Do the work in the order the shed needs it, not the order that is fun. A workshop with a good floor, dry walls and enough light is one you will use. Everything below comes from the shed conversion videos on this site; where they use one builder’s numbers, we say so.
Safety and permits
- Permit. Converting a shed to a workshop, or adding power or insulation, may need a permit. Ask your building office before you start; see Do You Need a Permit?.
- Power. The underground-power video says new circuits in the main panel should be done only by a licensed electrician with the service completely disconnected, and Digsafe was called before digging. Leave the power step to a licensed electrician; see When to Call a Licensed Electrician, Plumber or Gas Fitter.
- Spraying paint. Wear a respirator rated for spraying paint (the painting video says so). Ventilate when you prime or coat the floor.
- Demolition. Check what is holding up what. In the Joshua Tree shed, the 2×6 rafters turned out to be non-structural, held only by drywall screws; check before you cut.
Step 1: Fix the structure
Make sure the walls are standing, the door closes and the roof sheds water before you finish the inside. In the Joshua Tree shed, one wall and a door were about to fall off. He forced and clamped everything into place, screwed into secure header boards and added mending plates around the foundation. Loose exterior plywood got construction adhesive on every stud, and 2×4 blocks went behind every exterior seam.
Step 2: The floor
The slab video builds a new one:
- half-inch rebar laid in a grid on concrete riser blocks (dobies)
- expansion joint foam around the perimeter so the slab can expand with heat
- three yards of concrete, delivered, about $300 to $350 (his number)
- a straight 2×6 to screed, and a rented bull float
The front got rough because it started drying before screeding. His fix was a flood coat of self-levelling underlayment, mixed thinner than pancake batter. He notes it is not as strong as typical concrete mix. He sealed the plate with spray foam first to keep it waterproof.
Step 3: Light and the roof
He removed the top two feet of a wall on the east-facing high side and fit 2 ft by 4 ft polycarbonate panels into the opening using roofing screws with soft washers. He cut them with masking tape and a 60-tooth blade, leaving the plastic film on to protect the panels. The roof had a drip edge but no eave, so he built a ledge from a 2×4 and 2×6 and sealed it with waterproof seam tape as a quick repair. The metal roof method is in Replacing a Shed’s Asphalt Roll Roof With Corrugated Metal.
Step 4: Insulate, but keep the air moving
- Walls and ceiling. The Joshua Tree shop sealed seams with spray foam, then used R13 batts stapled by their paper flaps, in 2×4 walls. R13 was the only insulation his store had in stock.
- Ceiling with foam board. The other video uses 2 in. foam board, R-10, six sheets for a 12×16 ceiling, at about $350 to $400 USD.
- Ventilation. The number one mistake in that video is filling the rafter bays without thinking through ventilation between the roof surface and the indoor space, which can lead to condensation, moisture and mould, especially with fibreglass. See Insulation R-Values and Attic Insulation for the Department of Energy guidance on vents.
Step 5: Line the walls
Two options from the videos:
| Option | Why | Cost |
|---|---|---|
| 1/2 in. plywood | You can screw wall-mounted tool storage anywhere; drywall will not take it | Price locally |
| 5/8 in. OSB | Avoids taping and mudding; leave a quarter inch at the bottom so moisture can dry out | About $21.50 USD a 4×8 sheet |
Cut around electrical boxes with an oscillating tool and a new wood blade. A countersink bit on an impact driver stops the screws blowing out the edges. See Shed Interior Walls With OSB.
Step 6: Paint and coat the floor
From the painting video:
- Mask the floor with construction paper and tape.
- Prime (Kilz 3, thinned slightly in the video), then two coats of flat white on the walls and ceiling. His airless sprayer tips: stay square to the wall, keep 8 to 12 in. away, overlap each pass by about half, and stop the sprayer before starting the next row so paint doesn’t build up and run.
- Floor epoxy kit: wet the concrete, scrub with concrete etch, rinse with a hose before it dries, mask the base of the walls, mix, cut in the corners and roll with a 3/4 in. nap roller. Throw the chips upward rather than sideways, and work in sections small enough to broadcast chips evenly.
Step 7: Power
Plan the circuits and a panel with your electrician. The shed in the Arnold Electric video got a subpanel, a receptacle, an LED light and an outside light. The trench goes about two feet deep so the top of the conduit is 18 in. down, with sand around it, two ground rods and metallic caution tape. That is one job on one property; your code decides.
Tools and materials
- Circular saw, oscillating multi-tool, impact driver, level
- Wagner Control Pro airless sprayer, 3/4 in. roller
- Rebar, concrete, polycarbonate, insulation, plywood or OSB, primer, paint, epoxy kit
Put it on the calendar
Check the roof screws and the seams for leaks each season, and look at the floor coating at the edges. We have no sourced interval; go by what you see.
See also
- Shed to Workshop Conversion and Build a workshop from a shed
- Building a Small Shed
- The Workshop and Garage rooms, and the Electrical and Insulation systems
Sources
- Shown on this site, source of the slab, structural, window and insulation steps. Turning an Old Joshua Tree Shed Into a Insulated Woodworking Shop (video, Modern Builds) Source
- Shown on this site, source of the spraying and floor coating steps. Painting a Plywood Shed Workshop and Epoxy Coating the Floor (video, Modern Builds) Source
- Shown on this site, source of the OSB wall option and cost. Shed Interior Walls With OSB: Cutting Around Boxes and Doors (video, Everyday Home Repairs) Source
- Shown on this site, source of the ventilation warning. Insulating a Shed Ceiling With Rigid Foam and Vented Rafter Bays (video, Everyday Home Repairs) Source
- Shown on this site, source of the power guidance. Running Underground Power to a Shed: Trench, Conduit and Panel (video, Arnold Electric) Source