homestead.fyi / COLDFRAME-4X8

4x8 Cold Frame

A 4 x 8 ft cold frame of ground-contact 2x6s, sloped to the front, with two hinged lids covered in plastic.

Draft plan, generated from the model. Not yet build-tested.
94 x 48 inSize
11 to 22 inHeight
2Lids
5 to 8 hrBuild time
$246.37Materials

Drawings All dimensions in inches

3D viewfinished
3D view
3D view, framingsiding and roof removed
3D view, framing
Front elevation
Front elevation 96 in 23 7/8 in
Right elevation
Right elevation 50 3/8 in 23 7/8 in
Plan viewfrom above
Plan view 96 in 50 3/8 in

Cut list: lumber Long-point lengths; angles noted

QtyStockLengthPartCut
12x448Lid 1 rail frontlaid flat
12x448Lid 1 rail backlaid flat
12x448Lid 2 rail frontlaid flat
12x448Lid 2 rail backlaid flat
12x444 1/8Lid 1 stile leftlaid flat
12x444 1/8Lid 1 stile rightlaid flat
12x444 1/8Lid 2 stile leftlaid flat
12x444 1/8Lid 2 stile rightlaid flat
22x4 PT22Postinside the corner
12x4 PT22Postat the lid joint
22x4 PT11Postinside the corner
12x4 PT11Postat the lid joint
22x6 GC94Front boardon edge
42x6 GC94Back boardon edge

Cut list: sheet goods

PartStockSizeNote
Left side1/2 ply48 x 22top cut at the slope
Right side1/2 ply48 x 22top cut at the slope

Lumber cutting diagram Lengths chosen for the lowest cost; 1/8 in kerf, 1/2 in end trim

2x4 x 8 ft
Lid 1 rail front 48Lid 1 stile left 44 1/8
2x4 x 8 ft
Lid 1 rail back 48Lid 1 stile right 44 1/8
2x4 x 8 ft
Lid 2 rail front 48Lid 2 stile left 44 1/8
2x4 x 8 ft
Lid 2 rail back 48Lid 2 stile right 44 1/8
2x4 PT x 12 ft
Post 3 22Post 4 22Post 6 22Post 1 11Post 2 11Post 5 11
2x6 GC x 8 ft
Front board 1 94
2x6 GC x 8 ft
Front board 2 94
2x6 GC x 8 ft
Back board 1 94
2x6 GC x 8 ft
Back board 2 94
2x6 GC x 8 ft
Back board 3 94
2x6 GC x 8 ft
Back board 4 94

Sheet cutting diagrams Dashed = openings to cut out

Sheet 1: 1/2 in plywood, 4 x 8 ft
Left side48 x 22Right side48 x 22

Shopping list $246.37 checked / $0.00 estimated

ItemStoreQtyEachLineNote
2x4x8 stud, SPFHome Depot4$4.15$16.60see lumber cutting diagram
2x4x12 ground-contact pressure-treatedHome Depot1$7.18$7.18see lumber cutting diagram
2x6x8 ground-contact pressure-treatedHome Depot6$9.78$58.68see lumber cutting diagram
15/32 in (1/2 in) sheathing plywood, 4x8 sheetLowe's1$32.26$32.26see sheet cutting diagrams
6 mil greenhouse film, 20 x 25 ftWalmart Business1$83.99$83.99covers the lids; the rest is spare
Galvanized 6 in strap hinge, each (5-pack $32.99)Home Depot2$6.60$13.20lids
Exterior wood screws #9 x 2.5 in, 5 lb boxHome Depot1$29.97$29.97
Poultry staples 3/4 in, 1 lbSouthern States1$4.49$4.49
Total before tax$246.37
Filled dot: price read from a store listing on Oct 20, 2026. Hollow dot: estimate. Prices come from the master price list, so they change when it changes.

Build steps

  1. Cut the 2x6 boards, the posts and the plywood sides. Level the ground and spread 2 in of gravel.
  2. Screw the back boards and then the front boards between the corner posts, with a post at the middle of each long side for the lid joint.
  3. Cut the two plywood sides with a 13° slope on top from the back height to the front height, and screw them to the posts and boards.
  4. Build two lids from four 2x4s each, laid flat, and screw the corners with 2.5 in screws.
  5. Staple 6 mil plastic over each lid and trim, or screw a 1x2 batten over the edge.
  6. Hinge each lid at the back with two hinges and set a notched prop stick so it can open 8 in for ventilation.

Before you start