Make It Modular: Sustainable and Affordable Home Design

In the 2022 Make It Modular: Student Design Challenge, students are asked to reimagine a volumetric module and turn it into a usable space. For my entry, I transformed the module into an affordable living space. My name is Morgan, I am in 11th grade and currently enrolled in the Central Academy of Technology and Arts.

When first brainstorming for this project, I decided I wanted to approach my module’s design as realistically as possible. The 3D model provided is of a shipping container that is 20' long x 8' wide x 9'6” tall. When designing a home, a few things need to be taken into consideration:

• The insulation and outside look.
• Water.
• Heating/Cooling.
• Flooring.
• Roofing. 

For this challenge, I aim to address the features mentioned above in my design. 

General

• Fusion360
• Inventor
• An engineering notebook, graphing paper, or scratch paper.
• Pens, pencils, etc...

House Components (Rough List)

Insulation, Outside, Foundation, Roof, and Floor:

• Rigid R-Tech Insulation
• 2 x 4 Studs
• Cedar Planks
• Nails + Nail Gun
• OSB 7/16"
• Vinyl Flooring
• Concrete
• 8" CMU
• XPS 2" Thick
• Roof Shingles
• Doors
• Windows

Inside:

• Twin XL Mattress
• Cabinets (Floor + Wall)
• Oven
• Fridge
• Stainless Steel Sink
• Toilet
• Shower
• Trim Board

Extra Furnishings:

• Table
• Chairs
• Additional Shelves
• Towel Rings/Bars
• Toilet Paper Holder

Preface

Before I start any project, I love to do concept drawings and sketches of my design in my engineering notebook. For anyone interested in engineering, I also recommend you get one for jotting down your ideas and listing measurements! These are just here for display if anyone is interested in seeing my long thought process before I started the actual modeling. I drew out a few different versions of this container home before beginning. Some of them worked and didn't feel like the best option, and some didn't work at all!

A lot of design work is simply trial and error, research, feeling stumped, and changing little things over time. My best advice to anyone tackling a modeling project is to be patient... some parts of my model were redone 3-5 times.

Important Knowledge

This Instructable requires some basic understanding of Inventor design software. Before you start, make sure you understand how to use the sketch, extrusion, fillet, chamfer, and measure tools.

The sketch tool allows one to draw on a 2D plane (think length and width), and the extrusion tool allows you to turn that sketch into a 3D design by adding an object height (turning a square into a cube). The extrusion tool can also be reversed to cut down material. Fillet and chamfer change the edges of an object: fillet rounds edges, chamfer cuts them down. The measure tool allows you to pick two different edges, points, or faces, and displays the distance between them.

With a quick google search, I’ve found that shipping containers are typically 0.75-1” thick and the walls are made of Corten steel. Corten steel is meant to be heat and rust-resistant. That being said, if one wanted to live in a shipping container, the walls wouldn’t be insulated enough. House insulation assists in limiting temperature fluctuations in a given space. In other words, insulation keeps heat inside during the winter and keeps your cool air conditioning from escaping in the summer. To make a shipping container habitable, proper insulation is a must. Furthermore, a sealant (for example, Everbrite) can be applied to Corten steel to protect it further.

Walls

The inside of the module is small, so insulation on the inside may not be best in terms of available space. Outside insulation would help insulate the container while still saving the precious space inside the module. Because I aim to make this as realistic and replicable as possible, I did some research on how to approach insulating shipping containers on YouTube. The best example of exterior insulation for a shipping container is done by Containing Luxury. Wooden studs can fit within the corrugated walls of the module and rigid insulation can be nailed to them. Additionally, horizontal cedar planks can be nailed to the insulation. If you wanted to take it a step further, you could potentially paint or stain the cedar to give it a nicer look. Additionally, any house corners or cracks that are hard to reach can be packed with spray insulation!

Earlier this year, I did a project that required me to learn a lot about housing and design. “R-value” describes the ability of a material to insulate and prevent heat flow. The insulation I chose has an R-value of 7.7 (I chose 2" rigid R-Tech insulation), plus the R-value of the 2x4 studs (3.5" thick - 4.4), and the cedar planks (1" thick - 1.41). This gives us a total R-value of ~13.51 for the walls.

Floors & Roof

To ensure that heat isn’t lost from the bottom or top of the shipping container, the floor and roof have to be insulated. Starting with the floor, a similar framework can be built with wooden beams attached to the floor horizontally. Between the beams, more rigid insulation can be packed in. Sheets of plywood (OSB 7/16") can be added to cover the insulation and framing, creating a solid surface for additional flooring. Vinyl flooring can be added to create a nice finished look.

