Hot-Cold Flexing Can Curl Composition Roof
QUESTION: The composition shingles on my roof are curling up after only four years. They were installed over an existing composition roof. Is there anything that will correct it? Why is this happening?
ANSWER: If your roofing material is heated, it expands; if it cools, it contracts. Some expansion and contraction is to be expected, and the roofing material is intended to handle it.
But if too much heat is applied over too long a time--and if one side of the roofing becomes relatively cooler--the hotter side will expand more than the cooler side. The different rates of expansion and contraction, combined with the physical deterioration of the hot side from flexing, will cause the roofing material to curl up over time.
This problem is aggravated when new roofing is applied over old, as the old roofing helps store heat into the night, resulting in increased temperature differences between the top side and bottom side of the material.
Curling and degradation can sometimes be slowed by adequate ventilation. If the attic or under roof space cannot dispel heat, then temperatures may rise in the roofing materials at a more rapid rate than in a properly vented attic. Older attics were designed with about a square foot of vent space for every 300 square feet of attic floor. With additional insulation added to many attics, this level of ventilation is inadequate.
Currently, the Uniform Building Code requires twice that much ventilation--one square foot of vent space for every 150 feet of attic floor. Vent space is rated in the code by net free area. Net free area is marked on commercially manufactured vents and is calculated to indicate how much air actually moves through the vent.
You may need to have your ventilation system upgraded to prevent further damage to your roof. For this, contact a good insulation installer or general contractor. There are several venting systems on the market the contractor may recommend. These include soffit vents, gable vents, static vents and ridge vents.
Soffit vents are installed under the eves of the house and are designed to allow cool air to enter the home. It is important the soffit vents be designed to exclude birds from your attic space. Better soffit vents will also keep out insects. Mounted low in the roofing structure, soffits are often subject to plugging by insulation that may fall or be knocked into them. Insulation dams may need to be installed by your contractor.
Gable, static and ridge vents are designed to exhaust overheated air from the attic. They also should be reasonably pest proof. The amount of intake and exhaust venting installed should be balanced, that is, the net free vent of intake and exhaust should be the same.
Every attempt should be made to maximize the vertical distance between the intake and exhaust vents. Maximizing these distances will enhance the chimney effect and produce a cooler attic. Your contractor will help you choose between these types of venting systems.
While improved ventilation will slow the rate of degradation, it will not reverse it. If the roof is bad or damaged, it will need replacing. If you decide to replace your damaged roof, consider the alternatives. Some of them are composition or asphalt roofing, wood shakes, tile, metal, slate.
Water Heater Set Too High Can Be Hazard
Q: I just moved into a new home--my first. The hot water delivered at the tap seems too hot. When I measured it, the temperature was 142 degrees Fahrenheit. Isn’t this too hot? If so, what should the temperature setting be?
A: Yes, this is too hot. You should lower the thermostat on your water heater to 120 degrees or below. Some people find a temperature setting below 120 degrees acceptable. Most people shower at a temperature of 105 degrees.
Lower temperatures will also reduce the risk of scalding. Water above 120 degrees can cause serious burns and represents a hazard in your home. Not only will lower temperatures reduce the risk of scalding, but they will also reduce your hot water heating costs. In your case, you could save as much as 15% of your current water heating costs by lowering your hot water temperature to 120 degrees.
