A screen enclosure is not a sunroom with the glass taken out. It is an unconditioned structure whose whole job is to hold a mesh skin flat and in tension against wind, and to still be holding it after ten years of sun. That one difference moves the critical dimension on the drawing somewhere most buyers never look.

We are a custom aluminum extrusion manufacturer in China and an OEM supplier of screen enclosure, screen room, flyscreen and mosquito screen frame profiles: posts, top and bottom beams, roof members, kick plates, door frames, and the screen channel sections that hold the mesh. Everything is extruded, finished and machined to your drawing at one plant in Foshan, Guangdong — 26 extrusion presses, 100,000 tonnes a year, shipping to more than 50 countries since 2005.

What a Screen Enclosure Frame Has to Do

A screen frame is decided by three things, not by its thermal break: the screen channel, the member section, and the bottom rail drain path.

A sunroom specification is dominated by the thermal break, because a sunroom is conditioned. A screen enclosure is not. There is no glass to keep warm and no dew point to stay above, so a polyamide barrier is not the variable that decides whether the part works. It is available on request where part of an enclosure is glazed, and for the great majority of screen frames it is money spent in the wrong place. The sections we run for partly glazed work are cut on the same dies as our sunroom and veranda frame profiles, so a frame can carry glass and mesh on the same post line.

Three things decide a screen frame instead:

• The screen channel, because it decides whether the mesh stays in.
• The member section, because wind load on screening is higher than most people assume, and deflection is what the end customer actually sees.
• The bottom rail and the water path, because standing water destroys a frame from the inside, where nobody looks until the coating has already gone.

Everything else — finish colour, cap detail, corner joint — is visible, but rarely fatal.

The Screen Channel: Where These Frames Actually Fail

The channel mouth is the failure point. It is held to ±0.1 mm, at the GB/T 5237 high-precision grade, because the dimension grows as the die wears.

When a screened panel pops out after two summers, the mesh is not the problem and the spline is not the problem. The fit between the two is.

A screen channel has one job: compress the mesh against the base of the groove hard enough that friction and the undercut hold it, and gently enough that the mouth does not open up. Four dimensions do that work, and all four are cut into the die:

• Mouth width. Sized from the spline diameter, not picked from a table. A mouth that is wide relative to the spline lets the spline walk out under load; a mouth that is too tight will not let the installer seat the spline without distorting the channel, and a distorted channel never grips properly again.
• Groove depth. The spline has to push the mesh all the way to the groove base. In a shallow groove the mesh is trapped only at the lip, and the lip is the first thing that releases in a hard wind.
• Undercut or return lip. This is the mechanical lock. Channels without a return depend on friction alone, and friction is the first thing heat takes away.
• Base radius. A square groove base cuts the mesh under tension. The radius at the base is why a properly cut profile does not tear at the groove and a cheap one does.

We hold the channel mouth to ±0.1 mm. That is the GB/T 5237 high-precision grade — tighter, in our experience, than the equivalent EN and ASTM tolerance classes on the same dimensions — and it is the grade we run as standard rather than something upgraded per order. The mouth is measured through the run rather than once on the first billet, because it grows as the die wears. A channel that grips perfectly at billet five hundred can be loose by billet fifty thousand — and the customer discovers it as panels popping out a year after installation, long after the profile was accepted.

Send us the spline diameter, the mesh type — insect weave, a fine flyscreen mesh, or a heavier coated mesh — and the installation method, and the channel is cut to ±0.1 mm on that combination. We do not publish a generic channel, because a groove sized for one spline and one mesh crimp will not hold a different pair. The five field failures that follow from getting this wrong, and the other four, are set out in our note on sunroom and screen room problems and how to engineer them out.

Spans, Alloy and Deflection

Screen frames are governed by wind, not weight: 6063-T5 under 2.5 m, 6063-T6 past it, 6061-T6 for long spans. Check deflection, not stress.

