diff --git a/src/ol/array.js b/src/ol/array.js
index e2744ce3b7..a50cd774e9 100644
--- a/src/ol/array.js
+++ b/src/ol/array.js
@@ -37,6 +37,18 @@ ol.array.binaryFindNearest = function(arr, target) {
 };
 
 
+/**
+ * Default compare for array sort, will make sure number sort works okay.
+ * @param {*} a The first object to be compared.
+ * @param {*} b The second object to be compared.
+ * @return {number} A negative number, zero, or a positive number as the first
+ *     argument is less than, equal to, or greater than the second.
+ */
+ol.array.defaultCompare = function(a, b) {
+  return a > b ? 1 : a < b ? -1 : 0;
+};
+
+
 /**
  * Whether the array contains the given object.
  * @param {Array.<*>} arr The array to test for the presence of the element.
diff --git a/src/ol/geom/flat/interiorpointflatgeom.js b/src/ol/geom/flat/interiorpointflatgeom.js
index 59e69242b2..f73e423e14 100644
--- a/src/ol/geom/flat/interiorpointflatgeom.js
+++ b/src/ol/geom/flat/interiorpointflatgeom.js
@@ -1,6 +1,7 @@
 goog.provide('ol.geom.flat.interiorpoint');
 
 goog.require('goog.asserts');
+goog.require('ol.array');
 goog.require('ol.geom.flat.contains');
 
 
@@ -40,7 +41,7 @@ ol.geom.flat.interiorpoint.linearRings = function(flatCoordinates, offset,
   // inside the linear ring.
   var pointX = NaN;
   var maxSegmentLength = -Infinity;
-  intersections.sort();
+  intersections.sort(ol.array.defaultCompare);
   x1 = intersections[0];
   for (i = 1, ii = intersections.length; i < ii; ++i) {
     x2 = intersections[i];
diff --git a/src/ol/render/canvas/canvasimmediate.js b/src/ol/render/canvas/canvasimmediate.js
index 9d0a156e55..ae13f9def7 100644
--- a/src/ol/render/canvas/canvasimmediate.js
+++ b/src/ol/render/canvas/canvasimmediate.js
@@ -7,6 +7,7 @@ goog.provide('ol.render.canvas.Immediate');
 goog.require('goog.array');
 goog.require('goog.asserts');
 goog.require('goog.vec.Mat4');
+goog.require('ol.array');
 goog.require('ol.color');
 goog.require('ol.extent');
 goog.require('ol.geom.flat.transform');
@@ -721,7 +722,7 @@ ol.render.canvas.Immediate.prototype.drawText = goog.abstractMethod;
 ol.render.canvas.Immediate.prototype.flush = function() {
   /** @type {Array.<number>} */
   var zs = Object.keys(this.callbacksByZIndex_).map(Number);
-  zs.sort();
+  zs.sort(ol.array.defaultCompare);
   var i, ii, callbacks, j, jj;
   for (i = 0, ii = zs.length; i < ii; ++i) {
     callbacks = this.callbacksByZIndex_[zs[i].toString()];
diff --git a/src/ol/render/canvas/canvasreplay.js b/src/ol/render/canvas/canvasreplay.js
index af959ea9a5..421fab76db 100644
--- a/src/ol/render/canvas/canvasreplay.js
+++ b/src/ol/render/canvas/canvasreplay.js
@@ -2001,7 +2001,7 @@ ol.render.canvas.ReplayGroup.prototype.replay = function(
 
   /** @type {Array.<number>} */
   var zs = Object.keys(this.replaysByZIndex_).map(Number);
-  zs.sort();
+  zs.sort(ol.array.defaultCompare);
 
