|
|
| |
|
| |
There are many factors that must be considered when selecting the proper caulking material. Since there are many different types of caulking material on the market, it is helpful to understand what they are first.
Types of caulking material:
- Acrylic/Latex are water-based caulks that are used because of their cost, paintability, water clean up and come in a variety of colors that match the many vinyl siding offerings available. Acrylic caulking material has good adhesion to PVC, glass, metal, wood, concrete and other common substrates. Disadvantages of acrylics/latex caulks are they have little movement capability, shrink, harden and deteriorate over time when exposed to UV light.
- Urethanes are an excellent all-purpose caulk. They have excellent adhesion to a wide range of substrates including metal, glass, concrete, stone and masonry (typically without the need for a primer). Other advantages of urethane caulking material, include good movement capability (up to 50%) and color flexibility. You can match just about any color by adding color packs to an off-white base. The major disadvantage of this caulking material is that they deteriorate with long-term exposure to UV light.
- Silicone caulking material has the main advantage of resistance to UV light and other damaging atmospheric contaminants. Most manufacturers of silicone sealants offer a 20-year material warranty. Silicone caulking material also has excellent adhesion to glass, metal, plastics, concrete and masonry. They are very flexible and some silicone caulking material products can expand up to 100%. Some silicones can also be used in food contact applications such as food processing plants, restaurant kitchens, salad bars, etc. Disadvantages of silicones are that they are very difficult to clean up, are not paintable and are the most expensive.
Before you choose a caulking material you should consider the following:
- Joint Design--will always rule out what sealant not to use. If a joint is designed to move +/- 50%, then you will not be able to use an acrylic. You may be able to use a urethane, but only a few urethanes can withstand this much movement. It is very important to know how much a joint is designed to move.
- Substrate--The material you are trying to adhere to is one of the most important factors in determining which caulking material to use. Whichever caulking material you decide to use, you should always run an adhesion test on the actual substrate(s) to verify if you are going to get acceptable adhesion. Most caulking material & sealant manufacturers will run substrate adhesion tests (at no charge) if you submit a sample of the substrate to them.
- Service Life--is another factor that tends to rule out certain caulking material. If an owner or architect is specifying they want a 20-year material warranty, then you probably need to go with a silicone sealant.
- Paintability--If the caulking material is going to be painted over then you will not want to use a silicone.
- Special Requirements--Many applications require or demand a certain type of caulking material. A joint that needs to be caulked that will come in contact with food will be done with a silicone that has FDA approval.
Many Exterior Insulated Finish System (EIFS) manufacturers are now recommending a very low modulus silicone that can withstand a joint that moves +100/-50%.
Structural glazing can only be done with specially formulated silicones.
For more information on caulking material used in the construction industry please visit sealantsandcoatings.com
|
|
|
|
