Johns Manville Spray Foam Insulation in Boerne: What to Know First
We provide independent Johns Manville spray foam insulation service in Boerne, typically with same-day or next-day scheduling and a written price before any work starts. Most Johns Manville spray foam jobs in the Hill Country run between $1,800 and $4,500 depending on whether we’re treating an open-cell attic deck, a closed-cell rim joist, or a full garage ceiling. We’re not affiliated with or authorized by Johns Manville; we’re an independent service provider who knows their product lines from field experience, not a dealer manual.
This page is for Boerne homeowners who already have Johns Manville insulation in place and need repair, replacement, or augmentation with spray foam - or for those comparing Johns Manville against other brands before a new install. Call (830) 529-7780 for a free estimate with a written price delivered before anyone lifts a tool.
How Johns Manville Products Fail - and How We Fix Them
- JM Corbond III open-cell shrinkage in hot roof assemblies. We’ve pulled back Corbond III in several Boerne attics where summer roof deck temperatures pushed past 160°F and the foam retracted from rafter edges, creating thermal bypass channels. The fix isn’t more foam over the gap; we cut back to sound substrate, recondition the surface, and respray with a formulation rated for the actual temperature range of a Hill Country roof deck.
- JM SEALTITE closed-cell delamination from OSB in high-humidity crawl spaces. SEALTITE can pull away from oriented strand board when seasonal humidity swings exceed 35% differential, which happens regularly in low-lying Boerne neighborhoods near Cibolo Creek. We diagnose this with a calibrated moisture meter, remove the failed section, and reapply only after the substrate reads below 19% moisture content - otherwise we’re sealing water into the wall.
- JM SPF Pro system off-ratio curing from aging equipment. The SPF Pro line demands precise A-side/B-side ratio; when we encounter jobs where the original installer used worn mix chambers or dated transfer pumps, we find tacky, uncured centers that smell of amine blush. We remove the compromised foam entirely - no skim coats - and reapply with fresh equipment we calibrate before every job.
- JM Corbond Plus density failures at rim joists in pier-and-beam homes. Boerne has a stock of 1960s-1980s pier-and-beam construction where rim joists sit close to grade; Corbond Plus applied too thin here doesn’t achieve its rated 2.0 lb/ft³ density and crushes under seasonal soil pressure. We strip to framing, verify structural integrity, and respray to a minimum 2-inch pass thickness with proper substrate temperature.
- JM retrofit foam incompatibility with existing fiberglass batts. We’ve found JM spray foam blown directly over compressed fiberglass in attics near Boerne’s Historic Hill Country - the foam can’t bond to the glass fibers, creating a convection loop that nullifies both materials. Our fix: remove the batt, air-seal the ceiling plane properly, then spray. Seal the envelope first. Then fill it.
Our Johns Manville Spray Foam Insulation Process
- 1
Call and scheduling. A live person answers 24/7. We book a diagnostic window, text when the technician is en route, and arrive with a named technician - Haven Standard: Arrive on schedule.
- 2
On-site blower-door test and visual. We pressurize the house and measure CFM50 leakage before touching anything. In Boerne’s older stock, we regularly see 3,500+ CFM50 in homes where the owner assumed insulation was the problem; often it’s air leakage through top plates and can lights that any new foam would simply bury.
- 3
Written price and scope. We deliver a flat price, written scope, and written warranty before anyone lifts a tool - Haven Standard Clause 1. No exceptions. If you have a competing estimate, we’ll read it with you; our Free Second Opinion applies to any written quote.
- 4
Air sealing first, then foam. We seal top plates, electrical penetrations, can light housings, and duct boots with appropriate materials. Only after the blower-door reading drops from our sealing work do we begin spray foam application.
- 5
Application with documented ratios and temperatures. For Johns Manville products, we log substrate temperature, ambient humidity, and mix ratio on the job sheet. These numbers matter for warranty support if you ever need to file a claim with Johns Manville directly.
