diff --git a/core/src/mindustry/world/Build.java b/core/src/mindustry/world/Build.java
index 03a3db970b..bbc38dbdd4 100644
--- a/core/src/mindustry/world/Build.java
+++ b/core/src/mindustry/world/Build.java
@@ -198,16 +198,17 @@ public class Build{
 
         if(tile == null) return false;
 
+        //floors have different checks
+        if(type.isFloor()){
+            return type.isOverlay() ? tile.overlay() != type : tile.floor() != type;
+        }
+
         //campaign darkness check
         if(world.getDarkness(x, y) >= 3){
             return false;
         }
 
-        if(!type.requiresWater && !type.isFloor() && !contactsShallows(tile.x, tile.y, type) && !type.placeableLiquid){
-            return false;
-        }
-
-        if((type.isFloor() && tile.floor() == type) || (type.isOverlay() && tile.overlay() == type)){
+        if(!type.requiresWater && !contactsShallows(tile.x, tile.y, type) && !type.placeableLiquid){
             return false;
         }
 
@@ -231,7 +232,7 @@ public class Build{
                 (check.floor().isDeep() && !type.floating && !type.requiresWater && !type.placeableLiquid) || //deep water
                 (type == check.block() && check.build != null && rotation == check.build.rotation && type.rotate && !((type == check.block && check.team() == Team.derelict))) || //same block, same rotation
                 !check.interactable(team) || //cannot interact
-                (!check.floor().placeableOn && !type.isFloor()) || //solid floor
+                !check.floor().placeableOn  || //solid floor
                 (!checkVisible && !check.block().alwaysReplace) || //replacing a block that should be replaced (e.g. payload placement)
                     !(((type.canReplace(check.block()) || (type == check.block && state.rules.derelictRepair && check.team() == Team.derelict)) || //can replace type OR can replace derelict block of same type
                         (check.build instanceof ConstructBuild build && build.current == type && check.centerX() == tile.x && check.centerY() == tile.y)) && //same type in construction
diff --git a/core/src/mindustry/world/blocks/ConstructBlock.java b/core/src/mindustry/world/blocks/ConstructBlock.java
index 9e4ac3e719..df7434a222 100644
--- a/core/src/mindustry/world/blocks/ConstructBlock.java
+++ b/core/src/mindustry/world/blocks/ConstructBlock.java
@@ -75,10 +75,8 @@ public class ConstructBlock extends Block{
 
         if(block instanceof OverlayFloor overlay){
             tile.setOverlay(overlay);
-            tile.setBlock(Blocks.air);
         }else if(block instanceof Floor floor){
             tile.setFloorUnder(floor);
-            tile.setBlock(Blocks.air);
         }else{
             tile.setBlock(block, team, rotation);
         }