Screen enclosure members are light, and that is exactly why they deflect. A screen panel presents far more sail area than its weight suggests, so roof members and tall wall posts are usually governed by wind rather than by dead load, and glazing is not there to stiffen anything.

The alloy follows the span, the same way it does on any frame we extrude:

• Short spans and non-structural members — bottom rails, kick plate returns, screen stops, door surrounds. 6063-T5, usually 1.0–1.5 mm wall.
• Roof members and wall posts over roughly 2.5 m. 6063-T6, which gives about 30% more yield strength in the same section than T5.
• Long spans, high design wind speeds, or a member carrying both roof and screen load. 6061-T6 nearly doubles the yield strength of 6063-T5. 6005A-T6 is available on request where a project specifies it.

Two levers usually decide the outcome, and the cheaper one is almost always geometry. Deepening the section raises stiffness far faster than moving up an alloy family, and it does not change the finish, the fasteners, or the connection detail. The alloy change is what you reach for when the depth is already fixed by a cap, a head detail, or the space between two posts.

Check deflection to a stated limit — L/180 is a common limit for roof members — rather than checking stress alone. A screen frame almost never fails structurally. It goes out of sight line first: a roof member that sags between posts, a door that stops closing square, a panel that reads as bowed from the far side of the terrace. Those are deflection failures, and they are visible long before anything yields.

Tell us the span, the post spacing, the design wind speed your project is permitted under, and the deflection limit your engineer is working to. The die is sized around that set rather than chosen from a catalogue.

Wind, Water and the Bottom Rail

A bottom rail with no weep path holds water along its full length. Drain it at the low end of the run, and keep fasteners out of the water path.

Water always reaches a screen frame. The design question is where it goes next, and on a screen enclosure the answer is decided at the bottom rail, the kick plate and the post base.

• Drain the rail, do not seal it. A bottom rail with no weep path holds a bead of water along its whole length after every storm. That is where coating fails first, where the frame stains, and where the fastener at the lowest point corrodes.
• Put the weep holes where the water actually collects, which is the low end of the run, not evenly spaced. On a long level rail, evenly spaced holes let the middle of the rail hold water.
• Keep the fastening points out of the water path. A screw that sits in standing water is the first thing to fail, and it takes the coating around it with it.
• Detail the kick plate so water running down the mesh discharges outside the frame line, not into the joint between the rail and the deck.
• On sloped screen roofs, never rely on sealant as the primary barrier. Sealant is a secondary defence behind geometry.

Finish and Fasteners for Coastal and High-UV Sites

Powder coating is standard; anodizing runs AA10 or AA15. Isolate stainless fasteners — galvanic staining is the most common appearance failure.

Screen frames sit outdoors in full sun and are almost never cleaned. In the coastal, desert and high-UV markets these frames are usually specified for — the Gulf, North and West Africa, Latin America and Southeast Asia — the finish is competing with UV, heat, salt and dust at the same time.

Powder coating is the finish we run most for these frames. It holds colour across a batch, which matters when a frame is fabricated from several sections and assembled on site. Anodizing is available in AA10 or AA15 where a metallic finish or abrasion resistance is wanted. PVDF systems are quoted on request where a project's specification calls for them, and hard-coat anodizing is rarely specified on screen frames — it is quoted on request rather than offered as a standard route.

Three points decide how long a screen frame stays acceptable on a coastal or desert site:

• Isolate the fasteners. Stainless steel fasteners into aluminum in coastal air produce staining at every fixing point unless the joint is isolated. Nylon washers, isolating sleeves or a coated fastener take the couple out of the assembly. This is the single most common appearance failure we see on frames that were otherwise built correctly.
• Cover the cut ends and drilled holes. Extrusion is coated in line, so a profile is protected on its face and bare at every cut and every punch. Site-cut members and drilled fastener holes need a touch-up procedure or they will bloom first.
• Choose the colour for the coating's sake as much as the design's. A dark frame in high-UV service runs hotter and works the coating harder. Where a project has a free choice of colour and a long service life, a lighter tone is the lower-risk decision.

