Index: test/Plugins/Wti/Wti.IO.Test/Builders/SoilLayer2DTest.cs
===================================================================
diff -u -r2423a70958e7fecfc92afa462c34194cc695a81e -r4f83a029b2b4967a5f9e91dcd2ce06ecbbd09ddb
--- test/Plugins/Wti/Wti.IO.Test/Builders/SoilLayer2DTest.cs	(.../SoilLayer2DTest.cs)	(revision 2423a70958e7fecfc92afa462c34194cc695a81e)
+++ test/Plugins/Wti/Wti.IO.Test/Builders/SoilLayer2DTest.cs	(.../SoilLayer2DTest.cs)	(revision 4f83a029b2b4967a5f9e91dcd2ce06ecbbd09ddb)
@@ -309,27 +309,109 @@
             var innerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
                 "6",
                 "........",
+                "...12...",
                 "........",
+                "...43...",
+                "........",
+                "........"));
+
+            var innerLoop2 = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+                "6",
+                "........",
+                "........",
                 "...12...",
                 "........",
                 "........",
                 "...43..."));
 
-            var innerLoop2 = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+            var layer = new SoilLayer2D
+            {
+                OuterLoop = outerLoop,
+                InnerLoops =
+                {
+                    innerLoop,
+                    innerLoop2
+                }
+            };
+
+            // Call
+            double bottom;
+            var result = layer.AsPipingSoilLayers(3.5, out bottom).ToArray();
+
+            // Assert
+            Assert.AreEqual(1, result.Length);
+            Assert.AreEqual(4.0, bottom);
+            CollectionAssert.AreEquivalent(new[] { 5.0 }, result.Select(rl => rl.Top));
+        }
+
+        [Test]
+        public void AsPipingSoilLayers_OuterLoopInnerLoopOnBorderBottom_ReturnsTwoLayers()
+        {
+            // Setup
+            var outerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
                 "6",
+                "..1..2..",
                 "........",
+                "........",
+                "........",
+                ".4....3.",
+                "........"));
+
+            var innerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+                "6",
+                "........",
+                "........",
                 "...12...",
                 "........",
                 "...43...",
+                "........"));
+
+            var layer = new SoilLayer2D
+            {
+                OuterLoop = outerLoop,
+                InnerLoops =
+                {
+                    innerLoop
+                }
+            };
+
+            // Call
+            double bottom;
+            var result = layer.AsPipingSoilLayers(3.5, out bottom).ToArray();
+
+            // Assert
+            Assert.AreEqual(2, result.Length);
+            Assert.AreEqual(3.0, bottom);
+            CollectionAssert.AreEquivalent(new[] { 5.0, 1.0 }, result.Select(rl => rl.Top));
+        }
+
+        [Test]
+        public void AsPipingSoilLayers_OuterLoopInnerLoopOverlapTop_ReturnsOneLayer()
+        {
+            // Setup
+            var outerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+                "6",
                 "........",
+                "..1..2..",
+                "........",
+                "........",
+                ".4....3.",
                 "........"));
 
+            var innerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+                "6",
+                "...43...",
+                "........",
+                "...12...",
+                "........",
+                "........",
+                "........"));
+
             var layer = new SoilLayer2D
             {
                 OuterLoop = outerLoop,
                 InnerLoops =
                 {
-                    innerLoop2,
                     innerLoop
                 }
             };
@@ -340,11 +422,52 @@
 
             // Assert
             Assert.AreEqual(1, result.Length);
-            Assert.AreEqual(4.0, bottom);
-            CollectionAssert.AreEquivalent(new[] { 5.0 }, result.Select(rl => rl.Top));
+            Assert.AreEqual(1.0, bottom);
+            CollectionAssert.AreEquivalent(new[] { 3.0 }, result.Select(rl => rl.Top));
         }
 
         [Test]
+        public void AsPipingSoilLayers_OuterLoopInnerLoopOnBorderTop_ReturnsOneLayer()
+        {
+            // Setup
+            var outerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+                "6",
+                "..1..2..",
+                "........",
+                "........",
+                "........",
+                ".4....3.",
+                "........"));
+
+            var innerLoop = PointCollectionHelper.CreateFromString(String.Join(Environment.NewLine,
+                "6",
+                "...43...",
+                "........",
+                "...12...",
+                "........",
+                "........",
+                "........"));
+
+            var layer = new SoilLayer2D
+            {
+                OuterLoop = outerLoop,
+                InnerLoops =
+                {
+                    innerLoop
+                }
+            };
+
+            // Call
+            double bottom;
+            var result = layer.AsPipingSoilLayers(3.5, out bottom).ToArray();
+
+            // Assert
+            Assert.AreEqual(1, result.Length);
+            Assert.AreEqual(1.0, bottom);
+            CollectionAssert.AreEquivalent(new[] { 3.0 }, result.Select(rl => rl.Top));
+        }
+
+        [Test]
         public void AsPipingSoilLayers_OuterLoopVerticalAtX_ThrowsException()
         {
             // Setup