Understanding Construction Adhesives and Sealants
Construction adhesives are used for bonding different materials, such as wood, concrete, metals and more. They create a strong and durable bond that is resistant to water, heat, chemicals, and more.
It is important to choose the right type of adhesive for each job and surface to ensure you get a strong, long-lasting bond.
1. Strength
Construction adhesives and sealants join and bond different materials, offering reliability and structural integrity. Depending on the substrate and environmental conditions, these products can be designed to provide varying levels of strength and durability. The type of stresses — compressive, tensile or torsion — that will be experienced and the working temperature and chemical exposure may influence which adhesives to use.
Adhesives come in several forms, including physically hardened, chemically cured and pressure sensitive. Physically hardened types, which start out in liquid form and dry by evaporation or absorption of the carrier, can include solvent-based adhesives such as cyanoacrylates, silicones or methyl methacrylate and water-based construction adhesives like polyurethanes or epoxy glues.
Generally speaking, caulks are intended to serve a cosmetic purpose, while construction adhesives and sealants sealants will keep air, moisture or other unwanted elements out of a joint. They typically have lower strength than adhesives. On the other hand, construction adhesives can be formulated to meet many specific engineering and production requirements, such as high elongation at break or low shrinkage after application. This enables them to be used in applications that require long-term strength, but short-term handling or rapid production lines.
2. Versatility
A basic understanding of the different types of construction adhesives and sealants enables DIY enthusiasts to make informed choices that improve their results. They can also avoid common mistakes that cause a weak bond.
Whether you are bonding wood, metal, concrete, or plastics, these adhesives offer secure adhesion for projects of all sizes. They can even fill gaps and provide insulation to keep your work stable and structurally sound. They are also able to resist challenging conditions like extreme temperatures and humidity.
These adhesives are available in a variety of containers, including buckets, tubes, and sticks. Some are also formulated for specific materials and applications. To ensure you select the right one for your project, look at its viscosity and other characteristics.
For example, this one-component construction adhesive from Loctite offers the versatility of a strong bond, weather resistance, paintability, and a low VOC count. It is a good choice for large, long-term jobs, or on-the-go use on smaller projects and last-minute fixes. It also comes with UL Environment certification to confirm its eco-friendly properties.
3. Weather Resistance
There are a variety of weather conditions to consider when choosing construction adhesives and sealants. The environment, temperature and humidity are all key factors that impact curing times and long term performance. Choose a high quality product that can stand up to the conditions where it will be used.
Non-structural adhesives are used for bonding decorative materials, floor and wall coverings and other materials that do not need very high strength (panels, fibers and particle boards, trim and some interior doors). These include emulsion, dispersion, silane hybrid prepolymers and solvent-based adhesives.
Sealants are more flexible than adhesives and can fill gaps between components or substrates to form air-tight barriers. They are often used in conjunction with other fasteners and are characterized by high tensile and shear strength. Some sealants are elastomeric, and have up to 40% elongation at break and good construction adhesives and sealants fatigue resistance. Some are low odor, and therefore suitable for use in occupied spaces. They are typically used in the building and construction industry for sealing and caulking.
4. Sealing
Construction adhesives are designed to bond and seal joints in a variety of applications. They’re used to hold materials together and reduce the amount of fasteners needed. They also help distribute load and stress over a larger area, which reduces the chances of failure in high-stress areas.
A wide range of chemistries are available to meet the varied needs of contractors, builders and homeowners. Some of the most common construction sealants are silicones and elastomers that offer versatility and flexibility. Others are based on neoprene or polychloroprene rubber, which offer superior resistance to weathering and aging.
Most of these are one-component sealants that cure through a reaction with humidity in the air. They can be extruded through a caulking gun and used to seal gaps up to 20 mm thickness. These usually contain mineral fillers to reduce cost, improve the gap-filling properties and give a creamy consistency that can be easily spread with a notched trowel without sagging.
5. Protection
Adhesives offer the ability to bond and hold together surfaces in a wide range of applications including flooring installations, stair assemblies, molding and paneling, bathroom installations, and more. This helps to reduce the number of fasteners required and provides greater structural support than fasteners alone.
They form bonds, or stick, in one of two ways: mechanical adhesion, which happens when the fibers and pores of a porous substrate like wood or concrete physically interlock with the adhesive when it dries; and chemical adhesion, which relies on molecular forces, polarity, and surface energy to create a bond between the substrate and the adhesive.
Other considerations when choosing an adhesive include the ambient temperature and humidity where it will be used. High levels of humidity can slow the curing process, and low temperatures can cause the adhesive to become stiff or dry out prematurely. Contractors should also look for products that have been formulated with MoldGuard, which is a special additive that prevents the growth of stain-, odor- and mildew-causing mold and algae on the sealant.