What Do Structural, or Design Pressure, Ratings Mean?

What is Design Pressure, and how does it impact the windows or doors you are considering for your home?

Let’s start with the definition of Design Pressure. According to AAMA (American Architectural Manufacturers Association), WDMA (Window and Door Manufacturers Association), and the NAFS (North American Fenestration Standard), Design Pressure (DP) is a rating that identifies the load – induced by wind and/or static snow – that a product is rated to withstand in its end-use application. So basically, DP is a performance specification for how strong a window is, expressed in how many pounds per square foot (psf) of pressure the window can withstand. This specification can fluctuate based on several factors, such as geographic location, the height of the building, the location of the window in relationship to the building, etc. All of these factors are used to calculate what the Design Pressure (DP) is for a specific window or door.

Image of in house testing for design pressure.

In house testing of a Soft-Lite window for design pressure.

During testing, a window or door is attached to a wooden frame and clamped to a specially designed wall. Air pressure is gradually reduced on the inside of the window, which increases the pressure on the outside until the window fails (breaks beyond repair). The test pressure must reach 1.5 times the design pressure for 10 seconds without the window suffering permanent damage. In other words, a window with a DP of 30 would have to withstand 45 psf. The instant the window fails, the psf is recorded and is used for the calculation. Laboratories will then issue labels that indicate the DP for the window or door – labels used by the Window and Door Manufacturers Association (WDMA), the American Architectural Manufacturers Association (AAMA) and other organizations.

The Design Pressure that you need for the windows in your home will vary. For example, in the State of Florida, the DP required for a window can range anywhere from DP 35 (if you are in the center of the state) to DP 60 (if you are located along the coast). Your local building department can assist you in determining what DP rating you need, based on the location and design of your home. Most municipalities have maps or easy-to-read charts that clearly explain the requirements you will need to meet in order to effectively protect your home with the proper Design Pressure. You can then verify that the replacement windows you are considering meets the required DP rating by checking the sticker on the window and matching it to the engineering drawings for that window.

It’s also important to have a licensed and insured company install your windows and doors. Companies that are reputable will have no problem helping you verify the Design Pressure for your windows and doors. They will assist you with gathering all the information you need to make your decision. If they baulk at your request, you may want to reconsider purchasing from that company.

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What are Hurricane Windows or Impact Windows?

Hurricane Windows or Impact Windows are a product that have become prevalent over the past 25 years. Born in the aftermath of Hurricane Andrew, municipalities led by Miami-Dade in South Florida, saw the need for stronger window systems. Studies showed that if you were able to keep the exterior envelope intake during the storms (hurricanes), you have a greater chance of keeping the roof on the building in place and lessen the damage that could be created. To do this, the window industry didn’t have to go far to find a solution.

Soft-Lite Armor Max Plus Hurricane Windows

Soft-Lite Armor Max Plus Hurricane Windows

For years, the automotive industry had been using laminated glass for the windows in vehicles. Laminated glass is a type of safety glass that holds together when impacted with an object. In the event of breaking, it is held in place by an interlayer, typically of polyvinyl butyral (PVB) or ethylene-vinyl acetate (EVA), between its two or more layers of glass. The interlayer keeps the layers of glass bonded even when broken, and its high strength prevents the glass from breaking up into large sharp pieces. This produces a characteristic “spider web” cracking pattern when the impact is not enough to completely pierce the glass. Unlike the automotive industry, the window industry is trying reduce the shards of glass from flying, as well keep the window intact and not fail or “blow out” of the building.

Depending on the location, size of the panels, and design pressures, the interlayer used in the laminate may be of different thicknesses or types. For example, a .060-in PVB interlayer is a typical thickness and type of interlayer for Level C glazed areas. Other stiffer, more structural, interlayers, in thicknesses of .090, provide better resistance to tearing when subjected to Level D impacts at higher design pressures. The strength and other properties of laminated glass can be tailored to meet specific needs. The driving force behind the type of protection you are “required” to have is based on the geographic location of your home. These requirements are based on the local municipality building codes.