   // setup clipping so that the parts of over-simplified geometries are not
   // visible outside the current extent when panning
diff --git a/src/ol/render/webgl/webglimmediate.js b/src/ol/render/webgl/webglimmediate.js
index 4233c16c05..37ca04cb4f 100644
--- a/src/ol/render/webgl/webglimmediate.js
+++ b/src/ol/render/webgl/webglimmediate.js
@@ -1,4 +1,5 @@
 goog.provide('ol.render.webgl.Immediate');
+goog.require('ol.array');
 goog.require('ol.extent');
 goog.require('ol.render.VectorContext');
 goog.require('ol.render.webgl.ImageReplay');
@@ -79,7 +80,7 @@ goog.inherits(ol.render.webgl.Immediate, ol.render.VectorContext);
 ol.render.webgl.Immediate.prototype.flush = function() {
   /** @type {Array.<number>} */
   var zs = Object.keys(this.callbacksByZIndex_).map(Number);
-  zs.sort();
+  zs.sort(ol.array.defaultCompare);
   var i, ii, callbacks, j, jj;
   for (i = 0, ii = zs.length; i < ii; ++i) {
     callbacks = this.callbacksByZIndex_[zs[i].toString()];
diff --git a/src/ol/renderer/canvas/canvastilelayerrenderer.js b/src/ol/renderer/canvas/canvastilelayerrenderer.js
index bd11ddaf38..11c404996b 100644
--- a/src/ol/renderer/canvas/canvastilelayerrenderer.js
+++ b/src/ol/renderer/canvas/canvastilelayerrenderer.js
@@ -8,6 +8,7 @@ goog.require('goog.vec.Mat4');
 goog.require('ol.Size');
 goog.require('ol.TileRange');
 goog.require('ol.TileState');
+goog.require('ol.array');
 goog.require('ol.dom');
 goog.require('ol.extent');
 goog.require('ol.layer.Tile');
@@ -364,7 +365,7 @@ ol.renderer.canvas.TileLayer.prototype.prepareFrame =
 
   /** @type {Array.<number>} */
   var zs = Object.keys(tilesToDrawByZ).map(Number);
-  zs.sort();
+  zs.sort(ol.array.defaultCompare);
   var opaque = tileSource.getOpaque();
   var origin = ol.extent.getTopLeft(tileGrid.getTileCoordExtent(
       [z, canvasTileRange.minX, canvasTileRange.maxY],
diff --git a/src/ol/renderer/canvas/canvasvectortilelayerrenderer.js b/src/ol/renderer/canvas/canvasvectortilelayerrenderer.js
index 4be1bba678..ad9f8c588d 100644
--- a/src/ol/renderer/canvas/canvasvectortilelayerrenderer.js
+++ b/src/ol/renderer/canvas/canvasvectortilelayerrenderer.js
@@ -8,6 +8,7 @@ goog.require('ol.TileRange');
 goog.require('ol.TileState');
 goog.require('ol.VectorTile');
 goog.require('ol.ViewHint');
+goog.require('ol.array');
 goog.require('ol.dom');
 goog.require('ol.extent');
 goog.require('ol.layer.VectorTile');
@@ -405,7 +406,7 @@ ol.renderer.canvas.VectorTileLayer.prototype.prepareFrame =
 
   /** @type {Array.<number>} */
   var zs = Object.keys(tilesToDrawByZ).map(Number);
-  zs.sort();
+  zs.sort(ol.array.defaultCompare);
   var replayables = [];
   var i, ii, currentZ, tileCoordKey, tilesToDraw;
   for (i = 0, ii = zs.length; i < ii; ++i) {
diff --git a/src/ol/renderer/dom/domtilelayerrenderer.js b/src/ol/renderer/dom/domtilelayerrenderer.js
index 46ee7c2cf2..fbf77cde40 100644
--- a/src/ol/renderer/dom/domtilelayerrenderer.js
+++ b/src/ol/renderer/dom/domtilelayerrenderer.js
@@ -13,6 +13,7 @@ goog.require('ol.TileCoord');
 goog.require('ol.TileRange');
 goog.require('ol.TileState');
 goog.require('ol.ViewHint');
+goog.require('ol.array');
 goog.require('ol.dom');
 goog.require('ol.extent');
 goog.require('ol.layer.Tile');
@@ -177,7 +178,7 @@ ol.renderer.dom.TileLayer.prototype.prepareFrame =
 
