Understanding Roof Underlayment Warranties

Tile roof underlayment is something that most people never have to worry about – Unless they have a tile roof and the roof starts to leak. Then it is something that becomes very important. You will most likely have 2-4 roofing companies give you an estimate and the individual sales person that visits your home will have their opinion. The purpose of this article is to give an unbiased approach to these different underlayments based solely on what their warranties are. 

Before we go into any more detail I just want to write a disclaimer. I have used most if not all of these underlayments and they all have their different strengths and weaknesses. But these items are more in the “eye of the beholder” and include categories such as ease of installation, manufacture support and perceived product quality. The items we are discussing are the “black and white” items as outlined in the individual printed warranty by the manufacturer. Each warranty will be attached so as to allow anyone who desires to qualify those items that are discussed below. 

We are only going to discuss 40# SBS modified underlayments that are readily available in the Phoenix market, including the following products: 

• Fontana G40
• Boral Ply 40
• MB Technologies TU 43
• GBS 40
• Malarky RightStart UDL

Warranty Execution

This is a two edged sword. On one side you get the assurance that the manufacturer knows who you are, on the other It is an easy out if your contractor does not register the warranty. The one strange one is Malarky – they require that the HOMEOWNER register the warranty. 

Length of Warranty

This is pretty self-explanatory – the playing field is not even. While MB technologies and GMC underlayments have an edge – what they cover it the warranty is not as extensive as the others. 

Pro-Rated

This one seems to be a quick way to limit the extent to which a company will pay out if required. Only MB Technologies does this.

Labor and Materials

This is the biggest one in my mind. While a typical roof job is typically 100% due to underlayment failing or aging out, the total cost of the underlayment is usually about 1/10 of the overall job. So if the labor is not included in the warranty – your warranty is immediately reduced to about 10% of the overall cost of the job. This in my mind is probably the most important item to pay attention to. 

Special Install Instructions

In my mind this has less to do with the actual product as to making sure the manufacturer does not have to go out and incur the cost to deny claims. If the material fails, they have to replace it. It will fail regardless of how it is installed, and if it is installed improperly then they will just deny the claim -AFTER they have incurred the cost to inspect it. These special instructions benefit the homeowner as well as everyone – Manufacturer, contractor and homeowner – have a vested interest in doing everything they can to make sure the home does not leak. 

Transferability

This is a whole article worth of items. They are all different. But some manufactures use it as an early out on their warranty. 

Exposure

This is the amount of days that the underlayment can stand up to the sun without losing any of its viability. After this point you may lose the entire warranty. 

In a re-roof situation this is not an issue – in a new construction sometimes this could become a problem. 

Warranty Comparison Chart

	Fontana G40	Fontana G40 Premium	Boral Ply 40	MB Tech TU 43	Brand?? GBS 40	Malarky RightStart UDL
Required Registration	No	Yes	No	Yes	No	Yes
Length (Years)	10	10	10	15	15	10
Pro-Rating	No	No	No	Yes 1/15	No	No
Materials Covered
Labor Covered
Transferability	Automatic	Yes	Automatic	Yes	Once	Once
Post-Transfer Warranty	Remainder	Remainder	Remainder or 2 Years	Remainder	2 Years	Remainder or 1 Year
Exposure	180	180	180	?	90	90

Summary

While all these are great products, based on the warranties alone we recommend Fontana G40 or Boral Ply40 as a single layer underlayment. The Premium reflects installing the same underlayment in a slightly different fashion than normal by adding material to certain areas of the roof that are more susceptible to leaks. It also requires that the warranty be registered. But this is a small price to pay for the added security of knowing if there every arose an issue with the material on your roof you would not be paying 90% of the cost of re-roofing your house while the warranty only covers 10%