Soft-Lite Hurricane & Impact Windows Testing

Soft-Lite Hurricane & Impact Windows Testing

The State of Florida has been the driving force behind the development and implementation of building codes regarding hurricanes. After Andrew, Miami-Dade led the way with stricter codes for windows. In 2001, the rest of the state adopted the 2001 Florida Building Code standards. Since that time, several versions have come about. Florida is currently under the 2014 FBC standards. Taking Florida’s lead, other states in hurricane-affected areas began looking at their standards. Shortly after Florida rolled out its codes, states like Alabama, Mississippi, and Louisiana adopted the International Building Code or IBC. States like South Carolina and North Carolina followed as well. Texas developed the Texas Department of Insurance (TDI) for its protocols. All of these standards are designed to give a uniform standard to test and grade impact windows for safety and reliability to withstand hurricane-force winds and flying debris. But the term hurricane windows is a little misleading.

The benefits of these windows exceeds just those homes located in areas prone to hurricanes. Impact windows increase safety, noise reduction, and intrusion resistance. Burglars run once they try to smash one of these windows and realize that it is not going anywhere. Parents are not nervous when their small children play around a large picture window. And homeowners marvel just how much of the outside world’s noise no longer enters into the home. Impact windows are a great way to help reduce damage from severe thunderstorms that can have damaging wind. These types of storms can hit anywhere at any time. There is no replacing the peace of mind that a homeowner with impact windows goes to bed with.

As building designs and styles continue to evolve, many new features will come and go in the market place. One product that’s here to stay is impact windows. Their ability to add safety to any home provides you with more than just a return on investment. It provides you with the assurance that you have taken measures to protect your family and property from whatever life throws at you. For these reason, impact windows are an investment that all homeowners should evaluate.

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What is a bay or a bow window?

If you are asking the questions “What is a bay or a bow window, and when should I choose one for my home?”, you may receive several different answers. Let’s start with just a basic definition of each style.

Soft-Lite Bay window with copper roof and decorative glass

Soft-Lite Bay window with copper roof and decorative glass

Bay: A bay window is made up of three windows in a wood frame that’s projecting outward from the main walls of a building and forming a bay in a room. Bay window is a generic term for all protruding window constructions, regardless of height. The most common inside angles are 15, 30 and 45 degrees. Traditionally, the center window is larger than the end units.

Soft-Lite Bow Window in Light Oak

Soft-Lite Bow Window in Light Oak

Bow: A bow window, or compass window, is an equally curved bay window with three to six openings. Bow windows are designed to create space by projecting beyond the exterior wall of a building, and typically incorporate casement windows, which join together to form an equal arch or radius of 10 and 15 degrees.

Now that you know the difference between the two styles, the question that most often gets asked is where will one of these window fit? The simple answer is in any home with an opening at least 48 1/2” wide. Typically a bay or a bow would replace a series of windows or an existing bay or bow in the home. Most are in the front of the house and are the focal point of the house, offering a distinctive beauty that other window styles don’t. A bay or a bow can totally change the exterior look of a house and give it some real curb appeal. From the inside, it makes the existing room look bigger.

By choosing a bay or bow window for your home, you allow yourself the opportunity not only to be different, but also, if done correctly, create a new space for your home that is as comfortable as it is beautiful!

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Picture Windows: History of the first window

Picture windows, or fixed windows, were literally a hole in the wall, centuries ago, to allow light and air into a home. The holes were covered with animal hide, cloth or wood. It wasn’t until much later that windows were built to protect the occupants from the outside elements. When flattened pieces of translucent animal horn, thin slices of marble, or pieces of glass were placed into frames of iron, wood or lead, the first picture window was created.

Antique Roman picture window glass from Straubing Bavaria Germany.

