PuuBIM – A terminology and catalogue guide for wood elements

The wood element terminology guidelines published at Puupäivä (Wood Day) 2023 define the key principles for naming wood elements. The PuuBIM guidelines aim to standardise the information modelling used in the structural design of wooden buildings and to harmonise the data types and formats used for wood elements. A unified naming convention simplifies the flow of information between all the parties involved in construction projects, including designers, builders, component manufacturers, and maintenance personnel, making collaboration much easier.

Read the article in Finnish here.

Building Information Modelling (BIM) enables accurate information to be shared and used, which enhances collaboration and reduces the likelihood of error. Precise data on dimensions and shapes allows parties to reduce waste and optimise the use of materials. This reduces the environmental impact of construction projects and makes processes more efficient.

BIM plays a key role in modern wood construction projects. It aims to harmonise wood construction processes to make the construction industry more precise and efficient. In addition, it allows the construction industry to pursue more sustainable development and innovation.

The guidelines come in three parts: product identification, the definition of product geometries, and the definition of product requirements and properties. This article covers the key points of all these topics.

Identification and identity

BIM depends on identification and identity. Components and assemblies need to be defined and identified with attributes and data formats that are unambiguous, consistent, and agreed upon ahead of time.

Hierarchy levels

PuuBIM includes two hierarchical levels to indicate the applicability of the modelled item to either a higher or lower level of data and to connect to other information model structures. Wood design has two hierarchical levels: assembly and component, with volumetric elements representing a special case of the assembly level.

Verification of identification and identity

Type identifiers are used to identify assemblies and, when necessary, components. The identifiers defined in the guidelines have been selected to ensure that they do not conflict with BEC2012 type identifiers. While these identifiers describe and group the intended uses of assemblies, more specific attributes need to be added to the assembly ID. Examples include the block ID and assembly serial number that can facilitate placement. For instance, serial numbers can be matched to a floor-specific series of numbers. This will make the assembly uniquely identifiable in its entirety, making it easier to identify in building information models, plans, and catalogues.

A set of running Assembly Classification Numbers (ACNs) can be used to differentiate assemblies that are identical. In modelling software, it is good practice to assign an ID number to the main component in an assembly. This number should stay the same throughout the project, as it serves as an identifier in digital data transfers between software programs.

Catalogue contents

For catalogues, the guidelines only apply to assembly-related catalogues. Catalogue contents are extracted from information model records and include the size and number of components of each assembly. Nails, screws, hooks, glues, and other connectors needed for joints are excluded. These catalogues do not indicate the dimensions of the assembly, as this data is included in the geometry information. Equipment catalogues must include the prefabricated components and product components that supplement or equip each assembly. The units for the quantities and pieces are determined by the supplementary product. 


Geometries are a key element in successful modelling. It is no trivial exercise to precisely determine structural dimensions, and the relevant definitions must be agreed upon. BIM allows the creation of more detailed and complex structural models, which is important in the modern design and construction of wooden structures. The PuuBIM aims to create uniform and accurate geometric guidelines, extending from design to construction and maintenance.

Definition of geometry

The PuuBIM guidelines include the key geometries for wooden structural components and assemblies. The guidelines include geometrical definitions for different wood products. For example, the recommended method for defining pillar product profiles is based on the lamella structure of the product. An essential element in these geometry specifications is that products are modelled as if they were cast profiles, with the longitudinal axis reflecting the main bearing direction of the structure. This is just like the common procedure currently used to model hollow slabs.

The guidelines contain uniform definitions for the most common derived quantities such as weight, dimensions, centre of gravity, net and gross surface area, which are important in quantity calculation and logistics.

Component geometry includes different building components, such as pillars, beams, slabs, and panels. For example, the width, length, and thickness of a pillar component define its geometry, with the pillar width corresponding to the width of the pillar component’s individual lamella (applies to glulam, veneer, etc.). A similar procedure is used for beams. When it comes to panel products, the longitudinal axis determines the bearing direction of the product. This makes it easier to determine the bearing direction of veneer from the information model and gives production a better idea of how many blanks will be required.

Assembly geometries cover various building assemblies, such as vertical, horizontal, and supplementary structures. For example, a wall assembly geometry is defined by its height, width, and length, with the assembly height corresponding to the direction of the height axis of the building.

