We often hear about the benefits of insulated metal panels (IMPs): the high R-value, the cost efficiency, and the faster build speed. There are five common mistakes that can be made upon installation of IMPs when, if made, can negate those benefits, and cost your project time and money. Here’s how to avoid them.
When installed correctly, IMPs have many benefits
Steel Alignment
First, before any panel is installed, the steel alignment needs to be inspected. The steel needs to be in line with the panel manufacturer’s specifications. If the steel is out of plumb, it can cause issues with locking one panel to the other. It also can cause rippling of the panel called oil canning. This is a common mistake that installation crews make. The foam panel has an amount of flexibility that it can tolerate.
When the steel is out of alignment, contractors use clips and fasteners to pull the panel tight to the steel. This can cause a distortion to the panel edge and can also crush the edges causing a break in the panel seal which can cause an air or water leak.
Any obstacles such as bolt heads or weld marks could hold the panel away from setting flat to the steel and need to be addressed. These are some of the problems that can occur when the steel is left out of alignment.
Flashings
Flashings need to be installed before the panels are installed. This is a typical mistake that is made during installation. Flashings need to be installed with butyl sealant applied on the backside of the flashing flange to ensure a proper seal to the steel framing. Another bead of butyl needs to be added to the front of the flashing flange to ensure a proper seal between the panel and the flashing.
All flashings need to be lapped approximately 3 inches with two beads of butyl sealant to ensure a proper seal. These steps are commonly missed and if not completed properly, they can cause air and water intrusion.
Openings
A common mistake when installing wall panels is installing a full-length panel covering any openings such as windows and doors, then cutting the opening out after the panel is installed. This will not allow the contractor to install the flashings around the openings to include the application of butyl sealant to the steel framing and to the backside of the wall panels.
At times a pipe or steel column could penetrate through a panel joint. This needs to be avoided as much as possible. Once this happens, it is very difficult to seal with flashings and will leak over time. Therefore, planning the panel layout is critical.
Panel Layout
Panel layout is important to the aesthetics of the wall installation and allows for planning the alignment to the openings such as doors and windows. This is an important step to take before installation begins. It will also help eliminate any window or door openings falling between two panel joints. At the start of a wall, you always want to begin with a good width wall panel and end the wall with one that is comparable in width.
Moving Panels On-Site
A bundle of panels carries a lot of weight and needs to be moved with the proper equipment such as a forklift or a crane using straps. Long panels can flex when lifted in the center of the bundle when using one fork truck. This can cause a crease to the bottom panel in the bundle if the bundle flexes. Two fork trucks should be used for long panels over 30 feet. When bundles of panels are lifted with a crane and straps, the use of a spreader bar to support the center of the bundle and spreaders for the straps at the top and the bottom of the bundle are necessary. If spreaders for the straps are not used, it will cause damage to the edges of the panels.
Al Detmer is field technical services manager for Kingspan Insulated Panels North America, Deland, Fla. For more information, visit www.kingspanpanels.com.
