Walls built on metal foam instead of girders revert to metal foam when decon'd (#64553)

* raises cost of metal from foam

* goes with fikou's idea for metal foam girder_type

code/game/objects/effects/effect_system/effects_foam.dm

@@ -313,7 +313,7 @@
 	if(HAS_TRAIT(user, TRAIT_QUICK_BUILD))
 		platingmodifier = 0.7
 		if(next_beep <= world.time)
-			next_beep = world.time + 10
+			next_beep = world.time + 1 SECONDS
 			playsound(src, 'sound/machines/clockcult/integration_cog_install.ogg', 50, TRUE)
 	add_fingerprint(user)
 
@@ -323,7 +323,7 @@
 	var/obj/item/stack/sheet/sheet_for_plating = W
 	if(istype(sheet_for_plating, /obj/item/stack/sheet/iron))
 		if(sheet_for_plating.get_amount() < 2)
-			to_chat(user, span_warning("You need two sheets of iron to finish a wall!"))
+			to_chat(user, span_warning("You need four sheets of iron to finish a wall on [src]!"))
 			return
 		to_chat(user, span_notice("You start adding plating to the foam structure..."))
 		if (do_after(user, 40*platingmodifier, target = src))
@@ -331,7 +331,7 @@
 				return
 			to_chat(user, span_notice("You add the plating."))
 			var/turf/T = get_turf(src)
-			T.PlaceOnTop(/turf/closed/wall)
+			T.PlaceOnTop(/turf/closed/wall/metal_foam_base)
 			transfer_fingerprints_to(T)
 			qdel(src)
 		return