Frequently Asked Questions

General questions about LCAbyg

Is it the latest guidance integrated with LCAbyg?

Yes, it is the latest version of the Danish guide that is available under the tab "Help" in LCAbyg. The English guide can be downloaded with the software. The English version og the guide currently lacks descriptions og the latest updates. While this is being added we reffer to the FAQ in which all new updates and changes will be clearly explained under the version number they belong to.


Which version of LCAbyg is the latest that has been released?

Windows: LCAbyg 2023.3 (

Mac: LCAbuild 2023.3 (


Why do LCAbyg 2023 Windows ( and Mac ( have different version numbers?

We have had to make minor adjustments to publish LCAbyg 2023 on Mac. Due to adjustments, we have changed the version number to ( The database is the same version as Windows ( and still has the same problems.


Is there a version of LCAbyg for Windows 11?

The latest version of LCAbyg can be used on Windows 10. Download here.


Is there a version of LCAbyg for Mac and Linux?

Mac OS version developed. Download here.
Linux is not currently supported but is potentially being developed.


When LCAbyg is installed, the publisher i listed as unknown. Can this be changed?

Unfortunately, it is not possible to change the publisher from unknown.


Is there a difference between the Danish and Norwegian versions of LCAbyg?

Den Norske version er tilpasset de norske forhold også i forhold til levetider. Spørgsmål omkring dette henviser vi til


Can the order of materials be moved at the construction and building product level?

This is possible if you left-click and hold down on a construction or product. Then you will be able to drag-and-drop to the location you want.


Do you plan to structure building sub-groups and sub-groups as in the Voluntary Sustainability class?

Currently, LCAbyg is not planned to follow a classification system such as FBK, SfB, or similar systems. 


Is it a requirement to create environmental data from a specific calculation system when applying for a building permit?

There is no requirement that LCAbyg 2023 or other tools be used to document a building's climate impact. Therefore you decide which program to use. However, you must be aware that specific programs may be mentioned in the tender material.


ATTENTION: It is not possible to open LCAbyg 2023 projects in LCAbyg

If a project has only been opened in LCAbyg 2023, it cannot automatically be downgraded to an LCAbyg project.


ATTENTION: User-created paint products from older versions do not automatically change service life from 15 to 50 years

According to the building regulations, paint must have a service life of 50 years (the lifetime of the building), whereas LCAbyg has previously specified the service life as 15 years. A project created in LCAbyg version or earlier, which is opened in LCAbyg 2023, will automatically have these service lives updated for GenDK products. If you have a user-created paint product, the service life will not be automatically updated. The users must therefore be aware of this themselves.


Why does LCAbyg 5 look very large on my computer screen?

The reason may be a setting on your computer, which results in LCAbyg looking great. Feel free to check this out first.

Otherwise, there is an option for scaling in the upper right corner of LCAbyg. Remember to restart LCAbyg.


Is it possible to compare different variants in the same project in LCAbyg 5?

It is possible to work with several different scenarios in a project. Therefore, it is possible to work with different calculation assumptions for each scenario. Scenarios are activated under "Building and operation" on the button. "Click to enable scenarios for this project." This function replaces the project comparison function that was discontinued in LCAbyg 3.2.

General questions about LCAbyg - results

As a developer, how do you check that LCA calculations submitted to the authorities are correct? Can we "only" check that the result is below 12 kg/CO2?

Please contact Videnscenteret for Klimapåvirkningerne or the authorities.

The report from LCAbyg 2023 is prepared to give a complete picture of one’s building model.  Theoretically, it should be possible to recreate the same building based on the report only. 


Why is the sum of the different stages different from the key numbers in my LCAbyg report? 

The results in LCAbyg are rounded with the "Banker's rounding" method, which is the most numerically stable method for rounding numbers, where x.5 is rounded to the nearest even number. Therefore, the result may vary due to this rounding method.


