diff --git a/Build/ZoneBuilder.default.cfg b/Build/ZoneBuilder.default.cfg
index 4305693..f1ab87b 100644
--- a/Build/ZoneBuilder.default.cfg
+++ b/Build/ZoneBuilder.default.cfg
@@ -228,6 +228,7 @@ shortcuts
 	buildermodes_flooralignmode = 0;
 	buildermodes_scaledowny = 101;
 	buildermodes_toggleslope = 262227;
+	buildermodes_togglebackslope = 393299;
 	buildermodes_resettextureudmf = 196690;
 	buildermodes_rollcounterclockwise = 327675;
 	buildermodes_visualfittextures = 393281;
diff --git a/Source/Plugins/BuilderModes/Resources/Actions.cfg b/Source/Plugins/BuilderModes/Resources/Actions.cfg
index 0f5c957..0caf9e2 100644
--- a/Source/Plugins/BuilderModes/Resources/Actions.cfg
+++ b/Source/Plugins/BuilderModes/Resources/Actions.cfg
@@ -1119,15 +1119,26 @@ pastepropertieswithoptions
 //mxd
 toggleslope
 {
-	title = "Toggle Slope";
+	title = "Toggle Slope (Front)";
 	category = "visual";
-	description = "Toggles Slope for selected surfaces. Select or highlight upper/lower walls to add a slope. Select or highlight floors or ceilings to remove slope.";
+	description = "Toggles Slope for selected surfaces. Select or highlight upper/lower walls to add a slope to the front sector. Select or highlight floors or ceilings to remove slope.";
 	allowkeys = true;
 	allowmouse = true;
 	allowscroll = true;
 	default = 262227; //Alt-S
 }
 
+togglebackslope
+{
+	title = "Toggle Slope (Back)";
+	category = "visual";
+	description = "Toggles Slope for selected surfaces. Select or highlight upper/lower walls to add a slope to the back sector. Select or highlight floors or ceilings to remove slope.";
+	allowkeys = true;
+	allowmouse = true;
+	allowscroll = true;
+	default = 393299; //Ctrl-Alt-S
+}
+
 placevisualstart
 {
 	title = "Place Visual Mode Camera";
diff --git a/Source/Plugins/BuilderModes/VisualModes/BaseVisualMode.cs b/Source/Plugins/BuilderModes/VisualModes/BaseVisualMode.cs
index 795155b..9ba1bf9 100644
--- a/Source/Plugins/BuilderModes/VisualModes/BaseVisualMode.cs
+++ b/Source/Plugins/BuilderModes/VisualModes/BaseVisualMode.cs
@@ -3746,7 +3746,7 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			}
 
 			List<BaseVisualSector> toUpdate = new List<BaseVisualSector>();
-			General.Map.UndoRedo.CreateUndo("Toggle Slope");
+			General.Map.UndoRedo.CreateUndo("Toggle Slope (Front)");
 
 			//check selection
 			foreach(VisualGeometry vg in selection) 
@@ -3881,7 +3881,159 @@ namespace CodeImp.DoomBuilder.BuilderModes
 
