diff --git a/src/map_builders.rs b/src/map_builders.rs
index e18e173..822be8b 100644
--- a/src/map_builders.rs
+++ b/src/map_builders.rs
@@ -13,6 +13,7 @@ mod room_based_spawner;
 mod room_based_stairs;
 mod room_based_starting_position;
 mod room_corner_rounding;
+mod room_draw;
 mod room_exploder;
 mod room_sorter;
 mod rooms_corridors_bsp;
@@ -37,6 +38,7 @@ use room_based_spawner::RoomBasedSpawner;
 use room_based_stairs::RoomBasedStairs;
 use room_based_starting_position::RoomBasedStartingPosition;
 use room_corner_rounding::RoomCornerRounder;
+use room_draw::RoomDrawer;
 use room_exploder::RoomExploder;
 use room_sorter::{RoomSort, RoomSorter};
 use rooms_corridors_bsp::BspCorridors;
diff --git a/src/map_builders/bsp_dungeon.rs b/src/map_builders/bsp_dungeon.rs
index 023912d..d26802f 100644
--- a/src/map_builders/bsp_dungeon.rs
+++ b/src/map_builders/bsp_dungeon.rs
@@ -1,6 +1,5 @@
 use rltk::RandomNumberGenerator;
 
-use crate::map_builders::common::apply_room_to_map;
 use crate::map_builders::{BuilderMap, InitialMapBuilder};
 use crate::{Map, Rect, TileType};
 
@@ -41,11 +40,9 @@ impl BspDungeonBuilder {
             let rect = self.get_random_rect(rng);
             let candidate = self.get_random_sub_rect(rect, rng);
 
-            if self.is_possible(candidate, &build_data.map) {
-                apply_room_to_map(&mut build_data.map, &candidate);
+            if self.is_possible(candidate, &build_data, &rooms) {
                 rooms.push(candidate);
                 self.add_subrects(rect);
-                build_data.take_snapshot();
             }
 
             n_rooms += 1;
@@ -107,7 +104,7 @@ impl BspDungeonBuilder {
         result
     }
 
-    fn is_possible(&self, rect: Rect, map: &Map) -> bool {
+    fn is_possible(&self, rect: Rect, build_data: &BuilderMap, rooms: &Vec<Rect>) -> bool {
         let mut expanded = rect;
         expanded.x1 -= 2;
         expanded.x2 += 2;
@@ -116,12 +113,18 @@ impl BspDungeonBuilder {
 
         let mut can_build = true;
 
+        for r in rooms.iter() {
+            if r.intersect(&rect) {
+                can_build = false;
+            }
+        }
+
         for y in expanded.y1..=expanded.y2 {
             for x in expanded.x1..=expanded.x2 {
-                if x > map.width - 2 {
+                if x > build_data.map.width - 2 {
                     can_build = false;
                 }
-                if y > map.height - 2 {
+                if y > build_data.map.height - 2 {
                     can_build = false;
                 }
                 if x < 1 {
@@ -132,8 +135,8 @@ impl BspDungeonBuilder {
                 }
 
                 if can_build {
-                    let idx = map.xy_idx(x, y);
-                    if map.tiles[idx] != TileType::Wall {
+                    let idx = build_data.map.xy_idx(x, y);
+                    if build_data.map.tiles[idx] != TileType::Wall {
                         can_build = false;
                     }
                 }
diff --git a/src/map_builders/common.rs b/src/map_builders/common.rs
index f1ae857..5f98287 100644
--- a/src/map_builders/common.rs
+++ b/src/map_builders/common.rs
@@ -11,15 +11,6 @@ pub enum Symmetry {
     Both,
 }
 
-pub fn apply_room_to_map(map: &mut Map, room: &Rect) {
-    for y in room.y1 + 1..=room.y2 {
-        for x in room.x1 + 1..=room.x2 {
-            let idx = map.xy_idx(x, y);
-            map.tiles[idx] = TileType::Floor;
-        }
-    }
-}
-
 pub fn apply_horizontal_tunnel(map: &mut Map, x1: i32, x2: i32, y: i32) {
     for x in min(x1, x2)..=max(x1, x2) {
         let idx = map.xy_idx(x, y);
diff --git a/src/map_builders/room_draw.rs b/src/map_builders/room_draw.rs
new file mode 100644
index 0000000..f6f3c30
--- /dev/null
+++ b/src/map_builders/room_draw.rs
@@ -0,0 +1,37 @@
+use super::{BuilderMap, MetaMapBuilder};
+use crate::{Rect, TileType};
+use rltk::RandomNumberGenerator;
+
+pub struct RoomDrawer {}
+
+impl MetaMapBuilder for RoomDrawer {
+    fn build_map(&mut self, rng: &mut RandomNumberGenerator, build_data: &mut BuilderMap) {
+        self.build(rng, build_data);
+    }
+}
+
+impl RoomDrawer {
+    #[allow(dead_code)]
+    pub fn new() -> Box<RoomDrawer> {
+        Box::new(RoomDrawer {})
+    }
+
+    fn build(&mut self, _rng: &mut RandomNumberGenerator, build_data: &mut BuilderMap) {
+        let rooms: Vec<Rect>;
+        if let Some(rooms_builder) = &build_data.rooms {
+            rooms = rooms_builder.clone();
+        } else {
+            panic!("Room Rounding requires a builder with room structures");
+        }
+
+        for room in rooms.iter() {
+            for y in room.y1 + 1..=room.y2 {
+                for x in room.x1 + 1..=room.x2 {
+                    let idx = build_data.map.xy_idx(x, y);
+                    build_data.map.tiles[idx] = TileType::Floor;
+                }
+            }
+            build_data.take_snapshot();
+        }
+    }
+}
diff --git a/src/map_builders/simple_map.rs b/src/map_builders/simple_map.rs
index c15c029..590aa1e 100644
--- a/src/map_builders/simple_map.rs
+++ b/src/map_builders/simple_map.rs
@@ -1,6 +1,5 @@
 use rltk::RandomNumberGenerator;
 
-use crate::map_builders::common::apply_room_to_map;
 use crate::map_builders::{BuilderMap, InitialMapBuilder};
 use crate::Rect;
 
@@ -41,11 +40,7 @@ impl SimpleMapBuilder {
             }
 
             if ok {
-                apply_room_to_map(&mut build_data.map, &new_room);
-                build_data.take_snapshot();
-
                 rooms.push(new_room);
-                build_data.take_snapshot();
             }
         }