What are Joist Hangers?

Joist hangers are essential components used in construction, designed to anchor wooden beams or joists securely. They are primarily used in roofs, decking, floors, and ceilings to create strong, long-lasting structural support.

To achieve the best lifespan and preserve the strength of wooden joists, a joist hanger plays a crucial role. Over time, wood naturally twists and moves; however, joist hangers ensure that the beams maintain a true and stable fit, providing long-term strength and rigidity.

Typically, most joist hangers slot over or under the edge of a wooden beam on three sides and are attached with nails. There is also a connecting plate on the joist hanger that fastens to the surrounding frame. As a result, joist hangers are highly versatile and much stronger than using traditional nails or screws alone. Furthermore, they are easier to fit and relatively inexpensive considering their long lifespan. When properly installed, with all holes filled with nails or screws, they provide excellent stability. Additionally, joist hangers can be welded if necessary and can be attached to both masonry and timber structures.

Types of Joist Hangers

There are two main types of joist hanger applications:

Timber to Timber
Timber to Masonry

The term Joist Hanger covers a wide variety of uses — from a standard Jiffy Hanger for light- to medium-duty applications, to a Heavy Universal Hanger designed to support multiple timbers.

Standard Jiffy Hanger or Cullen KH Hanger (Light Loads)

The standard Jiffy Joist Hanger, or Cullen KH Hanger, is commonly used for light-duty applications such as flat roof joists, floor joist trimming, trimming for roof light windows, and flooring with lighter load requirements. However, since writing this article, Cullen has discontinued the manufacture of KH47, KH63, KH92, KH125, and KH150 models.

Long Leg Jiffy Hanger (Heavy Loads)

For heavier applications, such as floor joists, we recommend a Long Leg Jiffy Joist Hanger, such as the Cullen KHL or the Maxi Hanger (MH). These hangers are used in timber-to-timber applications due to their greater load capacity. Consequently, they are ideal for supporting structural flooring or larger frameworks.

Masonry Hanger (Cullen JHI Hanger)

A Masonry Hanger, or Cullen JHI Hanger, is predominantly used in timber-to-masonry applications. It can be built into the wall during construction, or the wall or mortar joint can be cut to install the hanger later. Typically, these are used between walls where building in the timber joist is not possible or desirable, for example, due to airtightness requirements. Therefore, masonry hangers offer a reliable alternative for structural connections in such cases.

Universal Joist Hanger (UH Hanger)

Cullen Universal Timber Frame Hangers, also known as UH Hangers, are designed for flexible use. The Cullen Universal Joist Hanger (UH) can be used for any joist-to-joist or joist-to-trimmer application. In essence, this hanger combines the functions of several models — including the FFI, TFI, U, and LUI — into one versatile product.

Loft Conversion Floor Joists (Cullen KHL Hanger)

For loft conversions, we recommend the Cullen KHL Hanger, which can be wrapped over steel beams or trimmers for maximum strength. For best results, always use galvanised twist nails to fix the hangers, ensuring that every nail hole is filled with either a 30mm, 35mm, or 40mm nail.

You can attach the hangers using conventional loose twist nails or a PPN nail gun. Both Paslode and Rawlplug offer PPN nails that can be fired by a Positive Placement Nail Gun (PPN).

Product Availability

Cullen offers a wide range of hangers, and we can supply one to suit virtually any requirement — whether for lightweight decking, loft conversions, masonry-built extensions, or timber-frame constructions. In short, whatever your project, we are confident that we can provide the right hanger to meet your needs.

At SEC Supplies & Fixings Ltd, we always keep the majority of Cullen products in stock and ready for collection or next-day delivery to UK mainland postcodes. If an item is not in stock, we can order directly from Cullen, also with next-day delivery. However, some specialist or bespoke hangers may require a minimum production time of two weeks. Therefore, please contact us if you have any specific or custom requirements.

If you need any advice, please feel free to contact us.

Tel: 01634 786766

emails: sales@secfixings.co.uk

Unit 13, Sabre Court

Valentine Close

Gillingham Business Park

Kent

ME8 0RW