Technology · Building science
Thermal Bridging in Camper Bodies: What It Is & Why It Matters
Updated
A thermal bridge is a conductive path — usually metal — that runs through a wall and shortcuts the insulation, letting heat move straight across it. In a camper body, thermal bridges lower the wall’s real-world R-value below its rated value and create cold lines on the inside surface where condensation forms. Controlling them is as important as the insulation itself.
What a thermal bridge is
Insulation works by putting a low-conductivity material in the path of heat flow. A thermal bridge defeats that locally: wherever a highly conductive material (typically metal) connects the warm side of the wall to the cold side, heat takes the shortcut. The insulation around it can be excellent, but the bridge sets the weak point — a chain-is-only-as-strong-as-its-weakest-link problem for heat.
Common bridge paths in a vehicle body
Framed and clad bodies have many potential bridges. The most important ones:
- Metal frame or stud members that span from the inner skin to the outer skin
- Fasteners — screws and bolts that pass through the insulation into a cold skin
- Edges and corners where a solid metal extrusion ties the walls together
- Window and door frames, roof penetrations, and mounting hardware
- Any continuous metal that touches both the inside and the outside
Why it matters: R-value and condensation
Two things go wrong. First, the wall’s effective (whole-wall) R-value drops below the rating of the insulation alone, because the bridges leak heat — a wall can lose a meaningful fraction of its rated performance to bridging. Second, and often worse in a camper, the inside surface over a bridge runs colder than the surrounding wall. When warm, humid interior air (from breathing, cooking, and showering) hits that cold spot, it condenses — you get damp lines, drips, and over time mold and corrosion, exactly where the bridge is.
How continuous insulation fixes it
The cure is continuous insulation — an unbroken layer of insulation with no conductive material spanning it — and, where a structural connection is unavoidable, a thermal break: a low-conductivity material inserted to interrupt the metal path. Building science treats continuous insulation as the reliable way to hit a wall’s rated performance, because it removes the bridges rather than trying to insulate around them.
How Foundation’s body addresses thermal bridging
Foundation’s wall is a one-piece composite structural insulated panel with continuous insulation and no metal stud frame running through it — so the field of the wall has no bridge to begin with. At the edges and corners, where the walls need to be joined, Foundation uses a hybrid aluminum-and-PVC co-extrusion: the PVC interrupts the aluminum so heat can’t walk straight across the joint. The result is a continuous R11 wall whose real-world performance stays close to its rating, with far less of the condensation-inside-the-wall problem that framed bodies fight.
Common questions
Questions people ask
What is thermal bridging in simple terms?
It’s a spot where something conductive — usually metal — runs through the wall and lets heat bypass the insulation. It lowers the wall’s real R-value and makes a cold line on the inside where condensation forms.
Why does thermal bridging cause condensation?
The inside surface over a bridge runs colder than the rest of the wall. When warm, humid interior air touches that cold spot it condenses into water — leading to damp lines, mold, and corrosion right at the bridge.
How does Foundation reduce thermal bridging?
The wall is a one-piece composite panel with continuous insulation and no metal frame through it, and the edges use a thermal-break aluminum-and-PVC extrusion so heat can’t bridge across the joints. That keeps the R11 wall performing close to its rating and reduces condensation inside the wall.
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