Every shipment leaves with the composition, mechanical properties, dimensional and coating reports. Mill test report supplied with every shipment.

Fabrication, Length and Container Loading

There is no standard length. A 20 ft container takes 5.85 m; a 40 ft takes 6.0 m with two lengths inside. Under 5 m adds a cutting charge.

There is no standard length on these profiles. Sections are cut to the length your program needs, from your cutting list.

What does matter is how the length loads:

• A 20 ft container takes a maximum of 5.85 m.
• A 40 ft standard container and a 40 ft high cube take 6.0 m, and two lengths fit along the container. This is the standard export route for 6 m material, and it is why 6.0 m is the practical module for full-length posts and roof members: two sections load end to end inside a 12 m cargo space.
• A 45 ft container will take up to 6.4 m, but we do not plan an order around one. 45 ft equipment is scarce on most trade lanes and a number of terminals will not handle the box, so a schedule that depends on it is a schedule carrying a risk.
• Lengths under 5 m carry an additional cutting charge. Short members mean more saw setups and more offcut per bundle, and on a frame set with many short elements — door surrounds, kick plate returns, screen stops — that cost is real.
• Members that will not fit the container are cut down and joined on site with connector stock, or split into two lengths with a splice detail on the drawing.

Cutting, punching, tapping, milling and notching are all carried out before shipment. Corner notches and mitre cuts are made on our machines so the joint closes properly on site rather than being filed to fit by the installer. Hardware holes can be pre-drilled to your bracket pattern. Profiles are bundled in shrink film for transit.

Ordering: MOQ, Tooling, Lead Time and Terms

MOQ is 500 kg per profile, tooling is quoted per project, and lead time is 15–25 days after die approval. Weight tolerance is ±10%.

• Minimum order quantity is 500 kg per profile. On a frame set with many sections, that lets a small system travel in the same container as a full one instead of forcing a separate order per section.
• Die tooling is quoted for the project. It depends on the section size, the number of hollow chambers and the screen channel detail, so it is priced against your drawing rather than from a public list.
• Extruded weight tolerance is ±10%. A 500 kg nominal order can arrive between about 450 kg and 550 kg, and it is worth building that into your costing before the PO rather than after.
• Typical lead time is 15–25 days after die approval, including finishing and machining.
• Terms are FOB Shenzhen or Guangzhou. Export packing is to your requirement, including mill-length bundles or cut-to-size crates.
• Profiles are supplied to GB/T 5237 high-precision tolerances. Critical dimensions are controlled at the die rather than corrected after extrusion.
• Export documentation travels with the goods. Composition, mechanical properties, dimensional and coating reports ship with every order.

As an OEM aluminum extrusion supplier and a custom aluminum extrusion manufacturer in China, we work from your drawing and your branding, on your packaging and your documentation requirements. If you are placing a first order and want to judge whether a factory is reliable before you commit a programme to it, ask for a section sample off the production die before the balance of the run is finished — we would rather catch a channel dimension at sample stage than hear about it as a claim.

Typical Applications and What to Send for a Quotation

Send drawings, alloy and temper per section, span and post spacing, design wind speed and cutting list. We check manufacturability before quoting.

• Patio and terrace screen enclosures, and pool surrounds
• Screen rooms, porch enclosures and covered outdoor areas
• Flyscreen and mosquito screen frames for windows, doors and ventilation openings
• Roof members, posts and beams for screened roofs and pergolas
• Kick plates, bottom rails and screen stops
• Door frames, screen door sections and hardware surrounds
• Partly glazed enclosures where a thermal break section is specified

To start a quotation, send cross-section drawings for the full set, the alloy and temper required per section, span and post spacing, design wind speed, the spline diameter and mesh type, finish type and colour reference, quantity per section, and your cutting list. We review manufacturability, flag any section that will not extrude cleanly or hold the channel dimension you need, and quote from there.