Using the same calculation method, the R-value of the floor will be ~8.25 and ~4.95 at the stud location.

Spray insulation will be used on the inner side of the roof. Tiger Foam’s E84 Closed Cell formula has an R-value of 7/in. It will be sprayed on about 6” thick, giving us an R-value of 42.

Foundation

Concrete reinforced with XPS will be used in the foundation of the house to help further insulate the floor. 2 in thick XPS gives an R-value of 10, two layers is 20. The foundation will be made out of 8” CMU (Concrete masonry unit) and have an R-value of 1.11

Although this may seem a little overwhelming to anyone who hasn't calculated R-values before, a lot of information on it can be found on it online and it is easy to get the hang of. Again, insulation is very important to residents! Builders want to strive to create a space that can easily retain the hot or cold air produced by heating/cooling systems. Having a well-insulated space is beneficial for residents as well as less money has to be spent to heat/cool their home.

That being said, let's move on to the actual model of the house!

I decided on creating a single person shipping container home. While combining multiple containers would make designing the floor plan a little easier; I wanted to go for a more "tiny house" inspired model. With such little space, good space management is key.

Although I was first going to use the model provided to us, I have some difficulties with the model in Inventor. Inventor is personally my preferred Autodesk program, so I decided to start from scratch there. I started off by taking the dimensions of the shipping container and taking off two inches to account for the wall's corrugation. The floor plan is based on the usable space of a shipping container. I tried to keep the model as realistic as possible and tried to use the measurements of actual home products while maximizing space.

Please note that the inside of exterior walls are also corrugated but not depicted as such in the model for time's sake. A material such as plywood can cover the corrugated walls without offsetting the rest of the house's dimensions and appliance placements by too much (if replicated). Wall and door trim can also be added to spruce up the walls a bit more.

Construction

For this portion, I linked the products that inspired the model designs I created. Most of these additions aren't completely like the real-life product, but are very similar. Rather than going with already made furniture models online, I build these from scratch.

To start off, I created one inner wall to separate the bathroom from the rest of the house, a base for the bed, and bases for the cabinets. The cabinets are 24" off the wall and 21" wide (1.75 '). Drywall is about 4" thick, so I created the wall accordingly.

Next, I extruded the base of the floor cabinets up 36 inches. You will also have to add an inch thick counter top that hangs over the cabinets themselves by an inch. The fridge is 2.385' off the wall, 2' wide, and 5' tall. The stove is the same measurements as the cabinets, minus the counters on top. The cabinets on the walls are 21" x 30" x 12". And finally, the sink is about 21" wide and 20" long.

The kitchen has a stove, fridge, sink, and multiple cabinets (wall and base).

Side Note: I made the decision to leave the bathroom without a sink. While this seems like an odd decision, the kitchen and bathroom are right next door and there is limited space in the unit. Rather than putting another sink in the bathroom, that space can be used to put a towel rack or other storage containers.

The bathroom should be 3.5' wide. The toilet is about 25" long, the bowl is 15" wide (and same with the toilet's tank). The shower was modeled after this product. Looking back over this model, it would be better to place a rectangular shower against the wall to save space, like this. However, the door can still swing open fine from the right, as seen in one of the pictures I took to test this.

The bed is a combination of a dresser and other storage containers. Directly under the mattress is four drawers for storing folded clothes and other personal belongings. To the left of the bed, there are vertical cabinets that could potentially contain clothing racks, shelves, or other storage bins. There are also shelves attached to the outside of the vertical cabinets, facing towards the bed. These shelves don't have to be exact and more of them can be installed on that surface or on the walls surrounding the bed. This full unit is 3.16 feet wide and extends the length of the container. The vertical cabinet itself is only 1.341' long and has the same width.

The exterior front door is 2.66' wide, 6.66' tall. The interior is the same height but exactly 2.5' wide.

Although the rounded features of the house may look daunting, I can assure you they aren't that difficult to replicate. For the sink's faucet, you can start with rectangular shapes only and go back with the fillet tool to round out any hard edges. I applied this strategy to other parts of the sink as well!

The first model I did was of a cross-sectional view of the house. One side wall is intentionally left off to help viewers see inside the house easier. I wanted to point out that I didn't include the external insulation in the final model but did add the cedar siding. One can assume that the external insulation would be put in place if the build was actually replicated. The insulation wouldn't interfere with the space inside the house as it is external rather than internal.

