diff --git a/treble/combined_build_test.sh b/treble/combined_build_test.sh
index b91ee1f5f..707c6fba2 100755
--- a/treble/combined_build_test.sh
+++ b/treble/combined_build_test.sh
@@ -21,7 +21,7 @@ usage() {
     echo "  -d DIST_OUT    : Path for dist out"
     echo "  -a ALTER_TARGET: Alternative targets that share the build artifacts with the primary target"
     echo "  -c             : Run the target build again after installclean for reference"
-    echo '  -o             : Write build time results to "build_time_results.txt" file in "${OUT_DIR}" or "${DIST_OUT}/logs" if -d defined'
+    echo '  -o             : Write build time ("build_time_results.txt") and disk usage results (disk_size_results.txt") to "${OUT_DIR}" or "${DIST_OUT}/logs" if -d defined'
     echo "  -r             : Dryrun to see the commands without actually building the targets"
 }
 
@@ -41,6 +41,7 @@ while getopts ha:cd:ort:v: opt; do
             ;;
         o)
             result_out="build_time_results.txt"
+            result_out_size="disk_size_results.txt"
             ;;
         r)
             dry_run="true"
@@ -94,34 +95,49 @@ run_command() {
     fi
 }
 
+read_df() {
+    # read the available disk size
+    df . | awk '{print $4}' | sed -n '2p'
+}
+
 write_output() {
-    if [[ -z "${result_out}" || -n "${dry_run}" ]]; then
+    if [[ -z "$2" || -n "${dry_run}" ]]; then
         echo "Output: $1"
     else
-        echo "$1" >> "${out_dir}/${result_out}"
+        echo "$1" >> "${out_dir}/$2"
     fi
 }
 
 get_build_trace() {
     run_command "cp -f ${out_dir}/build.trace.gz ${out_dir}/${1}"
     if [[ -n "${result_out}" ]]; then
-        write_output "$(python3 development/treble/read_build_trace_gz.py ${out_dir}/${1})"
+        write_output "$(python3 development/treble/read_build_trace_gz.py ${out_dir}/${1})" "${result_out}"
     fi
 }
 
 if [[ -n "${result_out}" ]]; then
     run_command "rm -f ${out_dir}/${result_out}"
-    write_output "target, soong, kati, ninja, total"
+    write_output "target, soong, kati, ninja, total" "${result_out}"
+fi
+
+if [[ -n "${result_out_size}" ]]; then
+    run_command "rm -f ${out_dir}/${result_out_size}"
+    write_output "target, size, size_after_clean" "${result_out_size}"
 fi
 
 # Build the target first.
+disk_space_source=$(read_df)
 echo; echo "Initial build..."
 run_command "${base_command} TARGET_PRODUCT=${target} TARGET_BUILD_VARIANT=${variant} ${goals}"
+size_primary=$((${disk_space_source}-$(read_df)))
 
 if [[ -n "${installclean}" ]]; then
     # Run the same build after installclean
     echo; echo "Installclean for incremental build..."
     run_command "${base_command} TARGET_PRODUCT=${target} TARGET_BUILD_VARIANT=${variant} installclean"
+    size_primary_clean=$((${disk_space_source}-$(read_df)))
+    write_output "${target}, ${size_primary}, ${size_primary_clean}" "${result_out_size}"
+
     echo "Build the same initial build..."
     run_command "${base_command} TARGET_PRODUCT=${target} TARGET_BUILD_VARIANT=${variant} NINJA_ARGS=\"-d explain\" ${goals}"
     get_build_trace "build_${target}_installclean.trace.gz"
@@ -135,10 +151,13 @@ for alter_target in "${alter_targets[@]}"; do
     count=$((${count}+1))
     echo; echo "Build ${alter_target}...(${count})"
     run_command "${base_command} TARGET_PRODUCT=${alter_target} TARGET_BUILD_VARIANT=${variant} NINJA_ARGS=\"-d explain\" ${goals}"
+    size_alter=$((${disk_space_source}-$(read_df)))
     get_build_trace "build_${alter_target}_ab${count}.trace.gz"
 
     echo "Installclean for ${alter_target}..."
     run_command "${base_command} TARGET_PRODUCT=${alter_target} TARGET_BUILD_VARIANT=${variant} installclean"
+    size_alter_clean=$((${disk_space_source}-$(read_df)))
+    write_output "${alter_target}, ${size_alter}, ${size_alter_clean}" "${result_out_size}"
 
     if [[ -n "${dist_dir}" ]]; then
         # Remove target-specific dist artifacts