Information about metal roofs

Above:  Standing seam Pac-Clad Metal roof installed by PDS.

Types of metal roofs

There are two generic types of metal roofing systems: concealed fastener systems and exposed fastener systems. Generally, exposed fastener systems cost less than concealed fastener systems. Depending on the aesthetic look you are trying to achieve and project budget, PDS can help you choose the system right for you and your roof design.

Galvanized steel is coated with zinc for corrosion resistance. Galvalume steel is coated with a predominantly aluminum alloy, also to achieve corrosion resistance. Both galvanized and Galvalume are available in various grades. The grade is determined by the thickness of the zinc or aluminum coating applied to both sides of the steel. G-60 is the recommended minimum grade of galvanized steel and AZ50 is the recommended minimum grade of Galvalume if it is to be painted. AZ55 is recommended for Galvalume if it is to be mill-finished or have a clear coat.  KYNAR 500 PVDF or HYLAR 5000 PVDF, is also used as the principal ingredient of high-end paints for metals. These PVDF paints have extremely good gloss and color retention and are generally backed by a 20 year warranty which guarantees the paint to maintain its color and finish.

Other metals being used include aluminum, copper, zinc, stainless steel and terne. Aluminum is used for its corrosion resistance and malleability -- such as its ability to be formed into detailed wood shake profiles. Aluminum roofing always has a paint finish or anodization applied to it for color and extra durability. Copper, zinc and stainless steel more commonly are used without additional coatings.

Copper is used for its durability and characteristic patina. Zinc also is used for its corrosion resistance, malleability and low-gloss gray look. Stainless steel is used to achieve a lasting, bright, silver metallic look or to meet the demands of an exceptionally corrosive environment.

PDS single crimp, standing seam metal installation

Metal Roofing Installation
Metal roof systems require underlayment, and it is critical for three reasons. One is to keep the structure dry during the roof system installation process. Another reason is to provide redundant protection. And third is to keep condensation on the back of the roof panels from saturating roof substrates.
Although for many years, 30 lb. asphalt saturated felt was the standard underlayment beneath metal roofing, PDS has switched to newer synthetics underlayments that are lightweight and offer more coverage per roll. For added protection, PDS also uses self-adhering underlayments, such as ice and water shield, in conjunction with the synthetic felt at all hip, ridge, and perimeter locations. However, it is critical these products always are smooth rather than mineralized so as not to damage the back of the metal panels.
During installation of the roof, some systems require roofing panels to be individually fastened together with special screws while others are clipped together by manufacture’s design.  Other systems require a specialty crimping tool to hem together the two sheets or the seams can be bonded together with heat using a seaming tool.  Installation methods vary depending upon the material specifications, roof design, aesthetic appeal, and budget.  We can consult you in determining the best design for your application and facility use goals.

Installing ice and water shield at the ridge in conjunction with synthetic felt on the field.

Benefits of Metal Roofing
Metal roofing has many benefits to the business or home owner, and we've tried to list as many as possible.
It doesn't rot, crack, warp, curl, split, flake, peel, break, burn, or blow off. It's the most resistant roofing material to hail, wind, fire, and freezing/thawing. It looks great, and is available in a wide variety of roofing styles, patterns, designs, and colors.  Most importantly, its long lasting and can often last 3-4 times longer than many alternate roofing products.
Metal roofing is lightweight -- most styles are less than one-third the weight of asphalt/fiberglass shingles. Metal roofing saves you money because it is energy efficient, leading to lower A/C and heating costs. It can also reduce the cost of your building’s insurance, as well as increase the resale value of your home or building. It's low maintenance, long lasting and durable, and carries a long warranty and in most cases carries a 20 year warranty that protects against color fade. Metal roofing can even usually be installed over your existing roof system (reroofing). 

Restoring Existing Metal Roof Systems
When metal roof systems begin to leak, PDS recommends two restoration processes for metal roof systems: Elastomeric Spray Coat and single-ply metal retrofits.  
Elastomeric Spray Coats
Elastomeric roof coatings are chemicals coated onto roofs in order to lessen the amount of heat that penetrates through the roof while providing a waterproof barrier.  The installation of elastomeric spray coats involves removing all rooftop debris, then pressure washing the roof surface and spot priming all areas affected with rust, if necessary.  Next all fastener heads are tightened down or replaced.  Then all seams, penetrations, and fastener heads are encapsulated with a thick, hardening seam and fastener treatment before 2-3 coats of Elastomeric is spray applied to waterproof and provide protection against deterioration and heat retention caused by the sun.  Elastomeric coatings provide high solar reflectance and thermal heat emittance while increasing the roof’s durability and aesthetic appeal.

Metal roof restored with Elastomeric Spray coat by PDS.

Single Ply Metal Retrofit
If you have a metal roof that has reached the end of its useable life, PDS can use “fill in the flute” techniques to turn your metal roof into an insulated single ply roof system.  We use your existing metal roof as the deck for your new roof system.  We then level the flutes in the deck by adding tapered insulation before fastening down the new single ply roof system of your choice.        
Contact PDS at 806 771-9780 or toll free at 800 PDS-4304 today for a free consultation to learn more about metal roofing solutions.

Tapered iso flute-fill + fanfold  preparing the deck to receive Duro-last single ply membrane performed by PDS.

www.pdscompany.com