Aluminum Exterior Window Sill — CTB Series
One-piece waterproof exterior window sill in 6063-T5 aluminum. 9 width options (50–210 mm), stock length 6 m, finished in Austrian Tiger Drylac® powder coating with a 10-year warranty. Snap-fit installation — no exposed fasteners.
WHY IT MATTERS
Why Window Sills Fail — and How Aluminum Exterior Window Sills Solve It
Aluminum exterior window sills solve a problem that concrete, tile, and marble can’t. These materials are porous. Years of rain and UV crack them, water seeps into the wall, and you get stains, mold and repairs. The CTB Series replaces all of that with a single extruded aluminum profile that water cannot penetrate — built to shed water, not just resist it.
100% Waterproof
One-piece extruded 6063-T5 aluminum. Water is shed, never absorbed — no more staining, no more wall damage.
Pre-Sloped Surface
Built-in slope sheds rainwater forward. No ponding, no seepage back to the wall.
Tiger Drylac® Powder Coat
Austrian-engineered Tiger Drylac® powder coating. 10-year color and weather resistance warranty.
Snap-Fit Installation
Clip-on design with concealed base. No visible screws, no need to dismantle the window frame.
CTB Series Variants
9 Widths to Match Every Project
Every building has a different opening. The CTB Series covers the full residential and commercial range: Each exterior window sill width is extruded from 6063-T5 aluminum and powder coated for a clean, consistent finish.
Aluminum exterior window sill (CTB series) installed in cross-section view — watertight seal at frame, sloped surface, drip edge.
CTB Series — 9 standard widths from 50 mm to 210 mm. Front lip 40 mm; wall thickness increases with width for rigidity.
| Model | Sill Width | Stock Length | Wall Thickness | Standard Colors |
|---|---|---|---|---|
| CTB-50 | 50 mm | 6 m | 1.5–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-70 | 70 mm | 6 m | 1.5–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-90 | 90 mm | 6 m | 1.5–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-110 | 110 mm | 6 m | 1.5–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-130 | 130 mm | 6 m | 1.5–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-150 | 150 mm | 6 m | 1.5–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-170 | 170 mm | 6 m | 2.0–3.5 mm | Tiger Black / Gray / Coffee |
| CTB-190 | 190 mm | 6 m | 2.0–3.5 mm | Tiger Gray / Coffee |
| CTB-210 | 210 mm | 6 m | 2.5–3.5 mm | Tiger Gray / Coffee |
- Pre-sloped surface with integrated drip edge — water runs off cleanly without staining the facade.
- 40 mm front lip height — uniform across all 9 widths for consistent appearance.
- Factory cut-to-length or 6 m stock — cut to your required length in-house, or shipped as full 6 m bars for site cutting.
- Color note: CTB-190 and CTB-210 are stocked in Tiger Gray / Tiger Coffee only; all other widths are stocked in all three colors.
Base & Snap-Fit System
Two Base Profiles, One Snap-Fit System
The CTB Series is designed to clip onto a separate aluminum base that is fixed to the window frame — never to the wall. This means the sill is fully removable for service, but invisible fasteners hold it tight under wind and weather.CTB base channels are engineered specifically for the aluminum exterior window sill system — they lock the sill down without exposing fasteners on the finished face.
CTB-DZ-G
For "G"-type window frames (with a specific rebate geometry)
CTB-DZ-F
For "F"-type / flat-frame window frames
Base width: 31 mm — slim enough to stay hidden inside the frame reveal, strong enough to carry the full sill without flex.
How to specify: when ordering, tell us your window frame type (or send a section drawing) and we will match the correct base. G and F bases can also be mixed on a project if different window suppliers are used.
End Caps & Joint Covers
End Caps & Joint Covers — Clean Finishing for Every Project
For premium residential and villa projects, raw cut ends are not acceptable. The CTB Series offers matching aluminum accessories — optional, project-priced add-ons — to finish every detail.Aluminum exterior window sill end caps and joint covers are quoted per project on request, since every project has different runs, corners and quantities.
- Aluminum end caps — factory-fitted left/right end caps close the open profile and give a clean termination on walls and window reveals.
- 45° mitered corners — sills can be supplied with factory-cut 45° miters for outside corners.
- Joint covers — for straight-run joints and corner joints alike, cover the raw cut for a clean, neat finish and improve waterproofing at the seam.
End Caps
Joint Covers
Pricing note: end caps and joint covers are optional paid accessories — not included in the standard sill price, quoted per project on request. Standard projects can skip them (cut ends are simply sealed against the wall); villa and high-end residential projects get the cleanest result with end caps, miters and joint covers.
Stock Colors & Custom Color
Three Stock Colors, Plus Custom Color
Our standard in-stock color range is finished with Tiger Drylac® Austrian powder coating — the same premium coating used on architectural facades across Europe and Australia.Our exterior window sills come in three powder-coated finishes：
- Tiger Black
- Tiger Gray
- Tiger Coffee — warm brown tone for wood-tone facades
Color naming convention: the official SKU is Tiger Black / Tiger Gray / Tiger Coffee (not a RAL code). Always use these exact names in inquiries so our China office can match the order correctly.
Availability note: CTB-190 and CTB-210 are stocked in Tiger Gray and Tiger Coffee only (not Tiger Black). All other widths are available in all three stock colors
Tiger Black
Tiger Gray
Tiger Coffee
Custom Color (RAL / Project-Matched)
Need a specific RAL, a project-matched color, or a custom Tiger Drylac® shade? We accept custom color orders.
