diff --git a/src/DotRecast.Detour.TileCache/DtTileCacheBuildResult.cs b/src/DotRecast.Detour.TileCache/DtTileCacheLayerBuildResult.cs
similarity index 55%
rename from src/DotRecast.Detour.TileCache/DtTileCacheBuildResult.cs
rename to src/DotRecast.Detour.TileCache/DtTileCacheLayerBuildResult.cs
index eb90d3a..661fb2e 100644
--- a/src/DotRecast.Detour.TileCache/DtTileCacheBuildResult.cs
+++ b/src/DotRecast.Detour.TileCache/DtTileCacheLayerBuildResult.cs
@@ -3,17 +3,17 @@ using System.Threading.Tasks;
 
 namespace DotRecast.Detour.TileCache
 {
-    public class DtTileCacheBuildResult
+    public class DtTileCacheLayerBuildResult
     {
         public readonly int tx;
         public readonly int ty;
-        public readonly Task<List<byte[]>> task;
+        public readonly List<byte[]> layers;
 
-        public DtTileCacheBuildResult(int tx, int ty, Task<List<byte[]>> task)
+        public DtTileCacheLayerBuildResult(int tx, int ty, List<byte[]> layers)
         {
             this.tx = tx;
             this.ty = ty;
-            this.task = task;
+            this.layers = layers;
         }
     }
 }
\ No newline at end of file
diff --git a/src/DotRecast.Detour.TileCache/DtTileCacheLayerBuilder.cs b/src/DotRecast.Detour.TileCache/DtTileCacheLayerBuilder.cs
index 5f2a50b..5a1a517 100644
--- a/src/DotRecast.Detour.TileCache/DtTileCacheLayerBuilder.cs
+++ b/src/DotRecast.Detour.TileCache/DtTileCacheLayerBuilder.cs
@@ -39,7 +39,7 @@ namespace DotRecast.Detour.TileCache
             _compFactory = compFactory;
         }
 
-        public List<byte[]> Build(IInputGeomProvider geom, RcConfig cfg, RcByteOrder order, bool cCompatibility, int threads, int tw, int th)
+        public List<DtTileCacheLayerBuildResult> Build(IInputGeomProvider geom, RcConfig cfg, RcByteOrder order, bool cCompatibility, int threads, int tw, int th)
         {
             if (threads == 1)
             {
@@ -49,25 +49,25 @@ namespace DotRecast.Detour.TileCache
             return BuildMultiThread(geom, cfg, order, cCompatibility, tw, th, threads);
         }
 
-        private List<byte[]> BuildSingleThread(IInputGeomProvider geom, RcConfig cfg, RcByteOrder order, bool cCompatibility, int tw, int th)
+        private List<DtTileCacheLayerBuildResult> BuildSingleThread(IInputGeomProvider geom, RcConfig cfg, RcByteOrder order, bool cCompatibility, int tw, int th)
         {
-            List<byte[]> layers = new List<byte[]>();
+            var results = new List<DtTileCacheLayerBuildResult>();
             for (int y = 0; y < th; ++y)
             {
                 for (int x = 0; x < tw; ++x)
                 {
-                    var list = BuildTileCacheLayer(geom, cfg, x, y, order, cCompatibility);
-                    layers.AddRange(list);
+                    var result = BuildTileCacheLayer(geom, cfg, x, y, order, cCompatibility);
+                    results.Add(result);
                 }
             }
 
-            return layers;
+            return results;
         }
 
 
-        private List<byte[]> BuildMultiThread(IInputGeomProvider geom, RcConfig cfg, RcByteOrder order, bool cCompatibility, int tw, int th, int threads)
+        private List<DtTileCacheLayerBuildResult> BuildMultiThread(IInputGeomProvider geom, RcConfig cfg, RcByteOrder order, bool cCompatibility, int tw, int th, int threads)
         {
-            var results = new List<DtTileCacheBuildResult>();
+            var results = new List<Task<DtTileCacheLayerBuildResult>>();
             for (int y = 0; y < th; ++y)
             {
                 for (int x = 0; x < tw; ++x)
@@ -75,12 +75,12 @@ namespace DotRecast.Detour.TileCache
                     int tx = x;
                     int ty = y;
                     var task = Task.Run(() => BuildTileCacheLayer(geom, cfg, tx, ty, order, cCompatibility));
-                    results.Add(new DtTileCacheBuildResult(tx, ty, task));
+                    results.Add(task);
                 }
             }
 
             return results
-                .SelectMany(x => x.task.Result)
+                .Select(x => x.Result)
                 .ToList();
         }
 
@@ -94,7 +94,7 @@ namespace DotRecast.Detour.TileCache
             return lset;
         }
 
-        protected virtual List<byte[]> BuildTileCacheLayer(IInputGeomProvider geom, RcConfig cfg, int tx, int ty, RcByteOrder order, bool cCompatibility)
+        protected virtual DtTileCacheLayerBuildResult BuildTileCacheLayer(IInputGeomProvider geom, RcConfig cfg, int tx, int ty, RcByteOrder order, bool cCompatibility)
         {
             RcHeightfieldLayerSet lset = BuildHeightfieldLayerSet(geom, cfg, tx, ty);
             List<byte[]> result = new List<byte[]>();
@@ -133,7 +133,7 @@ namespace DotRecast.Detour.TileCache
                 }
             }
 
-            return result;
+            return new DtTileCacheLayerBuildResult(tx, ty, result);
         }
     }
 }
\ No newline at end of file
diff --git a/test/DotRecast.Detour.TileCache.Test/TestTileLayerBuilder.cs b/test/DotRecast.Detour.TileCache.Test/TestTileLayerBuilder.cs
index 52e01f4..d5bb28e 100644
--- a/test/DotRecast.Detour.TileCache.Test/TestTileLayerBuilder.cs
+++ b/test/DotRecast.Detour.TileCache.Test/TestTileLayerBuilder.cs
@@ -19,6 +19,7 @@ freely, subject to the following restrictions:
 */
 
 using System.Collections.Generic;
+using System.Linq;
 using DotRecast.Core;
 using DotRecast.Detour.TileCache.Io.Compress;
 using DotRecast.Detour.TileCache.Test.Io;
@@ -70,6 +71,9 @@ public class TestTileLayerBuilder : DtTileCacheLayerBuilder
 
     public List<byte[]> Build(RcByteOrder order, bool cCompatibility, int threads)
     {
-        return Build(_geom, _cfg, order, cCompatibility, threads, tw, th);
+        var results = Build(_geom, _cfg, order, cCompatibility, threads, tw, th);
+        return results
+            .SelectMany(x => x.layers)
+            .ToList();
     }
 }
\ No newline at end of file