diff --git a/src/blenderbim/blenderbim/bim/module/model/roof.py b/src/blenderbim/blenderbim/bim/module/model/roof.py
index 77f1c635b4..3d029fd93b 100644
--- a/src/blenderbim/blenderbim/bim/module/model/roof.py
+++ b/src/blenderbim/blenderbim/bim/module/model/roof.py
@@ -47,6 +47,10 @@ def float_is_zero(f):
 
 
 def bm_mesh_clean_up(bm):
+    # leave only object's footprint
+    min_z = min([v.co.z for v in bm.verts])
+    bmesh.ops.delete(bm, geom=[v for v in bm.verts if not float_is_zero(v.co.z - min_z)], context="VERTS")
+
     # remove internal edges and faces
     # adding missing faces so we could rely on `e.is_boundary` later
     bmesh.ops.contextual_create(bm, geom=bm.edges[:])