TL;DR: Poor container loading adds 0.20 $/m² in freight waste. In this 5 000-word factory guide, SKW Roof shares 1 380-container data on 40ft HC loading plans, pallet vs loose cargo, moisture control, and live freight rates for 2025. Follow our step-by-step HowTo to load 2 640 m² without damage.
1. 40ft HC Container Specs & Limits
| Parameter | 40ft Standard | 40ft High Cube | Roofing Tiles Limit |
|---|---|---|---|
| Internal length | 12.03 m | 12.03 m | — |
| Internal width | 2.35 m | 2.35 m | — |
| Internal height | 2.39 m | 2.69 m | 2.50 m stacking |
| Door opening width | 2.34 m | 2.34 m | — |
| Door opening height | 2.28 m | 2.58 m | — |
| Payload | 26 680 kg | 26 580 kg | 25 000 kg (tiles) |
| Volume | 67.7 m³ | 76.4 m³ | 62 m³ usable |
Note: Usable volume limited by pallet height (2.30 m) and door opening.
2. Pallet vs Loose Cargo: Data Comparison
| Factor | Palletized Boxes | Loose Cartons |
|---|---|---|
| Capacity (m²) | 2 400 | 2 640 (+10 %) |
| Loading time (hours) | 2.5 | 4.0 |
| Unloading cost ($) | 180 (forklift) | 280 (manual) |
| Damage rate | 2 % | 12 % |
| Moisture exposure | Low (wrapped) | High (stacked) |
| Pallet cost ($/m²) | 0.04 | 0 |
| Total landed cost $/m² | 2.84 | 2.73* |
*Damage cost not included; actual cost 2.85 $/m² after 12% breakage.
2.1 When to Choose Pallet
- First 3 imports (quality assurance priority)
- Destination port labour cost >25 USD/hour
- Valuable custom colours (damage = re-production)
- Humid destination (Mombasa, Lagos, Caribbean)
2.2 When to Choose Loose
- Experienced importer with own forklift
- Price-sensitive market (sell to contractors)
- Dry destination (Dubai, Arizona)
- Large volume (>10 containers/month)
3. Step-by-Step Loading Plan (HowTo)
- Choose pallet or loose
For first 3 imports, use palletized boxes (480-600 pcs/pallet). For experienced importers with forklift, loose cargo saves 8% space. - Stack pallets in container
Load 20 pallets in two rows: front row 11 pallets (door to front), back row 9 pallets. Use air bags to fill gaps. Height: 17 layers max (2.30 m). - Place desiccant bags
Hang 8-12 x 1kg calcium chloride bags on container walls. Place 2 bags between pallets in centre. Total: 10-14 kg desiccant per 40ft HC. - Install data logger
Mount temperature/humidity logger on side wall at mid-height. Set to record every 6 hours for 35 days. SKW Roof uses Elitech RC-5+. - Seal and photograph
Close doors, seal with SKW Roof numbered seal. Photoseal number, container number, and loading pattern. Email photos to buyer before vessel departure.
4. Moisture Control: Desiccants & Data Loggers
4.1 Why Moisture Matters
Stone-coated tiles have exposed galvalume steel edges. Condensation >65% RH for 72h = white rust stains. Claim rate: 0.23% for containers without desiccants vs 0.01% with.
4.2 Desiccant Calculation
| Voyage days | Desiccant (kg) | Placement | Cost ($) |
|---|---|---|---|
| 20-25 (Asia-Pacific) | 8 kg | 4 walls + 2 centre | 12 |
| 30-35 (Africa, S-America) | 12 kg | 6 walls + 2 centre | 18 |
| 40-45 (Europe) | 14 kg | 8 walls + 2 centre | 21 |
4.3 Data Logger Evidence
SKW Roof provides free data logger download link for every container. If RH exceeds 65% for >24h, we reimburse desiccant cost and inspection fee.
5. Packaging Optimization for Sea
5.1 Box Design
- Inner box: 3mm white cardboard, 6 pcs/box (300×420×65 mm)
- Stacking strength: 350 kg compressive (tested by SGS)
- PE wrap: 25 μm UV-resistant, heat-sealed
5.2 Pallet Specs
| Pallet type | Size (mm) | Weight (kg) | Cost ($) |
|---|---|---|---|
| EURO (HT) | 1200×800×140 | 18 | 8.50 |
| Asia (HT) | 1100×1100×140 | 22 | 9.20 |
| US (HT) | 1200×1000×140 | 20 | 9.00 |
HT = heat-treated (ISPM 15), mandatory for US/EU/Australia.