The tab on the right of the results page shows the result that was clicked on

If a component is selected on the results page, it will be displayed in the right tab. This means that different values may appear. 


Why can't I export a report to PDF?

The report function in LCAbyg and is sensitive to incorrect naming of user-created building parts, constructions, building products, and phases.
Furthermore, you must avoid putting a space with 'tab' and end up making a line break. We always recommend downloading the latest version of LCAbyg.


Is it possible to export LCA-results to an Excel-fil?

The LCA results for the building model can be exported to an Excel file. Under the menu item 'Results,' you can select 'Export Excel,' after which the destination where you want to save the Excel export is selected. With this, all results on the building model are available.


Is it possible to save the analysis graphs in SVG files?

You can save the charts in LCAbyg 5 as SVG files under 'Analysis and report' via the 'Save chart' function.

General questions about LCAbyg - EPD's and stages

ATTENTION: EPD Danmark construction product in the project

When importing an EPD Denmark product which is part of GenDK, a new product will be created. In other words, you now have two products in your library based on the same EPD with identical indicators. It makes no difference which product you choose in your project, the result will be the same. However, it is recommended to avoid importing these EPDs, as they are already in the GenDK library. The EPDs in question are those specified as the data basis for calculation in the Building Regulations.


ATTENTION: Avoid import of EPD MD-20015-da rev 1, concrete wall elements from EPD Denmark.

The product called "Precast concrete wall element, 20 cm, 16-25 kg reinforcement (11% hollow)" is already available in the GenDK library and conflicts arise if the EPD is imported from EPD Denmark. If it is imported anyway, you can experience products that lose stages. However, there will always be an identical product available that one can choose instead. This issue will occur primarily in version 2023.2 ( and later.


Why can't I see my imported EDP files in LCAbyg 5?

The imported EDP file (.lb5epd) will appear in the building item or stage library, which can be accessed via the book icon.


Unable to create a stage

Check the following:

  1. Always fill from top to bottom. It is important that the general information is filled before entering the indicators.

  2. If you are copying indicators from a pdf or something else, be aware that there are no spaces before and after the numbers. If the box with indicators is red, it means that the stage has not been added.

General questions about LCAbyg - ILCD+EPD (XML) import


It is possible to import EPDs into LCAbyg via the ILCD+EPD format (XML). This should be seen as an aid in entering EPDs into the program. LCAbyg "reads" the information available in the digital XML format and LCAbyg is therefore not responsible if data is missing. Therefore, it is the responsibility of the users to ensure that the imported data is correct and add missing data if necessary. However, several features have been implemented to help identify empty data fields. The most common problems encountered when importing EPDs are mentioned below. 


Available application operators

It is possible to import EPDs from the following program operators via the ILCD+EPD import into LCAbyg:  

  • EPD-Norge Digi
  • ECOSMDP (includes EPD Denmark and other small operators)
  • The International EPD System (Environdec)


Import fails with error message

Users may find that EPDs from an otherwise available program operator cannot be imported. This is due to a lack of data in the digital format. Unfortunately, this means that users will have to manually enter the EPD by creating the necessary stages, see section 5.4.1. Example of entering EPD in the user guide.

The above applies to the following error messages:

Exception: Error, Cannot import incomplete component. - Data is missing in the digital format

Exception: URL Provided is not valid. - LCAbyg does not support the given program operator 


The created products and stages have the source "User"

This will be due to missing data or stages in the digital format. If data is missing, it means that the calculation will be incorrect if this data is not found. Therefore, the user must find the data and fill in any blanks, therefore the products and stages will be editable. In the field "External Source" you will still be able to see which program operator the EPD comes from even if the source is "User". 


The import is successful, but there is a warning about missing mass factor 

The mass factor is sometimes missing in the digitized EPDs, which is not compatible with LCAbyg. The mass factor is necessary for LCAbyg to calculate the correct weight of the product and for the user to have the opportunity to calculate the product in the unit kg. Often, however, the mass factor will be found in the pdf version of the EPD and therefore the user can fill in the mass factor themselves. See section 5.4 of the User Guide for examples of where the mass factor can be found in an EPD. In general, do not use the result from a calculation that contains warnings, as this may affect the result. 


