I'm a little late to this post but take a look at SolveSpace, they have a native Linux client and it's free (GPLv3). The downside is you'll have to build it yourself. - Source: Reddit / about 1 month ago
FreeCAD - An open-source parametric 3D modeler
Floorplanner - Floor plan interior design software. Design your house, home, room, apartment, kitchen, bathroom, bedroom, office or classroom online for free or sell real estate better with interactive 2D and 3D floorplans.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Sweet Home 3D - Sweet Home 3D is a free interior design application that helps to draw the plan of house, arrange furniture on it and visit the results in 3D.
SketchUp - 3D for Everyone
Planner 5D - Home Design Software & Interior Design Tool ONLINE for home & floor plans in 2D & 3D. Read more about Planner 5D.