 			General.Interface.DisplayStatus(StatusType.Action, "Toggled Slope for " + toUpdate.Count + (toUpdate.Count == 1 ? " surface." : " surfaces."));
 		}
-		
+
+		[BeginAction("togglebackslope")]
+		public void ToggleBackSlope()
+		{
+			List<VisualGeometry> selection = GetSelectedSurfaces();
+
+			if (selection.Count == 0)
+			{
+				General.Interface.DisplayStatus(StatusType.Warning, "Toggle Slope action requires selected surfaces!");
+				return;
+			}
+
+			List<BaseVisualSector> toUpdate = new List<BaseVisualSector>();
+			General.Map.UndoRedo.CreateUndo("Toggle Slope (Back)");
+
+			//check selection
+			foreach (VisualGeometry vg in selection)
+			{
+				bool update = false;
+
+				//assign/remove action
+				if (vg.GeometryType == VisualGeometryType.WALL_LOWER)
+				{
+					// MascaraSnake: Slope handling
+					if (vg.Sidedef.Line.Action == 0 || (vg.Sidedef.Line.IsRegularSlope && vg.Sidedef.Line.Args[0] == 0))
+					{
+						//check if the sector already has floor slopes
+						foreach (Sidedef side in vg.Sidedef.Other.Sector.Sidedefs)
+						{
+							if (side == vg.Sidedef || !side.Line.IsRegularSlope) continue;
+
+							int arg = (side == side.Line.Front ? 2 : 1);
+
+							if (side.Line.Args[0] == arg)
+							{
+								//if only floor is affected, remove action
+								if (side.Line.Args[1] == 0)
+									side.Line.Action = 0;
+								else
+								{ //clear floor alignment
+									side.Line.Args[0] = 0;
+									side.Line.SetSlopeTypeFromArgs(); //MascaraSnake: Arguments changed, so update slope type
+								}
+							}
+						}
+
+						//set action
+						vg.Sidedef.Line.Args[0] = (vg.Sidedef == vg.Sidedef.Line.Front ? 2 : 1);
+						vg.Sidedef.Line.SetSlopeTypeFromArgs(); //MascaraSnake: Set slope type
+						update = true;
+					}
+				}
+				else if (vg.GeometryType == VisualGeometryType.WALL_UPPER)
+				{
+					// MascaraSnake: Slope handling
+					if (vg.Sidedef.Line.Action == 0 || (vg.Sidedef.Line.IsRegularSlope && vg.Sidedef.Line.Args[1] == 0))
+					{
+						//check if the sector already has ceiling slopes
+						foreach (Sidedef side in vg.Sidedef.Other.Sector.Sidedefs)
+						{
+							if (side == vg.Sidedef || !side.Line.IsRegularSlope) continue;
+
+							int arg = (side == side.Line.Front ? 2 : 1);
+
+							if (side.Line.Args[1] == arg)
+							{
+								//if only ceiling is affected, remove action
+								if (side.Line.Args[0] == 0)
+									side.Line.Action = 0;
+								else
+								{ //clear ceiling alignment
+									side.Line.Args[1] = 0;
+									side.Line.SetSlopeTypeFromArgs(); //MascaraSnake: Arguments changed, so update slope type
+								}
+							}
+						}
+
+						//set action
+						vg.Sidedef.Line.Args[1] = (vg.Sidedef == vg.Sidedef.Line.Front ? 2 : 1);
+						vg.Sidedef.Line.SetSlopeTypeFromArgs(); //MascaraSnake: Set slope type
+						update = true;
+					}
+				}
+				else if (vg.GeometryType == VisualGeometryType.CEILING)
+				{
+					//check if the sector has ceiling slopes
+					foreach (Sidedef side in vg.Sector.Sector.Sidedefs)
+					{
+						// MascaraSnake: Slope handling
+						if (!side.Line.IsRegularSlope) continue;
+
+						int arg = (side == side.Line.Front ? 1 : 2);
+
+						if (side.Line.Args[1] == arg)
+						{
+							//if only ceiling is affected, remove action
+							if (side.Line.Args[0] == 0)
+								side.Line.Action = 0;
+							else
+							{ //clear ceiling alignment
+								side.Line.Args[1] = 0;
+								side.Line.SetSlopeTypeFromArgs(); //MascaraSnake: Arguments changed, so update slope type
+							}
+
+							update = true;
+						}
+					}
+				}
+				else if (vg.GeometryType == VisualGeometryType.FLOOR)
+				{
+					//check if the sector has floor slopes
+					foreach (Sidedef side in vg.Sector.Sector.Sidedefs)
+					{
+						// MascaraSnake: Slope handling
+						if (!side.Line.IsRegularSlope) continue;
+
+						int arg = (side == side.Line.Front ? 1 : 2);
+
+						if (side.Line.Args[0] == arg)
+						{
+							//if only floor is affected, remove action
+							if (side.Line.Args[1] == 0)
+								side.Line.Action = 0;
+							else
+							{ //clear floor alignment
+								side.Line.Args[0] = 0;
+								side.Line.SetSlopeTypeFromArgs(); //MascaraSnake: Arguments changed, so update slope type
+							}
+							update = true;
+						}
+					}
+				}
+
+				//add to update list
+				if (update) toUpdate.Add(vg.Sector as BaseVisualSector);
+			}
+
+			//update changed geometry
+			if (toUpdate.Count > 0)
+			{
+				RebuildElementData();
+
+				foreach (BaseVisualSector vs in toUpdate)
+					vs.UpdateSectorGeometry(true);
+
+				UpdateChangedObjects();
+				ClearSelection();
+				ShowTargetInfo();
+			}
+
+			General.Interface.DisplayStatus(StatusType.Action, "Toggled Slope for " + toUpdate.Count + (toUpdate.Count == 1 ? " surface." : " surfaces."));
+		}
+
 		#endregion
 
 		#region ================== Texture Alignment