
Drywall taping is an important step in installing drywall, and it is essential to ensure it is done correctly. Poorly taped drywall can cause various issues, from unsightly cracks and gaps to more serious problems like mould, water damage, and structural instability. This article looks at some of the most common problems that can arise from improper drywall taping and how to avoid them with a drywall installer.
A weak bond between the paper tape and the joint compound is what causes bubbled or loose paper tape. The tape may break loose and cause a bubble if it is not well anchored in the compound. The adhesive should be strong enough to keep the panels in place yet flexible enough to allow small amounts of movement between the panels.
When using tape for drywall taping, it is important to apply it correctly. First, the surface should be cleaned and dry before applying the tape. Next, the tape should be cut to the desired length and applied along the drywall seams. The tape should be pressed firmly to ensure it has fully adhered. Finally, the tape should be smoothed out with a putty knife or other smoothing tool to ensure it is flush with the drywall.
Concave and crowned seams are two of the most common problems with drywall taping. They occur when the joint compound is not evenly spread across the seam, leaving a low spot or a bump in the finished surface. This can be caused by numerous factors, including uneven pressure on the trowel, insufficient joint compound, or too much joint compound.
The first step is to remove any excess joint compound from the seam to fix these problems. If the wall has already been painted, the paint should be scraped off to inspect the seam properly. Once the excess compound has been removed, the seam should be sanded down smoothly. It is important to use fine-grit sandpaper and to sand in the direction of the seam.
Once the seam has been sanded, an additional joint compound should be applied to even out the surface. Using the proper compound amount and spreading it evenly over the seam is important. After applying the compound, it should be smoothed with a trowel. The trowel should be held at a slight angle and pressed firmly against the wall.
Lastly, the wall should dry for a few days before painting. This will allow any bumps or dips in the surface to settle and ensure a smooth finish. With proper care and attention, concave and crowned seams can be easily fixed, and the wall will look as good as new.
Pitting is a pattern of craters or pits on the taped finish's surface. The microscopic air bubbles that either weren't completely expelled or came to the top after sanding caused the holes. When the joint compound is mixed incorrectly or excessively, air bubbles form. When the joint compound is smoothed with insufficient pressure, tiny air bubbles may develop on a damp surface.
To avoid pitting, the drywall tape must be applied properly, and the joint compound must be mixed correctly. Before applying the joint compound, preparing the area by sanding the drywall is important to create a smooth surface. Additionally, the drywall tape should be pressed firmly into the joint compound with a drywall knife. It is also important to avoid overworking the joint compound, as this can create air bubbles.
When mixing the joint compound, using the right amount of water is important. Too much water will make the compound too thin and cause it to run off the wall. Too little water will make it too thick and difficult to spread evenly. The ideal consistency should be similar to that of cake frosting.
Drywall taping can pose a variety of problems if not done correctly. Poor taping can cause fireproof drywall to crack, bubble, peel, or blister. Using the right tools and techniques when taping drywall is important to avoid these problems. This includes using the correct type of joint compound, properly preparing the wall, and using the proper taping techniques. It is also important to allow the drywall to dry completely before applying any additional coats of joint compound. Following these steps ensures that your drywall taping job is done correctly and looks great.
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Common drywall taping mistakes include applying too much or too little joint compound, leaving air bubbles beneath the tape, and failing to feather the edges properly for a smooth finish. Skipping coats or not allowing adequate drying time between applications is another frequent error that leads to cracking and uneven surfaces. Using the wrong type of tape, such as paper tape without proper bedding compound, can also result in lifting, bubbling, or poor adhesion.
Adding a small amount of Dawn dish soap to drywall mud acts as a surfactant, making the compound smoother, creamier, and easier to spread and feather. It reduces drag on the knife, which helps achieve cleaner, thinner coats with fewer tool marks. However, this is considered a trade tip rather than a manufacturer-recommended practice, so it should be used sparingly to avoid weakening the compound's bonding strength.
Drywall tape most commonly fails due to insufficient joint compound behind the tape, which prevents proper adhesion to the drywall surface. Moisture intrusion, whether from leaks, high humidity, or improper vapour barriers common in GTA homes during winter, can cause the tape to soften, bubble, and peel away. Using the wrong tape for the application, such as standard paper tape in high-moisture areas like bathrooms where fibreglass mesh tape is preferable, also leads to premature failure.
Start by scraping away any loose, cracked, or bubbling compound and re-bed any lifted tape using fresh all-purpose joint compound, pressing it firmly and smoothing it flat. Once dry, sand the area smooth and apply additional thin coats of compound, feathering the edges at least 15 to 20 centimetres beyond the repair to blend it seamlessly with the surrounding surface. Prime the repaired area with a PVA drywall primer before repainting to ensure uniform texture and sheen across the entire wall.
Visible tape lines, ridges, or seams showing through paint are clear signs of a poor drywall job, often caused by inadequate feathering or too few coats of compound. Bubbles, cracks, or peeling tape along joints indicate improper bedding or moisture issues that were not addressed during installation. Uneven surfaces, screw pops, and shadowing along seams when light rakes across the wall are also telltale signs that the taping and finishing work was rushed or done without proper technique.
Factual claims in this post were verified by Konstruction Group against published industry standards, including ASTM product specifications for gypsum board, the Gypsum Association's installation guidelines, and Building Science Corporation's moisture and envelope management resources. Application techniques referenced align with manufacturer specifications and recognized Canadian construction practices for drywall installation in the Ontario market.

Written & reviewed by
Fadi MamarCo-founder, Konstruction Group Inc
Engineering graduate from Toronto Metropolitan University with 14+ years in Toronto construction. Has overseen 500+ residential and commercial framing, insulation, and drywall projects across the GTA.
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