   /** @type {Array.<number>} */
   var zs = Object.keys(tilesToDrawByZ).map(Number);
-  zs.sort();
+  zs.sort(ol.array.defaultCompare);
 
   /** @type {Object.<number, boolean>} */
   var newTileLayerZKeys = {};
@@ -203,7 +204,7 @@ ol.renderer.dom.TileLayer.prototype.prepareFrame =
 
   /** @type {Array.<number>} */
   var tileLayerZKeys = Object.keys(this.tileLayerZs_).map(Number);
-  tileLayerZKeys.sort();
+  tileLayerZKeys.sort(ol.array.defaultCompare);
 
   var i, ii, j, origin, resolution;
   var transform = goog.vec.Mat4.createNumber();
diff --git a/src/ol/renderer/webgl/webgltilelayerrenderer.js b/src/ol/renderer/webgl/webgltilelayerrenderer.js
index 8b5f4e3df7..a22b653e29 100644
--- a/src/ol/renderer/webgl/webgltilelayerrenderer.js
+++ b/src/ol/renderer/webgl/webgltilelayerrenderer.js
@@ -9,6 +9,7 @@ goog.require('goog.vec.Vec4');
 goog.require('goog.webgl');
 goog.require('ol.TileRange');
 goog.require('ol.TileState');
+goog.require('ol.array');
 goog.require('ol.extent');
 goog.require('ol.layer.Tile');
 goog.require('ol.math');
@@ -296,7 +297,7 @@ ol.renderer.webgl.TileLayer.prototype.prepareFrame =
 
     /** @type {Array.<number>} */
     var zs = Object.keys(tilesToDrawByZ).map(Number);
-    zs.sort();
+    zs.sort(ol.array.defaultCompare);
     var u_tileOffset = goog.vec.Vec4.createFloat32();
     var i, ii, sx, sy, tileKey, tilesToDraw, tx, ty;
     for (i = 0, ii = zs.length; i < ii; ++i) {
diff --git a/test/spec/ol/array.test.js b/test/spec/ol/array.test.js
index 4d68a2edea..ae142d3411 100644
--- a/test/spec/ol/array.test.js
+++ b/test/spec/ol/array.test.js
@@ -2,6 +2,16 @@ goog.provide('ol.test.array');
 
 describe('ol.array', function() {
 
+  describe('defaultCompare', function() {
+    it('sorts as expected', function() {
+      var arr = [40, 200, 3000];
+      var expected = [40, 200, 3000];
+      // default sort would yield [200, 3000, 40]
+      arr.sort(ol.array.defaultCompare);
+      expect(arr).to.eql(expected);
+    });
+  });
+
   describe('binaryFindNearest', function() {
     it('returns expected value', function() {
       var arr = [1000, 500, 100];
diff --git a/test/spec/ol/render/canvasimmediate.test.js b/test/spec/ol/render/canvasimmediate.test.js
index f6046771bf..d972a747dd 100644
--- a/test/spec/ol/render/canvasimmediate.test.js
+++ b/test/spec/ol/render/canvasimmediate.test.js
@@ -1,6 +1,22 @@
 goog.provide('ol.test.render.canvas.Immediate');
 
 describe('ol.render.canvas.Immediate', function() {
+
+  describe('#flush', function() {
+    it('calls callback in correct z-order', function() {
+      var canvas = new ol.render.canvas.Immediate();
+      var log = [];
+      canvas.drawAsync(11, function() {
+        log.push(11);
+      });
+      canvas.drawAsync(5, function() {
+        log.push(5);
+      });
+      canvas.flush();
+      expect(log).to.eql([5, 11]);
+    });
+  });
+
   describe('#drawMultiPolygonGeometry', function() {
     it('creates the correct canvas instructions for 3D geometries', function() {
       var log = {