diff --git a/source/build/include/buildtypes.h b/source/build/include/buildtypes.h
index caf5eda00..1ac86d561 100644
--- a/source/build/include/buildtypes.h
+++ b/source/build/include/buildtypes.h
@@ -94,6 +94,8 @@ struct walltype
 
     int xpan() const { return int(xpan_); }
     int ypan() const { return int(ypan_); }
+    void setxpan(float add) { xpan_ = fmod(add + 512, 256); } // +512 is for handling negative offsets
+    void setypan(float add) { ypan_ = fmod(add + 512, 256); } // +512 is for handling negative offsets
     void addxpan(float add) { xpan_ = fmod(xpan_ + add + 512, 256); } // +512 is for handling negative offsets
     void addypan(float add) { ypan_ = fmod(ypan_ + add + 512, 256); } // +512 is for handling negative offsets
 
diff --git a/source/games/exhumed/src/lighting.cpp b/source/games/exhumed/src/lighting.cpp
index ba2d39202..3b8b62a8c 100644
--- a/source/games/exhumed/src/lighting.cpp
+++ b/source/games/exhumed/src/lighting.cpp
@@ -745,8 +745,8 @@ void DoFlows()
             {
                 short nWall = sFlowInfo[i].objindex;
 
-                wall[nWall].addxpan(sFlowInfo[i].xdelta / 16384.f);
-                wall[nWall].addypan(sFlowInfo[i].ydelta / 16384.f);
+                wall[nWall].setxpan(sFlowInfo[i].xdelta / 16384.f);
+                wall[nWall].setypan(sFlowInfo[i].ydelta / 16384.f);
 
                 if (sFlowInfo[i].xdelta < 0)
                 {
@@ -765,8 +765,8 @@ void DoFlows()
             {
                 short nWall = sFlowInfo[i].objindex;
 
-                wall[nWall].addxpan(sFlowInfo[i].xdelta / 16384.f);
-                wall[nWall].addypan(sFlowInfo[i].ydelta / 16384.f);
+                wall[nWall].setxpan(sFlowInfo[i].xdelta / 16384.f);
+                wall[nWall].setypan(sFlowInfo[i].ydelta / 16384.f);
 
                 if (sFlowInfo[i].xdelta >= sFlowInfo[i].xacc)
                 {