diff --git a/src/r_segs.c b/src/r_segs.c
index 5395f414a..9e5060da9 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -1443,7 +1443,8 @@ static void R_RenderSegLoop (void)
 #ifdef POLYOBJECTS_PLANES
 					// Polyobject-specific hack to fix plane leaking -Red
 					if (ffloor[i].polyobj && top_w >= bottom_w) {
-						ffloor[i].plane->top[rw_x] = ffloor[i].plane->bottom[rw_x] = 0xFFFF;
+						ffloor[i].plane->top[rw_x] = 0xFFFF;
+						ffloor[i].plane->bottom[rw_x] = 0x0000; // fix for sky plane drawing crashes - Monster Iestyn 25/05/18
 					} else
 #endif
 
@@ -1467,7 +1468,8 @@ static void R_RenderSegLoop (void)
 #ifdef POLYOBJECTS_PLANES
 					// Polyobject-specific hack to fix plane leaking -Red
 					if (ffloor[i].polyobj && top_w >= bottom_w) {
-						ffloor[i].plane->top[rw_x] = ffloor[i].plane->bottom[rw_x] = 0xFFFF;
+						ffloor[i].plane->top[rw_x] = 0xFFFF;
+						ffloor[i].plane->bottom[rw_x] = 0x0000; // fix for sky plane drawing crashes - Monster Iestyn 25/05/18
 					} else
 #endif