- 6
Post-job blower-door test and photo record. We run the pressurization test again, print the pressure-differential report in pascals, and deliver it with a Documented Photo Record of the completed work. You leave with paper, not promises.
What Johns Manville Spray Foam Insulation Costs in Boerne
| Job Type | Typical Range | What Moves the Price |
|---|---|---|
| Open-cell attic roof deck (1,200-1,800 sq ft) | $1,800 - $3,200 | Accessibility, existing removal, rafter depth for full fill |
| Closed-cell rim joist (pier-and-beam) | $2,200 - $3,800 | Linear footage, crawl clearance, moisture remediation needed |
| Garage ceiling (2-car, conditioned above) | $1,600 - $2,800 | Fire-rated thermal barrier requirement, duct penetration count |
| Full encapsulation (crawl space, walls, rim) | $4,000 - $6,500 | Square footage, vapor barrier integration, dehumidifier sizing |
| JM foam removal and replacement | $2,500 - $4,500 | Volume of failed foam, disposal, substrate repair |
These ranges reflect what we’ve written on actual proposals in Boerne over the past three years. Your price may sit above or below depending on what the blower-door test and visual inspection reveal. Call (830) 529-7780 for a free estimate - the written price comes before any work starts, always.
Why Boerne Homeowners Call Topside Attic Insulation Boerne for Johns Manville Work
We’ve sealed and insulated over 9,000 homes since 2016, and a meaningful share of those have been in the Hill Country where Johns Manville products were specified by original builders or later retrofitters. Wes Okafor learned the trade at Olive-Harvey College’s building technology program and has run blower-door tests before and after every applicable job for going on eighteen years. When a homeowner in Boerne wants to understand why their JM Corbond attic isn’t performing, we can show them the pressure-differential report in pascals and explain thermal bridging with a copy of ACCA Manual J from the truck.
We don’t lock you into Johns Manville. Our materials come from Owens Corning, Knauf, Rockwool, CertainTeed, Icynene, Demilec, GreenFiber, and Reflectix too - if another product fits your assembly better, we’ll say so in the written scope. The 365-Day Done Right Promise covers all completed work. Calls are answered by a live person 24/7, and our technicians are background-checked and uniformed.
FAQs
No - Johns Manville’s product warranty covers manufacturing defects regardless of who installs or services it, provided the original application met their published specifications. We document substrate temperature, mix ratio, and pass thickness on every job so you have records if a warranty claim ever arises. For warranty filing help, call us at (830) 529-7780.
We source JM products through standard distribution channels when the job calls for them; we also apply compatible formulations from Icynene, Demilec, and other manufacturers when they better match the assembly’s performance requirements. We never use “compatible” products that don’t meet the original specification - that’s in the written scope, and you see the data sheet before we spray.
Repair is viable when the failure is localized - shrinkage at a rafter edge, a delaminated section under a bathroom vent - and the surrounding foam passes a core density test and bond strength pull. Full replacement is necessary when we find off-ratio curing, widespread moisture intrusion, or foam applied directly over compressed fiberglass. We determine this with a moisture meter, visual inspection, and core samples if needed, then put the finding in writing before pricing either option.
Most diagnostic appointments are available same-day or next-day; actual spray application typically follows within 3-5 business days depending on weather, since substrate and ambient temperatures must sit within manufacturer spec for proper cure. In Boerne’s spring and fall shoulder seasons, we sometimes book two weeks out when demand peaks. Call (830) 529-7780 to check current availability - estimates are free.
Repair is usually 40-60% less than full removal and replacement, but only when the substrate is sound and the failure pattern is localized. When we find systemic issues - off-ratio original application, moisture-compromised OSB, or foam buried over unsealed air leaks - replacement with proper prep is the only fix that holds. We give you both numbers in writing so you can decide. Call (830) 529-7780 for an exact quote - estimates are free.
Written by Wes Okafor, Owner, Topside Attic Insulation Boerne at Topside Attic Insulation Boerne, serving Boerne and nearby areas.