DIY 8x20 Gable Storage Shed Plan

The full plan is $19.99: buy the 8×20 gable shed plan. To see the drawing style first, open the free 8×20 gable shed plan PDF, an 8-page preview.

What is on the 8×20 shed plans materials list

The shopping list is split into sections, so you can buy the foundation and floor first and the roof later, in the stock lengths that waste the least. A cut list gives the length and count of every part.

Buy a few spare studs for bad boards. The temporary braces and the ridge post are on the list and can be reused after the build.

8×20 shed plans: the numbers for a site check

Square the corner stakes to matching 21′ 6 1/2″ diagonals before the gravel goes down, and check the pad frame to 24′ 2″ diagonals. Mark the roof footprint, not just the walls, when you check a narrow strip along a fence or property line. The ramp and landing reach out in front of the door, so leave room there.

How the 8×20 shed plans go together

Building 20 ft long from shorter stock

No 20 ft board is on the list, so the skids, rims, plates and ridge are spliced where the plan says:

• Skids. Each 20 ft skid is a 12 ft and an 8 ft piece butted on the gravel, the joint under a floor joist. The middle skid is flipped end for end, so the joints fall at 8 ft and 12 ft from the left end, 4 ft apart, each scabbed on both sides with a 3 ft pressure-treated 2×4 and six nails per scab.
• Rims. Each rim is cut 9′ 4 3/4″ + 10′ 7 1/4″ and breaks over a doubled joist, so both rim ends get three nails into a full joist.
• Wall plates. The back wall plates break at 10′ 7 1/4″ from the right corner and the front wall plates at 13′ 4 3/4″ from the left corner, one joint per wall. The second top plate bridges each section joint and lands its own joint on a different stud, so each layer covers the other’s joint.
• Ridge. The 20′ 8″ 2×6 ridge is 9′ 8″ + 11′ 0″, the joint centered on the rafter pair 9′ 4″ from the left corner and held on a temporary post, 9′ 7 5/16″ long, until that pair is nailed and a cleat goes under the joint.

The nailed floor frame weighs about 380 lb and racks out of square if you lift it, so the plan has you build it in place on the skids and square it there.

How the walls go up

Each wall is framed flat on the deck and raised as a bare frame, and the siding goes on after all four stand. Both 20 ft walls go up in two sections so that two people can raise each one.

• Hinge it. Stop blocks nailed to the outside of the rim keep the bottom plate from kicking out over the deck edge as the wall tips up.
• The narrow-deck trick. Once the back wall stands, only 7′ 8 1/2″ of deck is left, too little to frame the front wall at its own edge. The plan frames it facing the other way, tips it up there and walks it across on its bottom plate.
• Brace at once. Never leave a raised wall unbraced, even for a minute, and never raise one in gusty wind.
• Siding. A 4×8 sheet of 5/8″ T1-11 weighs about 60 lb. Screw a straight 2×4 ledger to the floor frame at the siding’s bottom line, stand each sheet on it, and have a helper hold it plumb while you tack the top corners.

What you can fit in an 8×20 shed

The plan includes a to-scale drawing of one way to fill the floor:

• A riding mower. The 72″ double door gives a clear width of about 5′ 11 1/2″ with both leaves open, so a 42″ deck clears each side by 8 1/8″. A 48″ deck fits with its deflector raised, and a 54″ deck does not.
• Back-wall shelves. The 20 ft back wall has no window, so 12″ deep shelves can run its length, split at the mower’s nose.
• Yard gear. A wheelbarrow and two bikes fit on the open floor beside the mower, with a cross aisle behind its tail.
• A window on each end. The two 24″ x 36″ windows sit near the front of the side walls, so light falls on the door area instead of the shelves.

The ramp, door and windows in the 8×20 plan

• Door. The 72″ double door is built from two new T1-11 sheets, each leaf 2′ 11 5/8″ wide and 6′ 5 1/4″ tall, hung on 6 T-strap hinges with 2 barrel bolts and a hook and eye per leaf. The plate is cut out so the opening runs to the floor, and an aluminum threshold cap and brush sweeps seal the bottom.
• Ramp. The detachable ramp is 6′ 9″ wide and 3′ 6″ out at a 1:6 slope, so wheels roll on at a beveled toe and meet only a 13/16″ lip at the door. Unhook it and lift it away when you want the step back.
• Windows. Both windows are prefabricated 24″ x 36″ units with 42″ sills.
• Back wall. It has no opening at all, which leaves all 20 ft free for shelves.

Stick-framed rafters vs trusses on an 8×20 gable roof

Many 8×20 plans use trusses. This 3DSHEDPLANS plan frames the roof with 32 2×4 rafters 16″ on center against a 2×6 ridge board, plus 4 fly rafters on the rakes, so two people can build it one pair at a time with no truss jig. Cut one rafter, test it on both sides, then trace the rest.

• Ridge first. A 1′ 8 13/16″ center stud on each gable wall carries the ridge while you set the end pairs, then the pair at the ridge joint, then the rest.
• Ties. A 2×4 rafter tie sits on the plates beside each of the 14 interior pairs to stop the walls spreading, and 7 collar ties hold the ridge together in wind. Keep anything stored on them light, since the plan does not build a loft.
• Venting. Air comes in through 8 screened 16″ x 8″ soffit vents, 4 under each eave, over a screened slot in the frieze, and leaves through an 8″ x 8″ louvered vent in each gable. The plan prints the arithmetic: 158.7 sq in in all against a common attic rule of thumb of 154 sq in, which is not a shed requirement. The gable side comes out short because 8″ x 8″ is the largest louver that fits under this ridge.

In heavy snow or high wind areas, ask about loads and check your local permit office before you build.

Free 8×20 shed plan PDF vs the full plan

The free 8-page PDF shows the shed, the stages of the build and the 3D views, so you can see the drawing style. It has no shopping list, cut list or measurements. The full 70-page plan adds the material list, the cut list, the cutting plan, the sheet maps and every build step with every dimension.

Before you build an 8×20 gable shed

• Permits. At 160 sq ft and 10′ 11 5/16″ tall, this shed may need a permit or meet setback limits, and rules vary by town and HOA. A long shed along a property line makes setbacks matter more. Check your local permit office before you buy lumber.
• Skids. Use ground-contact rated pressure-treated 4x4s (UC4A or higher), set each one crown up, and raise a low skid with more gravel or treated shims, never untreated wood.
• Anchors. An empty shed on skids can slide in a strong gust, so the plan adds 8 screw-in ground anchors with steel straps along the two outside skids.
• Upkeep. Keep 6″ or more between the siding and the soil, and check the roof, caulk, paint and skids every spring.
• Materials. Store lumber flat and covered, since wet wood decays faster (USDA Forest Products Laboratory Wood Handbook). Check the stamp on each OSB sheet for its span rating (APA: OSB).

Tools for the 8×20 gable shed

Beyond a circular saw, drill/driver and framing hammer, the tool list adds ladders tall enough for the eave and ridge, a 3 lb sledge for the brace stakes and a hand tamper for the pad. Shingle bundles weigh 60 to 80 lb, so ask the supplier to deliver them onto the roof if they offer it.

Related plans

• Same 20 ft length, 2 ft deeper: the 10×20 gable shed plan. 4 ft deeper: the 12×20 gable shed plan.
• Same 8 ft depth, shorter: the 8×14 gable shed plan and the 8×12 gable shed plan.
• A one-slope roof on a narrow footprint: the 8×16 lean-to shed plan.
• Every gable shed plan in one place.