Import is successful, but stages are missing

Some EPDs have only been executed for stages A1-A3 and do not have data for EoL available. These EPDs can be imported, but will be created with the source "User" and there will be a warning that a product is missing EoL stages. If you want to use this EPD in your calculation, you must create generic EoL stages that fit the type of material. These can be found in the generic data basis in BR. 


I can't find the EPD I just imported  

If an EPD has been successfully imported, it will be found in the product- or stage library, which can be accessed via the book icon in the upper right corner. It is recommended to search for the name the EPD has where you have copied the XML URL you have used for the import. It is also possible to search for the name of the program operator, but if it is not found under this, it will be found under the source "User". It is not recommended to search by material categories, as these are not always correct, see the next item. If you want to keep track of your EPDs, it may be an advantage to rename it, as the given name is not always sufficient. 


The categories for the stages are incorrect  

All the different application operators use different categorizations and some EPDs have no categorization. This is not compatible with LCAbyg's stage categorization. Instead of not allowing imports of these, they are assigned default categories. Therefore, you will encounter stages that do not have accurate categories. It is recommended that the user chooses the categorization for these EPDs so that it is easier to find them in the future. 


The expiration date is incorrect  

For some digitized EPDs, only the year and not the date is given. In order not to allow the use of data after its expiration date, these dates will automatically be set to January 1 of that year. Users can advantageously look up the expiration date in the pdf version of the EPD and correct it for the stages in LCAbyg. 


The results are NaN  

If you use ILCD+EPD import in an older version than LCAbyg 2023.3 ( and the EPD is missing data, the product will be found under results, but since the results cannot be calculated due to lack of data, the result from the product will be NaN. We therefore recommend updating to the latest version or correcting the missing fields in the stages. If data is missing in the stages of a construction product in the latest version of LCAbyg, the product will not be found at all in the results. 


What do I do when I want to use the same EPD in another project?

If you have imported an EPD and filled in the missing data, as well as corrected other aspects of the stages or the products, it is recommended to export the product to a file that can be downloaded into new projects. See how to do this in section 5.3 of the User Guide.


General about LCAbyg 2023 - GenDK updates

Adapted to meet legal requirements

GenDK has been updated and adapted to "Appendix 2, table 7: Generic database 2023". This update includes replacing generic data for concrete and wood materials with industry data from EPD Denmark. The database can be downloaded from:  In addition, the GenDK library is further updated for any defects. Projects created in LCAbyg or earlier will potentially vary as the database has been updated. Older projects opened in LCAbyg 2023 will automatically be updated to the latest database and cannot be rolled back to a later version after this.


New constructions

The construction library has been updated with more constructions. Among other things, standard values ​​have been added for installations that BPST has developed in collaboration with the industry.

General about LCAbyg 2023 - Features no longer available in LCAbyg and newer

Import of LCAbyg 3.2 projects and components

With the release of LCAbyg 2023, it is no longer possible to import projects or components (Building parts, Structures, Building Materials, and Stages) from LCAbyg 3.2. If the need arises, you must open these in LCAbyg, save and then open these in LCAbyg 2023. If, contrary to expectations, problems occur with opening projects from LCAbyg 3.2. in LCAbyg, then write to the LCAbyg mailbox.


DGNB as calculation type

As a result of the new DGNB manual applicable from March 2023, where documentation requirements for life cycle assessment are streamlined with the building regulations, the DGNB calculation type is taken from LCAbyg 2023. This means, in return, that new DGNB certifications must use the calculation type 'Building Regulations' to document the LCA criterion in DGNB. Point calculation is done elsewhere. Information on DGNB certification types can be accessed here:

Errors in LCAbyg 2023.3 ( (Published March 2024)

If you experience errors that are not mentioned below, you are very welcome to write to our mailbox at:

Known errors in LCAbyg 2023.3 (


No known errors

There are no known errors in the current version.

