Custom template suggestion
Let me explain you the template order 

In this, you can alter the header and footer if you wanted it to be different than normal page layout that is set in the page.tpl.php 

page--[content-type name].tpl.php = page--lab.tpl.php 
It will be used to theme all contents of type lab including header and footer

page--node--[content-id].tpl.php = page--node--12.tpl.php 
It will be used to theme  content with 12 including header and footer

Secondly,


node.tpl.php Will work for all type of content on the site
node--[content-type name].tpl.php (node--lab.tpl.php) will used to alter the content part only of lab type content excluding header and footer
node--[node-id].tpl.php(node--10.tpl.php) will use to alter the content part of node 10 only excluding header and footer 


Including and excluding meand control over header and footer. 

Hope it will help you!