Roof Ventilation Importance

This is very simple question, isn't it? Unfortunately, it's not. This is mostly due to all the misinformation regarding asphalt and metal roofing systems. While both roof types can be long lasting and provide protection for your home or business both types have pros and cons. We install both asphalt and metal roofs. Like most roofing contractors, we have a preferred type of roof. We've been doing this for a very long time and we draw on that experience to decide what we believe is the best value for our customers. So which is better, asphalt or metal roof? We've offered some information including pros and cons below. We truly hope this helps!

Asphalt Roof

An asphalt roof is made up of layers of different material to create water-proof roof.

• Underlayment - This comes in two general types, felt and synthetic. Felt is the most often used underlay material. It is time tested and works fine. Synthetic has been around for years and is touted as the best form of underlay in the roofing industry. We have had great success with both!
• Ice and Water Barrier - A membrane material that in laid at the eves of a roof to prevent water and ice from penetrating the edges of a roof.
• Drip Edge - Metal edging placed along the edges of a roof to prevent water from seeping into the roof edge and facsia boards. This edging also helps to prevent air driven water from penetrating roof edges.
• Shingles - Shingles come in many brands, materials, colors, wind ratings, and warranties. The correct type of shingle can vary based on your personal preference and geographical location. The wind rating and warranty period give great insight into the quality of the shingle. Shingle selection is extremely important! The cost between low end and high end shingles is not extreme. However, the life span of low end shngles and high shingles can vary greatly, 25 years or more in some cases. SBS type shingles are more weather resistant and offer better protection against hail.
• Roof Cap - Roof cap is specially designed to cover the peaks of a roof. Cutting shingles to cover peaks is very rarely done in modern time roofing.
• Flashing - Flashing is used to create a water proof connection at vertical walls or roof penetrations. Flashing is where most leaks occur do to poor installation techniques or failure to replace flashing when a roof is replaced. Reusing old flashing is common in the roofing industry. Always ask your roofer if they will be replacing all flashings. If the answer is no. Run! Instist that all flashings be replaced!
• Roof Vents - Both intake and outlet vents are required to ensure performance and longevity. Venting is required for all roofs that have an unconditioned space (non-heated/cooled space, like an attic) below them.

Pros

• Long lasting.
• Low maintenance (Hose off/remove debris).
• Long warranty. 25 year to lifetime warranties available. Long non-prorated warranty periods depending on brand, shingle rating and installer. Owens Corning has one of the best shingle warrantys when installed by an Owens Corning Preferred Contractor
• Elegant/Traditional appearance.
• Quiet during rain storms.
• Available in many colors and styles.
• Easy/cheaper repairs.
• Fast install process. Most roofs completed in one day.
• Time tested material and design. Backed by long time manufacturers.
• Much Lower cost than metal roofing. Metal roofing cost three times more on average.

Cons

• Messy roof removal process.
• Loud Installation process.

Metal Roof

Metal shingle roofs are similar to asphalt roofs but use metal shingles. The standing seam metal roof is significantly different in both looks and installation. We'll focus on the standing seam roof as it is the most common type of metal roof being installed. Whereas asphalt roofs are installed with nails standing seam metal roofs are installed with screws. A standing seam roof is a collection of metal panels and metal trim parts usually made of steel or aluminium. A standing seam roof must be installed on a completely flat surface or have runners installed to create a level surface. Failure to install a standing seam roof on a flat surface can cause water puddling and lead to premature roof failure. While acceptable by some manufacturers and contractors a standing seam roof should never be installed over existing shingles as this produces and unlevel surface and can damge the underside of the panels causing rust and corrosion. Metal roofs are not new. In fact they have been around for a long time. You may notice metal roofs on old barns and other out buildings.

Pros

• Long lasting.
• Durable powder coat paint.
• Long prorated warranty.
• Quieter installation process than asphalt.
• High wind rating. Can vary by installation type.
• Modern trendy look

Cons

• Louder than asphalt during rain. This can vary greatly depending on installation technique.
• Higher maintenance than asphalt. Debris need to be removed vias hose or pressure washer. Scratches must be painted to avoid rust or corrosion.
• Longer installation process.
• Not as many color choices as asphalt.
• Depending on installation technique panels may be damaged by walking on them.
• Expensive and time consuming repairs. Repairs may require entire panels be replaced.
• All metal roofs rust corrode over time.
• Much more expensive than asphalt roofs. You could replace your asphalt roof 3 times for the cost of installing a low end metal roof.

Conclusion

Metal roofs are not a new thing. In fact, metal roofs have been around since at least 1834 when architect William Strickland suggested corrugated steel panels for his design for a marketplace in Philadelphia. Asphalt shingles didn't make an appearance until 1903 when roofing contractor Henry Reynolds was credited with inventing asphalt shingles.

Asphalt shingles have under gone many improvements that have made them more durable and increased their useful life. The newest innovation in asphalt shingles is the introduction of SBS shingles. SBS shingles are much more resilient making them hail resistant and increasing their life expectancy even further. Quality asphalt shingles usually include a long warranty of at least 50 years.

Corrugated metal roof panels (Sanding Seam Roof) have not seen much improvement over the years except for one. Quality corrugated roofing panels are now covered with a powder coat paint system that is said to greatly increase the life cycle of the panels. Powder coat paint is a major improvement over both water born and solvent born paints. However, powder coat paint is not indestructible as the metal roofing panel manufactures would like us to believe. Proof of this is easy to find. For example, most automobiles are painted using powder coat paint. In snow kissed areas across the nation we have all seen how mother nature treats powder coat paint. Rust and corrosion is the inevitable fate of metal roofing.

Given the pros and cons of both asphalt shingles and corrugated metal panels I always suggest asphalt shingles. This is due to value per dollar spent. Asphalt roofs can easily last 30 plus years. I’ve seen asphalt roofs 50 years old that still do their job. An asphalt roof cost roughly 1/3 of the price of an equivalent metal roof. This means an asphalt roof can be replaced 3 times for the same cost of installing one metal roof. Until the cost of a metal roof is more competitive with an asphalt roof I can’t in good conscience suggest metal roofing to our customers.