diff --git a/specs/udmf_zdoom.txt b/specs/udmf_zdoom.txt
index 1a4dbeffab..6c2fde912f 100644
--- a/specs/udmf_zdoom.txt
+++ b/specs/udmf_zdoom.txt
@@ -1,5 +1,5 @@
 ===============================================================================
-Universal Doom Map Format ZDoom extensions v1.10 - 25.04.2010
+Universal Doom Map Format ZDoom extensions v1.15 - 14.12.2010
 
 
     Copyright (c) 2008 Christoph Oelckers.
@@ -84,6 +84,12 @@ field to 'strifeally', even for the 'Doom' namespace.
 In addition to the standard fields, ZDoom defines the following:
 Note: All <bool> fields default to false unless mentioned otherwise.
 
+   vertex
+   {
+      zfloor = <float>;         // Floor height at this vertex. Only applies to triangular sectors
+      zceiling = <float>;       // Ceiling height at this vertex. Only applies to triangular sectors
+   }
+
    linedef
    {
       alpha = <float>;          // Translucency of this line, default is 1.0
@@ -283,6 +289,9 @@ Added 'hidden' sector property.
 1.14 19.09.2010
 Added 'countsecret' actor property.
 
+1.15 14.12.2010
+Added vertex floor and ceiling height properties
+
 ===============================================================================
 EOF
 ===============================================================================
diff --git a/src/namedef.h b/src/namedef.h
index 684d447f63..d9573b7478 100644
--- a/src/namedef.h
+++ b/src/namedef.h
@@ -280,6 +280,8 @@ xx(Communicator)
 // Textmap properties
 //xx(X)
 //xx(Y)
+xx(ZFloor)
+xx(ZCeiling)
 xx(Height)
 //xx(Tid)
 //xx(Angle)
diff --git a/src/p_setup.cpp b/src/p_setup.cpp
index 4dec4a95c7..b2e3852862 100644
--- a/src/p_setup.cpp
+++ b/src/p_setup.cpp
@@ -102,6 +102,8 @@ bool P_IsBuildMap(MapData *map);
 //
 int 			numvertexes;
 vertex_t*		vertexes;
+int 			numvertexdatas;
+vertexdata_t*		vertexdatas;
 
 int 			numsegs;
 seg_t*			segs;
@@ -755,6 +757,7 @@ void P_LoadVertexes (MapData * map)
 	// Determine number of vertices:
 	//	total lump length / vertex record length.
 	numvertexes = map->MapLumps[ML_VERTEXES].Size / sizeof(mapvertex_t);
+	numvertexdatas = 0;
 
 	if (numvertexes == 0)
 	{
@@ -763,6 +766,7 @@ void P_LoadVertexes (MapData * map)
 
 	// Allocate memory for buffer.
 	vertexes = new vertex_t[numvertexes];		
+	vertexdatas = NULL;
 
 	map->Seek(ML_VERTEXES);
 		
diff --git a/src/p_slopes.cpp b/src/p_slopes.cpp
index 3ebaef144e..7cf6c5fbed 100644
--- a/src/p_slopes.cpp
+++ b/src/p_slopes.cpp
@@ -309,6 +309,27 @@ static void P_SetSlopesFromVertexHeights(FMapThing *firstmt, FMapThing *lastmt)
 			mt->type = 0;
 		}
 	}
+
+	for(int i = 0; i < numvertexdatas; i++)
+	{
+		if (vertexdatas[i].flags & VERTEXFLAG_ZCeilingEnabled)
+		{
+			vt_heights[1][i] = vertexdatas[i].zCeiling;
+			vt_found = true;
+		}
+
+		if (vertexdatas[i].flags & VERTEXFLAG_ZFloorEnabled)
+		{
+			vt_heights[0][i] = vertexdatas[i].zFloor;
+			vt_found = true;
+		}
+	}
+
+	// If vertexdata_t is ever extended for non-slope usage, this will obviously have to be deferred or removed.
+	delete[] vertexdatas;
+	vertexdatas = NULL;
+	numvertexdatas = 0;
+
 	if (vt_found)
 	{
 		for (int i = 0; i < numsectors; i++)
diff --git a/src/p_udmf.cpp b/src/p_udmf.cpp
index 0fba825b02..72c3cb24c9 100644
--- a/src/p_udmf.cpp
+++ b/src/p_udmf.cpp
@@ -390,6 +390,7 @@ class UDMFParser : public UDMFParserBase
 	TArray<mapsidedef_t> ParsedSideTextures;
 	TArray<sector_t> ParsedSectors;
 	TArray<vertex_t> ParsedVertices;
+	TArray<vertexdata_t> ParsedVertexDatas;
 
