Posts Tagged ‘roof ventilation’

What Are My Roofing Options?

February 15, 2011

Roofing Guide

Asphalt shingles—used on an overwhelming share of the U.S. residential roofs—can be reinforced with fiberglass materials. Fiberglass-reinforced products are more durable and dominate the market.

Fiberglass shingles have a fiberglass mat, top-and-bottom layers of asphalt and mineral granules. They are available in architectural grades and a variety of colors that offer a textured appearance.

Wood shingles and shakes are typically made from cedar, redwood, and southern pine. Shingles are machine-sawn; shakes are hand-hewn and rougher looking. Their natural look is popular but brush fire concerns limit their use.

Slate is quarried and applied mostly in the northeast and comes in different colors and grades. Considered virtually indestructible, it is, however, more expensive than other roofing materials.

Synthetic roof products simulate various types of traditional roof coverings, such as slate and wood shingles and shakes. A point to consider: Although synthetic roof products may simulate the appearance of traditional roof coverings, they do not necessarily have the same properties.

All roof systems have five basic components:

Structure: the rafters and trusses that support the sheathing.

Deck/sheathing: the boards or sheet material that are fastened to the roof rafters to cover a house.

Underlayment: a sheet of asphalt-saturated material used as a secondary layer of protection for the roof deck.

Roof covering: shingles, tiles, etc., that protect the sheathing from weather.

Drainage: the features of the roof system’s design, such as shape, slope, layout, etc., that affect its ability to shed water.

Flashing: sheet metal or other material laid into the various joints and valleys of a roof system to prevent water seepage.

Ventilation is Key

One of the most critical factors in roof system durability is proper ventilation. Without it, heat and moisture buildup in the attic area combine to cause rafters and sheathing to rot, roof shingles to buckle, and insulation to lose its effectiveness.

It is important never to block sources of roof ventilation, such as louvers, ridge vents, or soffit vents. Proper attic ventilation will help prevent structural damage, increase the life of the roofing material and reduce energy consumption.

In addition to the free flow of air, insulation plays a key role in proper attic ventilation. An ideal attic has:

  • A gap-free layer of insulation to protect again heat gain or loss
  • A vapor retarder under the insulation to stop moisture from rising into the attic
  • Enough vented spaces properly allow air to pass in and out freely
  • A minimum of 1 inch between the insulation and roof sheathing

Roof Enemies

Sun: Heat and ultraviolet rays cause roofing materials to deteriorate over time.

Rain: When underneath roofing, water can work its way to the deck and begin to cause rot.

Wind: High winds can lift the roof edges and force water underneath.

Condensation: The buildup of relatively warm, moisture-laden air in a poorly ventilated attic promotes decay of the wood sheathing and rafters.

Moss and algae: Moss can grow on wood shingles and shakes if they are kept moist by poor sunlight conditions or bad drainage. Once it grows, moss holds even more moisture to the roof surface, causing rot, and its roots actually work their way into the wood.

Algae also grows in damp, shaded areas on wood or asphalt shingle roof systems. Besides creating an ugly black-green stain, algae can retain moisture, causing rot and deterioration.

Trees and bushes should be trimmed away from the house to eliminate damp, shaded areas, and gutters should be kept clean to ensure good drainage. Tree branches touching the roof will scratch and gouge roofing materials as they are blown back and forth. Leaves retain moisture and cause rot.

Missing or torn shingles: No longer complete protection.

Shingle deterioration: When shingles get old and worn out, they curl, split, and lose their waterproofing effectiveness and are more easily blown off, torn, or lifted by wind gusts.

Flashing deterioration: Many apparent roof leaks really are flashing leaks around chimneys, vents, skylights, and wall/roof junctions.

How long can you expect a roof system to last?

The condition and lifespan of your roof system will depend on the type of roof system you have, the effects of the local environment. According to the American Society of Home Inspectors, asphalt shingles generally last 15 to 20 years; wood shingle/shakes, 10 to 40 years; clay/concrete tiles, 20+ years; slate, 30 to 100 years; and metal roofing, 15 to 40+ years. Most top-of-the-line roofing product manufacturers offer a variety of warranties.

When selecting a new roof, cost and durability are tops, but aesthetics and architectural style are important, too. The right roof balances these four considerations.

To discuss all of your options, contact a Minnesota roofing contractor today!

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Protecting Your Minnesota Home From Ice Dams This Winter

November 9, 2010

Protect Your Home From Ice Dams

What Is An Ice Dam?

