diff --git a/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php b/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php
index a6afb6be3df1c..b031199ed189c 100644
--- a/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php
+++ b/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php
@@ -132,12 +132,12 @@ public function update(Response $response)
         $maxAge = null;
         $sMaxage = null;
 
-        if ($this->ageDirectives['max-age']) {
+        if (\is_numeric($this->ageDirectives['max-age'])) {
             $maxAge = $this->ageDirectives['max-age'] + $this->age;
             $response->headers->addCacheControlDirective('max-age', $maxAge);
         }
 
-        if ($this->ageDirectives['s-maxage']) {
+        if (\is_numeric($this->ageDirectives['s-maxage'])) {
             $sMaxage = $this->ageDirectives['s-maxage'] + $this->age;
 
             if ($maxAge !== $sMaxage) {
@@ -145,8 +145,10 @@ public function update(Response $response)
             }
         }
 
-        if ($this->ageDirectives['expires']) {
-            $response->setExpires($response->getDate()->modify('+'.$this->ageDirectives['expires'].' seconds'));
+        if (\is_numeric($this->ageDirectives['expires'])) {
+            $date = clone $response->getDate();
+            $date->modify('+'.($this->ageDirectives['expires']+$this->age).' seconds');
+            $response->setExpires($date);
         }
     }
 
diff --git a/src/Symfony/Component/HttpKernel/Tests/HttpCache/ResponseCacheStrategyTest.php b/src/Symfony/Component/HttpKernel/Tests/HttpCache/ResponseCacheStrategyTest.php
index 6522c935c36c0..960b5cdcc65f9 100644
--- a/src/Symfony/Component/HttpKernel/Tests/HttpCache/ResponseCacheStrategyTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/HttpCache/ResponseCacheStrategyTest.php
@@ -249,6 +249,14 @@ public function testCacheControlMerging(array $expects, array $master, array $su
 
             foreach ($config as $key => $value) {
                 switch ($key) {
+                    case 'age':
+                        $response->headers->set('Age', $value);
+                        break;
+
+                    case 'expires':
+                        $response->setExpires((clone $response->getDate())->modify('+'.$value.' seconds'));
+                        break;
+
                     case 'max-age':
                         $response->setMaxAge($value);
                         break;
@@ -281,12 +289,19 @@ public function testCacheControlMerging(array $expects, array $master, array $su
         $cacheStrategy->update($response);
 
         foreach ($expects as $key => $value) {
-            if (true === $value) {
+            if ($key === 'expires') {
+                $this->assertSame($value, $response->getExpires()->format('U') - $response->getDate()->format('U'));
+            } else if ($key === 'age') {
+                $this->assertSame($value, $response->getAge());
+            } elseif (true === $value) {
                 $this->assertTrue($response->headers->hasCacheControlDirective($key), sprintf('Cache-Control header must have "%s" flag', $key));
             } elseif (false === $value) {
-                $this->assertFalse($response->headers->hasCacheControlDirective($key), sprintf('Cache-Control header must NOT have "%s" flag', $key));
+                $this->assertFalse(
+                    $response->headers->hasCacheControlDirective($key),
+                    sprintf('Cache-Control header must NOT have "%s" flag', $key)
+                );
             } else {
-                $this->assertEquals($value, $response->headers->getCacheControlDirective($key), sprintf('Cache-Control flag "%s" should be "%s"', $key, $value));
+                $this->assertSame($value, $response->headers->getCacheControlDirective($key), sprintf('Cache-Control flag "%s" should be "%s"', $key, $value));
             }
         }
     }
@@ -334,7 +349,7 @@ public function cacheControlMergingProvider()
         );
 
         yield 'resolve to lowest possible max-age' => array(
-            array('public' => false, 'private' => true, 's-maxage' => false, 'max-age' => 60),
+            array('public' => false, 'private' => true, 's-maxage' => false, 'max-age' => '60'),
             array('public' => true, 'max-age' => 3600),
             array(
                 array('private' => true, 'max-age' => 60),
@@ -342,7 +357,7 @@ public function cacheControlMergingProvider()
         );
 
         yield 'resolves multiple max-age' => array(
-            array('public' => false, 'private' => true, 's-maxage' => false, 'max-age' => 60),
+            array('public' => false, 'private' => true, 's-maxage' => false, 'max-age' => '60'),
             array('private' => true, 'max-age' => 100),
             array(
                 array('private' => true, 'max-age' => 3600),
@@ -352,7 +367,7 @@ public function cacheControlMergingProvider()
         );
 
         yield 'merge max-age and s-maxage' => array(
-            array('public' => true, 's-maxage' => 60, 'max-age' => null),
+            array('public' => true, 's-maxage' => '60', 'max-age' => null),
             array('public' => true, 's-maxage' => 3600),
             array(
                 array('public' => true, 'max-age' => 60),
@@ -368,7 +383,7 @@ public function cacheControlMergingProvider()
         );
 
         yield 'result can have s-maxage and max-age' => array(
-            array('public' => true, 'private' => false, 's-maxage' => 60, 'max-age' => 30),
+            array('public' => true, 'private' => false, 's-maxage' => '60', 'max-age' => '30'),
             array('s-maxage' => 100, 'max-age' => 2000),
             array(
                 array('s-maxage' => 1000, 'max-age' => 30),
@@ -376,5 +391,77 @@ public function cacheControlMergingProvider()
                 array('s-maxage' => 60, 'max-age' => 1000),
             ),
         );
+
+        yield 'does not set headers without value' => array(
+            array('max-age' => null, 's-maxage' => null, 'public' => null),
+            array('private' => true),
+            array(
+                array('private' => true),
+            ),
+        );
+
+        yield 'max-age 0 is sent to the client' => array(
+            array('private' => true, 'max-age' => '0'),
+            array('max-age' => 0, 'private' => true),
+            array(
+                array('max-age' => 60, 'private' => true),
+            ),
+        );
+
+        yield 'max-age is relative to age' => array(
+            array('max-age' => '240', 'age' => 60),
+            array('max-age' => 180),
+            array(
+                array('max-age' => 600, 'age' => 60),
+            ),
+        );
+
+        yield 'retains lowest age of all responses' => array(
+            array('max-age' => '160', 'age' => 60),
+            array('max-age' => 600, 'age' => 60),
+            array(
+                array('max-age' => 120, 'age' => 20),
+            ),
+        );
+
+        yield 'max-age can be less than age, essentially expiring the response' => array(
+            array('age' => 120, 'max-age' => '90'),
+            array('max-age' => 90, 'age' => 120),
+            array(
+                array('max-age' => 120, 'age' => 60),
+            ),
+        );
+
+        yield 'max-age is 0 regardless of age' => array(
+            array('max-age' => '0'),
+            array('max-age' => 60),
+            array(
+                array('max-age' => 0, 'age' => 60),
+            ),
+        );
+
+        yield 'max-age is not negative' => array(
+            array('max-age' => '0'),
+            array('max-age' => 0),
+            array(
+                array('max-age' => 0, 'age' => 60),
+            ),
+        );
+
+        yield 'calculates lowest Expires header' => array(
+            array('expires' => 60),
+            array('expires' => 60),
+            array(
+                array('expires' => 120),
+            ),
+        );
+
+        yield 'calculates Expires header relative to age' => array(
+            array('expires' => 210, 'age' => 120),
+            array('expires' => 90),
+            array(
+                array('expires' => 600, 'age' => '120'),
+            ),
+        );
     }
 }