New features in LCAbyg 2023.3 ( (Published March 2024)

In this version two errors have been corrected.


Error correction in table overview of products when selecting a construction. 

If a construction contains several of the same product with different quantities, these were shown with the same quantity in the table overview to the right when the construction was selected. This did not affect the calculation, but only the overview of construction products. 


Error correction in BR export for projects with special conditions 

For projects with special conditions, the result was not exported correctly to the standard format for documenting the climate requirement. The total climate impact is now correctly stated excluding the added impact from special conditions. 

Errors in LCAbyg 2023.3 ( (Published end of February 2024)

The bugs below have been fixed in the latest version, so we recommend updating to this version. See newest version number in the top under "General questions about LCAbyg.

Known errors in LCAbyg 2023.3 (


Errors in table overview of products when standing on a construction

There are errors in the table showing products and quantities when a particular construction has been selected in the building model. This error occurs only if there are several versions of the same products with different quantities. The table in this case will show the quantity from the first products, as the quantity for all the other versions of the same type of products. The results in the chart are displayed correctly and there are no errors in the calculation, it is only the numbers in the specific table that are displayed incorrectly.


Error in BR export for projects with special conditions

For projects that contain special conditions, the result is exported incorrectly. The total climate impact must be stated excluding supplement from special conditions, but will be stated with supplements. This is fixed in the next version.

New features in LCAbyg 2023.3 ( (Published end of February 2024)

In this version, the ILCD+EPD import has been updated. See the section further above for more detailed help.


More EPD program operators are available

It is now also possible to import EPDs from The International EPD System (Environdeck) and ECOSMDP, which includes EPD Denmark. 


Updated managing of imported EPDs, that are missing data

EPDs with missing data are created with the source "User" and the missing data fields will give an error message so it is clear where to enter the data. It is often the data field "Mass factor", which is missing, see an example in the user guide


Updates to the Danish user guide

The user guide, which can be found under "Help" in LCAbyg or online, has been updated with new details about how the ILCD+EPD import works. 


Corrections in the construction library

In GenDK one construction has been updated:
The Danish name of the construction "Flat roof, wood truss (H=620 mm) per 815 mm, 525 mm cellulosefibre insulation" has been updated.
In this construction the product "Mineral wool (blowable)" has been changed with "Cellulose fibre blowing insulation material".

New features in LCAbyg 2023.3 ( (published beginning of February 2024)

In this version, a few minor errors have been fixed, updates have been made in the Danish user guide, as well as updates of the standard format.


Correction of errors with A5 in the calculation type "building regulations" 

It will now no longer be a problem to create a project with the calculation type "User-specific LCA", fill in "Energy consumption on site" and then switch to "Building Regulations". If you switch back to e.g. "User-specific LCA", what you had filled in under "Energy consumption on the construction site" will still be available. 


Corrections in Excel export to the official standard format

The standard format for submission of LCA documentation is in its final version on the Building Regulations website. The export function in LCAbyg has been updated to follow the final version, but still without specifying Category and Type. The sample project with construction products from Table 6 has also been updated. In addition, there was an error in how the total GWP was summed up for each construction product. GWP total now does not include the contribution from the D phase. However, this can still be found in the column for the D phase itself. 


Corrections in the construction library

In GenDK, errors in two constructions have been corrected: 
In the construction "Middle layer, aerated concrete, 100 mm " the product "Reinforcement steel wire" has been exchanged "Tile adhesive". 
In the construction "Middle layer, aerated concrete, 200 mm" the amount of mortar has been changed from 4,8 kg/m2 to 8,4 kg/m2. 

Errors in LCAbyg 2023.3 ( (published January 2024)

The bugs below have been fixed in the latest version, so we recommend updating to this version. See newest version number in the top under "General questions about LCAbyg.

