Index: cart_apartment.xml
===================================================================
--- cart_apartment.xml
+++ cart_apartment.xml
@@ -2,16 +2,12 @@
 <Entity parent="structures/cart_house">
   <Cost>
     <PopulationBonus>15</PopulationBonus>
-    <BuildTime>75</BuildTime>
-    <Resources>
-      <wood>225</wood>
-    </Resources>
   </Cost>
   <GarrisonHolder>
     <Max>9</Max>
   </GarrisonHolder>
   <Health>
-    <Max>1500</Max>
+    <Max>1800</Max>
   </Health>
   <Identity>
     <GenericName>Apartment Building</GenericName>
@@ -19,6 +15,7 @@
   <Loot>
     <wood>45</wood>
   </Loot>
+  <Upgrade disable=""/>
   <VisualActor>
     <Actor>structures/carthaginians/apartment.xml</Actor>
   </VisualActor>
Index: cart_house.xml
===================================================================
--- cart_house.xml
+++ cart_house.xml
@@ -10,6 +10,17 @@
   <Obstruction>
     <Static width="13.0" depth="13.0"/>
   </Obstruction>
+  <Upgrade>
+    <Apartment>
+      <Entity>structures/cart_apartment</Entity>
+      <Tooltip>+50% health, +5 population bonus, and +3 garrison capacity.</Tooltip>
+      <RequiredTechnology>phase_village</RequiredTechnology>
+      <Cost>
+        <wood>75</wood>
+      </Cost>
+      <Time>30</Time>
+    </Apartment>
+  </Upgrade>
   <VisualActor>
     <FoundationActor>structures/carthaginians/fndn_house.xml</FoundationActor>
     <Actor>structures/carthaginians/house.xml</Actor>