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Simpson Strong-Tie

The leading manufacturer of builders metalwork.

The leading manufacturer of
builders metalwork.

FAQs for the Simpson Strong-Tie Range

Traditionally, the width of single joists are typically 50mm (2 inches) and the width of double joists are typically 100mm (4 inches), however, almost all timber merchants sell joists slightly less than what is referred to. Therefore, single joists are usually around 45mm (5mm smaller) and double joists are usually 90mm (10mm smaller). We advise using the 47mm wide joist hangers for single joists and  91mm joist hangers for doubles.

Normally, the sizes in the title of the joist hanger products refer to the size of the joist to be used, rather than the dimensions of the hanger itself. For example, an adjustable joist hanger could be named “Adjustable Joist Hanger – 47 x 270mm”, which means that the width of the joist can be up to 47mm and the height of the joist can be up to 270mm.  This can cause confusion to customers, because the height of the joist hanger is smaller that 270mm, therefore, we have named our adjustable hangers on the height of the joist hanger (47 x 237mm).

This is different for masonry joist hangers because they are not adjustable, therefore, the sizing in the title refers to the size of the joist to be used. In some cases, the height in the title is 10mm higher that the joist hanger itself.

The most common hole size on Simpson Strong-Tie metalwork is 5mm.  The sheradised square twist nails at 30mm and 40mm are usually fine when fixing to wood (most specification sheets list 30mm sheradised square twist). However, Simpson recently released a new range of screws called CSA Connector Screws, which offer a more secure fixing that can withstand heavier weight loads. The 4 x 30mm screw is the most popular because it fits most of the hole sizes on metalwork. These fixings (sheradised square twist nails and CSA screws) can be used on joist hangers, restraint straps, angle brackets, nail plates etc.

Some joist hangers have 13 and 11mm bolt holes to suit M12 and M10 bolts respectively. We advise that coach bolts are used for timber and masonry bolts are used for concrete and masonry substrates. Please ensure that you read any technical data sheets to match load bearing requirements.

For most restraint strap manufacturers, light duty straps are specified at 2.5mm thickness and  heavy duty straps are 5mm. However, the real sizes are usually slightly less than this (usually around 2mm for light duty and 4.2mm for heavy duty).