Sourcing Slate Window Sills from China

Zero duty on worked slate window sills

Heading 6803 covers worked slate and articles of slate or agglomerated slate. Finished slate window sills belong within the other worked slate category, 6803 00 90 00. The table shows sill variants under that same tariff line, rather than separate tariff subdivisions.

Read from the UK Trade Tariff on 4 October 2026, both lines in this heading carried 0% duty for goods from China. The supplied tariff record lists no anti-dumping or countervailing duty, no suspension and no attached import controls. Import VAT is normally 20%; see import duty and VAT.

Confirm the material and extent of processing with your customs broker using the commodity code guide. See our slate hearths guide for another worked slate product within the wider heading.

Specify the sill profile and exposure

State whether the sill is for an interior or exterior opening. Supply an approved drawing showing overall length, depth, thickness, projection, end details, edge profile and the position of any underside drip groove. Agree dimensional tolerances and whether the exposed face is honed or naturally split. Identify any sealant, coating or filled fissures.

Approve a colour range from the proposed stone source rather than relying on a single photograph. For exterior sills, ask for water absorption, frost resistance and flexural strength evidence relevant to the supplied slate. Agree the installer’s support and bedding details before approving the drawing.

For supply in Great Britain, construction products bearing legitimately affixed CE marking can continue to be supplied. Ask which product standard or technical assessment covers the sill’s intended use, and obtain the relevant performance documentation. Have the proposed route checked through testing and certification.

Worked duty example

Illustrative example, not a quote: Illustrative merchant stock order: 20 tonnes of crated slate window sills under 6803 00 90 00, invoiced at £16,000 free on board, with £2,600 of freight and insurance to the UK. The customs value is £18,600. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £18,600, so it is £3,720. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Dimensions: measure sampled sills from different crates against the approved drawing, including thickness, squareness, flatness, end details and drip-groove position.

Stone and finish: inspect faces, edges and undersides for cracks, splitting along layers, filled fissures, chipped corners and metallic inclusions. Compare colour and texture across pieces intended for the same elevation.

Performance documents: match reports to the supplied stone and intended exposure. Check the stated construction-product route and any marking against the actual product.

Packing: check separators, edge protection and bracing so long sills cannot move inside the crate. Solid wood crates and pallets must meet the applicable wood-packaging requirements; check treatment and compliance marks. Arrange quality inspection before dispatch and repeat the physical checks on arrival.

What goes wrong

A sill can look right in a photograph but arrive bowed, with an incorrectly positioned drip groove or end details that do not fit the opening. Mixed stone batches produce conspicuous colour changes. Thin edges chip in transit, while cracks and separation along slate layers may be hidden by packing or surface treatment.

For exterior work, colour alone does not establish suitability for frost and wet exposure. Obtain evidence for the supplied stone, retain the approved drawing and range sample, and photograph packing and arrival damage before installation. Keep replacement pieces matched to the original batch.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.