Designing our framing

Things are moving along! With the trailer ordered, and our floor plan set, it’s time for us to figure out the framing details so we can get materials ordered. We have spent quite a bit of time weighing the pros and cons of wood vs. steel framing over the past several weeks. Throughout all of this, we have gone back and forth on which we planned to use. So here’s the pros and cons for each:

Why steel?

The good:

  1. It’s significantly lighter than wood – Stud-for-stud, steel framing weighs roughly 70% less than conventional wood framing (20 gauge 2×4 equivalent steel framing @ ~0.448 lbs/linear foot vs. kiln-dried 2×4 dimensional lumber @ ~1.3 lbs/linear foot). In terms of final house weight, steel framed homes can weigh roughly 30% less than a conventional wood framed home. And when you have a monster tiny house on wheels (THOW) as we do, steel framing can end up saving you thousands of pounds of weight. Our 4-axle trailer is rated for 28,000 pounds, and with the size home we are building, we probably would have been close to that limit with wood framing. With steel framing, we could save ourselves up to ~8,400 pounds. This will reduce the amount of gas needed to move it to its final resting place, and reduce the towing capacity requirements of whatever truck is going to move it. It will also help reduce our nervousness about being too close or over the trailer weight capacity by the time we finish building.
  2. It doesn’t warp – Have you ever spent time picking through lumber at a hardware store, looking for pieces that aren’t warped? When building with lumber, you need to make sure that your studs are straight, or you will end up with walls that bow out or lean. This is a non-issue with steel framing. Because the pieces are formed by machinery and are impervious to water, they are all perfectly straight every time, and will stay that way. No need to buy 15% extra material just to account for the warped pieces you will inevitably get and be unable to use for framing. (At least those can be used for other projects!)
  3. It’s fire, rot, and pest resistant – I think pretty much everyone has had some kind of experience dealing with pests or rot in their home. It’s a miserable experience. Fortunately, steel framing is completely pest and rot proof. There’s also the added benefit of being fire resistant. (However, it’s important to note that steel framing can still lose its strength and melt in a fire.) All of these come together to create a house structure that requires very little long-term maintenance.
  4. It’s recyclable – When doing a construction project, you will inevitably end up with leftover materials. (If you don’t, please share this magic with us!) Steel is 100% recyclable, so none of it will go to waste. It’s worth mentioning that you can certainly use up scrap wood from projects as well, but it’s not recyclable and requires more creativity, time, and/or a wood stove.

The bad:

  1. It’s more expensive than wood – We were originally ruling out steel framing because getting a pre-made steel frame kit was (understandably) significantly more expensive than DIY wood framing. However, when we started looking in to building our own steel frame and just purchasing the materials, things started to even out. However, steel framing materials are still slightly more expensive than wood (for example, a 12′ long 20 gauge 2×6 steel stud costs $9.98 at Lowe’s, compared to $9.28 for the same length of 2×6 dimensional lumber.) So yes, the steel framing costs a bit more, but when you consider that you don’t have to buy 15% extra to account for warped lumber that is not suitable for framing, it kind of evens out.
  2. It’s more involved to build with – You can’t just nail studs together when working with steel framing. Everything is either screwed, bolted, or riveted together, which gets very tedious. Steel framing also has a bit of a learning curve. Overall, the framing methods are (mostly) the same as with wood, but the connections and interplay between the studs, tracks, and other components (like cabinets, trim, and window and door frames) is a bit different, and takes some getting used to before things start going relatively quickly.
  3. There is a lot of conflicting information out there – As DIY owner-builders, we have been doing a lot of research to learn about the different methods we will use in our build (we are a scientist and an engineer, after all…), and one of the trickiest things we have found when it comes to steel framing is just figuring out what is safe and strong enough for THOW builds. This is less of an issue for wood framing, since those methods are very well known and documented. The issue we have found primarily revolves around what gauge of steel to use. We have found multiple examples of DIYers using 25 gauge steel (the kind of stuff you can easily get at Home Depot and other big box home improvement centers), but there is never any kind of follow up after the house is transported to show how it did under the winds and shaking that THOWs are exposed to on the road. From digging around on the websites of companies that provide professionally-made tiny house steel kit frames (FRAMECAD, Volstrukt), we can see that they use 20 gauge steel for theirs. Even more confusingly, professional steel construction organizations designate 20 gauge steel framing as non-load bearing, but construction codes for earthquake-prone regions like Los Angeles, California (USA) deem 20 gauge (33 mil) steel acceptable for load bearing walls. You can see why we have gone around in circles on this one. Ultimately, the fact that professional tiny house framing kit companies use 20 gauge steel and the Los Angeles building codes deem it acceptable for load-bearing walls made us feel comfortable with the idea of using 20 gauge steel for the exterior, load-bearing walls and 25 gauge steel for the interior (non load-bearing) walls.

Why wood?

Rather than repeating a long list, let’s just say this is the opposite of the pros and cons for steel we listed above. The biggest appeal to using conventional wood framing is how easy it is to find resources and learn the correct methods. Since wood framing is so common, it’s not difficult to find any resources or materials you need as you work through your build. This is less simple for steel framing.

The other big thing that is appealing with wood framing is how simple it makes the building process. You can easily nail studs to bottom plates and connect all your receptacle boxes, cabinets, shelving, trim, etc. without the need for any extra furring strips or the use of screws. We liked the simplicity of using wood for this reason. While steel framing is great in its own right, everything was just a LITTLE bit harder or more complicated with steel compared to wood. And over the course of the build, that adds up.

So what did we pick?

Ultimately, after going back and forth from wood to steel and steel to wood a couple times, we landed on using conventional wood framing. (But we still reserve the right to change our minds again on this one! 😂) Bet you thought we were going to say steel! To be fair, we wrote that steel pros and cons list when we were heavily in the pro-steel camp. But we have since been lured back to wood by its simplicity and ease of use.

Designing the framing layout

Once the floor plan was set, it was time to start figuring out where all the framing components will go. Eventually we will put this all into our full Sketchup model, but we found it to be easiest to first lay everything out by hand on graph paper. Since the long exterior side walls on our house are very similar, we started with the long wall with the entry door. We figured this would be the most complicated wall to lay out, and were pleasantly surprised with how (relatively) easy it was to put together. (Note: The image below is from one of our “maybe we’ll use steel framing” phases.)

We will be using a 16″ o.c. (on center) stud spacing to give additional strength to the frame for transport. We may eventually switch that to the advanced framing method of 24″ o.c. spacing, but since that requires 2×6 studs, it’s unlikely we will sacrifice the interior livable space in the house to go that route. Plus for now we feel more comfortable adding a few additional studs/weight to have that extra sense of security when the house is being transported.

For this build, we are trying to follow the 2018 International Residential Code (IRC) Appendix Q, which was recently added to specifically address tiny homes. Tiny house living can be a challenge, given its still-illegal or strongly in a grey area status in many areas. By building to the IRC code, we hope to help make things go more smoothly if we ever need to get our building formally approved by our future town/county of residence.

Now that we have settled on the floor plan and our framing material of choice (until the next time we get lured by the call of steel framing, that is…), it’s time to continue on to building our tiny house model in Sketchup! Stay tuned…

Summer 2020 update: Ha! Just kidding! When it finally came time to pull the trigger on our framing material order, our worries about weight won out and we went with steel! Keep reading the blog and check us out on Instagram to see how that went!

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