hi guys im going to rebuild the outfaces of our extension and fit a 1500 wide window ,above the window will be 4 courses of brick before it meets the flat room and at the minute there is no lintal present which should i fit or is it nessasary also i will be replacing the upvc door with one 900 wide (external dimensions) also 4 courses above same again none present at the minute hense the reason i wish to rebuilt the walls as the brick work would have been better if a blind man had done it .many thanks guys