search for books, videos, and so on. I tried "drafting" but that seems more about the pure drawing aspect, skipping the measurements and recordings thereof. I don't think it's really "architecture" (and that's too broad anyway).

So, what should I be searching for, and where should I be looking to get started on this?

By the way, when I say I want to make "professional quality" drawings, I'm emphatically not saying that I want to take this up as a career, or to avoid hiring a pro when I need one. I just like this kind of stuff as a hobby and use drawings for playing with interior design ideas and such. And I tend to go overboard with my hobbies, and want to learn the "best" and "right" way to do stuff even if it's overkill for my actual needs :)

posted by primethyme to Grab Bag (15 answers total)

You can get consumer grade versions of autocad, which is the software, for less than $100 at places like home depot. Then find a good book or online tutorial or community college class.
posted by fshgrl at 8:36 PM on January 24, 2017 [2 favorites]

Best answer: primethyme -

Getting a sequence of measurements to "close" is extremely difficult due to a combination of compounding errors in sequences of short measurements and the high likelihood that whatever you are measuring isn't perfectly square, but the drawing you are making of it likely will be.

A few tips:

- Make sure you are measuring in a consistent way (e.g. from face of wall to face of wall above any wainscot or tile)
- If you are using an automatic measuring tool, make sure you double check it at times. I've worked with some that use a laser to show where they think they are measuring, but actually use sound pulses to report a distance, and in some circumstances they are off by just enough that the dimension seems plausible, but is actually quite wrong.
- Usually (but not always) all interior walls in a house will be of the same construction and likewise with exterior walls. This rule of thumb changes for special cases (like plumbing in the wall or walls built in different renovations), but it is a good place to start.
- Make sure your measurement is taken with the tape pulled taught and level. I've seen errors compound just because of sloppiness in this regard.
- Keep your accuracy reasonable. Differences of 1/4" across a room are hard to consistently measure, 1/8" is extremely difficult.
- Take overall measurements whenever possible. Outside corner to outside corner of the building, for example. If you can get a complete circuit of outside measurements that 'close' you then have a good 'container for the rest of your drawing. The same can be done for rooms or sequences of rooms. Again, when going outside pay attention to how materials may cause the wall to have different thicknesses at different heights of the ground. Aim for consistency in what you measure. Double check with different layers if possible (like a concrete foundation with a clapboard siding framed wall above likely has a a consistent offset and you could measure the circuit at both levels and compare.)
- Likewise, take an overall measurement of a wall, in addition to the sequential measurement to each opening or feature in that wall.
- Doing high accuracy drawings of repeating details (like a window or door trim) using a scribe can help you reconcile some inconsistencies and may help you figure things out like actual wall thickness.
- Recognize that it is possible to start in one corner and carefully measure the perimeter of a room, sit down to draw it and discover that when carefully applied, the sequence results in two ends of a line that are an inch or two apart. This is just what happens if things aren't quite all square. Unfortunately, at this point what you do is a bit dependent on the intent for the drawings, but in general you will use added context (like trying to keep wall thicknesses the same along with the measurements of an adjacent room, but 'rectify' the error.

Bottom line, I work in architecture office and "lots of measuring, re-measuring, a few guesses, and some swearing." sounds like a pretty professional approach to me. (Go back and confirm/check the guesses).
posted by meinvt at 9:21 PM on January 24, 2017 [8 favorites]

Check out Sketchup. It's free and I find it relatively intuitive—orders of magnitude easier to learn and use than any autocad program I fiddled around with years ago.
posted by she's not there at 9:29 PM on January 24, 2017 [6 favorites]

If you want to do this manually, you want to learn drafting and perspective. A book will do, but I took a class in high school and it was tons of fun. I imagine you could find a class via community college or open courses (or youtube, skillshare). How to measure might come... not at the beginning; but I do feel I was taught in my class what you are wanting to learn. We learned to draw first, and then learned autocad and sketch up.
posted by jrobin276 at 2:00 AM on January 25, 2017

Draftsight is a cross-platform freeware/registerware admirably faithful clone/knock-off of AutoCAD without 3D features, published by one of the drafting industry leaders; quite similar to AutoCAD LT, but you don't have to pay for it. I rather doubt AutoCAD is the right software for you, really, but I wanted to point this out in response to the first comment.

