Drywall 101: Prevent Drywall Cracks

Drywall is widely used in nearly every type of building because it’s easy to install, low cost and durable — its price-to-quality and price-to-safety ratios are hard to beat. But drywall only saves time and money if it’s installed well. Mistakes or lack of foresight can lead to costly repairs. Taking steps to prevent drywall cracks reduces risks to your bottom line and helps avoid unhappy clients calling you back weeks later.

Even more costly are the indirect expenses of cracked finishes — losing customers or damaging your reputation — making it harder to get future jobs. For example, drywall installed in summer may crack due to winter environmental fluctuations. A client who sees cracking months later may assume the work was poor and call someone else for repairs, costing you repeat business and referrals.

Cracks can form for many reasons. Depending on location, they may be caused by building movement, environmental factors or installer oversight. In the following sections, we’ll explain cracking based on location, explore causes and outline solutions to prevent drywall cracks before they ever start!

Prevent Drywall Cracks on Walls & Ceilings

EXPANSION

Both walls and ceilings can suffer from differential expansion in response to environmental concerns, expanding and contracting over time. As a result, in long runs of drywall, 15-30 feet or longer, it is important to leave a gap between sheets to allow them move freely to accommodate fluctuations in the ambient environment and prevent drywall cracks.

However, these gaps must be bridged by expansion joints that control the movement and create a unified surface. Without these expansion joints, the pressure of movement will eventually cause the joints between drywall boards to crack any tape and/or paint between them, as seen in the above image.

Solution: The best expansion joints to prevent drywall cracks are made of vinyl — the 093V Expansion Joint and its less noticeable counterpart, Hideaway Expansion Joint — which resists denting and remains permanently flexible, limiting wear-and-tear and the need for repairs. As we saw with deflection beads, we’ve also got a solution that allows you to meet the needs of an expansion joint while simultaneously meeting building codes for cutting off fire and smoke, all in a single easy-to-use solution: the Fire Rated 093V Expansion Joint, also known as 093X-V.

Discover more: When and Where to Use Vinyl Expansion Beads

AGAINST WINDOWS & OTHER ADJOINING SUBSTRATES

Adding to the complexity of solving problems related to building movement — especially expansion — is the fact that materials expand and contract at every single edge, including internal ones. That means that there is also the potential for expansion (and cracking!) at any place where different materials meet: doors, windows and wherever drywall meets concrete. The risk is especially high around windows, where the sometimes-extreme temperature differences on either side of the glass can cause an abundance of movement.

Solution: For these cases, you should consider products that not only seal against the environment, but offer the flexibility required to keep doors, windows, etc., functioning correctly and with no unsightly cracking around the edges. Where the drywall meets a window, as seen in the above image, the flexible apex gasket on our Super Seal Tear Away L Bead makes it the perfect solution to create a clean finished edge that offers protection for the drywall as well as a perfect, permanent seal, even where the adjoining substrate may be jagged or warped in places.

Discover more: What Is Super Seal L Bead?

BUTT JOINTS

Butt joints, where two pieces of drywall meet, are areas easily susceptible to cracking. It's ridiculously easy for less experienced drywallers to cause these kinds of cracks, but even true pros are no strangers to problems arising here.

Solution: To minimize cracking, do your best to place your butt joint where they are the least exposed to movement. For instance, notch your drywall around doors and windows instead of breaking drywall at these movement-prone areas. Next, leave a 1/8" gap between your boards — do not fit them tight against each other. This 1/8" gap give the boards room to move, so they won’t be as likely tear the tape or break the mud.

Limiting the amount of mud needed to feather the butt joint also reduces the likelihood of cracking. Cracking often occurs when the mud on the surface dries faster than the mud underneath. Buttboard is a product that creates an easy-to-fill recess, similar to a factory edge. While it may look like a standard piece of OSB, the board is cut with edges that taper off toward the middle, which allows the board to pull in the drywall edges. This recess requires less mud to fill than feathering a traditional butt joint that breaks on a stud, which often forms a hump that must be feathered, costing you significantly more mud and more time.

Discover more: What Is Buttboard and Why Should I Use It?

Prevent Drywall Cracks on Corners

TRAFFIC DAMAGE

While it may seem obvious, it's worth mentioning that one of the leading causes of cracked drywall, especially in commercial and multi-family environments, comes from natural wear-and-tear. As clients come and go or tenants move in with all their possessions, it is easy for them to bump into a corner and leave it cracked or dented.

