--- a/crates/adom-aiflow/src/thermalvias.rs
+++ b/crates/adom-aiflow/src/thermalvias.rs
@@ -81,7 +81,8 @@
         }
         f && bk
     };
-    let tracks = b.tracks(); let vias = b.vias();
+    // Planned holes are through vias: inner copper must remain an obstacle too.
+    let tracks = b.copper_tracks(); let vias = b.vias();
     // holes: drill edge to drill edge at least the hole-to-hole minimum from every via and through-hole pad
     let h2h = aiflow_pours::hole_to_hole(spec);
     let mut holes = aiflow_pours::board_holes(b);
@@ -272,6 +273,31 @@
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn through_thermal_vias_clear_tracks_on_every_inner_layer() {
+        let text = r#"(kicad_pcb (net 0 "") (net 1 "GND") (net 2 "SIGNAL")
+ (layers (0 "F.Cu" signal)(4 "In1.Cu" signal)(6 "In2.Cu" signal)(2 "B.Cu" signal))
+ (gr_rect (start 0 0)(end 30 30)(layer "Edge.Cuts"))
+ (footprint "x" (layer "F.Cu") (at 10 10) (property "Reference" "U1")
+ (pad "1" smd rect (at 0 0)(size 1 1)(layers "F.Cu")(net 1 "GND"))))"#;
+        let spec = serde_json::json!({"hot":{"U1":{"watts":0.3,"tabNet":"GND"}},
+            "clearance":0.2,"viaPower":[0.6,0.3],
+            "pours":[{"net":"GND","layers":["F.Cu","B.Cu"],"polygon":[[5,5],[15,5],[15,15],[5,15]]}]});
+        let b = aiflow_board::Board::from_text("fixture", text.into()).unwrap();
+        let (base, _) = super::plan(&spec, &b, &[]);
+        let (x,y) = base[0].planned[0];
+        for layer in ["In1.Cu", "In2.Cu"] {
+            let mut blocked = text[..text.len()-1].to_string();
+            blocked.push_str(&format!("(segment (start {} {})(end {} {})(width 0.25)(layer \"{layer}\")(net 2)))",x-2.0,y,x+2.0,y));
+            let b = aiflow_board::Board::from_text("inner-track", blocked).unwrap();
+            let (parts, _) = super::plan(&spec, &b, &[]);
+            for &p in &parts[0].planned {
+                assert!(super::seg_dist(p,(x-2.0,y),(x+2.0,y)) >= 0.3+0.125+0.2,
+                    "through via must clear {layer} track: {p:?}");
+            }
+        }
+    }
+
     #[test]
     fn local_regions_reject_remote_disjoint_and_edge_candidates() {
         let pours = serde_json::json!([