diff --git a/qbsp/surfaces.cc b/qbsp/surfaces.cc
index b20db449..add1e069 100644
--- a/qbsp/surfaces.cc
+++ b/qbsp/surfaces.cc
@@ -502,6 +502,27 @@ int MakeFaceEdges(mapentity_t *entity, node_t *headnode)
 
 static int c_nodefaces;
 
+static node_t *FirstClusterLeaf_R(node_t *node, int cluster)
+{
+    if (node->planenum == PLANENUM_LEAF) {
+        if (node->viscluster == cluster) {
+            return node;
+        }
+    }
+    
+    for (int32_t i = 0; i < 2; i++) {
+        if (node->children[i]) {
+            node_t *child = FirstClusterLeaf_R(node->children[i], cluster);
+
+            if (child) {
+                return child;
+            }
+        }
+    }
+
+    return nullptr;
+}
+
 /*
 ================
 AddMarksurfaces_r
@@ -514,6 +535,16 @@ fixme-brushbsp: all leafs in a cluster can share the same marksurfaces, right?
 static void AddMarksurfaces_r(face_t *face, face_t *face_copy, node_t *node)
 {
     if (node->planenum == PLANENUM_LEAF) {
+
+        if (node->viscluster >= 0) {
+            node_t *head;
+
+            for (head = node; head->parent; head = head->parent)
+                ;
+
+            node = FirstClusterLeaf_R(head, node->viscluster);
+        }
+
         node->markfaces.push_back(face);
         return;
     }
diff --git a/qbsp/writebsp.cc b/qbsp/writebsp.cc
index f32ff3d1..a1c354e9 100644
--- a/qbsp/writebsp.cc
+++ b/qbsp/writebsp.cc
@@ -165,25 +165,40 @@ static void ExportLeaf(mapentity_t *entity, node_t *node)
     dleaf.visofs = -1; // no vis info yet
 
     // write the marksurfaces
-    dleaf.firstmarksurface = static_cast<int>(map.bsp.dleaffaces.size());
+    bool clustered = false;
 
-    for (auto &face : node->markfaces) {
-        if (!options.includeskip.value() && map.mtexinfos.at(face->texinfo).flags.is_skip)
-            continue;
-        // FIXME: this can happen when compiling some Q2 maps
-        // as Q1.
-        if (!face->outputnumber.has_value())
-            continue;
-
-        /* emit a marksurface */
-        map.bsp.dleaffaces.push_back(face->outputnumber.value());
-
-        /* grab tjunction split faces */
-        for (auto &fragment : face->fragments) {
-            map.bsp.dleaffaces.push_back(fragment.outputnumber.value());
+    if (node->viscluster >= 0) {
+        for (auto &leaf : map.bsp.dleafs) {
+            if (&leaf != &dleaf && leaf.cluster == node->viscluster) {
+                clustered = true;
+                dleaf.firstmarksurface = leaf.firstmarksurface;
+                dleaf.nummarksurfaces = leaf.nummarksurfaces;
+                break;
+            }
         }
     }
-    dleaf.nummarksurfaces = static_cast<int>(map.bsp.dleaffaces.size()) - dleaf.firstmarksurface;
+
+    if (!clustered) {
+        dleaf.firstmarksurface = static_cast<int>(map.bsp.dleaffaces.size());
+
+        for (auto &face : node->markfaces) {
+            if (!options.includeskip.value() && map.mtexinfos.at(face->texinfo).flags.is_skip)
+                continue;
+            // FIXME: this can happen when compiling some Q2 maps
+            // as Q1.
+            if (!face->outputnumber.has_value())
+                continue;
+
+            /* emit a marksurface */
+            map.bsp.dleaffaces.push_back(face->outputnumber.value());
+
+            /* grab tjunction split faces */
+            for (auto &fragment : face->fragments) {
+                map.bsp.dleaffaces.push_back(fragment.outputnumber.value());
+            }
+        }
+        dleaf.nummarksurfaces = static_cast<int>(map.bsp.dleaffaces.size()) - dleaf.firstmarksurface;
+    }
 
     dleaf.area = node->area;
     dleaf.cluster = node->viscluster;