How to choose an air barrier system that cuts installation time and costs
Smart air barrier choices can help contractors install faster, saving time and money. Here are some tips to help keep your next project on-track and on-budget.
Pick a system based on building design
A building’s architectural design – that is, its general shape and geometric complexity – will greatly impact air barrier installation time and costs. Building height, substrate type and accessibility in tight spaces will also affect installation.
Use these building design parameters to help you determine which type of air barrier membrane type – self-adhered or fluid applied – will be the most effective in terms of time and costs. As you weigh the installation pros and cons of each type, don’t forget to consider the weather as well as your familiarity with applying both system types.
Self-adhered air barrier membranes
Thanks to their factory-controlled thickness, self-adhered membranes are a favorite of many architects and specification writers. They require careful preparation of the substrate to help ensure successful and timely application. The substrate must be relatively smooth to the touch and have no sharp edges or mortar droppings, etc. The substrate must also be dry in order for the membrane to properly adhere; wet weather conditions could delay installation. To ensure an air/water tight assembly, self-adhered membranes need proper overlaps between sheets, so it’s an installation aspect that requires some time and attention. Finally, some self-adhered air barriers require a primer before application of the membrane. While roll-on primers are available for most self-adhered air barriers, when speed is a factor, (and it almost always is), some primers are available in spray form to help accelerate installation.
Fluid applied air barrier membranes
Fluid applied membranes provide the benefit of a continuous, monolithic membrane application to the substrate. Particularly when applied on more complex building designs, fluid applied air barriers can help cut install time and labor costs. They can also be more forgiving on irregular surfaces than sheet applied membranes. Also, if you choose the right fluid applied membrane technology, you may see additional benefits such as application tolerance on slightly damp (to the touch) surfaces and quick material drying properties that allow application even when impending wet weather is in the forecast. To sum it up, with no primer required, potential tolerance of wet weather, and a monolithic application, a fluid applied air barrier can be a faster, more cost effective options to consider.
When fluid applied membranes are specified, of course there can be concern about how proper application thickness will be controlled and monitored. “Over-installing” fluid applied membranes by applying the material too thick can increase the installation time and material costs, as well as impact vapor permeability for permeable membranes. If the membrane is applied too thin, reapplication might be necessary which leads to increased installation time and costs. However, with proper installation training of your crew, achieving proper membrane thickness should be a non-issue.
Check the system installation manuals
Once you know the type of air barrier system you’ll be installing, familiarize yourself with the installation requirements for the membrane, plus the flashing and accessories that make up the entire system. For fluid applied systems, follow the manufacturer’s requirements for installation thickness so you don’t over-apply the product. You’ll avoid buying more product than you need, and won’t spend more time and labor installing it than necessary.
Likewise, be sure to avoid under-application of a fluid applied product. Applying too little membrane material can drive install expenses, because it’ll likely result in a call-back, to fix the installation. High-performing buildings will have must-pass inspections; fail them and you’ll be going back over the wall again, thus increasing your labor expenses and likely impacting your profit on the job. Instead of risking repairs, review your system installation manuals to do it right the first time or contact your manufacturer representative for guidance.
Double-check product compatibility and building design
Whether fluid applied or self-adhered, air barrier membranes MUST be fully compatible with all of the flashings and sealant components that make up the system. Incompatibility issues can lead to problems on the jobsite that cause significant project timeline delays, and/or callbacks. To avoid these expensive errors, make sure the flashings and sealants you intend to use are compatible with the air barrier membrane.
Compatibility problems can also arise at spots where two dissimilar materials intersect on the building envelope. Connection from the air barrier to dissimilar materials, relieving angles, windows/doors or other penetrations in the building envelope can also require extra installation time and effort. Prevent installation interruptions and time delays by connecting with the manufacturer’s rep for assistance when detailing difficult transitions.
Consider installation temperatures
Air barrier system selection should also be based on project location temperatures. Some air barrier products may not be suitable for installation when ambient temperatures are above or below a certain range; trying to apply them in unsuitable temperatures could cause installation problems and timeline delays.
Go to the pre-construction meeting
Usually included within the project specification and organized by the General Contractor, project pre-construction meetings will cover a range of building envelope issues. All professionals involved with the building envelope should be at the meeting: the architect of record, the general contractor, the envelope consultant, the owner’s rep, product manufacturer reps, and of course, the installing contractor. Having the right folks present can help ensure everyone is aligned with product installation sequencing, and wall system tie-ins – all of which are installation elements that can potentially impact project timelines.
Mock Walls
Constructing a mock wall assembly provides an extremely helpful visual model showing how all building envelope elements interact and affect buildability. Ultimately, reviewing a mock wall can help answer any questions that wouldn’t otherwise come up until air barrier installation is underway, thereby preventing unnecessary timeline delays during construction.
Installation training is a must
Finally, having your installation crew trained on how to install the selected air barrier system properly will also help you control costs and prevent costly re-dos or callbacks. Product manufacturers typically offer online installation guides, or in-person training, and both have their merits. However, in-person installation will also address product installation issues that can vary by region, giving you additional info that can help reduce installation time and costs.