Methodology

The way I modeled this house in Inventor mimics two different methods of creating a final product in manufacturing. Additive manufacturing is when a product is created by gradually building up layers. While additive manufacturing usually refers to 3D printing, I had to build from the ground up and add different features as I went along in Inventor. For example, the countertops were on a different layer and had to be build after making the actual cabinets. Subtractive manufacturing is when material is subtracted to create a final product. To make the sink, I had to subtract material from the center to create the sink's basin. While you are modeling, it is important to realize that there are always multiple ways to solve a problem. If one method doesn't work, try another one.

Once I completed the Inventor model, I had to make some decisions on the style and overall appearance of the container home. I wanted to give the home a modern but rustic look. I figured out six different color palettes and after some quick test drawings, I decided on number 3 for the final appearance of the house. Matching and trying out different colors is a great way to narrow down the final look you want for your house... or any other project for that matter. Looking at already existing houses is a great way to start this process. After gathering some inspiration, I used Krita, a free art program, to make a little palette sheet for my project (I also used it to make the insulation diagram!).

Lastly, I transported the part file to Fusion to create the final renders.

Appearances

In Fusion 360, I added different colors and textures to every face in the house. This can be done by locating the appearances tool or just pressing "a" on your keyboard. The materials available in the library were sufficient for me though some of them will need to be downloaded to use. This step is a little tedious but you can also edit materials appearances in Inventor beforehand.

Some notes/tips for this step:

• I used different kinds of wood for the flooring and door.
• Brass and steel can be used for doorknobs, sinks, and other metallic items.
• I used a glass with a slightly blue tint, but this probably wouldn't be used in a real-life application.
• Consider using a different material behind the kitchen sink. This would represent/act as a backsplash.
• Don't be afraid to try odd materials to get the look you are going for!
• Most importantly, have fun... you are nearly finished!

Rendering

To start rendering, open Fusion 360 and your model, click "design" to reveal a drop-down menu, then click the "render" tab. The second icon controls the presentation and background image of the model. The rendering settings are to the right of the "setup" section, by clicking the first icon for the "in-canvas" render tool, the program will begin to render your model. The longer you wait, the better quality your model be as you can see the rendering progress bar on in the bottom right corner of the screen. From here, you can chose to capture the image as-is or use the actual render icon (it's a teapot!).

After editing the appearances, rendered the model and chose a couple different background photos. Rather than using only default backgrounds, I used PolyHaven to find some HDRIs free for public download! Switching up the background is a nice way to present your model in a new way! As seen in the pictures, I tried out different kinds of background lighting along with different interior wall colors. After downloading an HDRI you like, try selecting the file and applying it as a backdrop. These files come with their own lighting and environmental settings. This is an amazing way to make your model really "pop" and give its presentation some attitude! If you are newer at working with Fusion, don't be afraid to utilize the backdrops already provided.

This step includes taking the first model and adding the fourth wall. For this side of the house, I added a window and a sliding patio door. The sliding patio door is 71" by 82" (see "overall unit dimensions", similar to this). A small table and chair would have a nice place in front of the stationary glass panel, but the space here is left open for creators to decide!

After that, I decided to go for the roof! To keep the roof simple, I stuck with a basic slanted roof with a 1:4 pitch and an approximately 6 inch overhang. To add an accent color, another material could be added where the cedar planks end on the container walls.

This part of modeling doesn't require many specifics and I used the top of the shipping container as a guide. Once all the changes were made, I transported it into Fusion 360 to render as well.

Digital Drawings

Here I turned the model into a .DWG file in the Inventor DWG program. I used three projected views of the home and included the isometric view as well. The top view of the house is the equivalent to a real-world floor plan, while the front and right represent the house's elevation plans. If you want to go the further mile, the DWG program has a dimensioning tool that you can use to fully dimension your model.

One of the goals I set for this project was to make it eco-friendly and have it give back to the environment in some way.

Below I listed some interesting ways to do this...I modeled two of these ideas in the image above!

• Adding rain barrels to the sides of the house can collect roof runoff. This water can be used to water a garden or any other household plants.
• Going off of the previous point, making a garden (I created raised garden beds)!
• Attaching birdhouses to one of the house's outside walls. As you can imagine, this is just a small way to provide shelter to nearby wildlife!
• Adding hummingbird feeders around your house.

Little features such as these can positively impact wildlife and even spruce up the exterior of your home!

Energy

A unit of this size could easily benefit from a solar or wind-powered energy source. From my research, I have found that Ductless Mini-Split Air Conditioners work best in tiny homes and small spaces. They also don't make up much space themselves. Since this model has a lot of space on the exterior, there wouldn't be an issue in finding space for one to go.

