diff --git a/pom.xml b/pom.xml
index 88ffc1d..d825fb4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
   <groupId>xyz.dcaron.bridges</groupId>
   <artifactId>RetractableBridges</artifactId>
-  <version>1.0-SNAPSHOT</version>
+  <version>1.1.1-SNAPSHOT</version>
 
   <name>RetractableBridges</name>
   <!-- FIXME change it to the project's website -->
diff --git a/src/main/java/xyz/dcaron/bridges/Bridge.java b/src/main/java/xyz/dcaron/bridges/Bridge.java
index ed73380..1b13145 100644
--- a/src/main/java/xyz/dcaron/bridges/Bridge.java
+++ b/src/main/java/xyz/dcaron/bridges/Bridge.java
@@ -1,15 +1,20 @@
 package xyz.dcaron.bridges;
 
+import java.util.Optional;
 import java.util.Set;
 
 import org.bukkit.Material;
 import org.bukkit.block.BlockFace;
+import org.bukkit.block.data.BlockData;
+import org.bukkit.block.data.type.Slab;
 
+import lombok.AllArgsConstructor;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.Setter;
 
 @EqualsAndHashCode
+@AllArgsConstructor
 public class Bridge {
 
     @Getter
@@ -24,18 +29,8 @@ public class Bridge {
     @Getter
     @Setter
     private Set<BlockFace> blockedDirections;
-
-    public Bridge(final String worldName, final int x, final int z, final int y, final int width, final int height,
-            final Material type, final Set<BlockFace> blockedDirections) {
-        this.worldName = worldName;
-        this.x = x;
-        this.z = z;
-        this.y = y;
-        this.width = width;
-        this.height = height;
-        this.type = type;
-        this.blockedDirections = blockedDirections;
-    }
+    @Getter
+    private final Optional<Slab.Type> slabType;
 
     @Override
     public String toString() {
@@ -50,4 +45,12 @@ public String toString() {
         return sb.toString();
     }
 
+    public static Optional<Slab.Type> getSlabType(final BlockData data) {
+        
+        if (data instanceof Slab) {
+            return Optional.of(((Slab) data).getType());
+        }
+        return Optional.empty();
+    }
+
 }
diff --git a/src/main/java/xyz/dcaron/bridges/BridgeBlockListener.java b/src/main/java/xyz/dcaron/bridges/BridgeBlockListener.java
index 69a6e57..e77a0bf 100644
--- a/src/main/java/xyz/dcaron/bridges/BridgeBlockListener.java
+++ b/src/main/java/xyz/dcaron/bridges/BridgeBlockListener.java
@@ -10,6 +10,7 @@
 import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.block.BlockFace;
+import org.bukkit.block.data.type.Slab;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
@@ -85,6 +86,10 @@ public void onRedstoneBlockChange(final BlockRedstoneEvent event) {
 
     }
 
+    private boolean materialWithSlabToBlockEquals(final Block blockToCompare, Material material, Optional<Slab.Type> slabType) {
+        return blockToCompare.getType().equals(material) && Bridge.getSlabType(blockToCompare.getBlockData()).equals(slabType);
+    }
+
     /**
      * Find a bridge above the adjacent block. A bridge is a rectangular area of 
      * slabs or double slabs, parallel to the ground. It can have no holes or bits 
@@ -110,30 +115,34 @@ private Optional<Bridge> findBridge(final Block block, final BlockFace direction
             int y = aboveBlock.getY();
             int z = aboveBlock.getZ();
             int width = 1, height = 1;
+
             final Material material = aboveBlock.getType();
 
+            // Record the slab orientation if the block is a slab.
+            final Optional<Slab.Type> slabType = Bridge.getSlabType(aboveBlock.getBlockData());
+
             Block adjacentBlock = aboveBlock.getRelative(BlockFace.WEST);
-            while (adjacentBlock.getType().equals(material)) {
+            while (materialWithSlabToBlockEquals(adjacentBlock, material, slabType)) {
                 x--;
                 width++;
                 adjacentBlock = adjacentBlock.getRelative(BlockFace.WEST);
             }
 
             adjacentBlock = aboveBlock.getRelative(BlockFace.NORTH);
-            while (adjacentBlock.getType().equals(material)) {
+            while (materialWithSlabToBlockEquals(adjacentBlock, material, slabType)) {
                 z--;
                 height++;
                 adjacentBlock = adjacentBlock.getRelative(BlockFace.NORTH);
             }
 
             adjacentBlock = aboveBlock.getRelative(BlockFace.EAST);
-            while (adjacentBlock.getType().equals(material)) {
+            while (materialWithSlabToBlockEquals(adjacentBlock, material, slabType)) {
                 width++;
                 adjacentBlock = adjacentBlock.getRelative(BlockFace.EAST);
             }
 