Known errors in LCAbyg 2023.3 (


A5 in calculation type "Building Regulation"

A project, which has the "Energy consumption on construction site" available and filled out should not be changed to calculation type "Building Regulation". This will remove the "Energy consumption on construction site" section, but the previously filled out information will still be added to the results as A5, which is not a part of the requirements. This will be fixed in the next update, but untill then change the calculation type back and delete the information entered in "Energy consumption on construction site".

New features in LCAbyg 2023.3 ( (Published in Januar 2024)

In this version, a few bugs have been fixed in the construction library, as well as added new features to improve the user experience. Major changes are mentioned below.


Products can be registered as reused  

It is now possible to set a product to be a recycled material by choosing a service life of 0 years. This is an implementation that follows the guidance on reused materials in the building regulation § 297, stk. 5 about generic data basis. Read more about how to model reused materials in LCAbyg, in the user guide 5.3.2. Genbrugte materialer.


VCBK cases as example projects

Under the menu item New, five projects from VCBK's casebank have now been added, which can be opened directly in LCAbyg. Read more about the individual cases on the website of VCBK and read about the five choosen cases in the LCAbyg userguide


Corrections in GenDK constructions

There have been errors in the quantities, units and links of individual construtions. These are now fixed and will be automatically updated in LCAbyg projects that are opened in this new version of LCAbyg 2023. However, please note that constructions that are copies of GenDK constructions will not be affected. Only constructions with the source GenDK will be updated. 


Corrections in the English version

The English version of LCAbyg has been thoroughly corrected for lack of translations and other things that have caused comprehension problems.


New Excel exsport to the new voluntary standard format

The new standard format in BR for documentation of the climate impact of buildings is implemented as a BETA export function in LCAbyg. It is voluntary to use until 2025. It is only exported to a limited extent, as some information is not available in LCAbyg. The information that is missing in the Excel document is marked so that users can fill it in afterwards. Because the standard format follows an additional categorization than that used in LCAbyg, the Category and Type columns cannot be filled out in this version of the export function. However, a template has been added that can help with this categorization, see below.


Template project with naming from the standard format

To help users follow the new standard format, a template project has been added under the menu item New, which opens a project with only elements added. The template project is called "BR Table 6, Element example". These elements are named according to Table 6 of the Building Regulations. All elements are created, even those that should not be included in the calculation. These have "Included in calculation" turned off. The individual names for the building parts contain both category, type and building part.


Imporvement of ILCD+EPD import

The import of ILCD+EPD via url has been improved, so that it works for more EPDs. The function itself is the same, but the amount of EPD that can be imported successfully has increased. It still only works for EPD Norway EPDs

New features in LCAbyg 2023.2 ( (Published October 2023)

In this version, bugs have been fixed, as well as general stability. Major changes are mentioned below.


Openeing json directly from files   

It is now possible to open json projects directly from LCAbyg instead of json folders/projects having to be opened through Engine.yaml. The feature is found file -> New project from json.


Opening json components directly from files   

It is now possible to create new projects only with json components (element, construction, product and stage). The feature is available in file-> New project with json components.


New feedback system directly in the program  

A new fedback system has now been implemented, which makes it possible to report bugs directly from the program. Here you can attach your project, and log files will automatically be sent. This allows us to resolve the issues submitted more quickly.


Constructions can now be moves between elements

It is now possible to move constructions directly between elements without editing amounts. This feature can be found by selecting your construction and then clicking on the "Move construction to other building part" button in the bar above the building model. It is not found by right-clicking on the construction.


LCAbyg now accepts both "," og "."

LCAbyg now accepts both "," and "." as a decimal separator. If you enter a number with "." and click away, it will be updated to ",". So you can now copy-paste values from EPDs that use "." as a separator.

Errors in LCAbyg 2023.2 (Published September 2023)

The bugs below have been fixed in the latest version, so we recommend updating to this version. See newest version number in the top under "General questions about LCAbyg.

