Wet-Seal vs. Rain-Screen ACM
What’s the difference and what are the advantages of each?
ACM, or aluminum composite material, has existed since the 1960s in Europe and the late 1970s in North America. Increasing in popularity and use since then, it is featured in numerous kinds of building types and applications today.
Architects and owners love ACM for its clean, sleek appearance and panel shape and size flexibility. Although it has increased in popularity, many do not know that two different ACM systems or installation types are available. Called many other things, the most common descriptions of these two versions are wet-seal and rain-screen ACM.
Before we get into the differences between the two systems, it is important to know what is not different. First and foremost, the panel materials are the same. We use the same 4mm ACM material from manufacturers such as Arconic, Alucobond, and Alpolic in wet-seal and rain-screen systems.
Second, the extruded clip systems are mostly the same. These are the aluminum pieces used to attach the ACM panels to the exterior skin, which means that the depth of the panel systems is consistent no matter which system is used. Finally, the designs can match. You can make the exact panel sizes with the same layout and wet and dry (rain-screen) seal ACM systems.
What is the difference between wet-seal and rain-screen?
So, what exactly is the difference? The joints. The joints are caulked with a sealant product such as Dow 795 in a wet seal system. The joints have a spline (small piece of matching ACM material) between the panels in a rain-screen system.
Rain-Screen ACM Panels
Wet Seal ACM Panels
What are the advantages and disadvantages of wet-seal vs. rain-screen ACM?
Why choose one system over another? Both systems are long-term solutions, have functional sound, and have strong aesthetic appeal on the outside of a building.
But there are two primary reasons for choosing the rain-screen system.
- First is the deep reveal joints created with the caulk-less system. Many appreciate this look and prefer it to the caulked joints of a wet-seal system.
- The second motive to pick the rain-screen system is long-term maintenance. Eventually, the caulked joints will have to be replaced (the amount of time is debatable, but somewhere around 15 years-ish), while the dry joints require no maintenance. Others also will say that the caulked joints must be cleaned occasionally to keep up their appearance.
Contrastingly to the dry seal of rain-screen systems, the wet-seal has one significant advantage: watertightness.
While the rain-screen system is technically a rain screen system (allowing water to pass through it), the wet-seal system is completely watertight. This type of watertight system requires less detailing in the design phase and less coordination in the installation phase of projects.
By design, the rain-screen system allows water behind it, which means that the layer behind the panels (often the exterior sheathing) is the dry line of the building and requires waterproofing. This additional layer of protection adds costs to an unnecessary project with a wet-seal system.
In addition, some joints of a rain-screen system must be caulked to maintain water tightness. These occur where the ACM system meets adjacent materials (brick, siding, EFIS, etc.), around windows and other penetrations in the building face, and at coping locations. This is why it is often recommended to use a wet-seal system in applications with lots of windows, as coordination of the waterproofing is tedious, and any failure along the way can lead to long-term leaks in the building envelope.
The PCG Recommended Standard
Overall, we can and have installed both ACM systems. In the end, we are a little old school at PCG and normally prefer the wet-seal system to ensure water stays on the outside of buildings where it belongs. Check out the variety of ACM projects we’ve successfully and safely completed for our clients.
How can we help you with your next architectural metal project? Let us know! Contact us today.