don't remove air above building platforms

const.lua

@@ -1,7 +1,7 @@
 --
 -- switch for debugging
 --
-settlements.debug = false
+settlements.debug = true
 --
 -- material to replace cobblestone with
 --
@@ -26,13 +26,13 @@ schem_path = settlements.modpath.."/schematics/"
 --
 schematic_table = { 
   {name = "townhall", mts = schem_path.."townhall.mts", hsize = 15, max_num = 0, rplc = "n"},
-  {name = "well", mts = schem_path.."well.mts", hsize = 11, max_num = 0.055, rplc = "n"},
+  {name = "well", mts = schem_path.."well.mts", hsize = 11, max_num = 0.045, rplc = "n"},
   {name = "hut", mts = schem_path.."hut.mts", hsize = 11, max_num = 0.9, rplc = "y"},
   {name = "garden", mts = schem_path.."garden.mts", hsize = 11, max_num = 0.1, rplc = "n"},
   {name = "lamp", mts = schem_path.."lamp.mts", hsize = 10, max_num = 0.1, rplc = "n"},
   {name = "tower", mts = schem_path.."tower.mts", hsize = 11, max_num = 0.055, rplc = "n"},
   {name = "church", mts = schem_path.."church.mts", hsize = 17, max_num = 0.050, rplc = "n"},
-  {name = "blacksmith", mts = schem_path.."blacksmith.mts", hsize = 11, max_num = 0.055, rplc = "n"},
+  {name = "blacksmith", mts = schem_path.."blacksmith.mts", hsize = 11, max_num = 0.050, rplc = "n"},
 }
 --
 -- baseplate material, to replace dirt with grass and where buildings can be built

foundation.lua

@@ -37,8 +37,10 @@ function settlements.foundation(pos, width, depth, height, rotation)
           minetest.after(1,settlements.ground,p)--(p)
         else
 --          minetest.remove_node({x=p5.x+xi, y=p5.y+yi, z=p5.z+zi})
-          minetest.swap_node({x=p5.x+xi, y=p5.y+yi, z=p5.z+zi}, 
-                             {name="air"}) 
+          if minetest.get_node_or_nil({x=p5.x+xi, y=p5.y+yi, z=p5.z+zi}).name ~= "air"
+          then
+            minetest.swap_node({x=p5.x+xi, y=p5.y+yi, z=p5.z+zi},{name="air"}) 
+          end                  
         end
       end
     end