diff --git a/mods/mcstair/init.lua b/mods/mcstair/init.lua
index 53de9c4c0..e17d19b98 100644
--- a/mods/mcstair/init.lua
+++ b/mods/mcstair/init.lua
@@ -602,6 +602,7 @@ function mcstair.add(name, stairtiles)
 		paramtype = "light",
 		paramtype2 = "facedir",
 		is_ground_content = false,
+		sunlight_propagates = false,
 		groups = outer_groups,
 		sounds = node_def.sounds,
 		node_box = {
@@ -622,6 +623,7 @@ function mcstair.add(name, stairtiles)
 		paramtype = "light",
 		paramtype2 = "facedir",
 		is_ground_content = false,
+		sunlight_propagates = false,
 		groups = inner_groups,
 		sounds = node_def.sounds,
 		node_box = {
diff --git a/mods/stairs/init.lua b/mods/stairs/init.lua
index 31856054f..0ac30d442 100644
--- a/mods/stairs/init.lua
+++ b/mods/stairs/init.lua
@@ -19,6 +19,7 @@ function stairs.register_stair(subname, recipeitem, groups, images, description,
 		tiles = images,
 		paramtype = "light",
 		paramtype2 = "facedir",
+		sunlight_propagates = false,
 		is_ground_content = false,
 		groups = groups,
 		sounds = sounds,
@@ -111,6 +112,7 @@ function stairs.register_slab(subname, recipeitem, groups, images, description,
 		tiles = images,
 		paramtype = "light",
 		paramtype2 = "facedir",
+		sunlight_propagates = false,
 		is_ground_content = false,
 		groups = groups,
 		sounds = sounds,