EXPLORING AN 1887 TINY HOUSE: A 20X20 FLOOR PLAN ANALYSIS
When designing small structures today, whether they are off-grid cabins, accessory dwelling units, or tiny homes, examining historical blueprints is an incredible educational tool. A floor plan from 1887 perfectly illustrates how to pack essential living spaces into a remarkably small footprint. At exactly 20 feet by 20 feet, this home encompasses 400 square feet of living space. To put that into perspective, that is the exact footprint of a standard modern two-car garage. Despite its size, this late 19th-century design manages to incorporate a sitting room, a cooking area, and two bedrooms.
ROOM DIMENSIONS AND SPATIAL LIMITATIONS
The layout of this historic home prioritizes functional living space by completely eliminating transitional areas like hallways. The front entrance features a modest 5-foot by 4-foot deck leading to a front door that measures just 2 feet 6 inches wide. By modern standards, this is quite narrow, as most contemporary front doors are 3 feet wide, with rear doors typically measuring 2 feet 8 inches. The windows are similarly modest, measuring 2 feet wide by 4 feet tall.
Inside, the main sitting room measures 11 feet by 9 feet. The bedrooms are incredibly compact, presenting unique challenges for modern furniture. For example, a modern king-size bed is over 6.5 feet wide and nearly 7 feet long, which would consume almost the entire bedroom and leave practically no room to walk. The closets reflect the limited wardrobes of the 1880s, measuring roughly one foot deep.
THE REALITIES OF 19TH-CENTURY AMENITIES
One of the most striking aspects of this 1885 floor plan is what it lacks. There is no indoor plumbing, no bathroom, no kitchen sink, and no electricity. The layout indicates a central chimney area behind one of the bedroom doors, which would have housed a wood stove essential for both heating the entire 400-square-foot space and cooking meals.
Living in this home meant relying on an outhouse located elsewhere on the property. While the simplicity of this floor plan is appealing for those looking to build an inexpensive cabin today, modern builders would need to significantly alter the design to incorporate modern sanitation, electrical panels, and HVAC systems.
STRUCTURAL FRAMING AND ROOF DESIGN
Moving to the exterior, the structural design provides a great study in traditional framing. The house sits on a classic brick foundation, which supports a wood-framed floor. The floor joists were likely spaced 24 inches on center, covered with 1x6 wood sheathing, and finished with solid wood flooring.
The roof is a classic hip roof design featuring a steep 12/12 pitch, meaning it rises 12 inches vertically for every 12 inches of horizontal run. Because the building is perfectly square, this hip roof does not have a traditional ridge board. Instead, all of the hip rafters meet precisely in the center apex. A secondary, lower-sloped shed roof is attached to the front fascia board to cover the small porch, adding a practical weather barrier for the entryway.
CONCLUSION
While the lack of modern conveniences makes this exact 1885 blueprint impractical for a primary modern residence without serious modification, the core structural concepts remain highly relevant. For those looking to build a simple, cost-effective structure, this 20x20 design proves that a functional living space can be achieved without a massive footprint or complicated architectural layouts.
THREE KEY TIPS FOR SMALL HOME CONSTRUCTION
UPGRADE TO MODERN DOOR SIZES: If adapting a historical or tiny home plan, always widen the exterior entryways. Framing for standard 36-inch exterior doors ensures you can easily move modern appliances and furniture into the home, which is nearly impossible with vintage 30-inch doors.
UTILIZE ROOF CAVITY SPACE: A steep 12/12 roof pitch on a 20x20 structure creates a significant amount of overhead attic space. When building a small home, utilize this vertical volume by adding a loft space or vaulted ceilings to make the small footprint feel much larger.
REINFORCE FLOOR JOISTS FOR MODERN LOADS: Historical plans often used floor joists spaced 24 inches on center. For modern builds, especially if adding heavy modern appliances, bathtubs, or tile floors, upgrade your floor framing to 16 inches on center to reduce floor deflection and meet current residential codes.
BONUS QUESTIONS AND ANSWERS
If you are feeling inspired to adapt a vintage 20x20 floor plan for a modern build, you will quickly realize that 19th-century designs must be updated to meet 21st-century safety and building standards. Here are a few common questions that arise when bringing a historic tiny home concept up to modern code.
HOW DO YOU HANDLE EGRESS REQUIREMENTS IN SUCH SMALL BEDROOMS?
When dividing a small floor plan into 11x9 bedrooms, you must account for modern emergency escape and rescue opening codes, commonly known as egress. Building codes require that every sleeping room have at least one operable window or door that provides a clear opening large enough for a person to escape and a firefighter to enter during an emergency. Typically, this means the window must have a minimum net clear opening of 5.7 square feet and a sill height no higher than 44 inches from the floor. The vintage 2x4 windows mentioned in the 1880s plan would likely fail to meet this standard. If you are retrofitting an older structure or building a new tiny home, you will need standard egress-rated casement or double-hung windows. A high-quality reciprocating saw is an essential tool for cutting through existing wall studs and exterior sheathing to frame out the larger rough openings required for these lifesaving modern windows.
WHAT IS THE BEST WAY TO MODERNIZE A HISTORIC BRICK FOUNDATION?
The original 1880s plan relied on a simple brick foundation, but modern structural requirements demand much more stability to prevent settling and resist natural forces. Modern building codes require foundations to be anchored securely to the earth, extending below the local frost line to prevent frost heave, which can crack foundation walls and warp the house framing. Additionally, high-wind and seismic zones mandate continuous load paths from the roof down to the footings. To update a design like this, you would typically swap the unreinforced brick for poured concrete continuous footings and stem walls. During the pour, contractors rely heavily on a concrete vibrator, a crucial tool that eliminates trapped air pockets in the wet mix, ensuring the concrete bonds tightly around the embedded steel rebar for maximum structural integrity.
HOW CAN YOU ADD PLUMBING TO A FLOOR PLAN WITH NO EXISTING BATHROOM?
Adapting a historic outhouse-era plan to include an indoor bathroom requires careful consideration of modern sanitary drainage and venting codes. Structural codes dictate that drain pipes must maintain a consistent downward slope, typically a quarter-inch per foot, to ensure gravity pulls waste to the sewer or septic system without clogging. You also have to route vertical vent pipes through the roof to prevent sewer gases from entering the home and to equalize pressure so drains empty smoothly. Because a 20x20 footprint is so tight, running traditional rigid pipes through standard 2x4 walls can severely compromise the structural integrity of the studs. To solve this, plumbers outfitting modern tiny homes frequently use flexible PEX piping for the water supply lines. PEX can easily snake around tight corners and through smaller bored holes without weakening the framing. By using a specialized PEX crimp tool, you can quickly secure watertight brass or poly-alloy fittings, making it much easier to squeeze modern plumbing into a highly restricted floor plan.
