Has the same manufacturer s warranty.
													
																	How to install a roof over existing shingles. 
									
	
		
	
																	Some roofers install a layer of waterproof shingle underlayment wsu over the existing shingles at the eave end as would be done for a roof laid on bare sheathing. 
																	Looks just as good and lasts as long. 
																	This provides added protection against ice dams. 
																	As long as it s done right and under the right conditions installing new shingles over old ones can last as long and look just as good as a complete re roof.