In many cases, builders can connect a truss using two or three nails. However, counties with good building codes, as well as contractors who take pride in making quality homes, use hurricane ties or a similar product to make the connection more secure. This is when a 6” TimberLOK screw can help.
There are two commonly used methods of roof-to-wall connections. Wraps: These are steel straps that are installed over the tops of trusses and anchored to wall along the side of the truss. Clips: These are steel straps that are attached to the sides, rather than the tops, of the trusses.
One method is to use toenails. The other method is to use readily available connectors that are made specifically for this purpose. If toenails are to be used, the resistance to withdrawal for the number and size of toenails to be used must exceed the uplift on the truss design drawings.
In older houses with masonry walls it is common to find a 2x8 lumber plate that is bolted or strapped flat like a plate to the top of the masonry wall. The trusses or rafters are then connected to this plate. In older homes the connection may be made using 2 or 6 16d nails in a toe nail configuration.
Where the truss is located between two studs, insert fastener point on bottom surface of the top plate no greater than ½" from the inside edge of the plate (Side View B). Drive fastener through underside of the top plate at a 221⁄2° angle (+/– 5°) and into the center of the truss.
In many cases, builders can connect a truss using two or three nails. However, counties with good building codes, as well as contractors who take pride in making quality homes, use hurricane ties or a similar product to make the connection more secure. This is when a 6” TimberLOK screw can help.
Trusses can be held down by fixing them directly to the wall plate using proprietary truss clips. Galvanised straps should be used to fix the wall plate to the masonry; these straps should be at no more than 2 m centres or alternatively, the wall plate can be fixed using bolts at 1.2m centres.
The truss will be anchored with nails, powder driven fasteners, or masonry anchors.
Often, wall plates are not mechanically fixed to the wall - other than by the straps installed for holding down purposes.
Truss members are connected to each other rigidly, by welding or joining the ends with a gusset plate. This makes the connecting joints rigid but also makes the truss difficult to analyze.
Once a truss is in place, it must be temporarily braced to prevent movement that could lead to misalignment or collapse. Temporary bracing involves installing diagonal braces that stabilize the trusses until permanent sheathing and bracing are applied.
Most truss failures are often attributed to one of the following: Improper or lack of temporary/permanent bracing. Incorrect loading or overloading during construction. High winds during erection.
In most situations, the trusses/joists bear on the double 2x top plates of the wall assembly below. The most direct load path would be to always align a stud (or studs if necessary) directly below each truss/joist. However, this may be undesirable from a design standpoint—e.g., when wall studs are at 16-in.
Trusses are generally designed to be supported on the outer wall with inner walls being non load bearing. Where it is necessary to use internal walls for load bearing, these will be clearly shown on layouts. Note that the supporting structure is stable in its own right.
Most exterior walls are load bearing, but not all. It all comes down to where the roof trusses/rafters and floor joists/trusses are bearing. Long skinny homes may only have two exterior load bearing walls.
The first thing you need to do is determine how well your roof structure is attached to the walls. In older wood frame construction, the connection of roof trusses or rafters to walls is 2 or 3 sixteen penny (16d) nails driven at angles (toe nailed) through the rafter or truss into the top plate of the wall.
INSTALLING THE WALL PLATES
The simplest is just the plate itself, which can be mounted with screws directly into a solid supportive wall like wood or metal. For less structural surfaces, like plaster or drywall, a mounting bracket is recommended to strengthen the attachment points.
It is important to know that the popular wedge anchor should be used in solid concrete applications, such as fastening to a concrete wall. Wedge anchors should never be used in a block wall or any hollow base material. Cinder block can sometimes be difficult for fastening: It is hollow, brittle, and inconsistent.
Common connection methods include using mechanical connections, such as bolts, dowels, or embedded connectors, as well as adhesives or grouts. These connections are designed to provide structural integrity, prevent movement, and ensure load transfer between adjacent panels.
A truss that is assumed to comprise members that are connected by means of pin joints, and which is supported at both ends by means of hinged joints and rollers, is described as being statically determinate.
A truss is essentially a triangulated system of (usually) straight interconnected structural elements; it is sometimes also referred to as an open web girder. The individual elements are connected at nodes; the connections are often assumed to be nominally pinned.
Trusses can have intermediate support, especially if one side is vaulted. If so, load goes into the wall, then through the floor joists to the lower floor walls and foundations.
If a wood truss becomes damaged, sometimes the only reasonable course of action is to replace the truss completely. But when only a portion of a truss has been damaged, localized repairs are often a viable option to restore the functionality of the truss.
Most roof trusses are designed to bear on the exterior walls only. Trusses touching interior walls can transfer roof loads to walls not designed to carry a structural load. Trusses touching interior walls can also create point loads on trusses at points not designed to support point loads.
A truss connector plate, or gang plate, is a kind of tie. Truss plates are light gauge metal plates used to connect prefabricated light frame wood trusses. They are produced by punching light gauge galvanized steel to create teeth on one side.