POLYWOOD vs SERWALL

POLYWOOD and SERWALL sell furniture made of the same thing: high-density polyethylene poly lumber, with color and UV inhibitors compounded through the material rather than coated onto it. What separates them is not polymer, it is paperwork. POLYWOOD publishes its material, its hardware grade and a 20-year residential warranty that names the failure modes it covers; SERWALL publishes a price. If you want the material and can accept an unverifiable specification, SERWALL is a genuine saving. If you are buying once and want to be able to check the claim, you are buying POLYWOOD.

The short answer

This comparison is not really about two brands. It is a worked example of the central problem in poly lumber furniture: the material is excellent and almost nobody has to prove they are using it properly. HDPE itself is cheap to source and simple to extrude into board, so the material floor in this category is high — which is why a budget poly chair is a much better object than a budget steel chair. The ceiling, though, is set by board thickness, hardware grade, joinery and whether anyone will stand behind the piece in eight years, and those are exactly the things an unbranded listing leaves out.

The material is the same

Worth stating plainly, because the brand gap invites the assumption that the plastics differ. They generally do not in kind:

• Both are HDPE. POLYWOOD describes its lumber as HDPE with colorants and UV inhibitors compounded through the material, and SERWALL's listings describe HDPE poly lumber construction. That is the same material family.
• Both are therefore rot-proof, insect-proof and inert. Neither absorbs water, neither supports fungi, neither needs sealing, oiling or refinishing — ever.
• Both fade the same way, which is barely. Compounded color cannot wear off the way a surface coat can. There is no coating to chalk.
• Neither can rust, structurally. Poly lumber has no metal in it except the fasteners, which is why hardware grade is the one metal question that matters — the HDPE reference page goes through this.

"POLYWOOD" is a brand name for HDPE lumber, not a rival material to it. That confusion is common enough that it has its own page: HDPE vs POLYWOOD.

What each brand publishes

What the price gap actually buys

Four things, in descending order of how much they are worth to a buy-it-for-life buyer:

• A warranty that names failure modes. "Twenty years against splintering, cracking, chipping, peeling and rot" is a claim about the material that someone can be held to. An unstated warranty is not a shorter warranty; it is an unknown one.
• Stated hardware. On a chair where nothing else can corrode, the fasteners are the entire corrosion exposure. Stainless, stated, removes it.
• Mass. Heavier board and heavier sections mean the chair is still where you left it after a gusty evening, which is a real functional difference on a lakeside deck and not a quality abstraction.
• Parts and continuity. A brand that stocks replacement slats and hardware in year eight is a different proposition from a listing that may not exist in year two.

What the gap does not buy is better plastic. Anybody telling you a budget HDPE chair will rot or rust is wrong about the material. It will not. The risks are flex, fasteners and nobody to call.

Which to buy

• Buy POLYWOOD if this is a once purchase, if the furniture lives on an exposed deck where weight matters, or if the published warranty is part of why you are paying more than big-box prices in the first place.
• Buy SERWALL if you need several seats at once and the budget is the binding constraint. Four poly stools that will not rot beats two premium stools and two steel ones, and it comfortably beats four steel stools. Go in knowing the warranty is unverified.
• Consider Trex Outdoor Furniture if you want POLYWOOD's manufacturing and terms in a different profile — the relationship between them is set out in POLYWOOD vs Trex.
• Consider LuxCraft or Berlin Gardens for small-batch US poly with options the volume brands do not offer, accepting patchier availability: POLYWOOD vs Berlin Gardens covers the trade.

If what you actually want is the cheapest honest route into poly furniture, the field is ranked in POLYWOOD Adirondack alternatives and the best HDPE Adirondack chairs.