diff --git a/Content.Shared/Construction/ConstructionConditions/TileNotBlocked.cs b/Content.Shared/Construction/ConstructionConditions/TileNotBlocked.cs
new file mode 100644
index 0000000000..6bc9dd084a
--- /dev/null
+++ b/Content.Shared/Construction/ConstructionConditions/TileNotBlocked.cs
@@ -0,0 +1,32 @@
+using Content.Shared.Maps;
+using JetBrains.Annotations;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Construction.ConstructionConditions
+{
+    [UsedImplicitly]
+    public class TileNotBlocked : IConstructionCondition
+    {
+        private bool _filterMobs = false;
+        private bool _failIfSpace = true;
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(ref _filterMobs, "filterMobs", false);
+            serializer.DataField(ref _failIfSpace, "failIfSpace", true);
+        }
+
+        public bool Condition(IEntity user, EntityCoordinates location, Direction direction)
+        {
+            var tileRef = location.GetTileRef();
+
+            if (tileRef == null || tileRef.Value.IsSpace())
+                return !_failIfSpace;
+
+            return !tileRef.Value.IsBlockedTurf(_filterMobs);
+        }
+    }
+}
diff --git a/Content.Shared/Construction/ConstructionPrototype.cs b/Content.Shared/Construction/ConstructionPrototype.cs
index 17d88a7f9e..ec78912b3f 100644
--- a/Content.Shared/Construction/ConstructionPrototype.cs
+++ b/Content.Shared/Construction/ConstructionPrototype.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Serialization;
 using Robust.Shared.Utility;
diff --git a/Resources/Prototypes/Entities/Constructible/Walls/girder.yml b/Resources/Prototypes/Entities/Constructible/Walls/girder.yml
index 1ec2f250fc..71e537adee 100644
--- a/Resources/Prototypes/Entities/Constructible/Walls/girder.yml
+++ b/Resources/Prototypes/Entities/Constructible/Walls/girder.yml
@@ -6,6 +6,7 @@
   - type: Clickable
   - type: InteractionOutline
   - type: Anchorable
+    snap: true
   - type: Construction
     graph: girder
     node: girder
@@ -17,13 +18,9 @@
     anchored: true
     shapes:
     - !type:PhysShapeAabb
-      mask:
-      - Impassable
-      - MobImpassable
-      - VaultImpassable
-      - SmallImpassable
       layer:
       - Opaque
+      - Impassable
       - MobImpassable
       - VaultImpassable
       - SmallImpassable
diff --git a/Resources/Prototypes/Recipes/Construction/conveyor.yml b/Resources/Prototypes/Recipes/Construction/conveyor.yml
index 0eae0c1a5c..30abd3ca51 100644
--- a/Resources/Prototypes/Recipes/Construction/conveyor.yml
+++ b/Resources/Prototypes/Recipes/Construction/conveyor.yml
@@ -12,6 +12,8 @@
   icon:
     sprite: Constructible/Power/conveyor.rsi
     state: conveyor_stopped_cw
+  conditions:
+    - !type:TileNotBlocked {}
 
 - type: construction
   name: two-way lever
@@ -26,3 +28,5 @@
   icon:
     sprite: Constructible/Power/conveyor.rsi
     state: switch-off
+  conditions:
+    - !type:TileNotBlocked {}
diff --git a/Resources/Prototypes/Recipes/Construction/structures.yml b/Resources/Prototypes/Recipes/Construction/structures.yml
index f192be3132..720c48b34e 100644
--- a/Resources/Prototypes/Recipes/Construction/structures.yml
+++ b/Resources/Prototypes/Recipes/Construction/structures.yml
@@ -13,6 +13,8 @@
   placementMode: SnapgridCenter
   canRotate: false
   canBuildInImpassable: false
+  conditions:
+    - !type:TileNotBlocked { }
 
 - type: construction
   name: wall
@@ -29,6 +31,8 @@
   placementMode: SnapgridCenter
   canRotate: false
   canBuildInImpassable: false
+  conditions:
+    - !type:TileNotBlocked {}
 
 - type: construction
   name: reinforced wall
@@ -45,6 +49,8 @@
   placementMode: SnapgridCenter
   canRotate: false
   canBuildInImpassable: false
+  conditions:
+    - !type:TileNotBlocked {}
 
 - type: construction
   name: low wall
@@ -55,7 +61,8 @@
   category: Structures
   description: A low wall used for mounting windows.
   conditions:
-    - !type:NoWindowsInTile { }
+    - !type:NoWindowsInTile {}
+    - !type:TileNotBlocked {}
   icon:
     sprite: Constructible/Structures/Walls/low_wall.rsi
     state: metal
@@ -131,6 +138,8 @@
   objectType: Structure
   placementMode: SnapgridCenter
   canBuildInImpassable: false
+  conditions:
+    - !type:TileNotBlocked {}
 
 - type: construction
   name: Table Frame
@@ -146,6 +155,8 @@
   objectType: Structure
   placementMode: SnapgridCenter
   canBuildInImpassable: false
+  conditions:
+    - !type:TileNotBlocked {}
 
 - type: construction
   name: Poker Table
@@ -161,6 +172,8 @@
   objectType: Structure
   placementMode: SnapgridCenter
   canBuildInImpassable: false
+  conditions:
+    - !type:TileNotBlocked {}
 
 - type: construction
   name: Catwalk
@@ -171,6 +184,7 @@
   category: Structures
   description: Just like a lattice. Except it looks better.
   conditions:
+    - !type:TileNotBlocked {}
     - !type:TileType
       targets:
         - lattice