Antique Roman picture window glass from Straubing Bavaria Germany. Photo by Bullenwächter

Romans were the first known to use glass for windows. In 100 AD, in Alexandria, cast glass windows started to appear. The glass was nothing more than blown glass jars flattened into sheets, making the glass difficult to see through. Techniques were developed to shear one side of the flattened blown glass to produce a thinner more rectangular shape. The blown glass later led to the creation of the stained glass window.

Around 532 AD, early Christian and Byzantine churches used pierced marble frames, enclosing panes of glass. The Islamic mosque builders took it a step further by using thin marble to create pattern designs and allowing color to be used. It wasn’t until the 12th and 13th centuries in western and northern Europe that the stained glass practice reached full expansion. Using strips of lead, called cames, European glaziers shaped the lead into patterns to separate the different colors, creating the elaborate stained glass windows seen in churches.
It would be over a millennium before window glass became transparent enough to see through, like it is today — allowing any homeowner to have a beautiful, decorative glass picture window to view outside and let light into their home.

Today picture windows:

  • Come in all shapes and sizes, from triangles to octagons, from floor to ceiling.
Picture Window Specialty Shapes

Picture Window Specialty Shapes

  • Can be paired with other window styles, such as a double-hung.
  • Are often used in a bay window
  • Are the most energy-efficient window, because they are inoperable, keeping air infiltration to a minimum and making many models ENERGY STAR certified
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What is a casement or awning window?

Casement and Awning Windows

Casement and awning windows in Light Oak Woodgrain

When deciding what style of window to put in your home, let the existing dimensional shape of the old window opening guide you to the best style available for you. In the 80s and 90s, many casement and awning windows were installed by builders; unfortunately, casement windows usually have to be replaced with casements.

There can be some drawbacks with older casements, however most of those drawbacks have been fixed by innovation. Premium vinyl casements windows and awning windows, such as those manufactured by Soft-Lite, are superior for several reasons:

First, it maximizes air flow and visibility because it swings outward to grab air passing by and brings it into the home.

Second, the casement dimensionally meets egress with the smallest size available by law. When egress is a must and you are limited by size, casements are your best option.

Third, unlike all the other window styles, casement and awning windows have their screens on the inside, which makes for easier removal.

Fourth, these are the only style windows that actually have a lever to tighten or compress the moving sash with Q-lon weather stripping – making it tighter than any other window. Consequently, the casement/awning is the most airtight of all styles of operating windows, which maximizes the warmth in the rooms to keep you comfortable year round.

One thing to be aware if is that most casements and awnings have ugly clips to hold their screen in place – but Soft-Lite is unique. With Soft-lite casement and awning windows, the unique pressure screen fits snuggly in the frame and stays in place. The rugged extruded screen frame is durable, plus color coordinated to match all six interior color options. You can also choose from 16 different glass options to make sure these windows meet or exceed the new ENERGY STAR requirements in your area.

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What is a double-hung window, and is it right for your home?

Soft-Lite Pro Double-Hung Window in Soft-White

Soft-Lite Pro Double-Hung Window in Soft-White

Double-hung windows: history.

A double-hung window is one of the most popular replacement window styles chosen by homeowners. Some of the oldest sash windows are dated as far back as 1670 in England. Double hungs have the Georgian and Victorian-style house look — the style most people think about with replacement windows. The term “hung sash window” is most common in the United States, referring to “double-hung windows.”