 	FDynamicColormap	*fogMap, *normMap;
 
@@ -1303,9 +1304,10 @@ public:
 	//
 	//===========================================================================
 
-	void ParseVertex(vertex_t *vt)
+	void ParseVertex(vertex_t *vt, vertexdata_t *vd)
 	{
 		vt->x = vt->y = 0;
+		vd->zCeiling = vd->zFloor = vd->flags = 0;
 		sc.MustGetStringName("{");
 		while (!sc.CheckString("}"))
 		{
@@ -1320,9 +1322,21 @@ public:
 			case NAME_X:
 				vt->x = FLOAT2FIXED(strtod(value, NULL));
 				break;
+
 			case NAME_Y:
 				vt->y = FLOAT2FIXED(strtod(value, NULL));
 				break;
+
+			case NAME_ZCeiling:
+				vd->zCeiling = FLOAT2FIXED(strtod(value, NULL));
+				vd->flags |= VERTEXFLAG_ZCeilingEnabled;
+				break;
+
+			case NAME_ZFloor:
+				vd->zFloor = FLOAT2FIXED(strtod(value, NULL));
+				vd->flags |= VERTEXFLAG_ZFloorEnabled;
+				break;
+
 			default:
 				break;
 			}
@@ -1520,8 +1534,10 @@ public:
 			else if (sc.Compare("vertex"))
 			{
 				vertex_t vt;
-				ParseVertex(&vt);
+				vertexdata_t vd;
+				ParseVertex(&vt, &vd);
 				ParsedVertices.Push(vt);
+				ParsedVertexDatas.Push(vd);
 			}
 			else
 			{
@@ -1534,6 +1550,11 @@ public:
 		vertexes = new vertex_t[numvertexes];
 		memcpy(vertexes, &ParsedVertices[0], numvertexes * sizeof(*vertexes));
 
+		// Create the real vertex datas
+		numvertexdatas = ParsedVertexDatas.Size();
+		vertexdatas = new vertexdata_t[numvertexdatas];
+		memcpy(vertexdatas, &ParsedVertexDatas[0], numvertexdatas * sizeof(*vertexdatas));
+
 		// Create the real sectors
 		numsectors = ParsedSectors.Size();
 		sectors = new sector_t[numsectors];
diff --git a/src/r_defs.h b/src/r_defs.h
index 22745f54c8..9d2822c33a 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -67,6 +67,16 @@ extern size_t MaxDrawSegs;
 // Note: transformed values not buffered locally,
 //	like some DOOM-alikes ("wt", "WebView") did.
 //
+enum
+{
+	VERTEXFLAG_ZCeilingEnabled = 0x01,
+	VERTEXFLAG_ZFloorEnabled   = 0x02
+};
+struct vertexdata_t
+{
+	fixed_t zCeiling, zFloor;
+	DWORD flags;
+};
 struct vertex_t
 {
 	fixed_t x, y;
diff --git a/src/r_state.h b/src/r_state.h
index 9044da72be..6529683853 100644
--- a/src/r_state.h
+++ b/src/r_state.h
@@ -55,6 +55,8 @@ extern DWORD NumStdSprites;
 
 extern int				numvertexes;
 extern vertex_t*		vertexes;
+extern int				numvertexdatas;
+extern vertexdata_t*		vertexdatas;
 
 extern int				numsegs;
 extern seg_t*			segs;