The geometry section also includes recommended practices for marking the installation direction of the elements and the visible surfaces on building components, information models, and plans.

Quality characteristics and requirements

Quality characteristics and requirements should always be reported to the extent required for the project’s information modelling. The structural designer for a project defines the quality requirements, whereby the requirements also become characteristics of the structural component.

For wood materials, there is a clear need for uniform naming in line with the labelling and naming methods of the upcoming Eurocode update. The connection between the materials used and the relevant EN standard or European Assessment Document (EAD) must also be identified.

The standardised strength class of the wood material should be stated whenever possible. The labelling method for CLT should be as clear and unambiguous as possible. Unfortunately, there is currently no harmonised product standard for CLT products, and each manufacturer has its own method for naming cross sections. On the other hand, the strength classification markings for lumber, glulam, laminated veneer lumber (LVL), and veneer are unambiguously defined.

The three-level usage classification markings for wood materials are based on the Finnish appendix that covers the design of wooden structures. The designed service life is defined according to SFS-EN 1990 (typically 50 or 100 years).

The visual, durability, and fire-safety requirements must be included in the surface classification of wood materials. There is a lot of variation among different engineered wood products when it comes to marking methods, particularly for the visual surface. This means it always makes sense to discuss marking methods and their purpose with the production facility.

The fire resistance classification defines the load-bearing capacity and/or sectioning capability of the structure or structural component in the event of fire.

The emission classifications (such as M1) for building materials should be reported when the material has one or when the project requires it.

The environmental impacts of wood materials can be reported as a conservative value and/or as reported by the manufacturer. It is also important to indicate which emissions database was used for the impact assessment.

The tolerance requirements stem from the manufacturing tolerances of the product in accordance with SFS 5978 and need to be indicated in the manufacturing class of the product.

It is also essential to indicate any lateral gluing, particularly for CLT, while any glue applied at the construction site is always indicated in the structural plans.

When a project proceeds, a manufacturer is selected for prefabricated components. This is when the commercial name of the product should also be indicated.

Scheduling and status information

Scheduling and status information are integral to the manufacture of prefabricated components. BIM facilitates discussions and the exchange of information between designers, production facilities, construction site personnel, and project management about the schedules for various structural components required by the project.

The plan status indicates the plan’s document group or intended use. Examples of statuses include “draft” or “calculation document.”

An 11-step scale is used to indicate how complete a plan is. In this scale, the numbers 01-09 are reserved for designers to use as desired to indicate the readiness of their element plan. Number 10 refers to a completed plan and number 11 is a revised version of a completed plan. The plan’s planned publication date also needs to be indicated.

For factory production, the manufacturing facility, the planned production date, the actual production date, and the production plant status need to be reported. The status can be used to indicate details such as whether the plan has been received or whether the structural components are in production or in stock.

For transportation, the planned delivery date to the construction site, and the actual delivery date are obligatory, and the installation number, load book number, and load number can be indicated if desired.

In summary

The guidelines are available in their entirety at https://puuinfo.fi/suunnittu/ohjeet/tietomallinnus/.

The guidelines need to be widely adopted to maximise their benefit to all parties. The largest players in the industry have already committed to using the guidelines, and the relevant practices will become the industry standard.

The terminology guidelines already create a foundation for coordinating modelling work, but the terminology collection process is still ongoing, for example for fasteners and other related structures not covered in the first version of the guidelines. In addition, modelling practices also require more extensive guidance and standardisation, and the industry is more than welcome to contribute to this work.

High-quality BIM is the foundation for increased productivity and will be a prerequisite for the entire industry in the future. Modelling will be required at different product levels when dealing with the authorities, and product information will need to be transferred from systems to customers in a timely manner. In a nutshell, proper modelling makes it possible to combine different components from different manufacturers into new products, introduce product variations without significantly losing production efficiency, and innovate new business models in general.

BIM is therefore not just a tool for experts or the domain of a specialist designer. Now and in the future, modelling will be a part of everyday working life and the question is: Do we use it because we must, or do we use it to effectively collaborate to gain a competitive advantage for the entire industry?


Emil Jansson, Ramboll Finland Oy Henri Salonen, A-Insinöörit Suunnittelu Oy Hannes Tähtinen, Sweco Finland Oy Sauli Ylinen, Puutuoteteollisuus Ry