straw nail

A straw nail is a long, thin nail typically 50, 75 mm in length, used to secure roof tiles and slate shingles, particularly at hips and ridges where standard nails would be too thick or short. The nail has a small head, a slender shank, and is usually made of mild steel or copper. Because of its length relative to its diameter, it can pass through or alongside clay or concrete tiles without cracking them, and reach solid timber batten beneath.

The name is believed to derive from its use in securing thatch repairs or from its resemblance to straw in thinness, though modern use is almost entirely for clay and slate roof work. Copper straw nails are preferred in coastal or damp climates because they resist rust and do not cause staining on lighter-coloured tiles. The long, thin profile means the nail distributes load over a smaller bearing area and relies on friction and shear rather than crushing the material it fastens.

Variants and applications

Common variants include plain steel (cheaper, used where rust is not a concern), copper (premium, for exposed locations and slate), and occasionally sherardized or galvanized steel. Hip and ridge work requires straw nails because these areas experience high wind uplift and settlement movement; standard roofing nails would either split the tile or pull through under stress. Some roofers use straw nails in preference to tingle plates or lead clips on repairs where the fixing point must remain thin.

A persistent problem is over-driving: the thin head can sink into soft or weathered tile, reducing holding power and creating a water trap. Poor installation also occurs when the nail is driven at an angle rather than perpendicular to the tile surface, which weakens the grip. Wind, frost expansion, and the settling of timber can gradually loosen the nail, especially if the original bore hole was too large or the tile itself is fractured.

Straw nails sit between general-purpose roofing nails and specialist fixings such as lead clips or stainless steel plates. They are not widely stocked in general builders' merchants; a roofer or slate supplier is the typical source. Understanding when to use them, rather than heavier alternatives, depends on tile type (clay tile, concrete tile, or slate), roof pitch, local wind load, and whether the work is new installation or repair.