Known bugs in LCAbyg 2023.2:

Stages for EPDDenmark EPDs dissapear

Projects created in previous versions where the user has imported EPDs from EPDDanmark, which in the current version is part of Gen_dk, will experience that the stages disappear. This is solved in the newest version of LCAbyg.


Problems displaying graphs

Problems with graphs not being displayed are solved both under "Analysis and report" and the results page for the building regulations.


Problems importing user-created components

Some may experience problems with importing user-created products losing stages. This is fixed in the latest version.

Errors in LCAbyg (published December 2022, fixed in version 2023.2)

These bugs appear in version but have been fixed in the latest version LCAbyg 2023.2. We therefore recommend updating to the latest version. See newest version number in the top under "General questions about LCAbyg.


The description of constructions for default values is incorrect

The amount must be equal to the heated floor area §256 subsection 3, plus the heated basement area


The area in the report has been swapped

In the table "Areas" of the report printout, Integrated garage and Additional area are swapped in a way that causes the numbers to have the wrong position. This does not affect the final result. 


Comma numbers are not visible in Calculation prerequisites.

There is a display error which means that when commas are entered in Integrated garages and Additional area, NaN is displayed. This is a display error; the number is still counted in the Reference area.


Error in GenDK constructions

Some constructions in GenDk have demolition turned on, which means that A1-A3 is not included in the calculation. This can be changed by cloning the build and manually turning demolition off.


Error in the lifetime table (DK: levetidstabellen)

Individual rows and columns are not shown in the lifetime table in LCAbyg v. 5.3. The entire table can be found in the BUILD REPORT 2021:32 – BUILD levetidstabel – Version 2021 (revised in November 2022 as version 2).


Error in constructions containing lightweight concrete and plaster

In GenDK constructions that contain "Lightweight concrete wall element, 100 mm thick wall (10% recesses)" and "Gypsum fiber board 10 mm", the building product is not included in the life cycle assessment due to a unit error. This can be remedied by cloning the build and then changing the unit.

ATTENTION: It is important to check whether the quantities make sense using the construction library. 


Error in the construction "Columns, concrete frame column 300/300"

The construction has a steel profile as a construction product but should have reinforcement


Silicate paint (indoors) has incorrect C3 stage

The building product has a concrete element in the C3 stage, which is incorrect according to the generic database.


Error in the default values ​​for other buildings

Other buildings, drains A1-A3

LCAbyg value: 0.125 kg CO2eq./m2

Actual value: 1.125 kg CO2eq./m2

Other buildings, water, stage D

LCAbyg value: -1.675 kg CO2eq./m2

Actual value: -1.28 kg CO2eq./m2


Missing stages in several concrete building products

When opening the LCAbyg project in LCAbyg 2023, in some cases, stages may be missing in the concrete building product.

New features in LCAbyg 5.3.10 (published December 2022)

These features are also available in the latest version 2023.2.


More area entries under 'Calculation prerequisites'

In calculation conditions, it is now possible to enter the area of ​​integrated garages for single-family houses, terraced houses, and the like, which are included at 50 percent. cf. the requirements on the climate impact of buildings, as well as an additional area which is included at 25 percent.


Import of emission factors from local supply facilities

It is now possible to import an EPD for a supply source if there is an encrypted and 'locked' .lb5epd file for the EPD. At the time of publication of LCAbyg 2023, EPDs from utility companies still need to be published. There will be more about this in the user guide and webinars when it becomes available.


Natureal gas has been replaced by pipeline gas

The emission factors for natural gas have been replaced with new emission factors for pipeline gas. See more about the data behind the operation in the associated Excel sheet, which can be downloaded at the same place as LCAbyg. 


The lifetime table (DK: levetidstabellen) has been updated .

The lifetime table has been updated cf. BUILD REPORT 2021:32 – BUILD levetidstabel – Version 2021 (revised in November 2022 as version 2), which can be found her.


