I guess you are not passing true parameter while passing view file.
please refer bellow tricks:
$output = $this->load->view('your_view', 'your_data', true);
$output .= $this->load->view('your_other_view', 'your_other_data', true);
$output .= $this->load->view('your_last_view', 'your_last_data', true);
$this->output->set_output($output);
**Second Method, you can be passing view with data like :**
$data['header'] = $this->load->view('your_header_view_file_name', true);
$data['footer'] = $this->load->view('your_footer_view_file_name', true);
$data['your_necessary_data'] = $your variables ;
$data['your_necessary_data2'] = $your variables ;
$this->load->view('blogview',$data);