Here at Karoly, we get a lot of questions about the window installation process. Lots of people are curious about how we put in windows and what we’ll need to do in their homes. So, to answer these questions, we figured we’d put together a few articles about window installation, starting with an explanation of window bucks and the bucking process.
It’s our hope that you’ll find this blog helpful and informative so you can go into your next window installation with more knowledge and confidence!
What IS a Window Buck?
A window buck is a kind of ‘frame’ that goes into a window opening to provide a flat, stable, and rigid surface for the window that will be installed later. It also supports the window ‘fin’ on those windows that have them, giving the window an extra point to secure to and provides a flush plane for window cladding.
Window bucks are a great way to ensure that a window will seat properly within the window opening and can help ensure a smooth, long-lasting fit.
Even when a window opening is rough or slightly warped from the building frame settling, a well-placed window buck can be a huge help in securing your new windows.For this reason alone, bucking a window is a key step in both new construction and in window replacement.
What Are Window Bucks Made Of?
There are several types of material used in window bucking. Each type of buck has its own pros and cons for different installation jobs.
The three most commonly-used types of window bucks are wood, vinyl, and metal (typically aluminum or steel). In addition to these, composite window bucks are picking up in popularity, like ThermalBuck’s coated EPS (Expanded Polystyrene) bucks.
Wood Window Bucks
Widely available and easy to make and assemble on-site, wood window bucks are an ever-popular option for window installers who want something easy to work with (and relatively cheap).
However, wood bucking has a few issues that make it less than ideal for use in Florida homes, especially if the installer doesn’t take the time to mitigate them!
The biggest thing about wooden bucks is that they are far more susceptible to moisture damage than other forms of bucking. Wood can absorb and retain moisture, potentially encouraging mold growth and letting water into the home.
However, this risk can be mitigated by expert installers taking some basic precautions. Treating the wood and adding moisture-proofing material over it can help limit the risk of moisture intrusion.
Metal Window Bucks
Metal window bucks are, hands down, the toughest bucking material on the market. They’re a great fit for window openings that need extreme durability to withstand events like, say, hurricanes.
This makes metal bucking a popular choice for high-rise buildings. However, there are a few trade-offs when it comes to this durable window buck material.
First, a metal buck is expensive compared to other forms of bucking. Using metal bucks will drive up the overall cost of window installation compared to wood, vinyl, or most composite materials.
Second, metal is a lot more thermally conductive than wood, vinyl, and composite. Because of this, the installer will likely need to create “thermal breaks” in the window opening to prevent heat from the outdoors being transferred into your home. This adds more complexity to the installation process, and thus, cost.
If thermal breaks aren’t added, it could impair your new window’s energy efficiency.
Still, metal bucks are a great option if you don’t mind spending a bit more on your window and want it to last for as long as possible.
PVC/Vinyl Window Bucks
Polyvinylchloride, or PVC, window bucks are quickly becoming incredibly popular. Why? Because, PVC is inherently resistant to moisture and doesn’t conduct thermal energy as readily as metal does.
It’s like having some of the best characteristics of wood and metal bucking at once. However, it’s not quite as tough as metal. Aluminum has a tensile strength anywhere between 80 and 570 MPa (or between 11,603 to 82,671.5 psi), depending on the alloy according to AZO Materials. Meanwhile, PVC has a tensile strength around 51.7 MPa (converted from a tensile strength measurement of 7,500 psi according to iPolymer).
Still, it’s incredibly low-maintenance compared to both wood and metal bucking, making it a great fit for homeowners who don’t want to constantly be checking their bucking for signs of moisture intrusion or rusting.
Composite window bucks have similar benefits to PVC bucks, but use different formulations of materials and thus may have different performance characteristics. This makes it hard to assemble a more specific list of pros and cons for composite that truly differentiates it from PVC.
What Are Some Requirements for Window Bucking?
The Florida Building Code (FBC) outlines some key regulatory requirements for installing wood bucks and shims to help ensure that the final window meets its intended design pressure rating and lasts for as long as possible.
For example, the FBC prohibits the use of tapered bucks when securing the window with a frame clip.
When a buck (particularly a wooden one) is less than 1 ½” (38 mm) thick, the window assembly “shall be anchored through the jamb, or by jamb clip and and anchors shall be embedded directly into the masonry, concrete or other substantial substrate material.”
The Florida Building Code also specifies that “Unless otherwise tested, bucks shall extend beyond the interior face of the window or door frame such that the full support of the frame is provided.”
When the buck is thicker than 1 ½”, the window should be “anchored through the jamb, or by jamb clip, or through the flange to the secured [buck].”
Window Bucking vs Shimming: What’s the Difference?
Shimming is an alternative to full window bucking, wherein window shims are used to level out a window being installed to make up for any irregularities in the window opening.
The main difference between the two processes is that bucking creates a secure opening to anchor the window frame to, while shimming is used to ‘fine-tune’ the way the window sits in the window opening.
Shims are often put into the window opening after the window is put in to help level the window and fill in minor gaps to enhance stability. Meanwhile, window bucks are put in before the window is installed in the opening.
In other words, window bucking is a structural process meant while shimming is a positional one.
Get Expertly-Installed Windows!
Are you looking for new windows for your home? Reach out to Karoly Windows to get expertly-installed windows to best suit your home’s needs.
With our expert installation service, you know that you’re getting great windows that will last you for decades to come.
Reach out to Karoly today to schedule an in-home window installation consultation where one of our experts will walk you through your window needs and options before giving you the most reliable quote for service in the industry!
