Beam connectors are sized by the width and depth of the timber they carry, with the U-shaped seat matching widths from around 45 mm up to 100 mm and beyond and a depth that supports most of the joist. Pick a hanger whose internal width equals the beam width so it seats without packing, and whose seat depth suits the joist height. Check both dimensions before ordering.

Galvanised beam connectors and joist hangers are weatherproof enough for outdoor decks, roofs and pergolas, as the zinc coating protects the steel from rust. For ground-contact framing, coastal exposure or timber treated with modern preservatives, choose hot-dip galvanised or stainless steel to avoid accelerated corrosion. Match the fixings to the same corrosion grade so the whole joint lasts.

Fix a joist hanger by driving the specified connector nails or structural screws through every pre-punched hole, both into the supporting beam and into the joist sides. The hanger only reaches its rated load when all holes are filled, so leaving any empty reduces capacity. Make sure the joist sits fully down in the seat and the back plate is flush against the support before nailing.

On an external-flange joist hanger the fixing tabs fold outward onto the face of the supporting beam, giving a bigger nailing area and higher load, while on an internal-flange hanger the tabs sit inside the seat so they stay hidden and save space. Choose external flanges for maximum strength and internal flanges where the hanger must not project past the timber. GeZu Impex stocks both styles in galvanised steel, with connector fixings sometimes supplied separately.