The worst thing you can do is nail vinyl tight. To ensure that the panel is free to move, the nailheads shouldn’t contact the hem, but should be left about 1/32 inch loose. But, if nailed too loosely the panels will rattle noisily whenever the wind blows.
Vinyl’s tendency to move means that panels can’t be butted tight to trim, either. Quality-conscious installers leave about 1/4 inch of clearance (3/8 inch in temperatures below 40°F) at the end of panel courses; at corners and door and window openings a trim piece called J-channel covers and conceals the resulting gap. Other proprietary trim pieces, made by manufacturers to fit their own brand of siding, include soffits, rake boards, and crown moldings. All help to improve the appearance of an installation, giving it a more custom look.
In addition to J-channels, one characteristic that distinguishes vinyl from other siding is its overlaps. While lengths of wood (or cement) siding meet in an unobtrusive butt, vinyl panels must be overlapped by about 1 inch wherever they meet, resulting in telltale vertical lines. The thicker the vinyl, the more obvious the overlap. Compounding the problem, most vinyl siding panels are molded to represent double or even triple widths of clapboards. This slashes installation time dramatically, but it also makes panel overlaps even more visible. A good installer will orient overlaps away from dominant views, for example, by running the siding from a back corner to a front corner. On the front of the house, panels should be installed so seams are least visible to someone approaching the front door. Another alternative that is becoming more common is to install a vertical H-channel to receive the siding eliminating the need for laps all together..
Contrary to what many people expect, vinyl is actually less likely than wood to trap moisture. There are tiny weep holes in the butts of the panels. And because it’s hung loosely, air can move behind it.” Just make sure your siding contractor first installs flashing and either housewrap or builder’s felt, just as he would under wood siding.
Every quality vinyl siding job starts with the contractor. Dont hesitate to ask potential installers for their certifications — most of the large manufacturers certify installers in proper installation techniques — and for the names of satisfied customers. Also check complaint lists established with local and state business associations, as well as with state contractor licensing boards.
Proper installation is necessary for optimal window performance, to ensure an airtight fit and avoid water leakage. Always follow manufacturers installation guidelines and use trained professionals for window installation.
Why Quality Window Installation Is So Important
Quite simply, windows are only as good as their installation. Proper installation will:
- Protect from water damage. Windows should form a continuous water barrier where they meet the wall. With improper installation, water may penetrate and cause damage—often unseen— in the wall.
- Limit air leakage. Windows must complement the wall’s air barrier. Even tiny cracks around the window frame can lead to substantial heat loss unless properly sealed.
- Prevent condensation. Windows must complement the wall’s vapor barrier to prevent water vapor from passing around a window frame. If vapor condenses on cold surfaces between the frame and the wall, rot or other damage may follow.
Due to these potential issues, windows should be installed by skilled and experienced individuals.
Finding Quality Installers
The first place to inquire about quality installers is the manufacturer or the replacement window company from whom you are purchasing the windows. You usually purchase windows from a window company that includes the installation with the sale of the window. You want to make sure the Installers are professional and experienced. They are usually Sub-contractors that window installation is all they do. Be wary of an employee installer, service technician are sometimes tasked with installing windows. It’s OK to that the company you just hired to install your windows uses sub-contractors. They are the professionals. That’s all they do day-in and day-out… Just as long as they are properly insured and company you hired guarantees the sub-contractors work. Don’t get stuck in the middle.
There are standards for proper window installation, and installers are well advised to follow these along with the manufacturer’s product-specific installation requirements. The most prominent of these standards is ASTM Standard E 2112. Trained installers are likely to be familiar with this standard. Window manufacturers may have training and certification programs for installers of their own products. Installers may also be certified by nationwide programs such as:
- InstallationMasters™: includes a directory of certified installers in the United States.
- WindowWise National Certification Program: includes a directory of certified installers in Canada.
Some Installation Basics
- Always follow manufacturer’s installation guidelines and specifications.
- Install level, plumb, and square.
- Install water tight: water must be prevented from penetrating behind the water control system of the wall. Different techniques apply to different water control systems:
- Surface barrier system (masonry, concrete or brick with no cavities): the window frame must be carefully joined with the surface barrier because no water must penetrate this barrier;
- Drainage membrane system (house wrap or building paper behind exterior cladding material such as siding, brick veneer, or stucco): the window must be installed so that any water that gets behind the cladding is drained down and out over the drainage membrane.
- Allow movement and thermal expansion (¼” to ½ tolerance around the frame)
- Seal it up: Maintain the integrity of any air barrier and vapor retarder used in the wall system and seal all gaps around the window frame with caulk. Insulate all voids with foam or batt, but only use low-expansion foam to avoid pressure that could distort the window frame.
Independently Tested and Certified Energy Performance
The energy performance of all ENERGY STAR qualified windows, doors, and skylights must be independently tested and certified according to test procedures established by the National Fenestration Rating Council (NFRC).
NFRC is a third-party non-profit organization that sponsors certified rating and labeling to help consumers compare the performance of windows, doors, and skylights. NFRC does not distinguish between “good” and “bad” windows, set minimum performance standards, or mandate performance levels. This is where ENERGY STAR comes in. ENERGY STAR enables consumers to easily identify NFRC-certified products with superior energy performance.
The NFRC label can be found on all ENERGY STAR qualified windows, doors, and skylights and provides performance ratings in five categories:
- U-Factor measures the rate of heat transfer and tells you how well the window insulates. U-factor values generally range from 0.25 to 1.25 and are measured in Btu/h·ft²·°F. The lower the U-factor, the better the window insulates.
- Solar Heat Gain Coefficient (SHGC) measures the fraction of solar energy transmitted and tells you how well the product blocks heat caused by sunlight. SHGC is measured on a scale of 0 to 1; values typically range from 0.25 to 0.80. The lower the SHGC, the less solar heat the window transmits.
- Visible Transmittance (VT) measures the amount of light the window lets through. VT is measured on a scale of 0 to 1; values generally range from 0.20 to 0.80. The higher the VT, the more light you see.
- Air Leakage (AL) measures the rate at which air passes through joints in the window. AL is measured in cubic feet of air passing through one square foot of window area per minute. The lower the AL value, the less air leakage. Most industry standards and building codes require an AL of 0.3 cf·m/ft².
- Condensation Resistance measures how well the window resists water build-up. Condensation Resistance is scored on a scale from 0 to 100. The higher the condensation resistance factor, the less build-up the window allows.
ENERGY STAR qualification is based on U-factor and SHGC ratings only.