Rust-Oleum 248656 Professional Grade Rubberized Undercoating Spray (15 oz)

The SDS §2 mixture classification includes H340 (germ cell mutagen, Cat 1B) and H350 (carcinogen, Cat 1A) from the liquefied petroleum gas propellant fraction — these are the most severe classification tiers under GHS. The SDS was revised February 2026 and supersedes the previous 2024 version. Prop 65 warning is present based on these classifications.

SDS §8 specifies a NIOSH/MSHA approved air purifying respirator with organic vapor cartridge or canister for conditions where airborne concentrations may exceed exposure limits. Overhead application under a vehicle in an enclosed garage is a high-exposure scenario; open the garage door and achieve cross-ventilation as a minimum step, per SDS §8 engineering controls guidance.

Community reviews at 4.6 stars across 7,475 ratings confirm adequate multi-season protection on properly prepared bare or primed metal. Amazon long-term reviewers in northern states cite protection through multiple winters when the product is applied correctly, though some edge lifting at wheel arches by year three is noted in northern-tier accounts. Manufacturer coverage is stated as 10–15 sq ft per can; plan 3–4 cans for a full undercarriage.

Yes — the any-angle spray technology on the 248656 allows continuous spray in any orientation including directly overhead, which is the primary application scenario for undercarriage work. The wide comfort spray tip is designed for extended use at uncomfortable angles.

This product is designed for bare or primed metal. Applying it over active rust perforation or loose scale traps moisture and can accelerate the problem underneath. Wire-brush or sandblast loose material first; if the surface has significant rust penetration, a rust converter or encapsulator is the correct first step before undercoating.