Special circumstances

If a building has special conditions, these can be added to the program, after which the given constructions covered by the special conditions can be selected in the building model. The additional impact due to special conditions for which the building is justified is then calculated. Read more about special building requirements in the new BUILD report 2022:27 her.


New display of the library

The display of the construction and construction material library has been updated. Getting more information about constructions and construction materials in the library is now possible.


Stages can be created cf. EN15804+A2

It is now possible to create stages according to the available EPD standards - both EN15804+A1 and EN15804+A2. When entering stages according to EN15804+A2, only the GWP-total indicator must be entered. Please note that the project will use environmental data from two standards when entering one or more stages according to the standard EN15804+A2. Therefore, the results for indicators other than GWP cannot be compared or summed. There will be a warning in several places in the program if EPDs from EN15804+A2 are used.


Scaling factor

All stages now have a scaling factor. The scaling factor can, e.g., is used when entering insulation materials, whereas, in an EPD, there is an associated table to scale to the material that must now be used. If the data set does not contain a scaling factor, this is set to 1.


Results display updated

It is now possible to close the display of results for the various environmental indicators and thus only display results for individual environmental indicators rather than all. By default, LCAbyg 2023 only shows results for the environmental indicator GWP when the calculation condition is set to "Building Regulations"


New result display for the building regulations (DK: Bygningsreglementet)

When selecting the calculation type 'Building Regulations', there is now a new results page called 'Building Regulations'. It provides a simple overview of the main results for the building's climate impact, which must be used to document the upcoming requirement for buildings' climate impact in the Building Regulations.


English version

Under settings, you can now change the program interface to English.

Report updated

The LCAbyg report has been updated and can be used to document the building regulations' requirements for buildings' climate impact.


Import of ILCD+EPD format

It is now possible to import EPDs in the digital format ILCD+EPD. From 1 January 2023, EPDs can be imported from EPD Norway, with a few exceptions for materials whose digital file needs the necessary information to be used for Life Cycle Assessment in LCA building. For more information see her.



LCAbyg's LOG is now updated to be more interactive so that you can double-click on any missing or errors in the LOG which directs you to the exact location of the error. 


Opening of LCAbyg projects

It is now possible to open LCAbyg projects by double-clicking on the files. However, this only works as long as the project is not destroyed. In that case, the LCA building must be opened first, after which the project can be opened and possibly repaired. ATTENTION: Be careful with double-clicking on files that will not be updated to the latest LCAbyg version.


Repair of LCAbyg projects

LCAbyg can now repair projects that have previously been destroyed. Most projects from, e.g., previous versions, can now be opened in LCAbyg (not by double-clicking the file), and you will get a message here that you can repair the project. Remember to save your original project, as there may be information that LCAbyg removes in connection with improving the project. Projects that have been repaired must be saved as new projects.


Shortcut keys

It is now possible to use shortcut keys in LCAbyg to access the various functions such as: renaming, removing, etc. These shortcut functions can be seen in the LCAbyg program by hovering the mouse over the function.

General questions about LCAbyg JSON 2023.3 (

Which third-party integrations can be used in LCAbyg 5?

It is possible to use the JSON format as third-party integration. 


What is the JSON format?

Third-party integration used outside LCAbyg's interface to create everything from entire projects to component libraries. It is also possible to extract results for his project in JSON. Watch or re-watch our webinar on the intro to the JSON format on LCAbyg's YouTube channel.


Where can I find a guide about the JSON format?

There are English guides about JSON projects, exports, and scenarios that can be downloaded here.


Where can I find the import example?

You can find the import example in the zip folder when you download the JSON-guide here.


Different versions of the JSON format and LCAbyg

In general, you can always open LCAbyg projects from an earlier version in a newer version of LCAbyg. LCAbyg autofills empty default values for fields missing in the JSON project. However, it is recommended, to model as much as possible in the JSON format. We are in the process of updating the guide to the 2023.3 fomat, where this will be elaborated.

