diff --git a/core/src/mindustry/entities/comp/BuilderComp.java b/core/src/mindustry/entities/comp/BuilderComp.java
index 89249cf507..286149ba85 100644
--- a/core/src/mindustry/entities/comp/BuilderComp.java
+++ b/core/src/mindustry/entities/comp/BuilderComp.java
@@ -53,7 +53,9 @@ abstract class BuilderComp implements Posc, Statusc, Teamc, Rotc{
             while(it.hasNext()){
                 BuildPlan plan = it.next();
                 Tile tile = world.tile(plan.x, plan.y);
-                if(tile == null || (plan.breaking && tile.block() == Blocks.air) || (!plan.breaking && ((tile.build != null && tile.build.rotation == plan.rotation) || !plan.block.rotate) && tile.block() == plan.block)){
+                if(tile == null || (plan.breaking && tile.block() == Blocks.air) || (!plan.breaking && ((tile.build != null && tile.build.rotation == plan.rotation) || !plan.block.rotate) &&
+                    (tile.block() == plan.block || (plan.block != null && plan.block.isFloor() && plan.block == tile.floor())))){
+
                     it.remove();
                 }
             }
diff --git a/core/src/mindustry/world/Build.java b/core/src/mindustry/world/Build.java
index fc6cd5f466..30f2b4c163 100644
--- a/core/src/mindustry/world/Build.java
+++ b/core/src/mindustry/world/Build.java
@@ -169,6 +169,10 @@ public class Build{
             return false;
         }
 
+        if(type.isFloor() && tile.floor == type){
+            return false;
+        }
+
         if(!type.canPlaceOn(tile, team, rotation)){
             return false;
         }
diff --git a/core/src/mindustry/world/Tile.java b/core/src/mindustry/world/Tile.java
index 2debd9effe..1b459a7d9b 100644
--- a/core/src/mindustry/world/Tile.java
+++ b/core/src/mindustry/world/Tile.java
@@ -303,7 +303,9 @@ public class Tile implements Position, QuadTreeObject, Displayable{
     public void setFloorUnder(Floor floor){
         Block overlay = this.overlay;
         setFloor(floor);
-        setOverlay(overlay);
+        if(this.overlay != overlay){
+            setOverlay(overlay);
+        }
     }
 
     /** Sets the block to air. */
diff --git a/core/src/mindustry/world/blocks/ConstructBlock.java b/core/src/mindustry/world/blocks/ConstructBlock.java
index 0d79403238..5dd9c35885 100644
--- a/core/src/mindustry/world/blocks/ConstructBlock.java
+++ b/core/src/mindustry/world/blocks/ConstructBlock.java
@@ -20,6 +20,7 @@ import mindustry.graphics.*;
 import mindustry.logic.*;
 import mindustry.type.*;
 import mindustry.world.*;
+import mindustry.world.blocks.environment.*;
 import mindustry.world.blocks.storage.CoreBlock.*;
 import mindustry.world.modules.*;
 
@@ -72,7 +73,12 @@ public class ConstructBlock extends Block{
         float healthf = tile.build == null ? 1f : tile.build.healthf();
         Seq<Building> prev = tile.build instanceof ConstructBuild co ? co.prevBuild : null;
 
-        tile.setBlock(block, team, rotation);
+        if(block instanceof Floor floor){
+            tile.setFloorUnder(floor);
+            tile.setBlock(Blocks.air);
+        }else{
+            tile.setBlock(block, team, rotation);
+        }
 
         if(tile.build != null){
             tile.build.health = block.health * healthf;
diff --git a/gradle.properties b/gradle.properties
index ce4c75a351..0c840299c5 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -25,4 +25,4 @@ org.gradle.caching=true
 #used for slow jitpack builds; TODO see if this actually works
 org.gradle.internal.http.socketTimeout=100000
 org.gradle.internal.http.connectionTimeout=100000
-archash=eb3b8bdd10
+archash=a0bdca954b