An alternative to building your own tiny house is to start with an unfinished pre-built shed shell. You may have seen buildings like these lined-up along side the highway in your community, outside your local home improvement store, or even inside your local Costco.
Typically these pre-built unfinished buildings are sold as sheds, but some are fitted with the right kind of windows & doors and sized appropriately to be used as a house. Photo credit to Mighty Shed.
- Cost – In some cases you can buy a pre-built shell for less than you can build one yourself, because professional shed builders often pay wholesale prices for their materials and have become very adept at building them efficiently.
- Financing – In some cases the makers of pre-built shells offer financing. I imagine the financing is some kind of personal loan and the interest is high, but for those looking for financing this may be a benefit.
- Speed to Completion – Since the buildings are delivered as complete shells, the time it takes to make them habitable may be quicker. But temper that with the reality that building the shell is often the quickest – albeit heaviest lifting – part of a tiny house project. So while you may get the big heavy part of the project done quickly, you’ll still have a lot of work to do after the shell arrives.
- Warranty – If you build something yourself, you have no farther to look than yourself for repairs. With some of these prebuilt sheds you’ll find that that come with warranties. This may offer some peace of mind.
- Aesthetics – You’ll probably have fewer choices in the style & color with pre-built shells than with custom designs since you have full control when you design and build from scratch.
- Quality – The quality will depend on the builder and the shell’s intended use. Inspecting the building and paying special attention to the materials & construction will help determine if the vendor’s shells will hold-up over time.
- Strength – The sturdiness of structure may vary from vendor to vendor and design to design. For example you may find a really low cost shed but while inspecting it closely you may find odd lumber sizes or little plywood or OSB (oriented strand board). While these details do not mean the building is lower in quality they may point to future difficulties when attempting to finish-out the building as a home.
- Mobility – Tiny houses on wheels are purpose built to be pulled down the highway. They are anchored tightly to their trailers and the external treatments are often chosen for their wind resistance. While most folks don’t move their tiny houses often, it can be a real benefit to have that option. A pre-built shed may or may not be sized to fit within the legal limit of a trailer, and it may not have been built with high winds in mind. So if your intention to have mobility, greater care should be taken when selecting the right pre-built shell.
With all that said, pre-built sheds are an option for some future tiny homeowners. They do take some of the heavy lifting out of the project and if up-front costs are a barrier, then these may help break through into tiny home ownership quicker.
You should also look into the legal limitations and allowances for using these tiny structures as dwellings in your area. The shed builders in your area may be able to help you with these details. Some of them may even offer specific models that they’ve built to meet local codes for use as dwellings.
In any event be sure to look at a lot of shells if you’re considering these options. Take notes about the construction details so you can compare later since after a while they will all look the same.
Construction Details to Consider
- Is the structure framed with standard 2×4 lumber (1.5″ x 3.5″ actual)? Rafters in the floor and joists in the floor are usually larger – depending on the span and weight loads needed.
- If you’re in a cold climate you may want to use at least 2×6 lumber (1.5″ x 5.5″ actual) in the walls.
- What is the spacing between studs in the walls, joists in the floor, and rafters in the ceiling? 16 inches on center (O.C.) is preferred. 24″ O.C. is still usually acceptable and common in mobile tiny houses to save weight.
- Are the walls, floors, and roof sheathed? In the walls and roof do you find at least 5/8″ thick plywood or OSB? Is the floor decking at least 3/4″ thick? Mobile tiny houses often use 1/2″ plywood sheathing in the walls and roof to save weight but thicker is stronger.
- Is there a separate layer of external siding on top of the plywood (or OSB) sheathing on the walls? The plywood (or OSB) add strength to the structure while the siding provides weather proofing. Some sheathing materials can do both, like T1-11. These materials can speed construction time and lower costs, but they put less material between you and the weather.
- Is there a layer of plywood (or OSB) decking between the roofing material and rafters? In many sheds you’ll look up and see the exterior roofing screwed right to the rafters. Just like adding extra layers to the walls, extra layers in a roof protect you better from the weather.
- Are the windows and doors good enough to use in a home? Windows and doors are expensive so if your intention is to save money, try avoiding buying a shed shell with doors and windows that you’ll have to replace later.
- Is any house wrap used in the walls? House wrap adds a breathable but weather resistant layer to walls and can significantly improve your home’s energy performance.
- Is there any roofing felt used in the roof? Roofing felt (a.k.a. tar paper) adds another water repelling layer to roofs.
- Are there any nailers in the walls for speeding the installation of interior sheathing, like drywall? These appear in the corners and look like redundant studs and rafters. Their purpose is to provide a nailing surface to attach the interior sheathing. All sheathing, on the inside and out, should be connected to framing for fire protection and strength.
- Does the building have the right number of fire exists, as defined by your communities local code? In some places this can be a 2′x2′ opening window and in other areas it’s two doors.
Below are a couple videos from folks considering using these building shells for homes. The opinions they express are their own and may or may not agree with mine – or yours. I’ve provided them here to add food for thought.