- Order quantity ≥ 100 m: no extra color-setup fee
- Order quantity < 100 m: a one-time color-setup fee applies (quoted on request)
Send your RAL code, Pantone reference, or physical color sample to our sales team and we will confirm feasibility, MOQ and pricing.
Installation
Installed in 4 Simple Steps
The CTB system is built so installers don’t need specialty tools. A standard foam gun, structural sealant and a cordless drill are all that is required.
- Choose the base. Match CTB-DZ-G or CTB-DZ-F to your window frame type.
- Fix the base. Screw the base channel to the underside of the window frame before the frame is fully installed.
- Install the window frame. Set the frame in the opening as normal.
- Apply foam / structural sealant on the exterior substrate, then clip the CTB sill down onto the base. Finish by sealing the seam between the sill back and the window frame with weatherproof sealant.
The snap-fit engagement, combined with sealant, holds the sill permanently — no rattle, no lift under wind load.
SPECIFICATIONS
Technical Specifications
| Parameter | Value |
|---|---|
| Material | 6063-T5 aluminum alloy |
| Series | CTB (9 widths: 50 / 70 / 90 / 110 / 130 / 150 / 170 / 190 / 210 mm) |
| Sill face height | 40 mm |
| Stock length | 6 m per piece |
| Wall thickness | 1.5–3.5 mm (CTB-50 to 150);2.0–3.5 mm (CTB-170/190); 2.5–3.5 mm (CTB-210) |
| Surface treatment | Tiger Drylac® powder coating (Austrian) |
| Stock colors | Tiger Black / Gray / Coffee (no RAL match; CTB-190/210 in Gray & Coffee only) |
| Custom color | RAL / project-matched; orders under 100 m incur color-setup fee |
| Pre-slope | Yes, built into profile |
| Base system | CTB-DZ-G (G-frame) / CTB-DZ-F (F-frame), 31 mm |
| End caps | Optional paid accessory, aluminum left/right pair |
| Corner treatment | Factory 45° miter; joint covers (straight & corner) as paid add-ons |
| Installation | Snap-fit onto base + structural sealant |
| Warranty | 10 years on powder coat |
| Lead time (stock color) | 3–7 days (larger orders may exceed7 days) |
| Lead time (custom color) | 15–30 days |
| Packaging | Protective film → protective cotton → optional wooden case/frame |
| Sample | Free sample, buyer pays international shipping |
PROJECTS
Where CTB Sills Are Installed
From residential towers to commercial facades, the CTB Series is specified wherever a low-maintenance, water-shedding sill is needed.Across the world, our exterior window sills protect facades on residential, commercial, hospitality and public projects.
Residential developments
Apartment towers and villas where a clean sill line completes the facade and protects the wall below.
Commercial buildings
Offices and retail facades that demand consistent color and a uniform sill profile across every window.
Hospitality projects
Hotels and resorts where powder-coated sills stay clean with minimal upkeep.
Public buildings
Schools, clinics and civic projects that need durable, fire-safe aluminum with a 10-year coating warranty.
Full project profiles are published as articles — check back or contact us for recent installations.
FAQ
Frequently Asked Questions
Q1: What widths of exterior window sill do you offer?
We manufacture 9 standard widths from 50 mm to 210 mm, in 20 mm increments. For widths beyond our standard range, we can custom-fold aluminum sheet to your required width — priced according to the actual dimensions.
Q2: What is the maximum single-piece length?
Stock length is 6 m per piece. Sills are cut to your required length in-house, so the actual delivered length is whatever your project needs up to 6 m in one run.
Q3: Can you match my project color?
Yes. In addition to the three stock colors (Tiger Black / Gray / Coffee), we accept custom RAL or project-matched color orders using Tiger Drylac® powder. Orders of 100 m or more are quoted at standard rates; orders under 100 m incur a one-time color-setup fee. Send your RAL code or color sample for a quotation.
Q4: How is the sill installed?
The CTB sill snaps onto a separate aluminum base (CTB-DZ-G or CTB-DZ-F) that is fixed under the window frame. Foam or structural sealant is applied on the substrate, the sill is clipped down, and the joint at the window frame is sealed. No screws are visible on the finished sill.
Q5: Do you supply end caps and joint covers?
Yes. Aluminum end caps and 45° mitered corners are available as optional paid accessories. Joint covers can be supplied for both straight-run and corner joints. All are recommended for villa and high-end residential projects, and quoted per project on request.
Q6: What warranty do you offer?
Tiger Drylac® powder coating is warranted for 10 years against color fade, chalking and film integrity under normal outdoor conditions.
Q7: Can I get a sample before ordering?
Yes. We provide samples of stock colors and standard widths for approval before mass production. The sample itself is free; international shipping (DHL / FedEx) is paid by the buyer at cost.
Q8: What is the production lead time?
For stock colors, lead time is typically 3–7 days depending on quantity. Very large orders may exceed 7 days. Custom color orders take longer — 15–30 days depending on order size and color scheduling. We confirm the exact date on quotation.
Q9: How is the product packaged for export?
Every piece is protected with surface film, then wrapped in protective cotton. Export wooden cases or wooden frames are available on request.
Q10: What information do you need for a quotation?
Please send us the sill width (or window opening size), total linear meters, color, quantity, and destination port. CAD or hand drawings of the project are helpful for end-cap and corner calculations.
Q11: How do I contact your sales team?
We respond fastest on WhatsApp (preferred for international buyers), Facebook Messenger, and WeChat for buyers already in China. Email is also available. All channels are linked in the page footer.
Request a CTB Series Quotation
Our team replies to exterior window sill inquiries within 12 hours. Send us your dimensions and we will return a quotation including FOB or CIF pricing, lead time, and accessories (end caps, joint covers, base channels) on request.