How to Finish the Inside of a Small Prefab Cabin

If you’ve recently purchased a small prefab cabin you may be getting ready to finish the inside. With some skilled labor, the right materials, and the right tools, a prefab cabin can easily be turned into a cozy living space. This guide is intended to give advice specifically for finishing the inside of a small "shed-type" portable cabin (pictured below) that is installed on a gravel or concrete pad. However, this information may also apply to other types of cabins. (Not what you're looking for? See our Cabin Design Ideas)

When compared to a building with a brick and mortar foundation, a portable cabin is a cost effective way to expand your living space. It is not considered to be a permanent structure because it can be moved to a new location if necessary. This makes it ideal for a variety of situations including campgrounds, hunting cabins, rental properties, an extra room in the backyard, etc.

Although some builders may offer to finish the inside for you, there’s a good chance you purchased your pre built cabin as a shell that still needs to be finished on the inside. If you haven’t purchased your cabin yet ask the builder to insulate the floor for you since it is almost impossible to do it later without removing the floor plywood. Also ask the builder for house-type windows and doors. The windows should be large enough for a window air-conditioner unit (unless you have other plans for cooling in the summertime).

Now we’ll take you through the different phases of finishing the inside and give a few pointers as we move along.


The first step is to set up any 2x4 divider walls if you plan to divide the cabin into different rooms. Begin by creating a floor plan for your cabin that's drawn to scale. This can be easily done using graph paper. Drawing a floor plan will help you visualize the layout of the cabin interior and make adjustments before you begin.

Sample Floor Plans for a Two Story Cabin

small prefab cabin floor plan

Lower Floor

small prefab cabin floor plan

Upper Floor

Photo Credits: Log Home Living

You may also choose not to install interior divider walls if your cabin is very small or if you prefer an open floor plan. A cabin with a loft can provide great sleeping quarters that is out of the way of the main living area (which can eliminate the need for a separate bedroom).

Depending on how your cabin was built you may need to install ceiling joists (unless you want to leave the ceiling open). You may be able to skip this step if your cabin was built using engineered trusses, however if the trusses are spaced at 48" apart you'll need to install 2x4 cross members on the underside of the trusses before installing drywall or panelling.

Electricity and Plumbing

The next step is to run wires for electricity in the shed and install water supply and drain lines if you plan to have running water in the shed. Since this is a highly technical step with lots of variables we won't go into detail here. Contact a plumber and electrician if you're not completely comfortable doing it yourself. Remember to add an outside light and electrical outlet and install any special wiring for heating and cooling.


This is one of the most important components for keeping your cabin comfortable and performing the way it should. Spray foam insulation is recommended but it is usually the most expensive option. Alternatively it’s ok to use fiberglass batt insulation if you take a few precautions. If you decide to use fiberglass insulation we recommend installing gutters on the cabin to catch the water that runs off the roof. This will help to eliminate any moisture that might enter the walls from water splashing against the bottom of the cabin (it’s a good idea to install rain gutters anyway to protect your cabin). Just remember that moisture plus fiberglass insulation equals the potential for mold which is something you'll want to avoid. Installing gutters will go a long way when it comes to keeping the bottom edge of your cabin or wood storage sheds dry (building a shed base also helps to keep your cabin dry).

Spray Foam Insulation

Fiberglass Insulation

Photo Credit: Atticare

Wall Board

There are a variety of materials that can be used to cover the walls. Drywall is one of them but is prone to cracking at the seams unless the shed is installed on a solid concrete foundation. If there’s a possibility that the cabin will shift over time then wood or paneling is a better option for covering the walls.

small prefab cabins interiors

Tongue and Groove

White Paneling

Photo Credits: Pinterest and Sarah

The remaining steps can be completed without any special instructions:

  • Trimming and Interior Doors
  • Painting
  • Flooring
  • Finish electrical and plumbing

Whether you place it in the backyard, on your vacation property, or at a campground, a quality prefab cabin is an excellent addition to your property that will add value and serve you for many years to come.

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