diff --git a/inc/system/hunk.h b/inc/system/hunk.h
index cc15ef473..e0511810b 100644
--- a/inc/system/hunk.h
+++ b/inc/system/hunk.h
@@ -25,6 +25,9 @@ typedef struct {
     size_t  mapped;
 } memhunk_t;
 
+// hunk allocation alignment is rounded to cacheline
+#define HUNK_ALIGN      64
+
 void    Hunk_Init(void);
 void    Hunk_Begin(memhunk_t *hunk, size_t maxsize);
 void    *Hunk_TryAlloc(memhunk_t *hunk, size_t size);
diff --git a/src/common/bsp.c b/src/common/bsp.c
index 4bcbf0d5e..cc8ace78e 100644
--- a/src/common/bsp.c
+++ b/src/common/bsp.c
@@ -1260,7 +1260,7 @@ static void BSP_LoadBspxNormals(bsp_t* bsp, const byte* in, size_t data_size)
 
 static size_t BSP_ParseNormalsHeader(bsp_t* bsp, const byte* in, size_t data_size)
 {
-    return data_size;
+    return data_size + HUNK_ALIGN - 1; // extra memory to account for alignment in ALLOC()
 }
 
 static void BSP_ParseDecoupledLM(bsp_t *bsp, const byte *in, size_t filelen)
@@ -1331,7 +1331,7 @@ static size_t BSP_ParseExtensionHeader(bsp_t *bsp, lump_t *out, const byte *buf,
                 break;
             }
             if (e->parse_header)
-                extrasize += e->parse_header(bsp, buf + ofs, len);
+                extrasize += ALIGN(e->parse_header(bsp, buf + ofs, len), HUNK_ALIGN); // to mirror Hunk_TryAlloc() overallocation
             out[j].fileofs = ofs;
             out[j].filelen = len;
             break;
@@ -1432,7 +1432,7 @@ int BSP_Load(const char *name, bsp_t **bsp_p)
         lump_count[i] = count;
 
         // round to cacheline
-        memsize += ALIGN(count * info->memsize, 64);
+        memsize += ALIGN(count * info->memsize, HUNK_ALIGN);
         maxpos = max(maxpos, end);
     }
 
diff --git a/src/unix/hunk.c b/src/unix/hunk.c
index c9fb4a02e..831aa1b6b 100644
--- a/src/unix/hunk.c
+++ b/src/unix/hunk.c
@@ -52,11 +52,11 @@ void *Hunk_TryAlloc(memhunk_t *hunk, size_t size)
 {
     void *buf;
 
-    Q_assert(size <= SIZE_MAX - 63);
+    Q_assert(size <= SIZE_MAX - (HUNK_ALIGN - 1));
     Q_assert(hunk->cursize <= hunk->maxsize);
 
     // round to cacheline
-    size = ALIGN(size, 64);
+    size = ALIGN(size, HUNK_ALIGN);
     if (size > hunk->maxsize - hunk->cursize)
         return NULL;