             adjacentBlock = aboveBlock.getRelative(BlockFace.SOUTH);
-            while (adjacentBlock.getType().equals(material)) {
+            while (materialWithSlabToBlockEquals(adjacentBlock, material, slabType)) {
                 height++;
                 adjacentBlock = adjacentBlock.getRelative(BlockFace.SOUTH);
             }
@@ -146,7 +155,7 @@ private Optional<Bridge> findBridge(final Block block, final BlockFace direction
 
                 for (int dz = 0; dz < height; dz++) {
                     Block edgeBlock = world.getBlockAt(x - 1, y, z + dz);
-                    if (edgeBlock.getType().equals(material)) {
+                    if (materialWithSlabToBlockEquals(edgeBlock, material, slabType)) {
                         // A block is sticking out.
                         return Optional.empty();
                     } else if (!edgeBlock.getType().isAir()) {
@@ -154,7 +163,7 @@ private Optional<Bridge> findBridge(final Block block, final BlockFace direction
                     }
 
                     edgeBlock = world.getBlockAt(x + width, y, z + dz);
-                    if (edgeBlock.getType().equals(material)) {
+                    if (materialWithSlabToBlockEquals(edgeBlock, material, slabType)) {
                         // A block is sticking out.
                         return Optional.empty();
                     } else if (!edgeBlock.getType().isAir()) {
@@ -164,7 +173,7 @@ private Optional<Bridge> findBridge(final Block block, final BlockFace direction
 
                 for (int dx = 0; dx < width; dx++) {
                     Block edgeBlock = world.getBlockAt(x + dx, y, z - 1);
-                    if (edgeBlock.getType().equals(material)) {
+                    if (materialWithSlabToBlockEquals(edgeBlock, material, slabType)) {
                         // A block is sticking out.
                         return Optional.empty();
                     } else if (!edgeBlock.getType().isAir()) {
@@ -173,14 +182,14 @@ private Optional<Bridge> findBridge(final Block block, final BlockFace direction
 
                     for (int dz = 0; dz < height; dz++) {
                         final Block bridgeBlock = world.getBlockAt(x + dx, y, z + dz);
-                        if (!bridgeBlock.getType().equals(material)) {
+                        if (!materialWithSlabToBlockEquals(bridgeBlock, material, slabType)) {
                             // There is a hole in the bridge.
                             return Optional.empty();
                         }
                     }
 
                     edgeBlock = world.getBlockAt(x + dx, y, z + height);
-                    if (edgeBlock.getType().equals(material)) {
+                    if (materialWithSlabToBlockEquals(edgeBlock, material, slabType)) {
                         // A block is sticking out.
                         return Optional.empty();
                     } else if (!edgeBlock.getType().isAir()) {
@@ -191,7 +200,7 @@ private Optional<Bridge> findBridge(final Block block, final BlockFace direction
                 // The bridge is a proper rectangle.
                 if (this.blockedInThreeDirections(blockedDirections) || 
                     this.opposingDirectionsAreBlocked(blockedDirections)) {
-                        return Optional.of(new Bridge(world.getName(), x, z, y, width, height, material, blockedDirections));
+                        return Optional.of(new Bridge(world.getName(), x, z, y, width, height, material, blockedDirections, slabType));
                 }
             }
 
diff --git a/src/main/java/xyz/dcaron/bridges/BridgeMover.java b/src/main/java/xyz/dcaron/bridges/BridgeMover.java
index 7983341..0c5a7ae 100644
--- a/src/main/java/xyz/dcaron/bridges/BridgeMover.java
+++ b/src/main/java/xyz/dcaron/bridges/BridgeMover.java
@@ -154,7 +154,20 @@ private boolean tryToMove(final BlockFace direction, final World world, final Se
         // Its bridge moving time.
         BridgesPlugin.log("Moving bridge " + direction + " one row", Level.FINE);
         for (int i = 0; i < length; i++) {
-            world.getBlockAt(bridge.getX() + dx + i * xMult, bridge.getY(), bridge.getZ() + dz + i * zMult).setType(bridge.getType());
+            final Block blockAhead = world.getBlockAt(bridge.getX() + dx + i * xMult, bridge.getY(), bridge.getZ() + dz + i * zMult);
+
+            // Change the block type.
+            blockAhead.setType(bridge.getType());
+
+            // Loop hoisting will occurr here.
+            // Modify the block's remembered slab state.
+            bridge.getSlabType().ifPresent(slabType -> {
+                final BlockData data = blockAhead.getBlockData();
+                if (data instanceof Slab) {
+                    ((Slab) data).setType(slabType);
+                    blockAhead.setBlockData(data);
+                }
+            });
         }
 
         // Moves entities standing on the bridge.