Everything You Need to Know About Choosing the Right Polyurethane Foam
Choosing the right polyurethane mounting foam shouldn’t feel like guesswork. But with all the brands and product options available, it can be overwhelming without the right information.
Whether you’re installing windows and doors or filling larger construction gaps, the right foam choice is critical to efficiency and long-term results. Understanding how expansion rates, application tools, and environmental conditions affect performance will help you avoid callbacks, reduce waste, and ensure quality installations every time.
Read on to learn all about polyurethane mounting foams—what they are, how they work, differences in expansion, available applicator tools, and more.
What Are PU Foams?
Polyurethane foams or PU foams, are one-component or two-component chemical sealants used in construction for things like insulation, filling, sealing, and installation. One-component foams (like our Tytan Professional foams) cure upon contact with moisture in the air to form a durable, insulating chemical structure.
PU foams are very versatile and have become a must-have tool in modern construction work. Their unique properties make them suitable for a wide variety of use cases throughout residential and commercial buildings.
Common Foam Uses:
- Installing windows and doors
- Filling gaps and cracks
- Sealing pipe penetrations
- Insulating walls, ceilings, and roofs
- Soundproofing
- Thermal insulation
PU Foam Options: Gun vs Straw
Polyurethane foams come in different expansion rates and with application tool options to meet the requirements of specific tasks. Understanding these variations and choosing the right variety helps ensure optimal results and minimize material waste.
The first factor to consider when choosing a mounting foam is expansion rate, which indicates how much the foam will fill out after initial application. There are two categories:
- Low Expansion: Foams that only expand about 30-50%, which prevents door, window, and other frames from becoming deformed from over-expansion.
- High Expansion: Foams that double in thickness after initial application to fill larger gaps and provide insulation.
The next factor to consider is the application tool: straw or gun. Many professionals choose gun foams for most jobs, but straw foams are helpful for DIYers, single-use applications, or occasional needs.
| Gun PU Foams | Straw PU Foams |
| Require a professional application gun, which must be properly cleaned between uses | Come with an attached straw applicator, which is disposed of after one use |
| Offer better control, precision, and yield, especially for trained professionals | Less precise than guns but easier for inexperienced users to learn |
| Suitable for professionals who apply foams frequently and repeatedly | Ideal for single-use applications or those who need foams only occasionally |
Best Foams For Specific Jobs
Different construction tasks require different foam properties. Here’s a quick overview of which type to use based on the specific installation.
Air Sealing Between Framing and Drywall
Traditional sealing materials are time-consuming to install and can be torn or pushed up during drywall installation. To avoid such complications, use Tytan Professional Gasket Foam for quick, convenient application. This foam eliminates air leaks and improves a home’s air efficiency rating by 1.6 ACH, which helps builders comply with energy requirements and pass blower door tests.
Sealing Around Wall Penetrations
Depending on the building code in your area, you might choose to use a fire block foam sealant for sealing around electrical boxes, wire penetrations, cracks, gaps, pipe penetrations, and similar applications.
Depending on the ambient temperature of your application, you might use:
- Fire Block Extreme PRO Insulating Foam Sealant, which is designed for the most extreme conditions, from -4°F to 100°F ambient temperatures
- Fire Block 113 PRO Insulating GUN PU Foam Sealant, which is designed for the most extreme high heat and low humidity regions
Both options offer orange color for easy identification.
Sealing Around Doors And Windows
For window and door installers, the crucial features of spray foam are:
- High R-value
- Low pressure formula for predictable expansion around frames
- High yields to install more from one can
For these installations, Window & Door PRO Insulating GUN PU Foam Sealant is designed for professionals who expect a reliable high-yield product with the best outcomes.
For extreme cold conditions, installers can upgrade to Window & Door Extreme Insulating Foam Sealant, which was designed to perform in the -4°F to 100°F temperature range. As a bonus, this spray foam also offers 20-50% more yield than similar products from other brands.
Multipurpose Sealing
Where local building codes don’t dictate fire block requirements, or when a low expansion foam is not needed, TYTAN Professional Fill All Insulating Foam Sealant Pro is an economic choice. The multipurpose formula creates a durable, airtight, and watertight seal with a high R-value of 4-5 per inch. A can of Fill All can be used across the job site on a variety of surface materials.
RV Undercarriage Sealing
Where foam performance and a clean, finished look both matter, RV & Automotive Insulating Foam Sealant is the choice of professionals. The special formula is adjusted for outdoor use and is resistant to discoloration from UV exposure. Choose this foam when you need the product to blend in with the application area and keep its color over time.
Final Thoughts
Polyurethane foams are a must-have for any professional contractor. Choosing the right expansion type, applicator tool, and product type for every scenario leads to a job well done.
