There are as many different types of roofs as there are materials to cover them, the important thing is that no matter what type of roof you have the proper steps and materials are used to build your roofing system.  We know most customers don’t care how the roof goes together as long as it doesn’t leak – but remember this one thing, your roof is a system and must be put together properly.

The information contained in this page is specific to “steep-slope” roofing systems (shingled roofs and the like), any other roofing system may or may not require the same.  This information is for educational purposes ONLY, at no time does this information replace that of a qualified professional.  Andes Contracting does NOT recommend working on or replacing your roof yourself.


Basic Roofing Definitions:

  • Steep Slope Roof:  A roof surface of at least 3 units vertical for every 12 units horizontal; a roof pitch of at least 25 degrees.
  • Roof Covering:  The top layer of material used to cover and protect the roof surface. (Shingles, Tile, Slate, Metal, etc.)
  • Roof Underlayment:  Base layer material installed above the sheathing but under the roof covering.
  • Sheathing:  Wooden boards or sheets fastened to the roof structure to form the roofing surface.
  • Roof Structure:  The framework of the roof; Rafters or trusses, constructed to support the sheathing.
  • Flashing:  Metal material installed in a roof system to protect and cover various joints and valleys and prevent water seepage. (Typically used around chimneys, side walls, and valleys)
  • Ridge:  The external angle formed by two or more sloping roof planes, typically at the top of a roof.
  • Valley:  The internal angle formed by the intersection of two sloping roof planes.
  • Gable or Gable Roof:  The vertical triangular portion of the end of a building having a single horizontal ridge and double-sloping roof; a roof that terminates at a gable end.
  • Hip or Hip Roof:  The inclined external angle (not horizontal) formed by the intersection of two sloping roof planes; a roof with one or more hips.



The Basics of Building a Roof System

A common misunderstanding in roofing is that the shingles (the part you can see) is the most important part; when in reality each part of the system is equally important.  Since you cannot see all of the components, this is where many contractors “cut corners” to offer cheap prices.  We not only strive to provide superior service, but also to install a premium roof; never cutting corners and using the right products for the right applications.

  • After the roof is removed, the decking/sheathing will be checked for damaged or rotten areas and then new underlayment must be installed over the sheathing.  The underlayment should be attached to the roof using “plastic cap” nails and each course should overlap the next by three to four inches.
    As with shingles there is a variety of types of underlayment to choose from.  For years tar saturated felt-paper, commonly called “felt” or “tar paper” has been the standard in roofing underlayment and is still the most used product today.
  • Special attention is to be taken around sensitive or vulnerable areas of the roof; valleys, skylights, chimneys, attic vents, plumbing vents, side-walls, etc.  This special attention may involve altering or customizing part or the roof to protect these areas and increase the roofs ability to shed the water efficiently.  In these areas, Andes Contracting will also use an ice & water shield barrier as an additional layer of protection to further prevent future problems.
  • Once the proper underlayment has been installed, all vents and pipe jacks should be installed (with the exception of ridge vent which is put on after the shingles).  While there are a variety of options, all of the vents and pipe jacks are specifically designed to cover and protect penetrations through the roof.  But that doesn’t make all vents equal.  Depending on the design of your roof, your Andes Contracting will recommend the most effective options for your home.  In addition, it is a standing policy that we replace all vents and pipe jacks along with rest of the roof.
    In contrast, this is often where low cost contractors will attempt to “make-up” some cost by NOT telling the customer and NOT replacing these fixtures – they simply reuse the old.  This is strongly discouraged as the useful life of these fixtures is limited and it is far more costly to replace them later than it is now along with rest of the roof.


  • At this point, you could say the roofing surface has been prepared and you are now ready to begin installing the shingles.  The shingles will be installed from the bottom up and will follow a repeating diagonal pattern with a staggered joints.   Each shingle must be properly nailed along the designated “nail line” with the nails penetrating at least ¼” through the decking.  When done properly with an attention to detail it will result in a waterproof roof that is both functional and cosmetically appealing.


  • Once the body of the roof is fully covered with shingles, then the ridge caps must be installed.  If the roof design calls for ridge vent, then the ridge vent will also be installed at this time with the ridge shingles being nailed over them.  Care should be taken to ensure the ridge lines are straight and that any exposed nail heads are covered with a UV resistant sealant to ensure a water-tight surface.


  • Andes Contracting not considered the roof finished until all of the little details are complete.  All fixtures on the roof will be painted to blend and match with the color of the roof you have chosen, the roof will be blown and/or swept off, your gutters will be cleaned out, and the roof will receive a final inspection by either Andrew or Mike Wendler.
  • On the ground, everything will be picked up and transported off of your property.  Care will be taken to protect and clean around sensitive areas, such as flower beds, hard surfaces will be swept or blown off, the lawn will be racked to pick-up the little pieces as well as the large ones, and large magnets will be used to ensure nails are not left all around your home.