diff --git a/src/r_segs.c b/src/r_segs.c
index 7495d788..c82554ac 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -854,8 +854,8 @@ void R_RenderThickSideRange(drawseg_t *ds, INT32 x1, INT32 x2, ffloor_t *pfloor)
 			if (leftheight > pfloorleft && rightheight > pfloorright && i+1 < dc_numlights)
 			{
 				lightlist_t *nextlight = &frontsector->lightlist[i+1];
-				if (nextlight->slope ? P_GetZAt(nextlight->slope, ds->leftpos.x, ds->leftpos.y) : nextlight->height > pfloorleft
-				 && nextlight->slope ? P_GetZAt(nextlight->slope, ds->rightpos.x, ds->rightpos.y) : nextlight->height > pfloorright)
+				if ((nextlight->slope ? P_GetZAt(nextlight->slope, ds->leftpos.x, ds->leftpos.y) : nextlight->height) > pfloorleft
+				 && (nextlight->slope ? P_GetZAt(nextlight->slope, ds->rightpos.x, ds->rightpos.y) : nextlight->height) > pfloorright)
 					continue;
 			}