Drywall installation

 Last time you visited the local hardware store or big box home improvement store looking for drywall mud you may have been puzzled by the variety. Do all joint compounds work the same or should you use a certain type of mud for certain applications? Let's discuss the two basic categories of mud and then we can break down the choices within these two categories. This article is not meant as a review of any brand or recommendation of a certain product line, rather this is a general discussion that applies to many different brands of drywall compound. 

Quick-setting drywall mud comes in powdered form usually in plastic lined paper bags. The plastic lining keeps moisture out and preserves freshness. Keeping the powdered mud dry is critical. When water comes in contact with hot mud it begins an irreversible chemical reaction that causes the mud to harden. Once quickset mud hardens you cannot reuse it. If a bag of hot mud contains even a few small parts of hardened mud, it can render the entire bag unusable. Hardened lumps of hot mud cause scratches in drywall seams and make it very difficult to create truly smooth finishes.

When it comes to hot-mud, there is a difference between hardening and drying. Hot mud hardens by means of a chemical reaction. Manufacturers mix different amounts of hardening agents into the material causing it to set up at different times. Hot mud is packaged according to the time it takes to harden. For example, quick-setting drywall mud is sold in packages labeled 5-minute, 20-minute, 45-minute, 90-minute or higher. This refers to the length of time it takes from when the powder comes in contact with water to when it hardens and can be recoated.

Actual working time is generally less than the time listed. For example, 45-minute hot mud may begin to set up in 30-35 minutes. The working time can vary slightly depending on a few factors. High humidity or cooler temperatures causes hot mud to take longer to set. Hot dry conditions can cause 5-minute mud to set before you even get a chance to spread it on your patch. If you need quick-setting drywall powder to set up faster than normal, using hot water when mixing will usually do the trick.

The other main category of drywall mud is pre-mixed drywall mud. It is what most people think of when referring to drywall mud. Pre-mixed drywall mud is sold in either 4.5 gallon buckets or in boxes/cartons containing a plastic bag of mud. Most often, the boxes of mud are also 4.5 gallons in volume but occasionally you will find 3.5 gallon boxes. Therefore, if you see a box of drywall mud that seems cheeper than most, make sure to check the volume. Pre-mixed drywall mud is, as the name indicates, pre-mixed and ready to use.

Pre-mixed drywall mud is almost always thinned with water before using. The amount of water used depends on how the mud will be applied. For example, bedding in tape requires a thinner than normal consistency. A thin consistency is also needed when using automatic taping tools to allow a smooth flow of mud through the drywall mud pump. However, if it is too thin, it will be difficult to spread and will shrink back, creating voids. Texture mud is the thinnest of all. It takes time and training to understand what consistency of mud should be used with each application.

When shopping for drywall mud you may notice different types of pre-mixed mud. The three most commonly used are "all purpose", "lightweight all purpose" and "topping". There are of course several other types of joint compound available however these are the most common.

All purpose drywall mud, as the name indicates, is made for all applications. All purpose mud has bonding agents that increase the holding power of drywall tape so it is good for bedding in seams. It is sometimes used to first coat seams and corner beads. It is not often used as a finish coat because it is more difficult to sand than "lightweight all purpose" joint compounds. However some professionals will use it in limited applications for finish coat because it creates a durable finish. The downside is that it is harder to sand and therefore, the finishing has to be of very good quality.

Lightweight all purpose drywall mud, as the name indicates, is made for all applications yet is lighter in weight than all purpose mud. Many pros believe that lightweight joint compound contains less binding agents and therefore is inferior when taping seams. However, it is hard to know for sure since manufacturers don't openly publish comprehensive lists of drywall mud ingredients. Lightweight compound is often used for first and second coat of seams and corner bead. It is almost always used as a finish coat because of its ease of sanding.

Topping compound is used less often then all purpose or lightweight mud. It can be used to top coat seams and corner bead. It is not recommended for taping joints. The color of topping is whiter than all purpose and even whiter than lightweight all purpose. It is many times used for texture applications.

Generally speaking, they are compatible with one another. Joint compounds can be used over each other but most manufacturers do not recommend mixing the compounds together. It is always the best practice to refer to the manufacturer's specific recommendations.

 We keep up-to-date with the latest trends in drywall taping and finishing tools allowing us to complete jobs in record time. this gives us an upper hand to our competition. the Columbia taper and finish boxes applys the perfect amount of mud for you. allowing us to be consistent in providing a professional finish every time.