diff --git a/src/c3nav/mapdata/render/renderer.py b/src/c3nav/mapdata/render/renderer.py
index 751bf0ae..1bcd7b96 100644
--- a/src/c3nav/mapdata/render/renderer.py
+++ b/src/c3nav/mapdata/render/renderer.py
@@ -106,7 +106,8 @@ class MapRenderer:
             # add obstacles after everything related to ground for the nice right order
             for i, altitudearea in enumerate(geoms.altitudeareas):
                 for height, obstacle in altitudearea.obstacles.items():
-                    engine.add_geometry(obstacle, fill=FillAttribs('#B7B7B7'), category='obstacles')
+                    engine.add_geometry(obstacle, fill=FillAttribs('#B7B7B7'),
+                                        stroke=StrokeAttribs('#888888', 0.05, min_px=0.2), category='obstacles')
 
             # add walls, stroke_px makes sure that all walls are at least 1px thick on all zoom levels,
             walls = None