diff --git a/src/main.lua b/src/main.lua
index 3217028..27d8f6e 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -92,9 +92,11 @@ local function newdesign()
             for z=1+camy,dimensions["z"]+camy,1 do
                 local currentbuf = buf[posasstring(x-camx, currentfloor, z-camy)]
                 term.setCursorPos(x, z)
-                if currentbuf then
+                if currentbuf == 1 then -- wall
                     term.blit(" ", colors.toBlit(colors.white), colors.toBlit(colors.white))
-                else
+                elseif currentbuf == 2 then -- no ceiling
+                    term.blit(" ", colors.toBlit(colors.red), colors.toBlit(colors.red))
+                elseif currentbuf == 0 then -- nothing
                     term.blit("\127", colors.toBlit(colors.gray), colors.toBlit(colors.black))
                 end
             end
@@ -115,10 +117,13 @@ local function newdesign()
             event[4] = event[4]+camy
             if event[3] <= dimensions["x"] and event[4] <= dimensions["z"] then
                 if event[2] == 1 then -- left button, set
-                    buf[posasstring(event[3], currentfloor, event[4])] = true
+                    buf[posasstring(event[3], currentfloor, event[4])] = 1
+                end
+                if event[2] == 3 then -- middle button, set no ceiling
+                    buf[posasstring(event[3], currentfloor, event[4])] = 2
                 end
                 if event[2] == 2 then -- right button, erase
-                    buf[posasstring(event[3], currentfloor, event[4])] = false
+                    buf[posasstring(event[3], currentfloor, event[4])] = 0
                 end
             end
         end
@@ -259,7 +264,7 @@ local function place(direction)
     end
 end
 local function placebuf(buf, x, y, z)
-    if buf[posasstring(x,y,z)] then
+    if buf[posasstring(x,y,z)] == 1 then
         place("down")
     end
 end
@@ -268,7 +273,7 @@ local function printdes(buf, dimensions)
     move("forward")
 
     for cy=1,dimensions["y"],1 do
-        for _=1,3,1 do -- build floor
+        for _=1,3,1 do -- build walls
             for cz=1,dimensions["z"],1 do
                 for cx=1,dimensions["x"],1 do
                     placebuf(buf, cx, cy, cz)
@@ -294,9 +299,11 @@ local function printdes(buf, dimensions)
             move("up")
         end
         -- build ceiling/floor
-        for _=1,dimensions["z"],1 do
-            for _=1,dimensions["x"],1 do
-                place("down")
+        for cz=1,dimensions["z"],1 do
+            for cx=1,dimensions["x"],1 do
+                if buf[posasstring(cx,cy,cz)] ~= 2 then
+                    place("down")
+                end
                 move("forward")
             end
             -- return to standard pos but +1 to z