Short answer: Poly lumber is solid high density polyethylene (HDPE) plastic formed into board sizes, with UV stabilized color mixed all the way through. It does not rot, splinter, absorb water, or need paint or stain, and it cuts and screws with ordinary woodworking tools. Wood is cheaper up front but needs refinishing and eventually fails outdoors. Composite decking mixes wood fiber with plastic, comes mostly in deck board profiles, and is built for decks rather than furniture. For outdoor furniture that you want to build once and never maintain, poly lumber is the material. The tradeoffs are cost, weight, and the fact that it expands and contracts with temperature far more than wood.
Bear Hollow Supply sells HDPE poly lumber made in the USA, in 10 board sizes and 26 colors, shipped from Fredericksburg, Ohio. This guide compares poly to wood and composite, explains where it works and where it does not, and covers what changes when you build with it. For the full engineering numbers, see our HDPE poly lumber product data sheet.
What poly lumber actually is
Poly lumber is extruded from high density polyethylene, the same plastic family used for milk jugs and detergent bottles. Much of it is recycled. The plastic is melted, pigment and UV inhibitors are mixed in, and the material is formed into solid boards in standard furniture dimensions. Because the color is in the material rather than on the surface, a scratch or a cut end shows the same color as the face. There is no cap layer to wear through and no finish to peel.
This is the material used in the poly Adirondack chairs, gliders, and picnic tables sold by outdoor furniture brands. Buying the lumber instead of the finished chair lets you build the design you want, repair existing furniture, or produce furniture to sell.
Poly lumber vs wood
| Poly lumber (HDPE) | Wood (cedar, treated pine, teak) | |
|---|---|---|
| Rot, insects, mold | Impervious. Does not absorb water. | Cedar and teak resist it; treated pine resists it for a while. All eventually fail without maintenance. |
| Finish | None needed. Cannot be painted or stained. | Needs sealing or staining every one to three years to keep its look. |
| Splinters and checking | None. | Checks and splinters as it weathers. |
| Color | UV stabilized, through the board. 26 colors. | Natural color grays without finish. Any color you can paint. |
| Weight | Heavy. Roughly twice the weight of cedar for the same board. | Light (cedar) to moderate (treated pine). |
| Thermal movement | Large. Expands and contracts with temperature much more than wood. | Small with temperature; moves with humidity instead. |
| Stiffness | Lower than wood. Needs closer support spacing. | Higher. Spans farther. |
| Structural use | Furniture and decorative use only. Not for framing, joists, or supports. | Rated structural lumber available. |
| Up front cost | Higher. | Lower. |
| Lifetime cost | Low. No refinishing, no replacement. | Adds up over years of finish and eventual replacement. |
| Tools | Standard woodworking tools. | Standard woodworking tools. |
The honest summary: wood wins on price and stiffness, poly wins on everything that happens after the furniture goes outside. If you are building a bench for a public park, a glider for a porch that gets rained on, or furniture you are selling with a warranty, the lack of maintenance is the whole point.
Poly lumber vs composite decking
People often lump these together because both are plastic based. They are different products.
- Composite decking is a blend of wood flour and plastic, usually with a thin plastic cap on the visible faces. The wood fiber inside can take on moisture at cut ends and screw holes, which is why composite boards can swell or mold at the ends. Composite is also sold almost entirely as deck boards, roughly 1 inch by 5-1/2 inches, with grooved edges for hidden fasteners. You can build furniture from it, but you are limited to that one profile and the cut edges show the uncapped core.
- Poly lumber is solid HDPE with no wood fiber and no cap. It is sold in furniture dimensions: 3/4 inch boards for seats and backs, 1-1/2 inch square stock for legs and rails, 2 by 4 and 2 by 6 for frames. Every cut edge looks like the face.
If you are building a deck, buy decking. If you are building furniture, buy poly lumber. Composite is the wrong shape and the wrong construction for chairs and tables.
Where poly lumber is the right choice
- Adirondack chairs, gliders, rockers, and porch swings
- Outdoor dining tables and benches, especially with metal bench legs or a pedestal base carrying the load
- Planter boxes, raised beds, and garden furniture
- Replacement slats for worn out wood benches and park furniture
- Dock and poolside furniture that lives wet
- Furniture you sell and do not want warranty calls on
Where it is not the right choice
- Anything structural. Our poly lumber is not rated for load bearing applications like framing, joists, deck structure, or stair stringers. Build the frame from wood or steel and use poly for the parts you see and sit on.
- Long unsupported spans. HDPE is less stiff than wood and will sag over a long span, more so when hot. Keep supports closer together than you would with wood. The data sheet gives recommended spacing.
- Projects where you want to paint or stain. Nothing bonds to HDPE reliably. Pick the color you want from the start.
- Glue joints. Standard wood glues and construction adhesives do not hold on polyethylene. Every joint is mechanical: screws, bolts, or hardware.
- Tight budgets. If the project will be replaced in five years anyway, treated pine is cheaper.
Sizes and how it is sold
We stock these profiles. Titles are actual dimensions, not nominal.