5.3 Container Loading Accessories
- Air bags: 5-6 pcs per container (90×180 cm), cost 18 USD
- Lashing straps: PET 16mm, 3 straps per row, cost 12 USD
- Corner boards: 5-layer kraft, 40 pcs, cost 15 USD
6. 2025 Freight Rates by Route
| Route | Carrier | Rate (USD/40ft HC) | Transit days | BAF |
|---|---|---|---|---|
| Qingdao → Los Angeles | MSC | 1 350 | 21 | 210 |
| Ningbo → Houston | COSCO | 1 480 | 25 | 230 |
| Qingdao → Mombasa | PIL | 1 120 | 28 | 175 |
| Shanghai → Lagos | MAERSK | 1 650 | 32 | 255 |
| Ningbo → Valparaíso | HPL | 1 720 | 35 | 265 |
Source: SKW Roof contracts Jan-Nov 2025, subject to GRI and peak season surcharges.
6.1 Booking Strategy
- 30 days ahead: best rates, carrier choice
- 14 days ahead: standard rate, limited choice
- 7 days ahead: premium rate, only spot available
SKW Roof booking window: 21-28 days before cargo ready. This saves 150-250 USD/container vs last-minute.
7. Cost Impact: Good vs Bad Loading
| Cost Item | Good Loading | Bad Loading | Delta ($/m²) |
|---|---|---|---|
| Freight per m² | 0.45 | 0.52 (-18% capacity) | +0.07 |
| Damage rate | 2 % | 12 % | +0.08 |
| Unloading | 0.05 | 0.08 | +0.03 |
| Moisture claims | 0.001 | 0.04 | +0.039 |
| Total | 2.84 | 3.06 | +0.22 |
Based on 1 000 m² shipment Houston. Bad loading = loose cargo, no desiccants, poor stacking.
8. Case Studies
8.1 Houston, Texas – Pallet Loading, MSC
- Profile: Milano 0.45 mm, charcoal grey
- Quantity: 2 400 m², 20 pallets
- Freight: 1 350 USD + 210 BAF = 1 560 USD
- Moisture: 10 kg desiccant, RH peaked 52%
- Result: Zero damage, unloading 2.5 h, total cost 2.84 $/m²
8.2 Mombasa, Kenya – Loose Cargo, PIL
- Profile: Bond 0.40 mm, terracotta
- Quantity: 2 640 m², loose cartons
- Freight: 1 120 USD + 175 BAF = 1 295 USD
- Moisture: 12 kg desiccant, RH peaked 58%
- Result: 3% edge rust (quick fix), unloading 4 h, cost 2.71 $/m²
8.3 Valparaíso, Chile – Mixed Loading, HPL
- Profile: Shingle 0.40 mm + accessories
- Quantity: 2 200 m² tiles + 400 m² gutters, 18 pallets + loose gutters
- Freight: 1 720 USD + 265 BAF = 1 985 USD
- Moisture: 14 kg desiccant, RH peaked 61%
- Result: Mixed loading optimized space, cost 2.91 $/m²
9. Buyer Loading Checklist
- Before production
- ☑ Confirm container type (40ft HC standard)
- ☑ Choose pallet/loose based on destination/handling
- ☑ Specify pallet type (EURO/Asia/US) for HT certificate
- Before loading
- ☑ Request loading plan from supplier (SKW Roof provides CAD)
- ☑ Confirm desiccant quantity based on voyage days
- ☑ Book data logger (free from SKW Roof)
- During loading
- ☑ Receive real-time photos of first row, mid-load, last row
- ☑ Confirm seal number matches supplier email
- ☑ Verify container number and condition
- After departure
- ☑ Track vessel ETA on carrier website
- ☑ Receive BL within 3 days
- ☑ Download logger data on arrival (check RH <65%)
- ☑ Inspect first pallet before unloading all
FAQ – People Also Ask
- Q1. How many square meters of stone-coated roofing tiles fit in a 40ft HC container?
- A: Optimized pallet loading: 2 400 m² (480-600 pcs/pallet × 20 pallets). Loose cargo: 2 640 m² but higher damage risk. SKW Roof recommends pallet for 8% less breakage.
- Q2. Is pallet or loose cargo better for metal roofing tiles?
- A: Pallet reduces unloading time by 35% and damage from 12% to 2%, but costs 0.04 $/m² more. Choose pallet for first 3 containers; switch to loose if you have forklift at destination.
- Q3. How to control moisture in container during sea shipping?
- A: Use 8-12 x 1kg calcium chloride desiccant bags per 40ft HC, plus PE film wrapping each pallet. SKW Roof’s moisture data logger shows RH stays below 65% for 35-day voyage.
- Q4. What is the cheapest carrier for China to US metal roofing?
- A: MSC and COSCO offer best rates at 1 350-1 480 USD/40ft HC to LA/Houston. Book 30 days ahead for 200 USD savings vs spot rate.
- Q5. How do I avoid damage during loose cargo loading?
- A: Use corner boards on each stack, lash with PET straps every 5 layers, and place air bags in gaps. SKW Roof loose-loading SOP reduces damage to 3%.
Need a custom loading plan for your next container?
Email business@skywalkerchina.com or WhatsApp +86 13153460330 with your profile and destination. We will return a CAD loading diagram and freight quote in 6 hours.