Lean-To Greenhouse Plans: DIY Greenhouse Against a Wall

The Lean-To Greenhouse: the lean-to greenhouse against a sunny wall

The piece

What you are building

Lean to greenhouse plans PDF with three complete plan sets: an 8x12 and a 9x12 lean-to greenhouse that stands against a house or garage wall, and a freestanding 8x16 gable greenhouse. Twin-wall polycarbonate glazing, wood frame, a door, roof vents and an optional potting bench.

The lean-tos: 8 ft and 9 ft out from the wall by 12 ft along it. A treated ledger on the house wall carries 2x8 rafters in sloped hangers, the front wall is 6 ft 6 in tall, and the roof falls away from the house at 3/12. The plans cover the ledger screws, the wall flashing, a note on checking the wall before you build, a sloped end wall with a 36 x 72 in door, hinged roof vent lids at the house end, a front louver, and two benches, one of them a potting bench with a low shelf. The freestanding 8x16 has a 4/12 gable roof, a 36 x 72 in door, hinged vent lids on both slopes and two benches. Every member (rafters, studs, header, bench parts and the ledger fasteners) is checked against a stated load, and the plans give spans, panel layout, vent area and anchor figures.

Who these plans are for

Home gardeners comfortable with a circular saw, a drill and a level who want a greenhouse against a sunny wall, or a freestanding one, with a shopping list for the lumberyard and the panel supplier.

How the set works

Choose lean-to or freestanding, check your house wall with the wall checklist, then follow the design basis, drawings, ledger and flashing details, wall framing, roof and vent lid, panel layout, benches, foundation and anchoring, cut list and materials list for the greenhouse you are building, plus the site, tools, build sequence, fastener, budget and maintenance pages.

Sheets inside

Plan selector, Greenhouse basics, Site, permit and safety checklist, How to read the plans, 8x12 and 9x12 lean-to plan sets (A design basis and member schedule, B the house wall, ledger and flashing, C sill, walls and door, D roof, rafters and vent lid, E panel layout and fasteners, F benches and potting bench, G foundation and anchoring, H cut list, I materials list), the 8x16 freestanding plan set (A to H), Tools, Build sequence, Fastener schedule, Build day checklist, Budget planner, Growing and vent log, Maintenance log, Quick-reference card, Glazing options.

In the download

Materials cost workbook (Excel and Google Sheets)
Every sheet as its own printable page (ZIP)
Printable plans (PDF)
How to open the workbook in Google Sheets (PDF)

Build cost

Price the build before you buy a board

These are the materials lists from the plans themselves, priced at typical US home-center prices. Type your own prices to see your total. Hardware and finishes link to Amazon so you can compare.

MaterialQtyHome-center estimateHardware links

2x4 lumberLumber, 520 ft at about $0.75 per ft 33 boards $

2x4 pressure-treatedLumber, 24 ft at about $0.86 per ft 2 boards $

2x6 lumberLumber, 46 ft at about $1.05 per ft 4 boards $

2x6 pressure-treatedLumber, 28 ft at about $1.21 per ft 2 boards $

2x8 lumberLumber, 70 ft at about $1.45 per ft 7 boards $

2x10 pressure-treatedLumber, 12 ft at about $2.24 per ft 1 boards $

6 mm twin-wall polycarbonate, 4 x 8 ft panelSheet goods, about $66 per sheet 7 sheets $

6 mm twin-wall polycarbonate, 4 x 10 ft panelSheet goods, about $82 per sheet 2 sheets $

8 mm twin-wall polycarbonate, 4 x 8 ft panelSheet goods, about $88 per sheet 6 sheets $

1/2 in plywoodSheet goods, about $48 per sheet 1 sheets $

#10 x 1-1/2 in exterior screws with EPDM sealing washersGlazing hardware, about $11 per boxes of 100 4 boxes of 100 $ Find on Amazon

Solid aluminum tapeGlazing hardware, about $14 per rolls of 33 ft 2 rolls of 33 ft $ Find on Amazon

VentedGlazing hardware, about $14 per rolls of 33 ft 2 rolls of 33 ft $ Find on Amazon

H-connector or 1x2 batten strip at panel jointsGlazing hardware 6 lengths of 8 ft not in estimate Find on Amazon

Aluminum wall flashing, bent to an L, 6 in up the wall and 4 in onto the roof panelsHouse wall, about $12 per lengths of 10 ft 2 lengths of 10 ft $

Self-adhesive flashing tapeHouse wall, about $7 per roll of 33 ft 1 roll of 33 ft $

Exterior-grade polyurethane or butyl sealantHouse wall, about $8 per tube 2 tubes $

Foam closure strip, to fit the flutes of the roof panels at the wallHouse wall, about $32 per strips of 4 ft 3 strips of 4 ft $

1/2 in x 4 in structural or lag screws with washersHouse wall, about 12 cents each 20 each $

SlopedHouse wall, about 12 cents each 7 each $

Hinges for the vent lids, exterior, 3 inHardware, about $6 per each 6 each $ Find on Amazon

Lid prop or openerHardware 3 each not in estimate Find on Amazon

Door hinges, exterior, 4 inHardware, about $6 per each 3 each $ Find on Amazon

Door latch or hasp, exteriorHardware, about $7 per each 1 each $ Find on Amazon

Louver vent, 22 x 22 in openingHardware 1 each not in estimate Find on Amazon

Rafter-to-plate tiesHardware, about 12 cents each 7 each $ Find on Amazon

#10 x 3 in exterior screwsFasteners, about $11 per boxes of 100 4 boxes of 100 $ Find on Amazon

16d hot-dip galvanized nailsFasteners, about $11 per lb box (5 lb) 1 lb box (5 lb) $ Find on Amazon

#8 x 2-1/2 in exterior screwsFasteners, about $11 per boxes of 100 2 boxes of 100 $ Find on Amazon

Crushed gravel for the pad, 4 in deep, 1 ft past the front and the endsSite, about $1 each 1.6 cubic yards $

Woven landscape fabric under the gravelSite, about 25 cents per sq ft 126 sq ft $

Ground anchors or 1/2 in x 24 in rebar stakes, with a washer or strap through the sillAnchoring, about $5 per each 7 each $

Exterior stain or sealer for the framingFinish 1 quart not in estimate Find on Amazon

Estimated materials, 8 x 12 lean-to $2,276 Our range: $1,820 to $2,620, not counting 4 items you choose yourself

MaterialQtyHome-center estimateHardware links

2x4 lumberLumber, 572 ft at about $0.75 per ft 48 boards $

2x4 pressure-treatedLumber, 28 ft at about $0.86 per ft 2 boards $