What's inside
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A wooden sun lounger is a manageable weekend project if you can make straight cuts, drill accurately, and sand thoroughly. The adjustable backrest is the part that needs careful planning: it must support your weight without slipping, yet fold down far enough for storage. This design uses a fixed rectangular frame, a slatted seat, and a separate backrest held by a removable support bar.
Contents
Choose the design and materials
Build the lounger about 24 inches wide, 76 inches long, and 12 inches high at the front of the seat. Those dimensions suit most adults without making the chair unnecessarily heavy. Use pressure-treated lumber if the lounger will stay outdoors, or cedar if you want lighter weight and easier finishing. Standard construction pine is the cheapest option, but it needs a thorough outdoor finish and more frequent inspection.
| Material | Advantages | Drawbacks |
|---|---|---|
| Pressure-treated pine | Lowest cost, widely available, durable outdoors | Heavy, often damp, can twist as it dries |
| Cedar | Light, naturally rot-resistant, easy to work | More expensive and softer, so dents easily |
| Exterior-rated plywood | Useful for brackets and gussets, stable when sealed | Edges must be sealed; avoid indoor-grade plywood |
Buy straight 2x4s for the long frame rails and legs, 1×3 or 1×4 boards for the slats, and 2×2 stock for the backrest frame and support bar. You will also need exterior screws, waterproof wood glue, two corrosion-resistant hinges, and a pair of bolts or pins for the adjustable support. A stainless steel exterior screw set costs more than coated screws but is worthwhile near saltwater or in persistently damp climates.
Cut list and tools
For one lounger, cut two 2×4 side rails at 72 inches, two 2×4 end rails at 21 inches, and four legs at 12 inches. Cut the seat slats into eleven pieces of 1×3 at 24 inches. For the backrest, cut two 2×2 side pieces at 30 inches, two crosspieces at 21 inches, and five 1×3 slats at 24 inches. Cut one 2×2 support bar at 22 inches.
These measurements assume actual lumber dimensions close to the nominal sizes. Measure your stock before cutting, particularly if you use dressed hardwood. A tape measure, square, pencil, drill, countersink bit, saw, clamps, and random-orbit sander are sufficient. A random-orbit sander saves time on the broad surfaces, but sanding by hand is perfectly adequate for a single build.
Build the base frame
Lay the two side rails parallel on a flat surface. Position the end rails between them, flush with the ends, and check the rectangle by measuring both diagonals. The diagonals should match within 1/8 inch. Apply glue to the joints, drill pilot holes, and drive two 3-inch exterior screws through each side rail into each end rail.
Attach a leg inside each corner. Keep the top of every leg flush with the top edge of the frame, then fasten each leg with two screws through the side or end rail. Do not rely on glue alone; outdoor wood movement can open a glued joint. Set the frame upright and check for rocking. If it rocks, identify the short leg and trim it rather than forcing the frame level with screws.
Add a center support beneath the seat slats if the lounger will carry more than about 180 pounds. A 21-inch 2×4 spanning between the side rails prevents the slats from flexing and reduces squeaking. Place it halfway along the length and fasten it with pocket holes or metal angles.
Fit the seat slats
Space the eleven slats across the length of the frame, leaving about 1/2 inch between boards for drainage and expansion. Start at the head and foot with the same margin, then adjust the final gaps slightly rather than ending with a very narrow space. A scrap of 1/2-inch plywood makes a consistent spacer.
Pre-drill two holes at each end of every slat. Use screws long enough to penetrate the frame by roughly 1 1/4 inches, but not so long that they protrude through the side rails. Countersink the screw heads lightly. Over-tightening can crush soft cedar and create puddles around the fasteners.
Make and install the adjustable backrest
Assemble the two 30-inch backrest sides between the crosspieces, forming a rectangle 21 inches wide. Check it for square, then add five slats across the frame with 1/2-inch gaps. Round or ease every exposed edge with sandpaper; sharp slat corners are uncomfortable against bare skin.
Position the backrest at the head of the seat with its lower crosspiece resting just above the rear seat slat. Attach it with two hinges mounted underneath or on the outside of the side rails. Leave a small clearance—about 1/8 inch—so the wood can swell without binding. Test the hinge movement before installing all screws.
The simplest adjustment system is a support bar with a row of notches. Cut five or six shallow, rounded notches into the bar, each about 2 inches apart. Attach the bar to the backrest with a bolt through each side, allowing it to pivot. The free end rests against a fixed 2×4 crosspiece under the seat. More notches provide finer adjustment, but leave at least 1 1/2 inches of wood between notches so the bar does not split.
For a cleaner appearance, use stainless steel quick-release pins through holes in the backrest sides and matching holes in fixed side brackets. This is stronger and less likely to slip than a loose support bar, but it takes more accurate drilling.
Sand, finish, and test safely
Sand exterior surfaces with 80-grit paper first, then 120 grit. Use 150 grit on hand-contact areas if you want a smoother feel. Remove dust and apply two or three coats of an exterior penetrating oil or deck finish, following the drying times on the container. A clear finish preserves the color briefly but usually needs more frequent recoating than a pigmented outdoor finish. Use an exterior wood deck finish rated for outdoor furniture.
Before use, place the lounger on a level surface and load the seat gradually with at least 250 pounds of distributed weight. Check for twisting, loose screws, hinge movement, and support-bar slippage. Sit in every backrest position and shift your weight backward. If the bar lifts, the notches are too shallow or the support contact point is too far forward. Deepen the notches carefully or add a positive retaining pin. Inspect the lounger at the start of each season, especially around hinges, end grain, and any cracked support member.