Sourcing limestone window sills from China

Duty on limestone window sills

Heading 6802 covers worked monumental or building stone and articles made from it. For limestone window sills, distinguish simply sawn blanks from further-worked calcareous stone and hand-made carvings. Honed and polished sills can share the same commodity line; the table separates these finishes for purchasing purposes.

Read from the UK Trade Tariff on 1 October 2026, the relevant lines carry 0% duty for goods from China. The supplied tariff data lists no anti-dumping or countervailing duty, suspensions or attached import controls. Import VAT is separate from customs duty.

Give your customs broker the stone identification, photographs and manufacturing details, then confirm the commodity code. See the marble and granite stone guide for the wider heading.

Specify the sill profile and limestone

State whether the sill is internal or external. Identify the quarry and stone type, approve a colour range from the proposed production block, and record the finish, permitted filling and sealing. Specify length, depth, thickness, edge profile, end details and tolerances on an approved drawing.

For external sills, show the fall, projection and underside drip groove on the drawing. Ask for water absorption, flexural strength and frost-resistance results relevant to the proposed stone. Agree the acceptance criteria with the project designer rather than relying on a supplier's statement that the stone is suitable outdoors.

Check whether the intended use falls within a designated construction-product standard before agreeing the documentation. Confirm with the relevant construction-products authority whether a declaration of performance and CE or UKCA marking are needed for supply in Great Britain. CE marking continues to be recognised there. Do not assume a report for floor slabs or cladding covers the proposed sill.

Worked duty example

Illustrative example, not a quote: One container of honed limestone window sills for a building contractor, illustrative only under 6802 92 00 90, invoiced at £18,000 free on board, with £3,500 of freight and insurance to the UK. The customs value is £21,500. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £21,500, so it is £4,300. 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

Geometry: measure length, depth, thickness and squareness against the drawing; check the fall, drip groove, end details and edge profile before shipment and on arrival.

Stone and finish: compare pieces with the approved colour range under consistent lighting; inspect faces, edges and undersides for cracks, chips and undisclosed resin repairs.

Performance documents: match the stone identification, intended use and finish to the supplied reports and, where applicable, the declaration of performance and marking. Arrange testing and certification support before shipment if evidence is missing.

Packing: check separators, edge protection, bracing and piece identification. Solid wood crates must meet the international phytosanitary packaging standard and carry a legible compliance mark; a certificate cannot replace that mark. Record transit damage during arrival inspection.

What goes wrong

Mixed production blocks produce visibly different sills across a facade. Thin edges chip, filled fissures open during handling, and a missing or misplaced drip groove defeats the agreed profile. Check the actual production pieces against the approved drawing and colour range rather than accepting photographs of an unrelated sample.

Limestone can stain and etch, so agree the cleaning and sealing instructions before supply. External performance needs evidence for the selected stone, while unsupported packing can leave long sills cracked on arrival. Photograph the opened crates and retain piece labels so defects can be traced to the production 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.