Updates in LCAbyg JSON 2023.3 (

Version has a change in engine.yalm.

See the example under Step 3.3, page 15, in the JSON guide. The guide can be downloaded here.


New import function for JSON projects and components

The 2023.3 version of LCAbyg can handle direct import of JSON projects or individual JSON components (e.g. JSON element, construction or product).


New fields in the JSON format

Export of JSON projects from the latest version of LCAbyg contains new in the "building-node". The fields person_count, building_topology, project_type have been implementet to help follow the Standard format BR, but are not currently included in any calculations are therefore not mandatory to complete. 

Typical error messages in LCAbyg JSON 2023.3 (

LCAbyg_debug.exe will not open or crash when I try to open my JSON project.

Check that the file 'engine.yalm' has no errors. Typical errors include incorrect indexing, incorrectly placed characters, e.g., character. To help troubleshoot, type 'cmd' and press 'enter' in the path where lcabyg_debug.exe is stored. This will open a terminal describing errors in your engine.yalm file.


How can I check that my JSON files are correct?

We recommend that you regularly test that you import your JSON project into LCAbyg. By opening LCAbyg_debug you can get error messages printed in the LCAbyg terminal. LCAbyg does not work if you place the cursor or type inside the terminal, and if you make changes to the JSON project, you must restart LCAbyg_debug.You can read more about the debug feature in the updated guide on JSON projects (coming out in early March 2022).


How can I find out why I get the "Missing UUID" error message in the LCAbyg_debug.exe terminal?

You can search your JSON file/files in Notepad ++ and check that all UUIDs are written correctly, that you have not inserted the UUID incorrectly, or that you must include UUIDs.


Why does the same error message appear twice in the LCAbyg_debug.exe terminal?

It does not affect the overall error. Both error messages will disappear by resolving one of the two identical errors and restarting LCAbyg.exe.


What does the following error message mean: 

"Collision between CategoryToConstruction(069983d0-d08b-405b-b816-d28ca9648956) and ElementCategory(069983d0-d08b-405b-b816-d28ca9648956"?

Often this error is because the unique ID has been used more than once. Therefore, check that the unique ID or referring unique ID has been used only once.


What does the following error message mean: 

"Missing target source at badfcf92-804a-5902-a5c4-0ea1460c202e for ConstructionToProduct(0dd0b7a2-6f15-496c-88e0-8b64bcb663ba)"?

If you have created nodes and edges for nodes, and then deleted some of nodes, then the referring/related edges must also be deleted. One way "blank" edges can be found quickly is by opening the JSON project in Nodepad ++, then performing a search on "amount: 0", which returns the search result for all blank edges in the searched JSON file/project.


I cannot find any constructions when I export the building model from LCAbyg to JSON.

If you have only used the gen_dk library to model your constructions, then no constructions are exported to JSON, as they are already in the gen_dk folder, built into LCAbyg.


Why do I get the error messageCollision on Building…", when importing a component for an existing project in LCAbyg?

One reason may be that your import component is not set up correctly or that you have imported a non-UUID component already in an LCA building component.


Why can I not open the import example?

This may be because you are using different versions or, respectively, the import example and LCAbyg. For example, a change has been made to the edge, CategoryToStage, from version to You must download the latest version of LCAbyg and the latest version of the JSON guide.

Excel tool (lite)

What is Excel tool (lite)?

The Excel lite tool can be used to build the building model via Excel, intended for the earlier design phase and faster import of the building model.

Excel lite is continuously developed. If there is feedback, you can write to the lcabyg mailbox


Is there a guide to Excel tool (lite)?

Introduction and help can be found in a sheet in the Excel file, which can be downloaded


Is there a version of Excel tool (lite) for Mac?

Currently, the Excel tool does not work for Mac (import of the csv file). This will be developed soon.


Why do I make a mistake when copying a row?

To copy a row, paste it at the bottom / below the existing rows.

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