diff --git a/debug/map/grid.html b/debug/map/grid.html
index 06e71d7f..fb733830 100644
--- a/debug/map/grid.html
+++ b/debug/map/grid.html
@@ -31,7 +31,7 @@
 
 			// test async
 			setTimeout(function () {
-				done(tile);
+				done(null, tile);
 			}, Math.random() * 500);
 
 			return tile;
diff --git a/src/geo/crs/CRS.EPSG3857.js b/src/geo/crs/CRS.EPSG3857.js
index 670ca49a..6d668b79 100644
--- a/src/geo/crs/CRS.EPSG3857.js
+++ b/src/geo/crs/CRS.EPSG3857.js
@@ -14,6 +14,8 @@ L.CRS.EPSG3857 = L.extend({}, L.CRS, {
 
 		return new L.Transformation(scale, 0.5, -scale, 0.5);
 	}())
+
+	wrapLng: true
 });
 
 L.CRS.EPSG900913 = L.extend({}, L.CRS.EPSG3857, {
diff --git a/src/layer/tile/GridLayer.js b/src/layer/tile/GridLayer.js
index 1bae8154..66bce929 100644
--- a/src/layer/tile/GridLayer.js
+++ b/src/layer/tile/GridLayer.js
@@ -108,15 +108,6 @@ L.GridLayer = L.Class.extend({
 		return this;
 	},
 
-	isValidTile: function (coords) {
-		if (!this.options.bounds) { return true; }
-
-		var tileBounds = this._tileCoordsToBounds(coords),
-			bounds = L.latLngBounds(this.options.bounds);
-
-		return bounds.contains(tileBounds);
-	},
-
 	_getPane: function () {
 		// TODO pane in options?
 		return this._map._panes.tilePane;
@@ -274,7 +265,7 @@ L.GridLayer = L.Class.extend({
 				coords = new L.Point(i, j);
 				coords.z = zoom;
 
-				if (!this._tileIsAdded(coords) && this.isValidTile(coords)) {
+				if (!this._tileIsAdded(coords) && this._isValidTile(coords)) {
 					queue.push(coords);
 				}
 			}
@@ -305,6 +296,21 @@ L.GridLayer = L.Class.extend({
 		this._tileContainer.appendChild(fragment);
 	},
 
+	_isValidTile: function (coords) {
+		var crs = this._map.options.crs,
+			limit = this._getWrapTileNum();
+
+		if (!crs.wrapLng && (coords.x < 0 || coords.x >= limit.x)) { return; }
+		if (!crs.wrapLat && (coords.y < 0 || coords.y >= limit.y)) { return; }
+
+		if (!this.options.bounds) { return true; }
+
+		var tileBounds = this._tileCoordsToBounds(coords),
+			bounds = L.latLngBounds(this.options.bounds);
+
+		return bounds.contains(tileBounds);
+	},
+
 	_tileIsAdded: function (coords) {
 		return this._tileCoordsToKey(coords) in this._tiles;
 	},
@@ -319,8 +325,6 @@ L.GridLayer = L.Class.extend({
 		    nw = this._map.unproject(nwPoint),
 		    se = this._map.unproject(sePoint);
 
-		// TODO rectangular
-
 		return new L.LatLngBounds(nw, se);
 	},
 
@@ -379,19 +383,23 @@ L.GridLayer = L.Class.extend({
 	},
 
 	_addTile: function (coords, container) {
+		var tilePos = this._getTilePos(coords);
+
+		this._wrapCoords(coords);
+
 		var tile = this.createTile(coords, this._tileReady);
 
-		// TODO wrapping happens here?
+		this.fire('tileloadstart', {tile: tile});
 
 		this._initTile(tile);
 
+		// if createTile is defined with a second argument ("done" callback),
+		// we know that tile is async and will be ready later; otherwise
 		if (this.createTile.length < 2) {
-			// if tiles are sync, delay one frame for opacity anim to happen
-			setTimeout(L.bind(this._tileReady, this, tile), 0);
+			// mark tile as ready, but delay one frame for opacity anim to happen
+			setTimeout(L.bind(this._tileReady, this, null, tile), 0);
 		}
 
-		var tilePos = this._getTilePos(coords);
-
 		/*
 		Chrome 20 layouts much faster with top/left (verify with timeline, frames)
 		Android 4 browser has display issues with top/left and requires transform instead
@@ -406,7 +414,11 @@ L.GridLayer = L.Class.extend({
 		container.appendChild(tile);
 	},
 
-	_tileReady: function (tile) {
+	_tileReady: function (err, tile) {
+		if (err) {
+			this.fire('tileerror', {error: err});
+		}
+
 		L.DomUtil.addClass(tile, 'leaflet-tile-loaded');
 
 		this.fire('tileload', {tile: tile});
@@ -435,6 +447,23 @@ L.GridLayer = L.Class.extend({
 		return tilePoint.multiplyBy(tileSize).subtract(origin);
 	},
 
+	_wrapCoords: function (coords) {
+		var crs = this._map.options.crs,
+		    limit = this._getWrapTileNum();
+
+		if (crs.wrapLng) {
+			coords.x = ((coords.x % limit.x) + limit.x) % limit.x;
+		}
+		if (crs.wrapLat) {
+			coords.y = ((coords.y % limit.y) + limit.y) % limit.y;
+		}
+	},
+
+	_getWrapTileNum: function () {
+		var size = this._map.options.crs.getSize(this._map.getZoom());
+		return size.divideBy(this.options.tileSize);
+	},
+
 	_animateZoom: function (e) {
 		if (!this._animating) {
 			this._animating = true;