Ice dams are formed when heat from inside of a home escapes into the attic and warms the roof decking during the winter.  The heat, combined with the heat from the sun, can melt snow on the roof.  Melting snow on the upper roof and in the valleys runs down toward the eaves as water.  When it reaches the cold eaves and gutters it freezes.  This continuous thaw and re-freezing process creates an ice dam.  The result is water backing up under the roof shingles or behind fascia boards where It can soak through the roof decking or wall sheathing, causing tremendous damage to attics, ceilings, and walls.

Ice Dam Defense
There are 3 ways to defend against the damage ice dams cause.  All 3 work together.

  • Insulation/ Insulation keeps heat from escaping from your home’s living space into your attic.
  • Ventilation/ Ventilation removes the heat and keep the roof deck evenly cool to help prevent snow from melting on the roof.
  • Water-proofing/Water-proofing is laid across the roof before shingles are applied and protects against dams that form on the roof.

With existing roofs, waterproofing underlayment is only an option if you remove the existing shingles or are building a new addition. Either way, increasing the insulation R-value in the attic is always possible, and ventilation can usually be added to your attic quite easily.

An energy efficient roof minimizes problems with ice dams.  Contact a professional roofing contractor to do an in-home evaluation to diagnose the performance of your home and together decide what the best course of action is for your situation.

Why Does It Mean That A Roof Should Breathe?

April 27, 2010

Why is it said that a roof should breathe?   How can you determine if the roof is properly ventilated?

When roofing contractors say a roof should breathe, they are usually referring to the ventilation system beneath the roof deck.

Most shingle warranties require a lot of ventilation—as much as one square foot of net free ventilation area for each 150 square feet of floor space to be vented or one square foot per 300 square feet when both ridge and soffit ventilators are used.

An effective ventilation system will help:

• Reduce attic heat buildup

• Reduce attic moisture and condensation

• Prevent weather infiltration, i.e., drifting snow, wind-driven rain

• Prevent ice dam build-up (See  ice dam discussion)  Even if you feel you have had satisfactory ventilation performance with your old roof for as long as 20 years, it might be necessary to add ventilation with your new roof to meet the standards mentioned previously.

Why is it said that a roof should breathe?   How can you determine if the roof is properly ventilated?

When contractors say a roof should breathe, they are usually referring to the ventilation system beneath the roof deck.

Most shingle warranties require a lot of ventilation—as much as one square foot of net free ventilation area for each 150 square feet of floor space to be vented or one square foot per 300 square feet when both ridge and soffit ventilators are used.

An effective ventilation system will help:

• Reduce attic heat buildup

• Reduce attic moisture and condensation

• Prevent weather infiltration, i.e., drifting snow, wind-driven rain

• Prevent ice dam build-up (See the following question for ice dam discussion.)  Even if you feel you have had satisfactory ventilation performance with your old roof for as long as 20 years, it might be necessary to add ventilation with your new roof to meet the standards mentioned previously.

Is It Always Necessary To Tear Off Existing Shingles Before Reroofing?

April 20, 2010

Is it always necessary to tear off existing shingles before reroofing?  If they are torn off, who is responsible for the disposal of the old shingles?

There are two options available for re-roofing installations.  One would be to tear off the old roof before applying the new one (tear off).  The second would be to lay new shingles over the existing roof (lay over).  While the second choice is the less expensive of the two options, it is not necessarily always the best choice.

There are advantages to tearing off the old roof before installing a new one.  For example:

• If there are any defects in the roof deck, they will be revealed when the roof is torn off.

These defects should be repaired before applying the new roof.

• If condensation problems exist in the attic, they too will be revealed when the roof is torn off.

Properly designed attic ventilation can then be installed in order to help eliminate such problems.

• When the old roof is torn off, waterproofing shingle underlayment can be installed before applying the new roof.  This will help protect against leaks created by cyclical ice damage and wind-driven rain.

• Tearing off the old roof and starting with a clean deck before reroofing may result in a smoother finished roof system.

Although there is added cost to these advantages, each lessens the likelihood that the validity of the manufacturer’s shingle warranty will be impaired.  If the old roof is torn off, your contractor should be responsible for the cleanup and disposal of the old shingles, but make sure your contract states this clearly.

If you do plan to re-roof over existing shingles, first check if your local building codes limit the number of roof layers that can be applied to a residence in your area.  Your roofing contractor will know the pertinent code requirements.

