This product is a 115 g blue marking chalk designed primarily as a refill for chalk line reels and hand-held line markers, used to transfer straight, high-visibility lines onto masonry, concrete, timber and other building substrates. It provides a clear, contrasting blue mark that helps set out brickwork, tiling, roofing and joinery quickly and accurately on site.

The chalk is a finely milled calcium carbonate/gypsum blend with a coloured pigment and light lubricating additives to ensure free-flowing powder in chalk boxes. It is supplied as a 115 g refill suitable for most standard chalk line reels and dispenser cartridges. There is no single DIN/ISO/BS standard that specifically governs basic line-marking chalks; the formulation follows common industry practice for construction marking compounds, with attention to safe handling and minimised dust generation.

Typical applications include brick and block setting, floor screeding and tiling layout, roof battens and rafter alignment, long timber or sheet material cutting guides, and any other trades where rapid, straight-line setting out is required. Trades and industries that commonly use this product are builders, roofers, floor layers, tilers, carpenters and landscape contractors who need quick temporary marks that are readily visible against a range of backgrounds.

Key benefits of the 115 g blue chalk are its high contrast colour for clear visibility on light and medium-toned surfaces, a non-corrosive powder formulation that will not damage metal chalk reels, and an anti-clumping finish that helps prevent blockages and uneven line transfer. Marks are temporary and can usually be brushed or washed away from most surfaces, making the product compatible with common construction materials while avoiding permanent staining in normal use.

Duchy Fasteners stocks the Blue Chalk 115 g refills individually and in multi-packs suitable for site crews and workshops. We also supply a range of chalk colours and sizes to fit most chalk line reels and dispensers—please contact us for availability and pack options.