Choosing a connector for a roof truss system is one of those decisions that, at first glance, seems like a minor detail in the overall project, but in practice, it translates into the durability of the entire structure. The question of which connector to choose—whether it should be a perforated plate, a truss plate, or perhaps another type—most often arises during the truss design phase, when it’s necessary to decide if the connection will be made in factory conditions or manually on the construction site. The answer is not straightforward, as different connectors solve different problems. Below is a practical comparison of both solutions, i.e., the perforated plate and the truss plate, along with guidance on how to select the right type for a specific application.

What is a Truss Plate?

A truss plate is a steel connector with spikes embossed on one side, which is pressed directly into wood under high pressure. The spikes embed into the timber structure much like nails, with the difference that they do so simultaneously across the entire surface of the plate, creating a uniform and predictable connection.

In practice, installing this type of connector requires a hydraulic, pneumatic, or mechanical press, which is why it is almost exclusively done in a prefabrication plant. The length of the spikes in most plates available on the market typically ranges from 10–20 mm, depending on the manufacturer and variant, and the thickness of the steel sheet itself usually falls between 0.9 and 3 mm, in accordance with the requirements of standard PN-EN 14545:2011 concerning insert and ring-type connectors used in timber structures. This standard specifies not only the material thickness but also strength requirements, geometry, and corrosion protection, making the truss plate a product subject to strict quality control, not an element chosen “by eye.” In Poland, compliance of such connectors with construction requirements is supervised, among others, by the Building Research Institute, which issues approvals and technical assessments for products introduced to the market.

What is a Perforated Plate?

A perforated plate is a flat steel sheet with regularly spaced holes, installed using nails or screws. Unlike a truss plate, it does not require a specialized press, allowing it to be installed manually, directly on the construction site.

This is a significant practical difference, as on many Polish industry websites, the topic of perforated plates only appears as a mention when describing truss plates, without a separate explanation. In practice, however, this connector most often saves the day when construction takes place outside a prefabrication plant, for example, for temporary joint reinforcement, building a small shed or pergola, or repairing an already erected roof truss system. A perforated plate generally has a lower load-bearing capacity than a truss plate, which is why it is treated more as an auxiliary solution than a primary connector for roof trusses.

Truss Plate vs. Perforated Plate — Key Differences

Installation Method

A truss plate requires pressing into wood under high, uniform pressure, which in practice means working with a press in a prefabrication plant. A perforated plate is installed manually by driving nails or screwing in screws into prepared holes, without any additional equipment beyond basic carpentry tools.

Strength and Load-Bearing Capacity

A connection made with a truss plate is characterized by high and predictable load-bearing capacity for static and dynamic loads, as the spikes embed into the wood simultaneously and across the entire surface. A perforated plate transfers smaller forces, and its load-bearing capacity largely depends on the quality of manual fastener installation, which introduces greater variability in results than factory production.

Application Area

Truss plates dominate in the industrial production of roof trusses, where each structural node is created under the same controlled conditions. Perforated plates are suitable where there is no access to a press and installation takes place on-site, such as for small garden structures, repairs, or temporary reinforcements.

Criterion	Truss Plate	Perforated Plate
Required Equipment	Hydraulic, pneumatic, or mechanical press	Hammer, screwdriver
Installation Location	Prefabrication plant	Construction site
Load-Bearing Capacity	High, predictable	Lower, dependent on installation quality
Typical Application	Roof trusses, industrial and agricultural structures	Small structures, repairs, temporary reinforcements
Standard Compliance	PN-EN 14545:2011	Usually used as an auxiliary element

Combi Plate — A Solution Combining Both Technologies

Some truss designs require combining the advantages of both connector types. The answer to this problem is the combi plate, which has holes for nailing in one part and factory-pressed spikes in the other. This way, half of the connector arrives at the construction site as a nailed element, while the other half is pressed in at the prefabrication plant.

This solution has practical application for trusses that are too tall for standard transport, exceeding approximately 3.2 meters, where using a hydraulic press along the entire length of the element would be difficult. Dividing the truss and using a combi plate avoids oversized transport, which in practice can reduce transport costs by up to several thousand PLN for larger projects.

