04/14/2026
🔥 We set it on fire. Here’s what happened.
We’ve seen plenty of “fire tests” floating around online — so we decided to do our own. No editing. No tricks. Just open-cell spray foam and a torch.
The result? It burns. Easily.
Here’s what every Texas homeowner needs to understand:
🟡 Open-cell spray foam is excellent for insulation and air sealing — helping improve comfort, reduce drafts, and increase energy efficiency.
But it is NOT fire-resistant on its own. When exposed to flame without protection, it can ignite and continue to burn.
🔴 This is exactly why building codes require fire protection over foam insulation.
Per the International Residential Code (IRC):
• Section R316.4 – Thermal Barrier
Foam plastic insulation must be separated from interior living spaces by an approved thermal barrier, typically ½” gypsum wallboard (drywall).
• Section R316.5 – Ignition Barrier
In attics and crawlspaces with limited access (service-only, not regularly occupied), an ignition barrier may be permitted instead of drywall. This can include materials like mineral fiber, insulation coverings, or approved coatings.
👉 Which one applies depends on how the space is used and accessed — not just whether there’s a door or opening.
👉 The goal is the same: slow flame spread and give occupants more time to react in a fire event.
✅ What you SHOULD know before choosing insulation:
→ Open-cell foam = great insulation + air sealing, requires proper code-approved protection
→ Closed-cell foam = denser, higher R-value, more fire-resistant by nature
→ Attics/crawlspaces may allow ignition barriers instead of drywall (if code conditions are met)
→ Always ask your contractor how the installation will meet IRC fire protection requirements
We conduct tests like this because an informed homeowner is a protected homeowner. Transparency is how we do business at Lone Star Insulation.
📞 Got questions about which insulation is right for your home? We’ll give you straight answers — no sales pressure.
👇 Drop a comment, DM us, or call (817) 632-4345 for a FREE estimate.
🔗 lonestarinsulation.net
