Roofing Underlayment for Waterproofing

Posted on: December 30th, 2016 by Lori Smith
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An average roof lasts around 25 years depending on the type of roofing material you use. If you have an older home or live in an area with harsh weather, you are going to need to replace the shingles and underlayment at some point. It is a costly undertaking, so you want to be sure and call a reputable roofing contractor that uses proper materials to best manage your investment.

Everyone has to work within their own budget, but usually insurance will cover the majority of replacing your roof, especially if it is damaged by unpreventable reasons. You don’t want to have leaks that threaten the integrity of your structure, but you do have options for protecting your home.

After you have sheeted the roof deck, the next step is apply underlayment. This is a method for waterproofing your covering before you install shingles that traditionally came in rolls of what is referred to as felt or tar paper. There are also synthetic options that are more lightweight and stronger, but also more expensive.

This article provides a description of roofing underlayment for waterproofing:

Applying Underlayment – How to Install Shingles – Roofing. DIY Advice

http://www.diyadvice.com/diy/roofing/install-shingles/apply-underlayment/

Image from DIYadvice.com

Before applying roofing, cover the sheathing with roofing felt, also often called “tar paper.” Do not use felt as a temporary protection against rain: If it gets wet it will wrinkle, making it harder to shingle. If you need to temporarily protect a roof, cover it with plastic sheeting or a tarp.

Most local codes call for using 30-pound felt. Some roofers prefer to attach felt underlayment with 1-inch roofing nails or special nails with plastic washers, but most codes allow staples, which are easier to drive. For the lower portion of the roof — especially the part that overhangs the eaves and is susceptible to ice dams — it is a good idea to apply self-stick waterproof shingle underlayment (WSU), also called ice guard.

Original blog posted here:  Applying Underlayment – How to Install Shingles – Roofing. DIY Advice

Managing the moisture in your attic with ventilation is a big part controlling condensation which can lead to buckled or damaged roof sheathing. With synthetic breathable underlayment, there are some experts that feel it helps your attic breathe, but others feel it is unnecessary. This video boasts the benefits of breathable roofing underlayment:

What is the different in cost of synthetic vs felt underlayment? Synthetic is significantly higher in cost, but is said to hold up better as well as being easier to install. There are ways to check online reviews for felt vs synthetic, so do some research yourself before contacting a roofing contractor in your area. They will likely have a preference, but you are wise to educate yourself in case they are just trying to sell you higher priced materials.

This is a review from an online buying guide and review site to help make the decision easier:

REVIEW: Best Roof Underlayments – Roof Underlayment Reviews – Synthetic Underlayment vs Felt

http://www.galttech.com/research/household-DIY-tools/best-roof-underlayments.php

Image via galttech.com

The cost per square foot goes from $.10 up to about $.40. FelTex is the one that was recommended by my roofer, although we didn’t go with it. FelTex is a woven polypropylene fabric that features a waterproof backing. One roofer mentioned online that he couldn’t get the FelTex to take a chalk line.

Synthetic underlayments are good if you plan on leaving the roof with just roofing paper for a few months – not sure why you would do that. Also, they are perfect for homeowners who may not check their roofing shingles that often and need to know that the roofing paper can hold up when perhaps the shingles have failed.

The long term durability is not totally proven amongst roofers, eventhough the manufacturers assure us that they will last longer than the felt option. More videos and resources are here on our Roof Underlayment Resource Page.

Read the full post here:  REVIEW: Best Roof Underlayments – Roof Underlayment Reviews – Synthetic Underlayment vs Felt

 

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