diff --git a/components/layout/table.rs b/components/layout/table.rs
index 8df43d0821d..4f70c334dc7 100644
--- a/components/layout/table.rs
+++ b/components/layout/table.rs
@@ -784,14 +784,14 @@ impl TableLikeFlow for BlockFlow {
 
         if self.base.restyle_damage.contains(ServoRestyleDamage::REFLOW) {
             let mut sizes = vec![];
+            let mut incoming_rowspan_data = vec![];
 
             for kid in self.base.child_iter_mut() {
                 if kid.is_table_row() {
                     sizes.push(kid.as_mut_table_row()
-                        .compute_block_size_table_row_base(layout_context))
+                        .compute_block_size_table_row_base(layout_context, &mut incoming_rowspan_data))
                 }
             }
-
             let mut effects_rows = 0;
             let mut i = 0;
             for kid in self.base.child_iter_mut() {
diff --git a/components/layout/table_row.rs b/components/layout/table_row.rs
index 8e9e94c6356..3f8f5b54d4d 100644
--- a/components/layout/table_row.rs
+++ b/components/layout/table_row.rs
@@ -114,8 +114,20 @@ impl TableRowFlow {
     /// inline(always) because this is only ever called by in-order or non-in-order top-level
     /// methods
     #[inline(always)]
-    pub fn compute_block_size_table_row_base<'a>(&'a mut self, layout_context: &LayoutContext) -> Au {
+    pub fn compute_block_size_table_row_base<'a>(&'a mut self, layout_context: &LayoutContext, incoming_rowspan_data: &mut Vec<Au>) -> Au {
         if self.block_flow.base.restyle_damage.contains(ServoRestyleDamage::REFLOW) {
+            fn include_sizes_from_previous_rows(col: &mut usize,
+                                                incoming_rowspan: &[u32],
+                                                incoming_rowspan_data: &mut Vec<Au>,
+                                                max_block_size: &mut Au) {
+                while let Some(span) = incoming_rowspan.get(*col) {
+                    if *span <= 1 {
+                        break;
+                    }
+                    *max_block_size = max(*max_block_size, incoming_rowspan_data[*col]);
+                    *col += 1;
+                }
+            }
             // Per CSS 2.1 § 17.5.3, find max_y = max(computed `block-size`, minimum block-size of
             // all cells).
             let mut max_block_size = Au(0);
@@ -124,7 +136,9 @@ impl TableRowFlow {
                 - self.block_flow.fragment.border_padding
                 - self.block_flow.fragment.margin;
 
+            let mut col = 0;
             for kid in self.block_flow.base.child_iter_mut() {
+                include_sizes_from_previous_rows(&mut col, &self.incoming_rowspan, incoming_rowspan_data, &mut max_block_size);
                 kid.place_float_if_applicable();
                 if !kid.base().flags.is_float() {
                     kid.assign_block_size_for_inorder_child_if_necessary(layout_context,
@@ -133,19 +147,28 @@ impl TableRowFlow {
                 }
 
                 let row_span;
+                let column_span;
+                let cell_total;
                 {
                     let cell = kid.as_mut_table_cell();
                     row_span = cell.row_span as i32;
-                    max_block_size =
-                        max(max_block_size, cell.total_block_size() / row_span);
+                    column_span = cell.column_span as usize;
+                    cell_total = cell.total_block_size();
                 }
-                {
-                    let child_node = kid.mut_base();
-                    child_node.position.start.b = Au(0);
-                    max_block_size = max(max_block_size, child_node.position.size.block / row_span);
+                let child_node = kid.mut_base();
+                child_node.position.start.b = Au(0);
+                let cell_block_size = max(cell_total, child_node.position.size.block);
+                max_block_size = max(max_block_size, cell_block_size / row_span);
+
+                if row_span > 1 {
+                    if incoming_rowspan_data.len() <= col {
+                        incoming_rowspan_data.resize(col + 1, Au(0));
+                    }
+                    incoming_rowspan_data[col] = cell_block_size / row_span;
                 }
+                col += column_span;
             }
-            // XXXManishearth include overages from spanning cells from previous rows
+            include_sizes_from_previous_rows(&mut col, &self.incoming_rowspan, incoming_rowspan_data, &mut max_block_size);
 
             let mut block_size = max_block_size;
             // TODO: Percentage block-size