Timber connectors for roof framing: types and selection

A connector is usually a shaped steel component that encloses or supports part of a structure. It may be an angle bracket or a beam hanger. Fasteners are used to fix it in place. These include suitable nails, screws and bolts. Both groups together form a connection that works as one.

This distinction makes the order easier to read. Buying the right angle bracket does not complete the selection if fastenings other than those specified are used to install it. The technical data sheet should show the possible combinations. A substitute may only be accepted under the conditions permitted in the documentation or after verification by the designer.

Angle brackets connect components positioned at a specific angle to one another. They can stabilise beams, columns and parts of the roof structure. They are available in versions with different legs, holes and embossments. However, a similar outline does not mean identical load capacity in all directions.

In the tables, check whether the load acts along the leg, transversely or pulls the component away from the support. Sometimes the arrangement requires two connectors on both sides of the beam. One angle bracket does not replace such a pair without assessment. Access to the holes must also be taken into account so that the required fixing can be carried out once the timber is in position.

Beam hangers have a supporting flange for the end of the component and arms fixed to the structure. They allow beams to be connected at a similar level without large support from below. The version is selected according to the width and height of the timber. There are also split solutions and ones intended for unusual arrangements.

The beam must sit correctly against the bearing surface. The hanger should not be treated as a universal clamp that can be bent open or shortened at will. Such changes modify the geometry of the product. The rules for placing holes in the supporting and supported beam may differ, which is why a complete hole pattern is needed.

Steel straps can carry tensile forces and help to stiffen the structure. Their effectiveness depends on the run, the tension and the anchoring of the ends. A loosely hung length of strap does not become effective bracing simply because it has been nailed to a few rafters.

Perforated plates are used for other designed connections, while toothed connector plates are used, among other things, in the prefabrication of trusses. These products should not be treated as equivalent. A toothed connector plate is installed using the appropriate technology. Driving it in by hand on site is not equivalent to producing a factory-made node.

Column bases and anchors allow load to be transferred between the timber and the foundation or another reinforced concrete part. Some solutions keep the timber away from the surface on which moisture can collect. The choice also depends on whether the connection is to carry only compression or also uplift and horizontal forces.

Fixing to timber and anchoring in concrete are assessed separately. The strength class of the substrate, the distance from the edge and the method of setting the anchor all matter. Load-bearing capacity given for one substrate cannot be transferred to another. The hole in the connector does not by itself determine the correct diameter, length and type of anchor.

The table relates to a specific configuration. It covers the type of timber, the set of fasteners and the direction of loading. The documentation may permit full or partial nailing. Partial does not, however, mean omitting holes at random. The specified pattern and the value assigned to it are what count.

The largest numbers from two catalogues should not be compared on their own. They may relate to different conditions or to different types of design value. It is the designer’s task to move from the roof loads to the verification of a specific node. The contractor should receive a clear designation of the connection and an installation drawing.

The order should list the connector models, dimensions, quantity and the appropriate fasteners. Corrosion protection and the conditions of use must be checked. An item intended for a dry interior need not be suitable where it is permanently exposed to moisture. A decorative coating does not replace the declared protection.

On site, new holes should not be drilled and bends should not be altered without agreement. A doubtful solution is better clarified before the first nail is driven in. It is worth photographing the connections before they are covered. Such an inspection makes it possible to detect missing fixings at a point when making them good is still straightforward.