As-built drawings for something as complex and difficult to measure/inspect/disassemble as a house are going to be a real challenge compared to doing design drawings for an identical future house. You may simply have to compromise the accuracy and detail of your drawings for it to be realistic goal; keep in mind the actual useful purposes of your drawings, and ask whether the features/precision that is so difficult to obtain would even really matter for that.

Knowledge of the residential construction industry's standards and practices would probably help you a good bit; a carpenter can guess a lot about what's inside your walls and precisely where with a high success rate. I can't help you much with that, though... I know a lot more about mechanical drafting.

Drafting as a hobby or a private individual is quite frustrating, at least for me as a person who trained in school on industry-standard full-featured softwares and then didn't pursue a real career in it: The stuff I want is astronomically out of my price range, whereas the stuff I can get all involve real drawbacks and compromises of my goals, all in different but near-equally frustrating ways. Usually I'd turn to open-source in that kind of situation, but IME it's not quite there yet.

Although, since it sounds like you may be primarily interested in 2D drawing, you may have significantly less pain in that regard than me. I could tolerate at least one or two of the open-source tools for 2D-only work, for example. And there are other free or cheap 2D options that don't entirely suck.

What does kinda suck is that 3D, while usually more of a gimmick in actual working drawings, is a pretty compelling gimmick, and you can leverage 3D capability to do a lot of real work too if you like, which is always very tempting and satisfying. Oh well.

Best of luck.
posted by teatime at 2:15 AM on January 25, 2017

Best answer: This is a good book for the drafting part of your task. Used at architectural design courses all over the world.

About the measuring, meinvt has some good advice. I think it would be smart to start with one room at a time, to learn the basics. All buildings move, all the time, so already directly after the construction, a building's measurements will have changed. After several years, it will be hard to make the measurements match up, because the building will be more or less skewed, depending on the method of construction. That is how it is meant to be. For this, diagonals are your primary source of alignment. Every time you measure the sides of a surface, you need to also measure the diagonals.
You will do well by dividing every space or form you measure up into surfaces. For each surface, have one sheet of squared paper for noting down the measurements. If there are surfaces within the surface (such as windows), you may want to have a main sheet with the overall measurements, and then extra sheets for each detail, depending on how far you want to go into that. When you have measured all the surfaces, you can construct your drawings, either on paper or in a drafting software. I agree sketch-up is easy to use and it may be fine for your purposes, but it is not ideal for measured drawings because it is essentially 3-d and as said, measuring is best done in 2-d. I usually teach students how to do it by hand first, so they get why things work the way they do before diving into auto cad. If you do this, you will need tracing paper, long rulers and triangles and not least a wide-reaching compass for finding the measuring points of every surface.
For each surface, you initially make one drawing, then later you can combine them. You decide on a scale that fits with your level of knowledge. You tape a large piece of trace to your desk. Then you decide on a fix-point from your sketch drawing (lower left hand corner, for instance). Now with your compass, you set of all the distances you know from this point. Then you draw a baseline from that point to the next point using a ruler or triangle. This should be were you have most faith the actual thing you are measuring is a straight line, which depends on the construction. From this point, you repeat the compass maneuver. Now you should have two places where two of the circles meet, these are your next fix-points, and you can connect them, using the ruler or triangle. With this outline in place, you can begin to add in the details, again using diagonals everywhere, even when you don't think you need them.
At last you will have a big messy drawing, and then you turn to the book I recommended as a style guide for the new drawing you will make by putting a new layer of trace on top of it and using different line weights for different materials and situations. Or you can use the sketch as the reference for an auto cad drawing (but again, try to do it manually first).
When you have measured all the spaces in your house, including doorways and windows, you can put them together into a whole plan and sections. The doorways and windows (divided up into surfaces) are your measurements of the thicknesses of the walls. And your facades are of course the external measurement.
Unless you have a very specific reason to do so, you will not need to draw the materials inside the walls, or the plumbing or wiring. You just leave walls and voids as white (or pink) spaces outlined with a heavy line.
posted by mumimor at 6:28 AM on January 25, 2017

Best answer: meinvt pretty much has it covered. Especially this:

Bottom line, I work in architecture office and "lots of measuring, re-measuring, a few guesses, and some swearing." sounds like a pretty professional approach to me. (Go back and confirm/check the guesses).