Rain Barrels and Water Treatment

Although this portion is mainly about saving water through a rain collection system (rain barrels), I decided to refer to an old housing project I did to provide information about wastewater treatment.

Water that runs through your sinks, washing machines, bathtubs, and showers can be reused and is called "greywater". Greywater can be cleaned with a special filter system and used to water large gardens or recycled as water for flushing toilets. This system efficiently saves water and repurposes it. But, how much water do rain barrels save?

According to pccd.org, “Approximately 550 gallons of rainwater can be collected for every 1000 square feet of collection surface per inch of rain." The US gets about 30 inches of rain on average in a year.

By using the Inventor measurement tool, I found my modeled roof was a total of 202.25 sq.ft. Taking that number, we can divide it by 1000, then multiply it by 550, and 30” to get the final value of rainwater collected in a year.

The roof of this house can collect up to 3,337 gallons of rainwater a year.

This is a small virtual tour that I made to go along with this Instructable.

Fusion 360's animation tab has a camera that you can guide and move around to create your own "tour". Once I had finished working on the camera movements, I downloaded the animation (using "publish") and imported it to DaVinci Resolve to edit. From there I just added some background music, text, and title screens to make the presentation look a bit more professional. Both videos contain two separate models I created for this project.

Exploring Community Options

One of the other design challenges students were asked to consider was designing a structure that can be repurposed. Shipping containers are great because they themselves are separate modules. After being worked on, these modules can be stacked and combined to create complexes for people to live. Although this isn't a new concept, I decided to create a small demonstration model of this.

When these mini homes are combined, they can form complexes similar to apartments, motels, or dorms. When making this model, I started with a blank assembly file, then imported my three-wall model in the assembly twice. I also added in the full model (with roof) on the top. To get all of these buildings or "parts" to sit on top of one another, I used the "align" tool. Within this assembly, I had to create a new (plain) fourth wall for the back of the two three-wall models. I also took off the back door and window trim off the full model so it wouldn't stick out when the new back wall was built. To do this, just draw a sketch over the trim and extrude it in to the surface of your cedar planks (making the surface flush). The final result is a three-story building

To get up to higher floors and connect all three modules, exterior stairs should be added in the front. For every level off of the ground floor, there should also be a landing that can also act as a porch. The bigger the landings, the more space residents have to decorate, install small garden beds, plant pots, and more. Keep in mind, all staircases have certain regulations and standards they have to follow. The guardrails on the landings should also be at least 42".

Rather than making a plain back wall for all of the floors, you can decide to recreate the cedar plank pattern and add windows or a balcony. I personally wanted to re-imagine this back wall as a large area to place a living wall. Rather than modeling both, I took images of the original model and used them to create some concept art. Inspiration for the living wall came directly from the Make It Real Autodesk resources. As the diagram shows, a living wall is made up of a structural component, waterproofing material, and some sort of growth medium. Polyamide and other felt pouches are readily purchasable on the market and a timed drip system could be used to water the plants at different time periods throughout the day. To connect this back to one of my previous sustainable features, water from rain barrels could be used to keep a living wall happy and healthy.

An Interesting Alternative

Thermosiphon solar air heaters are passive heaters driven by convection. This is a system that is quite different from collecting solar energy from traditional solar panels. Firstly, cold air from inside or outside your home will enter the solar air heater. Located inside the air heater is a series of holes in which the cold air has to pass through. These holes are evenly spaced out to distribute the air evenly along a black surface. Sunlight heats the material on the inside of the heater and heats up the cold air. After this, the warm air is recollected by another series of evenly spaced out holes and reenters the building.

The inner material of the collector can be made of metal that is corrugated or flat, and even black, layered window screen. In the images you will see a model of one that I made for a school-related project. I won't be adding a tutorial portion on how to make one, but I felt it was important to discuss. Mentioning thermosiphons is important to me because they are a cheap alternative to traditional AC units. These can be made out of simple materials such as scrap metal, a bit of wood, PVC, and don't require much extensive knowledge on electrical systems... which means residents who built them can easily repair one themselves without spending a lot of money on hiring a specialist. In the long run, these units might be perfect for someone with a low budget, and they work better than one might believe.

It would be very cool to see one of these systems implemented in a small container home or tiny home in general. They would be best placed on the side of the house that is exposed to the most sunlight and can be small or large. Especially in cold environments, these can be used to utilize the little sunlight available and even work alongside a traditional heating system.

And with that, thank you for viewing my Instructable! Have a great day!