create 2 storey duplex house over apartment on ground floor.

[Naza34DXB]

Im having trouble to create 2 storey duplex house/ townhouse over 1 apartment unit at ground floor. The whole block calculated as 3 units instead of 2 units. Does anyone have any idea how to solve this?

Naz

[fredrik.morken]

Hi, this isn't currently possible to model in Forma. Only the house building type supports multi story units at the moment, and they can only be placed on terrain, not on top of other buildings. We could envision this being modelled either by placing two story house on top of a basic building, or creating a basic building with a two-story unit and stack that on top of another basic building, but neither is possible at the moment. We are aware of the limitations here and are looking into ways of improving our modelling capabilities. 

Regards, Fredrik from the Forma team

[patrick.maher8BDHU]

any progress on allowing this 

[scottwakefield445]

From my experience, this issue usually happens because of how the building code defines a “unit.” If the ground floor has one apartment and the upper floor works as a duplex (two separate living spaces with kitchen and bathroom), the authority will count it as 3 units, not 2. It’s based on independent living spaces, not just the number of floors. I’ve seen this affect approvals and services like HVAC design Ontario, so it’s important to check local zoning and building code definitions early and confirm with the local authority.

[melvin22rogers]

It sounds like the model is reading your layout as three separate units instead of combining the duplex correctly. You may want to double-check how spaces are defined—especially shared walls, entrances, or unit boundaries. Even a small separation can sometimes cause the system to count an extra unit.

This type of issue is also common in Heating system design in Ontario, where correct unit classification is important for proper system sizing and zoning, so clearly defining which areas belong to each unit can help avoid confusion.