It’s not easy to control thermal energy and moisture in buildings, even when we’re talking about the middle and primary areas like walls, roofs, etc. Taking care of the details is crucial, though. The expansion joints are a crucial detail in bigger buildings because they let parts of the building move due to seismic loads, thermal expansion, or other factors. When expansion joints break a building’s thermal, moisture, and air barriers, how they’re treated and addressed determines how these barriers stay continuous or don’t.
Development joints are used in dissimilar ways or locations in different types of buildings. Some people use them on the outside of their roofs or on pedestrian decks. Some people put them on walls vertically. Several are concrete, some are steel, and some are hybrid. All of them require something expandable on both sides that is securely secured on both sides to fill the gap. It depends on how durable and pretty that filler material is whether you cover it or not. When it comes to Construction Estimating Services, selecting the right material or system to fill the expansion joint gap is the key to maintaining the needed barriers. We’ll comment on their appropriateness for different construction applications and look at some of the more common ones below.
There’s no way water can get into closed-cell foams because they’re very watertight. Whenever there’s water pooling on horizontal runs, this is the best application. Compressing them is tougher, but they expand well under tension. One of the big advantages of closed-cell foam is that it’s heat-weldable. As a result, water can’t infiltrate the installation since it’s monolithic.
You should limit the use of closed-cell foam seals to joints that are less than 8 inches (200 millimeters) wide. When you use foam for expansion joints over 8 inches, you get these things:
- Performance characteristics exceed those of the foam. In vertical applications, “super-wide” foam seals can also sag due to their weight.
Foams with open cells
Water vapor does flow through these products. A building system lets moisture wick out of a wall cavity if moisture gets trapped there. I like the quality and the focus on removing mold issues from vertical applications. It’s therefore best to use open-cell foams in vertical installations where water can drain away from the enclosure.
For open-cell foam expansion joints, architects should know that they come in a maximum of five feet, and since they can’t heat fuse, caulk must be used at the seams. There’s a higher chance of future failures if you have to constantly recaulk the seams.
There are waxed foam and wax-free foam
Joint foams have been around for about 50 years. There’s nothing wrong with copious wax, but only to a point. It’s best to impregnate the foam with 2–3 percent wax to boost its hydrophobicity.
If the specifier doesn’t want wax impregnated, what’s the big deal? Plain foam can make a sponge. Additionally, plain foam assumes unrealistic expectations, such as perfect silicone welds and perimeter caulk seals to keep it safe. Caulk gun jamming between foam and material is likely to damage the silicone seal itself, causing leaks. Since wax doesn’t dry out, it won’t leak if the silicone seal fails.
Seals for compression
Compression seals work by compressing and expanding the joint seal to absorb movement and flexing. Block-out joints get them. It’s also great for outdoor applications that need waterproofing because it looks like rubber. It’s best to use these seals for heavy pedestrian traffic and moderate vehicle traffic. Heat-welded seams ensure watertight performance, and two-part epoxies ensure solid adhesion. As of now, these systems can only handle joint widths between 312 and 43 inches (89 and 111 millimeters). By using colorful compression seals, you can enhance the aesthetics of your building since these are often left visible.
Systems with hybrid compression seals
A tied-in waterproofing system on expansion joints is essential to prevent water from infiltrating adjacent spaces. Split slab construction is waterproofed more effectively with a hybrid compression seal system. This system’s main advantage is its integrated counterflashing, which channels water away from joints. Counterflashing needs to be compatible with the adhesives and materials adjacent. Flashing can fail to adhere or react with the adhesive, causing waterproofing problems. There’s no need to add metal cover plates over the seal when load factors require it.
Seals that reinforce the vapor barrier
Using a reinforced vapor barrier (RVB) or a drain tube can be a solution for preventing water infiltration or channeling water to drain locations in certain applications. In the concrete block-out area or along the frame during installation, apply a bed of butyl sealant to make RVB expansion joints waterproof. You’ll get a watertight seal around the perimeter of the joint, which will keep the moisture barrier from leaking. If you want to open your moisture barrier to its maximum, leave enough drape so the expansion cover doesn’t interfere.
Migration of thermal energy
Construction Estimating Services providers often ignore expansion joints’ thermal performance, but it’s just as important as air and moisture. In expansion joints, RVs are the go-to standard. RVs are durable membranes that sit inside joints. There are no air, debris, or pests getting in through the joint. Injection vapor barrier (IVB) systems can provide some minor insulating benefits, but where thermal performance is important, RVB joints should be considered. A dual-walled vapor with insulation gives you a higher R-value — and you’ll also get better HVAC performance and interior occupant comfort because it’s better shielded from outside conditions throughout the joint. It doesn’t let heat or cold penetrate the joint, so heat and cold don’t penetrate.
Thermal and Moisture Protection Estimating Services include materials that seal the building exterior from moisture, thermal, and air infiltration, along with insulation and accessories. The package includes waterproofing, insulation, and roofing.
The construction department focuses on protecting building envelopes from rain, air, heat, and vapor to make the construction more durable and sustainable. The energy and environmental performance of a building depend on the envelope.