get_setting in wp_customise

I’m trying to create a setting that allows users to change the layout of a page.

I have other settings working just fine, but I just cannot for the life of me figure this one out, and the codex is of little to no help with it.

So, adding a new section, control etc.

$wp_customize->add_setting(‘layout’, array(

'default'           => 'stream',
  ));

$wp_customize->add_control('layout', array(
  'label'      => __('Select layout', 'Ari'),
  'section'    => 'layout',
  'settings'   => 'layout',
  'type'       => 'radio',
  'choices'    => array(
    'stream'   => 'Stream',
    'grid'  => 'Grid',
  ),
)); // two options, Stream and Grid.

$wp_customize->add_section('layout' , array(
    'title' => __('Layout','Ari'),
));

Then I want to be able to display the loop with different html/markup/php based on the selected setting.

<?php if ( get_theme_mod( 'stream' ) ) : ?>
          	<p>php/loop/layout for stream option</p>
            <?php elseif ( get_theme_mod( 'grid' ) ) : ?>
     		<p>php/loop/layout for Grid option</p>
            <?php else : //Nothing ?>
            <?php endif; ?>

Except it displays nothing. How do I make an if/else statement for a particular setting?