diff --git a/src/material/block/nonfull/Slab.php b/src/material/block/nonfull/Slab.php
index feeeacca8..d72ca7537 100644
--- a/src/material/block/nonfull/Slab.php
+++ b/src/material/block/nonfull/Slab.php
@@ -46,6 +46,9 @@ class SlabBlock extends TransparentBlock{
 				if($target->getID() === SLAB and ($target->getMetadata() & 0x08) === 0x08 and ($target->getMetadata() & 0x07) === ($this->meta & 0x07)){
 					$this->level->setBlock($target, BlockAPI::get(DOUBLE_SLAB, $this->meta), true, false, true);
 					return true;
+				}elseif($block->getID() === SLAB and ($block->getMetadata() & 0x07) === ($this->meta & 0x07)){
+					$this->level->setBlock($block, BlockAPI::get(DOUBLE_SLAB, $this->meta), true, false, true);
+					return true;
 				}else{
 					$this->meta |= 0x08;
 				}
@@ -53,6 +56,9 @@ class SlabBlock extends TransparentBlock{
 				if($target->getID() === SLAB and ($target->getMetadata() & 0x08) === 0 and ($target->getMetadata() & 0x07) === ($this->meta & 0x07)){
 					$this->level->setBlock($target, BlockAPI::get(DOUBLE_SLAB, $this->meta), true, false, true);
 					return true;
+				}elseif($block->getID() === SLAB and ($block->getMetadata() & 0x07) === ($this->meta & 0x07)){
+					$this->level->setBlock($block, BlockAPI::get(DOUBLE_SLAB, $this->meta), true, false, true);
+					return true;
 				}
 			}elseif(!$player->entity->inBlock($block)){
 				if($block->getID() === SLAB){