FAQ
Spray Foam Insulation FAQ Guide
Open-Cell vs. Closed-Cell Spray Foam
In short, open-cell foam is softer, more affordable, and allows moisture to pass through. Closed-cell foam is denser, stronger, and provides more insulation per inch.
Open-cell foam is around R-3.6 to R-3.9 per inch. It works well when there’s plenty of room for thicker insulation. Since it’s vapor permeable, the wall or roof assembly can dry out if moisture gets in.
Closed-cell foam is around R-6 to R-7 per inch, so you get much more insulation in less space. It also helps control moisture and can make the surface it’s applied to more rigid. The downside is that it costs more.
Closed-cell foam is usually the better choice when space is tight or moisture is a concern. It’s commonly used around rim joists, in crawl spaces, on basement walls, below grade, and in some unvented attics.
Basically, if you need the highest R-value possible without using a thick layer of foam, closed-cell is usually the way to go.
Open-cell foam makes sense when you have enough room for a thicker layer and want to keep costs down. It’s often used in interior walls, vented attic floors, and soundproofing projects.
It’s also softer than closed-cell foam, which helps absorb sound. That makes it a popular choice between bedrooms, bathrooms, offices, and other rooms where noise matters.
Open-cell foam is an industry-standard option for roof decks because it can make roof leaks easier to detect. Since water can pass through the foam, a leak is more likely to show up as a wet spot or ceiling stain.
Closed-cell foam does not allow water to move through as easily. If a roof leak occurs, moisture may become trapped between the foam and the roof deck. By the time the problem is discovered, it may have already caused mold, rot, or damage to the roof deck.
That doesn’t mean open-cell is always the right choice for every roof. Climate, local building codes, roof design, and moisture control all matter.
Choose closed-cell foam when space is limited, moisture is a concern, or you want extra strength. Think rim joists, crawl spaces, basements, and places where every inch counts.
Choose open-cell foam when you have more room, want better sound control, or want the assembly to dry more easily if it gets wet. It’s also usually the less expensive option.
When it comes to roof decks or other moisture-sensitive areas, have the full assembly checked before deciding. The right foam depends on more than just the R-value.
Spraying Spray Foam in Cold Weather Without Losing Ratio
If one drum is warmer than the other, the material can flow differently and cause off-ratio foam.
Don’t wait until you get to the site to start warming cold material. In winter, properly conditioned drums make a big difference in how the foam sprays.
Pay attention to the hose temperature and material temperature at the gun. Also give the primary heaters enough time to recover between passes, especially when you’re spraying a lot of material quickly.
Spraying warm foam onto a freezing-cold roof deck, wall, or other surface can cause poor adhesion, condensation, and bad foam quality.
Always check the substrate temperature before spraying.
If the substrate is below the minimum, warm the area before spraying or wait until conditions improve. Trying to force the job in temperatures that are too low can lead to problems you’ll have to fix later.
Good winter foam starts with good temperature control.
How to Choose a Spray Foam Proportioner (Reactor)
Start with output, not price. Look at how many pounds per minute the machine can spray at your normal working pressure, then match it to the number of spray guns you’ll be running.
Not always. A large machine can easily handle one spray gun, but a smaller machine may struggle with two. If the machine can’t keep up, both guns may lose pressure and performance.
Spray foam equipment uses a lot of power, especially the primary heaters and heated hose. If the electrical supply is too small, the machine may struggle to maintain temperature, leading to off-ratio or soft foam.
Yes. Every extra section of heated hose makes it harder to keep the material at the right temperature. Make sure your hose length is within the machine’s rated heated capacity.
It depends on how much material you plan to spray, how many spray guns you’ll be running, and the type of jobs you do. A one-person residential contractor will have different needs than a crew spraying large commercial projects.
If you’re not sure which size is right, our team can help. We’ll recommend the right machine based on your production goals, spray setup, power availability, and budget, so you get the best fit without overspending.
Choose a proportioner based on the output you need, not the price. Make sure it can support the number of spray guns you’re using, has enough electrical power to maintain temperature, and can heat the full length of hose you’re running. A properly matched machine will produce more consistent foam and fewer problems on the job.
Equipment Service & Repair
A standard gun rebuild is usually same day if you drop it off in the morning and the seal kit is in stock, which it normally is. Ship-in guns are typically turned around within one to two working days of arrival. If we find something beyond a normal rebuild we call you with a price before we go further.
It depends entirely on the fault. Straightforward items — heaters, transducers, pump packings, hose ends — are often same day or next day. Board-level electrical faults and anything needing a part we do not stock depend on the manufacturer. We will always give you a realistic time once we have diagnosed it, not an optimistic one.
Yes, and plenty of customers do. Pack it clean and dry, include a note with your name, phone number, the fault and your return address, and send it to the Brooklyn or Bridgeport address above. Call or use the form first so we know it is coming and can watch for it.
Please do what you reasonably can — purge it and wipe it down. We understand cured foam happens; that is part of the job. But a gun arriving full of wet, uncured chemical is a handling hazard for our technicians, and we may have to charge extra cleaning time.
Ask us when you book — it depends on the machine and the fault. If the repair goes ahead with us, diagnostic time is normally absorbed into the job. What we will not do is start work of unknown cost without telling you first.
New equipment carries the manufacturer’s warranty, and we administer the claim for you. Warranty generally does not cover normal wear, consumables, running a machine dry, incorrect pressure or temperature settings, off-ratio or contaminated material, freezing, missed maintenance or unapproved parts. We will tell you honestly what the manufacturer decides. See our Refund & Returns Policy.
Start with the basics before you call: A and B pressures at the gauges, hose temperature at both sides, whether both transfer pumps are keeping up, filter screens, and whether either drum is low or crusted. Note the actual numbers you see — that single detail lets us narrow the cause on the phone in minutes rather than guessing.
Yes. We service the platforms listed above regardless of where you bought them.
Often, yes. Tell us the location and the fault when you book and we will tell you whether a site visit or a bench repair gets you spraying sooner.
Yes, and it is far cheaper than an emergency. An annual or seasonal service — seals, filters, screens, lubrication, calibration check — prevents most of the failures we see in the middle of a job. Choose “Preventive maintenance” in the form below.
Still have questions?
Call us at (718) 788-6800 or contact us and we’ll get you the right answer.