A Readers Question

You seem to be the only site I can find that has built tiny houses out of metal but there is conflicting information on the internet as to the benefits of using wood versus metal so could you please give me your take on it. Some are saying the metal is to flimsy and screws back out.

I’m trying to learn. My goal is to combine a tiny house with a minimal roof pitch for more sleeping area and a mobile diabetic bakery. I would appreciate any information.

Thank you

Hi,

There are not many people that use steel in homes, let alone tiny homes. I do remember seeing Tortoise Shell Homes of southern California using steel in some of their homes. We are unique as we use predominately steel as we build for a lot of people with chemical and environmental sensitivities, which means using a hardwood or steel. I have been a carpenter that specialized in wood frame homes for 30+ years, so steel was something new to me. But when the costs from hardwood to steel were compared, the buyer decided to use steel. Steel weighs in at 1.09lbs per lineal foot, while a typical hardwood 2×4 material weighed in at 2.73 lbs per lineal foot.  As you can see, steel was substantially less in weight, or the hardwood studs would weigh double what a steel stud weighs.

 

Welded Tiny House Frame

Welded Tiny House Frame

Then there is the price difference. Hardwood 2×4 ash material costs $1.42 per lineal foot, while steel costs $0.88 per lineal foot.

The steel used in tiny homes can be confused easily with steel seen in the local box stores, such as Lowes or Home Depot. That steel is usually flimsy and rated at a 25 gauge. Screws used to connect this type have limited holding power and will loosen over time, especially if used in a mobile unit that is subject to vibration.  To obtain the steel we use, requires a commercial source such as a large drywall supplier of sheetrock and related materials for commercial buildings such as offices, high rises, and large condominiums.

The weight difference I described above was for the structural steel we use in our tiny houses. Tortoise Shell Homes uses the same gauge (thickness) as we do. We use a 16 gauge for the floor system and 18 gauge for wall and roof structure.  Since we also weld all the connection, the steel gauge must be 18 or better, as any higher gauge, a welder will burn through the pieces rather than bond the pieces together. Once the frame is welded, the screws can be removed, as they are not really necessary to hold the structure together. The welds also serve as a bracing as bond the entire joint together which greater increases structural integrity of the tiny house.

In a wood framed tiny house, screws do loosen up, nails do loosen up and pop, as the material is always drying out and adjusting to the air and humidity around it; steel it does not absorb moisture, thus it stable.

Some of the quick advantages of steel ; termite proof, fire proof, earth quake tested, lower insurance premiums,  steel is “true”, tensile strength,  healthy, sustainable,  and design flexible. We can do things with steel that a carpenter wished he could do with wood.

Finally, we like sleeping at night, and that requires a healthy confidence in what the company does. The Spruce Goose made by Howard Hughes only flew once, yet the airplanes that we see now fly countless miles with nary a structural failure. The tiny house that is mobile meets a lot of the same forces and “G’s” that a plane encounters, so it just seems common sense to build them in a similar way with similar products.

Now, steel does have one drawback from wood. With steel framing, a thermal break is needed to reduce the transfer of cold or heat to interior surface of the steel; if steel is cold on the outside of the wall, it will be cold on the living side of that steel studs/plates. Installing a thermal break of ½” foam in the outside of the wall makes a big difference in heating/cooling.

Thanks for the inquiry

Jim

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