Double-hung windows: Facts

  • The double hung has two operating sashes — movable parts that slide vertically up and down, held in place by a window frame.
  • The sashes tiltin for easy cleaning.
  • Double-hung windows offer the ability to open both sashes, allowing good air flow.
  • Double hungs are usually made of wood, vinyl, aluminum or and composite. The most energy-efficient and maintenance-free choices are vinyl windows and composite windows.
  • Some of the most important considerations that add value to double-hung windows are: if they incorporate Low–E glass and achieve low U-value ratings; whether they are ENERGY STAR certified (energystar.gov); what type of air infiltration and Design Pressure (DP) ratings they achieve; and whether they are Gold Labeled by AAMA (www.aamanet.org).
  • Double-strength glass, triple-pane glass, and laminated glass are all features that will help with sound transmission – keeping exterior noises out of your home.
  • Additional features to look for are: high-performance glass systems with Super Spacer or Stainless Steel Intercept; reinforced meeting rails; air and water barriers built into the sill design; and sleek-looking locks. Double-hung windows also come with half and full screen options.
  • Double hungs are available for both replacement window and new construction window applications — with nailing fins and J-channel for siding, brick and stone installations.
  • Impact windows are available in the double hung window style for areas that require hurricane windows.
  • Overall, vinyl double-hung windows have the ability to retain their beauty, continue to offer thermal efficiency benefits, and last generations with minimal maintenance.


Click here for more information and specific details about double-hung windows.

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Why are Vinyl Windows Considered “The Best” Option?

Cleaning of woodgrain vinyl window

Lady cleaning her easy maintenance interior woodgrain vinyl windows.

When considering new windows for your home, there are many things to consider. How important is cost to you? Is more energy efficiency important? Do you currently have leaky/drafty windows that you want replaced? Are you looking to have added beauty/looks? Will they be easy to maintain and clean? What type of warranty are you being offered? Is safety and security a concern? Are you concerned about health and mold, rot, and creating a healthier living environment?

For the purposes of this blog, I will be focusing on consumers who would consider vinyl their best option. Consumers who would consider a high-end vinyl window would be the consumers who are looking for more energy efficiency and to drastically lower drafts into the home, and for products that are easy to maintain and last a lifetime. Premium vinyl windows offer all this, as well as creating healthier living environments and adding security to your home. With newer machinery and technology, higher-end vinyl windows now offer stunning new looks and beauty that were never before possible. Vinyl windows are commonly white in color, but with woodgrain interior color options and many companies offering a PVC exterior bond (painted) option, more colors have become available to satisfy any consumer.

Wood windows offer great beauty and natural looks, but are many times very expensive in cost, not as energy efficient as high-end vinyl, leak more air, and are not maintenance free. Wood windows can rot and mold over time as well. Fiberglass windows offer some impressive thermal ratings and are often portrayed as being stronger than vinyl. Fiberglass windows have strength linearly, but are generally weak in the corners where they cannot be welded. Many fiberglass windows are not as strong structurally as higher-end vinyl windows, in fact, and can cost significantly more.

When choosing new windows, it’s also important to consider whether you are looking for your NEXT window purchase or LAST window purchase for that home. Many windows offer 10, 20, or even 30 year warranties; many of the higher-end vinyl windows offer a 50 year to lifetime warranty.

When investing in your home, it’s important to research and understand what option is best for you and your family. If many of the questions above relate to you, consider high-end vinyl windows as the best option for you, your family and your home.


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What Characteristics Should You Look for in Replacement Windows?

Puzzled People’s Perfect Product Picking Process

Young couple getting information on replacement windows.

Young couple getting information on replacement windows.

While alliteration can be fun, I like it because it can also be memorable. With that in mind, please consider my six P’s of the product picking process.

Provider: How do you feel about the replacement window company or remodeling company you are considering? Are they experienced? Do they have outstanding references? Who will you be dealing with, and are you confident that they will do what they say?

Producer: Who is the manufacturer? Are they highly regarded? Are they a leader in their industry? What do third-party sources have to say?

Priorities: What is most important to you regarding your new replacement windows? Is it beauty, or perhaps durability? What about the warranty? Is ease of operation important? How about energy efficiency? Whatever your priorities are, make sure you consider those up front and weigh them accordingly. Only then can you make a good decision. I have seen countless homeowners get hung up on the tiniest details, which will be meaningless once the job is complete. For instance, I know of a person who purchased a lesser-performing window because of a molding detail that will never be seen from six feet away. That window, while beautiful, leaks air like crazy–and the buyer feels cheated. Know what is important to you, and let that be your guide.