Your Roof’s Ventilation System Could Be Costing You Money

March 11, 2010

Letting Moisture Out Of Your House Is Important Too!

Just as keeping moisture from coming into your home is important, letting moisture out of your home is equally important. You may not realize it, but your home houses a lot of moisture.  Air conditioners, humidity and moisture in the air are consistently rising and needs to escape through your home.  This is where attic and roof ventilation comes into play.  Moisture that accumulates in your home or on your roof must be properly ventilated.  Without proper ventilation, mold, mildew, and fungus will grow and wood will rot.

Your roof ventilation system is composed of two parts: intake and exhaust vents.  These vents allow air to flow in your roof and allow air to leave through the vents.  This is the most important aspect of keeping your home’s moisture level at a healthy balance.  If there is a problem with your ventilation system, your home is vulnerable to serious damage.

It is always best to hire a professional roofing contractor who can advise you on the best types of vents that are suitable for your home.  Just as there are many different types of roofs, there are many different types of vents that are best suited for each roof.  A roofing contractor will explain to you the different types of ventilation systems and help you choose the vents that are best for your needs.

You may need to hire a roofing contractor if you notice that you are not getting enough ventilation through the vents.  If you do not feel any ventilation at all, you may discover that your energy bills skyrocket and structural damage to your roof may occur as mold, mildew, and fungus will grow rapidly.  Without proper ventilation, moisture will continue to wreak havoc on your roof. If there is a problem with your ventilation system, you must have it repaired immediately by an experienced roofer.

The Proper Insulation and Ventilation For Your Home

March 9, 2010

Insulation and Ventilation For Your Home

Insulation and ventilation work together to keep your home comfortable.  Adequate ventilation creates a positive flow of air that allows a house to breathe and helps prevent moisture from damaging your attic and walls year-round.  Because warm air rises, vents are placed in the soffits or low on the rooftop to let fresh air in, and along the ridge of the roof, or in the gables to let the warm air escape.  Ventilation is especially needed in unused attics where insulation has been added to keep heat from leaking out of the rooms below in winter months.

Ventilation Recommendations:

1. Natural or static ventilation systems consist of simple vent or covered openings in your attic.  Many experts agree that externally baffled ridge vents combined with vented soffits are the most effective method for ventilating an attic.

2. Many codes require a ventilation area equal to at least one three-hundredth of the attic floor area. Ideally, 50% of the required ventilating area should be provided by vents located in the upper portion of your attic, while the remaining 50% should be provided by eave vents.  Baffles at the soffits are necessary to protect insulation from airflow due to wind.  Air movement through the material will reduce the effective thermal resistance.

Ventilation Systems: Protect your roof from premature deterioration by providing effective ventilation
Insulation: With the price of energy rising, insulation is one of the most important items for your home or building.

Choosing who installs it, is as critical as choosing the right products for your home.  Contact your local roofing professional to advise you on how to help increase the value of your home while keeping maintenance costs low.

Protecting Your Minnesota Home From Ice Dams

August 20, 2009

What Is An Ice Dam?

Ice dams are formed when heat from inside of a home escapes into the attic and warms the roof decking during the winter.  The heat, combined with the heat from the sun, can melt snow on the roof.  Melting snow on the upper roof and in the valleys runs down toward the eaves as water.  When it reaches the cold eaves and gutters it freezes.  This continuous thaw and re-freezing process creates an ice dam.  The result is water backing up under the roof shingles or behind fascia boards where It can soak through the roof decking or wall sheathing, causing tremendous damage to attics, ceilings, and walls.

Ice-Dam2Ice Dam Defense
There are 3 ways to defend against the damage ice dams cause.  All 3 work together.

  • Insulation/ Insulation keeps heat from escaping from your home’s living space into your attic.
  • Ventilation/ Ventilation removes the heat and keeps the roof deck evenly cool to help prevent snow from melting on the roof.
  • Water-proofing/Water-proofing is laid across the roof before shingles are applied and protects against dams that form on the roof.

With existing roofs, waterproofing underlayment is only an option if you remove the existing shingles or are building a new addition.  Either way, increasing the insulation R-value in the attic is always possible, and ventilation can usually be added to your attic quite easily.

An energy efficient roof minimizes problems with ice dams.  United Roofing & Remodeling can do an in-home evaluation to diagnose the performance of your home and together decide what the best course of action is for your situation.

Call us at 612-617-1717 for a free home inspection!