Roofing..The Process and The Products
Let’s walk through the process of installing the complete roofing system on a new structure with asphalt shingles.
First I want to cover some basics. When working with roofing or with siding all materials are discussed in terms of quantity required to cover one square or 100 square feet. As such I am going to list all the required products we will use in our roof project and explain how to calculate your material need per one square of coverage.
I am going on the basis that we already have an engineered roof truss set in place with 24” on center spacing. This list will be created in the order it is installed.
Structural roof sheathing:Ref A
This is typically either plywood or osb (oriented strand board) materials. Standard minimum thickness is 7/16” used on garage and storage buildings and ½” or 5/8” used on residential structures to avoid roof sag. Since these products all come in 4’x8’ sheets we will factor 3.25
sheets per one square coverage.
Plywood roof clips:Ref A
These “H” style spacers serve two purposes, first they space the sheets apart to ensure no buckling during natural expansion of the sheets and second they act as a bridge tying the sheets together in the edge space between truss connections. Figure 13
per one square coverage.
“D” Style roof edge:Ref B
This is either an aluminum or steel edge trim mounted on all exposed edges that comes in either 10’ or 12’ lengths and is available in a variety of colors so select a color and material that will match your soffit system. You will need to measure length all around roof edges then add 5% for waste and divide by product length you have chosen to determine the number of pieces required.
Roofing felt:Ref C
Felt is most commonly sold either under the name 15# or 30# products. A roll of 15# felt will cover approximately 400 square feet or 4 squares of roof while 30# being twice as thick will cover 200 square feet. 15# is the standard for shingle roofs while most metal roofs are laid over 30#. There are also many new engineered products on the market offering the following features. They will cover between 4 and 10 squares per roll depending on product. They will not wrinkle when left exposed to moisture, they are more durable if left exposed and are easier to walk on during damp weather.
Eave guard:Ref D
Eave guard is a self adhering 3’ wide roll of material applied along all eave areas running parallel to the ground, some area codes will also require this product be run up any edge rake area also. This self adhering product acts as a sealed barrier between the edge of the roof sheathing and any moisture or Ice build up working its way up from the gutter system. Eave guard is typically sold in 33’ long rolls so you will divide your length of eave area by 33
to determine number of rolls required.
Shingle starter:Ref D
Starter is sold either in bundles or as a roll product and is placed as the first course on all eaves or surfaces running parallel to the ground. The first layer of actual shingles will be placed over this starter row to create a protective double layer. Roll starter is typically in 33’ rolls and bundled starter in 110’ bundles so I would advise you to take your eave length measurement and determine your needs accordingly.
Valley membrane:Ref E
A common product CertainTeed’s Winterguard is a heavy self adhering rubber membrane used to seal valley areas prior to shingle installation. As a nail is driven through this product when installing shingles it seals itself around the nail shaft creating a watertight seal in the valley.
There are a variety of flashings common to roof installation. Most notable is the pipe perforation flashing. Take an inventory of each material type and size of pipe you will be sealing to your material supplier and acquire the appropriate flashing for that pipe. Rubber flashings are common for plastic vent pipe while a galvanized metal flashing is required for any heat conducting vent. You will also need to determine metal flashing requirements for any area where the roof meets a vertical wall or chimney.
Ridge or can vents:Ref G
Every roof will require some kind of roof exhaust vent as close to the peak or ridge as possible to allow for natural exhaust of warm air in the attic space. There are many popular roll out venting materials that apply directly to the peak and are then covered by a ridge shingle to blend for curb appeal. Another option is either an aluminum or plastic strip ridge vent that nails directly over the top shingles in a color to compliment the roof or a metal or plastic can vent that laces into the shingle side close to the ridge. In any case I can not stress enough the urgent need to select and install an approved exhaust venting system on every shingle roof project. Check your local supplier for product options and proper application.
The actual shingle product will come in bundles and the size and quantity of bundles will vary by product quality and cost. Most typical 30 year architectural shingles will be packaged at 3 bundles to equal one square. Higher quality shingles will tend to be thicker and thus heavier in weight requiring them to be placed in more bundles per square. Consult your material supplier to calculate your material needs and costs.
Hip and Ridge cap shingles:Ref I
The standard cap shingle will be bundled separate from the regular shingles and precut to fit. Old method used with 3 tab shingles and split them into 3 separate tabs to create a cap however most manufacturers have changed their color schemes so their 3 tab shingle colors do not match their architectural profile colors. Consult your supplier for coverage as it tends to vary from 20 to 30 running feet per bundle.
Roofing Nails: Most shingle manufactures want either 4 or 5 nails per shingle so the rule of thumb is: Use 1-1/4” nails for a new single layer roof and figure 1.5# per square if nailing by hand or one box of coils per 16 squares of shingles if using an air gun.
There you have it, all the products for your new roof and the info you need to calculate quantities and then pricing.
From here I will get more in depth first covering the subject of
Decra Stone Coated Steel Roofing
This is a rapidly expanding category with many attractive new options.
From here we will dive right into
Asphalt Shingle Roofing
and discuss the many options as well as some common service issues often incorrectly thought to be product problems.
This article will make great reading. In our market we still do an occasional
WOOD SHAKE ROOF
so I will spend some time discussing the options currently available. I’m going to conclude this section with a topic I will call
here. In this article I will touch on the areas of tile and slate and a couple of hybrid vinyl products I have researched. When we are finished here you will have a good understanding to help you in selecting the right products to get the looks and durability you want for your new home.
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