diff --git a/src/ui/BuildButtonGrid.cpp b/src/ui/BuildButtonGrid.cpp
index 465866a..02d9252 100644
--- a/src/ui/BuildButtonGrid.cpp
+++ b/src/ui/BuildButtonGrid.cpp
@@ -143,6 +143,19 @@ BuildButtonGrid::BuildButtonGrid(Simulation* sim, const GameConfig* config,
     m_deconstructButton->setIcon(loadBuildingIcon(
         QString::fromStdString(m_iconDir) + "/deconstruct.svg"));
     m_deconstructButton->setIconSize(kIconSize);
+    // Refund tooltip composed from world.refund_percentage (REQ-UI-DECONSTRUCT-BUTTON,
+    // REQ-BLD-DECONSTRUCT). A finished building refunds the configured percentage; a
+    // construction site removed before it is built is refunded in full. When the
+    // percentage is 100% both cases coincide, so the tooltip is simplified to one case.
+    const int refundPercentage = m_config->world.refundPercentage;
+    const QString deconstructTooltip = (refundPercentage >= 100)
+        ? tr("Deconstruct buildings. Refunds %1% of the building block cost.")
+              .arg(refundPercentage)
+        : tr("Deconstruct buildings. A finished building refunds %1% of its building "
+             "block cost once removed; a construction site removed before it is built "
+             "is refunded in full.")
+              .arg(refundPercentage);
+    m_deconstructButton->setToolTip(deconstructTooltip);
     layout->addWidget(m_deconstructButton, row, col);
     connect(m_deconstructButton, &QPushButton::clicked, this, [this]() {
         EventManager::getInstance()->sendEventImmediately(