- 3/4 x 1-3/4, 3/4 x 2-5/8, 3/4 x 3-1/2, and 3/4 x 5-1/2 for seats, backs, slats, and tabletops
- 1 x 5-1/2 and 1-1/8 x 3-1/2 for thicker tops and arms
- 1-1/2 x 1-1/2 square stock for legs, rails, and stretchers
- 2 x 4, 2 x 6, and 2 x 10 for frames and heavy parts
Boards are sold in packs: 3 or 6 boards at 44 inches, 2 boards at 72 inches, or a full pallet at 144 inches. Boards are cut from longer stock after you order, so poly lumber sales are final. If you are matching colors or deciding between several, the color sample box has 30 small pieces to compare in daylight. Shops and builders buying pallet quantities can apply for a wholesale account.
Colors
All 26 colors are UV stabilized through the board: Anchor Gray, Aruba Blue, Black, Blue, Bright Pink, Cedar, Charcoal Gray, Coffee, Cranberry, Dark Green, Golf Green, Light Gray, Lime Green, Orange, Patriot Blue, Peacock, Purple, Red, Sage, Sand, Sea Foam, Stone Mountain Gray, Tudor Brown, Weatherwood, White, and Yellow. Dark colors get hotter in direct sun than light colors, which matters for seats. Lighter grays, Sand, and White stay cooler.
What changes when you build with poly instead of wood
Poly lumber machines like a dense hardwood, but a few habits from woodworking need adjusting. The data sheet has the specifics; here is the short version.
- Cutting. Use sharp carbide blades. A triple chip grind blade leaves the cleanest edge. Feed steadily; stopping mid cut lets the plastic heat and smear. Chips are stringy rather than dusty.
- Routing. Sharp carbide bits, moderate speed. A 1/8 inch or 1/4 inch round over on edges is standard on poly furniture and hides any saw marks.
- Drilling and screws. Pre-drill pilot holes. Use stainless steel or coated exterior screws so the fasteners outlast the lumber. Coarse thread screws hold better in HDPE than fine thread. Keep screws back from board ends and edges to avoid splitting. Do not overdrive; the plastic will not crush the way wood does and the head will strip out.
- Allow for movement. HDPE grows noticeably in summer heat and shrinks in winter cold, many times more than wood. Leave gaps between slats, do not butt long boards tight against fixed stops, and avoid trapping a long board between two rigid points. Slotted holes or a single fixed end with the other end free are good practice on long runs.
- No glue, no paint, no stain. All joints are mechanical. Pick your color at purchase.
- Sanding. Not needed and not recommended. Sanding scuffs the surface and dulls the color. Clean saw and router cuts are the finish.
- Cleaning. Soap and water. Stubborn marks come off with a soft brush. Pressure washing at low pressure is fine.
- Hardware. Because the lumber will outlast everything else, match it with stainless hardware. For gliders, use stainless steel glider bearing arms so the mechanism does not rust while the poly stays new. Our outdoor furniture hardware collection covers glider arms and stainless chair swivels.
Is poly lumber worth the cost?
Compare a cedar bench and a poly bench over ten years. The cedar bench costs less on day one, then needs cleaning and resealing every couple of years, and somewhere in year eight to twelve the slats check, the fasteners loosen, and you rebuild it. The poly bench costs more on day one and then costs nothing. For a single chair on a covered porch, the math may favor cedar. For a set of furniture in full weather, a commercial installation, or anything you sell, poly comes out ahead.
There is also the environmental argument. Much HDPE lumber is made from recycled bottles and jugs, and the finished board is itself recyclable. It also never sends treated wood or stain runoff into the soil.
Frequently asked questions
What is poly lumber made of?
High density polyethylene (HDPE), a solid plastic with UV stabilized pigment mixed through the entire board. There is no wood fiber and no surface cap. Much of it comes from recycled bottles and jugs.
Is poly lumber the same as composite decking?
No. Composite decking is wood fiber blended with plastic and usually capped. Poly lumber is solid HDPE with no wood in it. Composite comes mainly in deck board profiles; poly lumber comes in furniture sizes.
Can you cut and screw poly lumber with regular tools?
Yes. Sharp carbide saw blades and router bits work well. Pre-drill and use stainless or coated exterior screws. Do not glue, paint, or stain it; nothing bonds to HDPE reliably.
Does poly lumber fade?
The color is UV stabilized and runs through the board, so it holds up far better than paint or stain. Like any material in full sun it may soften slightly in tone over many years, but it will not peel, chip, or gray the way wood does.
Does poly lumber get hot in the sun?
Dark colors do, like any dark surface. Lighter colors such as White, Sand, and the light grays stay noticeably cooler. If the piece is a seat in full sun, pick a lighter color.
Can poly lumber be used for structural framing or a deck?
No. Our poly lumber is for furniture, outdoor projects, and decorative use. It is not rated for framing, joists, or load bearing supports. Build structure from wood or steel.
How much does poly lumber expand and contract?
Much more than wood. Thermal movement is the main design difference. Leave gaps between boards, do not trap long boards between fixed points, and allow for movement in your joinery. The product data sheet gives the expansion figures.
What lengths does poly lumber come in?
We sell 44 inch boards in 3 and 6 packs, 72 inch boards in 2 packs, and 144 inch boards by the pallet. Boards are cut to order from longer stock, so sales are final.