diff --git a/Source/CombatExtended/CombatExtended/Projectiles/ProjectileCE.cs b/Source/CombatExtended/CombatExtended/Projectiles/ProjectileCE.cs
index d75c85b226..e6461d8ca1 100644
--- a/Source/CombatExtended/CombatExtended/Projectiles/ProjectileCE.cs
+++ b/Source/CombatExtended/CombatExtended/Projectiles/ProjectileCE.cs
@@ -112,6 +112,7 @@ public virtual float DamageAmount
         public bool canTargetSelf;
         public bool castShadow = true;
         public bool logMisses = true;
+        protected bool ignoreRoof;
 
         public GlobalTargetInfo globalTargetInfo = GlobalTargetInfo.Invalid;
         public GlobalTargetInfo globalSourceInfo = GlobalTargetInfo.Invalid;
@@ -358,6 +359,7 @@ public override void ExposeData()
             Scribe_Values.Look<bool>(ref logMisses, "logMisses", true);
             Scribe_Values.Look<bool>(ref castShadow, "castShadow", true);
             Scribe_Values.Look<bool>(ref lerpPosition, "lerpPosition", true);
+            Scribe_Values.Look(ref ignoreRoof, "ignoreRoof", true);
 
             //To fix landed grenades sl problem
             Scribe_Values.Look(ref exactPosition, "exactPosition");
@@ -563,6 +565,10 @@ public virtual void Launch(Thing launcher, Vector2 origin, float shotAngle, floa
                 this.lerpPosition = props.lerpPosition;
                 this.GravityFactor = props.Gravity;
             }
+            if (shotHeight >= CollisionVertical.WallCollisionHeight && Position.Roofed(launcher.Map))
+            {
+                ignoreRoof = true;
+            }
             Launch(launcher, origin, equipment);
         }
 
@@ -879,7 +885,7 @@ protected bool CheckCellForCollision(IntVec3 cell)
 
         protected virtual bool TryCollideWithRoof(IntVec3 cell)
         {
-            if (!cell.Roofed(Map))
+            if (!cell.Roofed(Map) || ignoreRoof)
             {
                 return false;
             }
@@ -1215,6 +1221,11 @@ public override void Tick()
             {
                 DangerTracker?.Notify_BulletAt(Position, def.projectile.damageAmountBase * dangerFactor);
             }
+            //If a flyoverhead ignore roof projectile is descending, enable roof check.
+            if (ignoreRoof && def.projectile.flyOverhead && shotAngle < 0)
+            {
+                ignoreRoof = false;
+            }
         }
 
         /// <summary>