diff --git a/app/build_log4qt.sh b/app/build_log4qt.sh
new file mode 100755
index 000000000..72f694096
--- /dev/null
+++ b/app/build_log4qt.sh
@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# build_log4qt.sh - build and install Log4Qt into /usr/local
+# Designed to be run inside the Docker build or by a runner that has Qt installed at $QT_ROOT
+
+QT_ROOT=${QT_ROOT:-/opt/Qt/6.8.3/gcc_64}
+INSTALL_PREFIX=${INSTALL_PREFIX:-/usr/local}
+
+echo "Building Log4Qt (QT_ROOT=${QT_ROOT})..."
+
+TMPDIR=$(mktemp -d)
+trap 'rm -rf "$TMPDIR"' EXIT
+
+cd "$TMPDIR"
+if ! git clone --depth 1 https://github.com/MEONMedical/Log4Qt.git ./log4qt; then
+  echo "Warning: failed to clone Log4Qt from github. Exiting build." >&2
+  exit 0
+fi
+
+mkdir -p log4qt/build
+cd log4qt/build
+cmake -DCMAKE_BUILD_TYPE=Release \
+      -DCMAKE_CXX_STANDARD=20 \
+      -DCMAKE_CXX_EXTENSIONS=OFF \
+      -DCMAKE_PREFIX_PATH="${QT_ROOT}" \
+      -DCMAKE_INSTALL_PREFIX="${INSTALL_PREFIX}" ..
+
+cmake --build . -- -j$(nproc) || true
+cmake --install . || true
+
+# Create minimal CMake config so find_package(Log4Qt) will work
+mkdir -p "${INSTALL_PREFIX}/lib/cmake/Log4Qt"
+libpath=$((ls "${INSTALL_PREFIX}/lib/libLog4Qt.so"* 2>/dev/null || ls "${INSTALL_PREFIX}/lib/liblog4qt.so"* 2>/dev/null) | head -n1 || true)
+if [ -n "$libpath" ]; then
+  cat > "${INSTALL_PREFIX}/lib/cmake/Log4Qt/Log4QtConfig.cmake" <<EOF
+# Minimal Log4QtConfig.cmake created by build_log4qt.sh
+if (NOT TARGET Log4Qt::log4qt)
+  add_library(Log4Qt::log4qt UNKNOWN IMPORTED)
+  set_target_properties(Log4Qt::log4qt PROPERTIES
+    IMPORTED_LOCATION "${libpath}"
+    INTERFACE_INCLUDE_DIRECTORIES "${INSTALL_PREFIX}/include"
+  )
+endif()
+set(Log4Qt_FOUND TRUE CACHE INTERNAL "Log4Qt found by package config")
+set(Log4Qt_INCLUDE_DIRS "${INSTALL_PREFIX}/include" CACHE INTERNAL "Log4Qt include dir")
+set(Log4Qt_LIBRARIES "${libpath}" CACHE INTERNAL "Log4Qt library")
+EOF
+fi
+
+echo "Log4Qt build script finished."
+
+exit 0