Posts Tagged ‘ventilation’

Attic Condensation & Ice Dam Leaks

February 10, 2011

Preventing Ice Dam Leaks

Attic condensation and ice damming are related. Both can be caused by warm, moist air leaving the house and entering the attic. Attics will be in good shape if there are no holes, air leaks, or bypasses from the house to the attic and there is sufficient insulation to keep house heat from escaping. If you can ensure good air sealing and insulation, the attic will remain cool and dry, as if it were outside. For example, it is rare to see moisture problems or ice damming on the roof of a detached garage or unheated barn.

Formation Of An Ice Dam

Where to look for leaks

  • around plumbing stacks or plumbing walls
  • chimneys through the attic
  • any light fixtures from the ceiling below
  • electric wiring
  • ducting for fans or heating systems
  • perimeter walls
  • partition walls
  • party walls
  • above pocket doors
  • above lowered ceilings
  • where the side of a cathedral ceiling meets an open attic
  • split level discontinuities
  • where additions meet an older section of the house
  • above rounded corners or staircases
  • balloon frame walls

Prevent Ice Dams With Ventilation

Attic Venting

If you have properly sealed the attic you should not need more attic ventilation. Attic ventilation is overrated. In winter, the cold outside air cannot hold much humidity or carry moisture away from the attic. In summer, attic temperatures are more affected by the sun and shingle color than by the amount of ventilation.

Ice Damming

Ice dams are the large mass of ice that collects on the lower edge of the roof or in the gutters. As more melting snow (or rain) runs down the roof, it meets this mass of ice and backs up, sometimes under the shingles and into the attic or the house.

Ice damming usually occurs with a significant depth of snow on the roof. If the attic temperature is above freezing, it warms the roof sheathing which melts the snow lying on the shingles. This water runs down the roof until it meets the roof overhang, which is not warmed by the attic and will be at the temperature of the surrounding air. If the air and the overhang are below freezing, then the water will freeze on the roof surface and start the ice dam.

The balance between removing ice and damaging the roof

Thick ice is hard to remove. You must decide if trying to remove it will cause more damage than leaving it on the roof. Tools, such as hammers, shovels, scrapers, chain saws, and devices such as shoes with ice spikes can damage roofing materials or the structure below. Chemical de-icers can discolor shingles, break down membranes and corrode flashings and drains. De-icers can also damage plants on the ground.

Has your roof been damaged by a winter storm and you’re now looking for a Minnesota roofing contractor to fix it?

If damage has occurred and ice must be removed, hiring professionals that use steamers is strongly recommended.

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!

Fundamentals Of Insulation And Ventilation For Your Home

August 18, 2009

I-VentilationHouse_2United Roofing & Remodeling Inc For All Your Roofing Needs

Insulation and Ventilation Fundamentals:
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.  United Roofing is a full service company for commercial and residential property owners in Minnesota.  We can help increase the value of your home while keeping maintenance costs low.

We help by making their homes energy-efficient, maintenance free and beautiful.  All of our products are top rated.  We like to help homeowners by providing ideas and educating them about the options that are available to improve their homes.  We offer a variety of services from our seasoned experts in the field to give you the best services available.

Now is the time to call a roofing contractor!