diff --git a/src/battle.c b/src/battle.c
index 599631e30..4159cf0c7 100644
--- a/src/battle.c
+++ b/src/battle.c
@@ -1926,8 +1926,7 @@ int skilldiff(troop at, troop dt, int dist)
             }
         }
         if (b->type->flags & BTF_FORTIFICATION) {
-            int stage = buildingeffsize(b, false);
-            int beff = bt_protection(b->type, stage);
+            int beff = building_protection(b);
             if (beff > 0) {
                 skdiff -= beff;
                 is_protected = 2;
diff --git a/src/kernel/building.c b/src/kernel/building.c
index 7dd4a523f..86c0d2b35 100644
--- a/src/kernel/building.c
+++ b/src/kernel/building.c
@@ -335,6 +335,10 @@ int bt_protection(const building_type * btype, int stage)
     return watch_bonus[stage];
 }
 
+int building_protection(const building* b) {
+    return bt_protection(b->type, buildingeffsize(b, false));
+}
+
 void write_building_reference(const struct building *b, struct storage *store)
 {
     WRITE_INT(store, (b && b->region) ? b->no : 0);
diff --git a/src/kernel/building.h b/src/kernel/building.h
index 7b48aa3ad..3ebb52ec2 100644
--- a/src/kernel/building.h
+++ b/src/kernel/building.h
@@ -106,7 +106,7 @@ extern "C" {
 
     const char *buildingtype(const building_type * btype,
         const struct building *b, int bsize);
-    const char *write_buildingname(const building * b, char *ibuf,
+    const char *write_buildingname(const building *b, char *ibuf,
         size_t size);
     int buildingcapacity(const struct building *b);
     struct building *building_create(int id);
@@ -115,12 +115,13 @@ extern "C" {
     int build_building(struct unit *u, const struct building_type *typ,
         int id, int size, struct order *ord);
     bool building_finished(const struct building *b);
+    int building_protection(const struct building *b);
 
     int wage(const struct region *r, const struct race *rc);
     int peasant_wage(const struct region *r, bool mourn);
 
-    typedef int(*cmp_building_cb) (const struct building * b,
-        const struct building * a);
+    typedef int(*cmp_building_cb) (const struct building *b,
+        const struct building *a);
     struct building *largestbuilding(const struct region *r, cmp_building_cb,
         bool imaginary);
     int cmp_wage(const struct building *b, const struct building *bother);