If I were measuring a house, this is how I’d do it:
-Exterior measurements, all the way around. Both overall and opening to opening. They won’t match up, due to rounding, tape sag, un-square corners, etc. But it’s a good starting point.

-Interior measurements , as long of runs as you can.

-Room by room measurements last. Don’t forget to place openings. Sometimes you can interpolate wall thicknesses by using distance from the edge of a door frame to the inside and outside corners as a reference.
posted by Kriesa at 7:31 AM on January 25, 2017

If you're just interested in the floorplan and not going 3d I would just learn inkscape. I've done a lot of scale plans where 1 px = 1 cm. I tend to measure entire walls to get the dimensions of the box corrent and then just measure the distances required to get the features in about the right place. For example if a wall has a window and a door I would only need the width of each item and the distance of any edge from the closest wall. That gets things close enough and makes a good picture. In Inkscape you can then scale the finished vector drawing to whatever size raster drawing you want when you export the rasterised image.
posted by koolkat at 7:35 AM on January 25, 2017

Oh, one other thing. Unless an angle is waaaaay off 90, just draw it as a right angle and fudge it. It will just screw things up if you try to accurately represent 89.4 degrees and draw the north and south walls of a room at different lengths. If the room looks like it's "supposed" to be square, it will save you a world of pain if you just draw it that way.
posted by Kriesa at 8:02 AM on January 25, 2017 [1 favorite]

With respect to minor discrepancies, you are probably trying to achieve "as designed" rather than "as built." Try to figure out the intent, and confirm with measurement. Any particular detail may have off a little since day one, and changed since then.
posted by SemiSalt at 9:19 AM on January 25, 2017

Best answer: I've used inkscape for 2D also. I suggest not doing 1 px=1" and just setting the units under File->document properties to inch or cm. On the other hand you can just do 2D just fine in sketchup.

For odd angles: avoid measuring angles. Say you have a room with four walls that has two 90 degree angle corners, an obtuse angle corner and an oblique angle corner. Measure the easy part of the room, then measure the length from the 90 degree corner to the obtuse angle corner and the other 90 degree corner to the oblique angle corner. Then draw those three walls, then draw the 4th wall at the angle. You are done and you didn't have to measure an angle. If you have a garden with curves, a similar technique can be used, just take more measurements and 'connect the dots'.
posted by bdc34 at 9:37 AM on January 25, 2017 [1 favorite]

If you just want to noodle around, Sweet Home 3D (yeah, terrible name), is super easy to use. Free.

When you're drawing walls, it'll tell you in realtime the length that you're drawing. You can also tell it how thick the walls are (which makes reconciling interior/exterior measurements easier).
posted by porpoise at 11:34 AM on January 25, 2017

Response by poster: Thanks all!

I should have mentioned this in the original post, but I do already use Sketchup for 3D stuff, and I've been using OmniGraffle for 2D. In the distant past I used Autocad for class and I'd probably use that now if it weren't for the price. But the combo of Omnigraffle and Sketchup is adequate so far. The hard part is the stuff around the measurements and notation. Thanks for the great advice on that!
posted by primethyme at 11:37 AM on January 25, 2017 [1 favorite]

Are you a student? AutoCAD can be had for free for 3 years if so. I'd never suggest AutoCAD to a casual user, but if you can already use it it's a good option.
posted by deadwax at 3:25 PM on January 25, 2017

There are some good pieces of advice above for how to do measurements, but I've measured out a bunch of houses and other types of buildings and I do want to echo that getting things spot on is basically impossible. If I measure a whole house with a tape and end up where one of my walls is 2" thicker than the others but everything else works as measured, that's an excuse for a party.
posted by LionIndex at 4:45 PM on January 25, 2017 [1 favorite]