How to Build a Backyard Tiny Home Gym: A Complete DIY Guide
Building a tiny home in your backyard can be an excellent way to add functional space to your property. Whether you're looking to create a home gym, office space, or guest house, this comprehensive guide will walk you through the entire process from foundation to finishing touches.
Setting a Solid Foundation
The foundation is arguably the most critical part of any structure. For this tiny home gym project, concrete deck blocks served as the base, with pressure-treated 2x6s set into the grooves of these blocks. Ensuring the foundation is perfectly level and square is essential before securing everything together.
After establishing the main frame, additional 2x6s were placed at 16-inch centers, crowned and secured with 3.5-inch screws and 3-inch framing nails. Joist hangers provided additional support, ensuring the structure would last for years to come.
Insulating the Subfloor
Proper insulation is vital even for tiny structures. Half-inch foam insulation with an R-value of 5 was installed between the 2x6s, then sealed with spray foam. Small drainage holes were drilled to allow any trapped moisture to escape.
A 6mm plastic vapor barrier went on next, followed by 1.5-inch tongue and groove OSB for the subfloor. The subfloor was secured with both 2-inch nails and screws for maximum stability.
Framing the Structure
For the wall framing, 2x4s were used at 16-inch centers and secured with both screws and nails. The design featured a 10-foot tall front wall and an 8-foot tall back wall, creating a sloped roof that makes the interior feel more spacious.
After the walls were up and squared, 2×6 rafters were installed for the roof. A template was created to ensure consistent bird's mouth cuts across all rafters. The design included generous overhangs: 3 feet in front, 10 inches on the sides, and 18 inches in the back.
Exterior Sheathing and Roofing
Half-inch OSB was used for exterior sheathing with clips to provide proper spacing. The roof was similarly sheathed and secured with adhesive for added strength.
Waterproofing began with drip edge installation around the roof perimeter, followed by self-sealing waterproof wrap and asphalt shingles. For first-time roofers, a stair-step pattern with six nails per shingle provides excellent protection.
Windows and Doors
After routing out openings, a house wrap was installed for weather protection. Windows (sourced from Facebook Marketplace for cost savings) were installed with proper flashing and sealed against moisture intrusion.
French doors were installed with a custom-built frame made from 1x4s. Four custom windows were also built for the upper portion of the structure, with glass set in dadoed frames and sealed with silicone.
Exterior Finishing
Board and batten siding gave the tiny home a contemporary look. Each sheet was carefully measured, especially around windows, and secured with both adhesive and nails. Trim pieces covered the seams between boards for a uniform appearance.
For visual interest, treated tongue and groove pine was installed on one corner. Windows received mitered trim for a professional look. After caulking nail holes, the exterior was sprayed with Behr Dynasty exterior paint for a smooth, professional finish.
Electrical Work
A 125-amp breaker panel was installed, with receptacle boxes positioned to extend about half an inch from the studs to align with the future drywall. Wiring was run through 3.5-inch holes drilled at 2-foot heights in the studs, with metal wire protectors installed to prevent accidental damage during later construction stages.
Exterior softfit lighting and a GFI outlet were also installed, with spray foam used to seal potential entry points for bugs.
Insulation and Interior Walls
Five bags of havelock wool, a non-toxic alternative to traditional insulation with an R-value of 15, were used to insulate the walls. This natural product eliminates the need for protective gear during installation.
After insulation, sheetrock was installed, joints were taped, and compound was applied. For the ceiling, the same tongue and groove pine from the exterior was used, first stained and sealed with polyurethane.
Interior Finishing
After sanding the walls smooth, Sherwin Williams Showcase Paint and Primer was applied. For flooring, high-quality Flooret Nikon LVP flooring with built-in underlayment was installed, with an additional 2mm underlayment layer for extra comfort.
Receptacle outlets, switches, and baseboards completed the interior finishing.
Deck Construction
A deck was added to enhance the tiny home's usability. 4×4 posts were set in quick-setting concrete, followed by pressure-treated 2×6 framing with joists at 16-inch centers. Waterproof deck tape was applied to the joists to extend the deck's lifespan and reduce squeaking.
Trex composite decking was installed using a hidden fastening system for a clean look. A custom-designed Moosata cable railing system with integrated LED lighting in the handrail completed the deck.
Creating the Home Gym
The space was ultimately outfitted as a home gym with a Spirit B52 5-in-1 training system, which includes a power rack, Smith machine, and cable pulley system—perfect for a small space.
Final Thoughts
This backyard tiny home gym project demonstrates how a well-designed small space can add significant functionality to your property. At approximately $15,000 and six weeks of construction time, it represents an achievable DIY project for those with basic building skills and determination.
Whether you're looking to create your own home gym or another type of backyard retreat, the techniques and approaches outlined here can help guide your project to success.
