diff --git a/src/simulation/Simulation.cpp b/src/simulation/Simulation.cpp
index c4e6fbb83..2a61e2452 100644
--- a/src/simulation/Simulation.cpp
+++ b/src/simulation/Simulation.cpp
@@ -2352,7 +2352,7 @@ int Simulation::create_part(int p, int x, int y, int tv)//the function for creat
 	int t = tv & 0xFF;
 	int v = (tv >> 8) & 0xFF;
 
-	if (x<0 || y<0 || x>=XRES || y>=YRES || ((t<0 || t>=PT_NUM)&&t!=SPC_HEAT&&t!=SPC_COOL&&t!=SPC_AIR&&t!=SPC_VACUUM&&t!=SPC_PGRV&&t!=SPC_NGRV))
+	if (x<0 || y<0 || x>=XRES || y>=YRES || ((t<=0 || t>=PT_NUM)&&t!=SPC_HEAT&&t!=SPC_COOL&&t!=SPC_AIR&&t!=SPC_VACUUM&&t!=SPC_PGRV&&t!=SPC_NGRV))
 		return -1;
 	if (t>=0 && t<PT_NUM && !elements[t].Enabled)
 		return -1;