Arizona Roofer

Your Roofing Questions Answered

Tile Roofs

June 25th, 2009

Description:

Tile roofs come in a variety of styles and materials.  They consist of one piece “S Tiles” that are seen on many office building roofs.  There are two piece tiles, called “Pans and Tops,” that are placed on Spanish style homes.  The tiles are made of sand-cast, fired clay, concrete construction, and “light concrete.”  All tile roofs require roofing felt underlayment,  because the tile is simply a decorative watershed.

Uses:

Tile is installed most often to add beauty to a building project.  Tile roofing by itself is not waterproof.   A felt underlayment is required.

Approximate Life Span:

Some tile manufactures proclaim their products have a 50 year life span.  The underlayment felt usually needs to be replaced on or before the 18th to 25th year.  The existing tile can be reinstalled over the new felt.  The slope of the roof is a determining factor in the life expectancy.  The greater the slope, the longer the felt will last.

Caution:

The Uniform Building Code has very specific installation procedures for mechanically fastening tiles in place.  Our experience has shown that approximately 75% of the tile roofs that have been inspected do not meet the Uniform Building Code.  These tile roofs lack the necessary perimeter mechanical fasteners.

Limitations:

  • Slope requirements for the installation of tile roofs are a minimum of 3 inches of vertical drop for every 12 inches of run in order to meet the local building code and have an effective waterproof system.
  • Tile roofs are difficult to walk on and break easily, especially the sand-cast and clay varieties.

Fiberglass Shingles

June 25th, 2009

These 12” by 36” granular surfaced shingles are installed on slopes of 2 inches per running foot or greater.  They are installed over a felt under layment of usually a 15 or 30 pound felt, depending on the slope.  Shingles come in weights between 180 and 400 pounds per 10’ X 10’ or 100 square feet.

 

Uses:

 

The basic shingle is a commodity product typically used for residential applications.  Shingles may also be used on vertical parapet wall applications, provided special fastening patterns are followed.

 

Approximate Life Span:

 

The greater the slope of the roof, the faster the water runs off.  This is a determining factor in the life expectancy of the shingle.  The heavier the shingle, the longer the wearing surface lasts.  If shingles are dark in color and lightweight(180 lbs) expect a life of  7 to 9 years.  For a 400 pound fiberglass shingle, you can expect about 17 years.  For weighs somewhere in the middle, expect a life of about 12 to 15 years.

 

Caution:

 

  • Stay with lighter colors for longer shingle life expectancy.

 

  • Shingle exposure should be carefully measured to insure proper installation patterns.  A small error can throw off the entire roof pattern and allow leaks to occur.

 

Limitations:

 

Shingle manufactures require a minimum slope of 2” in 12”.  If you go below this and have a “blow off, “ your insurance company may not cover the damage.

Modified Bitumens

June 25th, 2009

Description:

 

These roofing systems are typically a single sheet, reinforced in the middle with either a polyester or fiberglass mat for strength and modified with rubberized asphalt.  This allows the roof to expand and contract with building movement.  The Modified sheet should be installed over a mechanically fastened base-sheet.  These systems are mopped in place with hot asphalt.  These roof systems are also installed using a cold process called permanent bond.  It is applied with a torch to melt it to the base sheet.  The surfaces of the modified bitumen roof  are either smooth or granular finish that come in a selection of colors.

 

Uses:

 

These roof systems are used as an upgrade from built-up roofing systems.

 

Life Span:

 

The expected life span of this system will exceed 15 years.  The roofing industry has seen excellent results from the modified bitumens roof.

 

Caution:

 

  • Torch applied systems can be dangerous and can cause fires.  Extra attention in the application phase is very important.

 

Limitations:

 

Proper installation of this roof system is critical.  Details in the construction and installation procedures need to be planned very carefully.

 

The video above is an overview of the hot applied asphalt roof installation process. The Arizona Roofer dose’nt lay any claim to ownership of this video and dose not endorse Garland company’s products. We just thought the video was thorough, and in agreement with the correct installation process of this particular type of roof system. it should be noted that every material manufacture may have different specifics for their materials but the process is the same.

Built-Up Roofing

June 25th, 2009

Description:

 

Built-up Roofing consists of alternate layers of roofing felt and individual moppings of “Hot Asphalt.”  Built-Up Roofing may include either 3 or 4 piles of roofing felt.  Top surfacing can consist of gravel, smooth of granular surfaces similar to the look of a roofing shingle.

 

Uses:

 

A Built-up Roof is the most common type of roof for flat applications.  They can be installed over insulation, on metal roof decks, or directly on plywood roof decks with or without insulation.

 

Life Span:

 

A Four-Ply Built-Up roof will last 9 to 11 years and a Three-Ply normally lasts 6 to 8 years.  If the roofs are professionally maintained, they should last another 4 to 5 years.

 

Caution:

 

  • Asphalt is the waterproofing.  Be sure to install enough asphalt.
  • Although over heating the asphalt during installation aids the crews to install a job faster, it lowers the quality of the roof.  Use proper techniques to insure the best installation and quality of your roof.

 

 

Limitations:

 

  • It’s recommended that the old roof be removed before re-roofing.
  • Proper flashing details are critical to ensure a roof that will last.

Polyurethane Foam Roof System

June 25th, 2009

Description:

 “Foam” is a closed cell plastic insulation spray applied to a minimum thickness of one inch.  It is usually sprayed in only one to two inches thick, primarily because of the cost.  There are two important factors to take into consideration about these roof systems.  One, the foam by itself is not waterproof and with limited exposure, the foam is damaged by the ultraviolet(UV) rays of the sun.  The waterproofing is a liquid coating applied over the foam.  These coatings are made of acrylic, urethane rubber, silicone, or other products.  The absolute minimum thickness of the coating is 25-30 dry mils.

Uses:

This system is often used to “Foam Slope” onto an existing structure and to help move ponded water to drains or scuppers.  It also has very good insulating qualities at over 6.5 per inch.  If used on poorly insulated structures it can substantially reduce energy consumption.

 

Approximate Life Span:

Given that foam is inorganic, its life expectancy should be indefinite provided it is kept “properly coated.”  You can expect about 20 years for maximum life expectancy if new coating is applied every 5-7 years.

 

Caution:

  • Foam should not be used on roof areas that have heavy foot traffic.  For example, roofs with a lot of mechanical equipment, unless fortified for that purpose.
  • Never spray foam over a wet roof.  Be careful, because most roofs that leak show internal moisture content.

 

Limitations:

  • Ponded water will destroy the coating over the roofing material in a short period of time.  Water ponds on the roof must be corrected.
  • No less than 25-30 mils of waterproof coating should be installed, depending upon the type of coating.  This is a NRCA minimum.