Connection-plate — When Length, Not Height, Is the Issue

While the combi plate solves the problem of an overly tall truss, another variant of the truss plate, the Connection-plate, addresses a different limitation: the length of C24 structural timber available on the Polish market, which usually does not exceed 5.4 meters. When the bottom or top chord of a truss needs to be longer, the timber elements are joined lengthwise using this plate.

Thanks to its elongated geometry and fewer spikes per square meter, the Connection-plate can transfer up to 40 percent greater forces in the longitudinal direction of the wood grain than a standard truss plate. This allows for the use of narrower plates in lengthwise connections compared to classic truss nodes.

Why Does the Truss Plate Win in Industrial Roof Truss Production?

From the perspective of a prefabrication plant, the difference between the two types of connectors is not just about the installation method. It’s primarily a difference in repeatability and the scale of the production process.

Precision and repeatability of connections – every truss plate is pressed under the same controlled factory conditions, so the connection parameters do not depend on the experience of a specific person on the construction site or the weather. Prefabrication plant practice shows that this repeatability, rather than the strength of a single plate itself, is what most distinguishes industrial production from manual assembly.

Speed of serial production – pressing a truss plate into wood takes literally a few seconds, which, when producing dozens of trusses a day, directly translates into line efficiency. A perforated plate, manually installed with nails or screws, would be time-inefficient on an industrial scale.

Higher and predictable load-bearing capacity – a connection made with a truss plate is designed and certified in accordance with PN-EN 14545:2011, which precisely defines procedures for determining the characteristic strength and stiffness of truss plates. By receiving parameters from the plate manufacturer specified according to the aforementioned standard, the designer relies not on approximation, but on verified technical parameters.

Quality control in factory conditions – in a prefabrication plant, the pressing depth of the plate can be continuously verified and press pressure adjusted, which is practically impossible to control during manual installation of a perforated plate on a construction site. This is one of those differences that are hard to appreciate without experience in serial production, but which, in the long run, determine the uniformity of quality for the entire batch of trusses.

Product scalability – the availability of variants with different sheet thicknesses and spike lengths allows for selecting a truss plate precisely for the loads of a specific structural node, and stainless steel variants are suitable for chemically aggressive environments, such as poultry houses, cattle sheds, or biogas plants.

Material and construction cost savings – using truss plates instead of traditional joining methods can reduce the cost of the entire roof truss system by up to 40 percent, as noted by the industry publication Inżynier Budownictwa in a study dedicated to modern timber structure connections.

When is a Perforated Plate a Better Choice?

Despite the clear advantage of truss plates in industrial production, there are situations where a perforated plate remains the better choice.

• Small timber structures – pergolas, gazebos, or garden sheds rarely require the load-bearing capacity of a roof truss, and investing in a press for such a small scope of work usually doesn’t pay off.
• Repairs and reinforcements – when a structure is already erected, pressing in a new truss plate can be impossible, whereas a perforated plate can be manually attached anywhere.
• No access to a press on-site – if assembly takes place on a construction site without prefabrication facilities, a perforated plate remains the only practical solution.

How to Choose the Right Plate for Your Project?

1. Determine the installation location – if the structure will be built in a prefabrication plant, a truss plate will almost always be the better choice. If assembly will take place on-site without access to a press, it’s worth considering a perforated plate immediately.
2. Check the required structural loads – plate selection should result from design calculations, not from an “eyeball” estimate. A plate that is too small for the loads can cause structural deflection as early as the first winter season.
3. Verify equipment availability – installing a truss plate requires a hydraulic, pneumatic, or mechanical press. Without this equipment, the only real option remains a perforated plate.
4. Consult your supplier who has load-bearing verification tools – a good plate manufacturer can recommend the appropriate type and size based on the specific truss parameters, rather than leaving this decision solely to the contractor.
5. Consider the combi variant for oversized trusses – elements exceeding approximately 3.2 meters in height should be designed with a division and the use of a combi plate, which helps avoid costly oversized transport.

Summary

Truss plates and perforated plates solve different problems, so the question “which is better” rarely has one correct answer. In the industrial production of roof trusses, where repeatability, efficiency, and predictable load-bearing capacity are crucial, the truss plate remains the primary and irreplaceable solution. The perforated plate retains its place where assembly occurs outside a prefabrication plant, and the combi plate allows combining the advantages of both technologies for elements that cannot be transported in one piece. A conscious choice during the roof truss design phase is the simplest way to avoid costly corrections at a later stage of construction.