Product: Choose a product that meets your needs and satisfies your priorities. Most manufacturers make a wide range of replacement window products that fit most any budget and performance criteria. Although I am a product guy, I mention this because if you work hard on the first three P’s, it will go a long way in helping you complete this step. There are options galore, and having a remodeling company and manufacturer that you trust and priorities that are thought out in advance make choosing the right replacement window much easier.

Performance: Performance could be the most important thing to consider. Every time I have asked a consumer to tell me their three “must haves” for their new windows, energy efficiency is never off the list. The other two items vary, but efficiency and performance are always in the top three. So consider the following three performance criteria: The NFRC test results and whether the window is ENERGY STAR certified; the structural rating, or DP rating; and last–but certainly not least–the air rating. All three of these are important, but most window salesmen don’t bring up the air rating, and that’s unfortunate because the NFRC rating–which most folks use to determine energy efficiency–does not take into account air leakage. So while a particular window may test great without wind, how happy would you be if–when the wind blows–so did your curtains?

Price: You may question why I put price last. It’s not because it isn’t important, it is. But it also needs to be considered in its proper context. Because in reality there is no right price for the wrong product, performance, provider or producer. I have met more than a few folks who felt the need to replace their replacement windows and trust me, that’s the most expensive path to take–especially if you’re on a budget…and aren’t we all on a budget?

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Why Should Homeowners Purchase Vinyl Replacement Windows?

Soft-Lite Vinyl Replacement Windows with Light Oak Woodgrain Laminate

Soft-Lite Vinyl Replacement Windows with Light Oak Woodgrain Laminate

There are many different types of replacement windows on the market today. There are fiberglass windows, aluminum replacement windows, wood replacement windows, composite-type windows, and many styles of vinyl replacement windows. There are pros and cons with each of these different materials.

For the purposes of this blog article, I am going to focus on vinyl replacement windows. There are all types of vinyl replacement windows on the market today, from inexpensive vinyl windows to high- quality vinyl windows. As with any product, you really do get what you pay for.

There have been some significant advancements with vinyl replacement windows. Today, if you look hard enough, there are manufacturers out there that can provide you with any exterior color you can imagine. On top of this, there are interior woodgrain laminates that look and feel like real wood. The benefit is you eliminate the need to paint and stain.

Also, vinyl replacement windows can be manufactured to fit the existing opening of your home. We are long past the days that you need to make your home fit the window – at least with vinyl windows. There are companies that still use standard sizes, and this means some additional and costly renovation to your home. But with vinyl replacement windows, companies can manufacture down to 1/16th of an inch so the windows will fit your home’s opening exactly – and eliminate the extra installation/labor costs.

Energy efficiency has long been a reason for replacing your existing windows. Today, vinyl replacement windows can give you overall window U-values as low as .14 or .15, depending on the type of window. Vinyl windows have also been on the forefront of innovation, whether it be high-performance glass, colors, mini-blinds or glass that shades with the brightness and heat of the sun.

Vinyl replacement window manufacturers have been able to adapt faster to newer technology and be more nimble. Vinyl windows offer great standard features with top-notch warranties and, as I mentioned, are more aesthetic and offer a variety of energy options.

So if you are looking to replace your windows, research the vinyl replacement window companies out there. And remember, when you are investing in your home, you want to invest in high-quality and high-value products.

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Soft-Lite Offers Impact Windows, Doors and Tips for Hurricane Season

June marks the official beginning of hurricane season, which runs through November. Although Dr. William Gray of Colorado State University has forecasted that this Atlantic hurricane season will be one of the least active since the 1950s, hurricane protection and preparedness are still important to residents in any hurricane-prone region — and this is no longer just a concern in Florida.

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