Solution: Traditional metal corner beads offer some protection against these kinds of impacts because they offer a fair amount of tensile strength. However, the downside of metal beads is that once deformed, they do not spring back, so any dents or damage will be permanent. Alternatively, vinyl corner beads offer a higher degree of resistance to damage, with a flexibility that allows them to bounce back. This reduces the need for repairs, as vinyl can deform temporarily in response to impact and then return to its original shape. Nine times out of 10, if repair is required, a simple mud patch will have it looking as good as new.

Discover more: The Ultimate Guide to Soft Profile Corner Beads

Prevent Drywall Cracks Running Along Ceilings

VAULTS & OFF-ANGLES

Off-angle inside corners, like the kinds you'd find on vaulted and cathedral-style ceilings, can crack when lumber shrinks on both sides of the peak, adding stress to the inside peak. Cracking can also result from improper application of joint compound in an inside corner angle. Meanwhile, you can simply paper tape off-angles, but off-angles are prone to poor framing and hanging, and cracks should be expected eventually.

Solution: You’ll need a highly malleable solution that can flex, expand and contract along any inside corner, no matter the angle. You’ve got a lot of options here, but your best bet in most situations would be our versatile Magic Corner solution, which offers a flexible center channel, allowing for installation at any angle and controlled movement up to 3/8".

A vinyl solution like Magic Corner also prevents you from having to worry about paper scuffing or blistering, but if you’re a fan of paper-covered solutions in these areas like these, you have got to try Trim-Tex's Fast Edge® Roll, a hybrid paper-vinyl solution that pro drywall finishers love to use in areas like these.

Discover more: The Ultimate Guide to Off-Angle Inside Corners

TRUSS UPLIFT

Many new and recently built structures use trusses, which are manufactured assemblies that transfer load to the outside walls, allowing an open interior with few, if any, load-bearing interior walls. While they are a great solution for modern design and often cheaper than stick-built roof framing, trusses are subject to a seasonal problem called uplift.

Truss uplift is where the bottom cord of the truss is subjected to significantly different environmental conditions (moisture/temperature) than the rest of the truss. When this happens, usually during the winter months, the bottom chords, buried in heavy insulation, stay dry and contract, while the rest of the truss assembly does not. In fact, the upper part of the truss may expand as it is exposed to high humidity. This causes an upward expansion that pulls the drywall up with it, causing cracking at the interior ceiling corners.

Solution: Install a backing angle designed to minimize inside corner movement and thus prevent truss uplift. Trim-Tex’s Truss Backing Angle is installed along the length of the wall, and holds the drywall inside corner together while allowing the trusses to move as needed. The drywall should be attached to the truss 18" out from the backing angle to allow for movement without cracking.

Discover more: Cracks Along Your Ceiling Corners? Here's How to Prevent Truss Uplift

BUILDING DEFLECTION

Like truss uplift, building deflection results from movement of the building itself, except this time we’re usually talking about multi-story structures. Deflection is when a load on the building, over time, gradually deforms any number of building materials (joists, trusses, rafters, concrete decks, et al.), causing movement that can easily cause cracks in your finish. Most often, you’ll find these cracks at your head-of-wall joints.

Solution: Any multi-story building, especially those that occasionally take an unexpected load or deal with widely variable loads, should consider preventative measures to avoid cracking from deflection. Traditionally, that meant some kind of caulk, but sealants come with their own set of setbacks — it’s tricky to apply evenly, and will become less and less flexible through the years. When it eventually hardens and shrinks back, it can cause its own set of cracks.

Instead, we’d recommend using a Deflection Bead (pictured above) in these head-of-wall gaps, which comes with a flexible gasket that can compress under load. This way, the bead spares the less flexible materials (like concrete and drywall) from having to bear the burden of building movement. This gasket, unlike caulk, remains flexible for the lifetime of the wall assembly. Similarly, our family of code compliance solutions accommodate deflection while also providing added benefits like preventing the passage of fire, smoke and/or sound.

Discover more: When and Where to Use Drywall Accessories Made for Movement

A drywall finisher’s ability to prevent drywall cracks over time places them ahead of the pack, and is the mark of a true pro. For more pro tips like these, Trim-Tex is here to help — every week, we publish something new to help drywallers of all skill levels. Never miss an update by hitting the button below to sign up for our monthly newsletter!