diff --git a/app/src/frontend/building-edit.js b/app/src/frontend/building-edit.js
index 8af3716e..50e3324b 100644
--- a/app/src/frontend/building-edit.js
+++ b/app/src/frontend/building-edit.js
@@ -27,9 +27,9 @@ class BuildingEdit extends Component {
             facade_upper: props.facade_upper,
             facade_lower: props.facade_lower,
             facade_source: props.facade_source,
-            size_attic: props.size_attic,
-            size_core: props.size_core,
-            size_basement: props.size_basement,
+            size_storeys_attic: props.size_storeys_attic,
+            size_storeys_core: props.size_storeys_core,
+            size_storeys_basement: props.size_storeys_basement,
             likes_total: props.likes_total,
             liked: props.liked
         };
@@ -41,7 +41,7 @@ class BuildingEdit extends Component {
 
     handleChange(event) {
         const target = event.target;
-        const value = target.value;
+        const value = (target.value === '')? null : target.value;
         const name = target.name;
 
         this.setState({
@@ -202,24 +202,24 @@ class BuildingEdit extends Component {
                         <legend className="h3 bullet-prefix size">Size</legend>
                         <div id="data-list-size" className="data-list">
 
-                            <label htmlFor="size_attic">Attic storeys</label>
+                            <label htmlFor="size_storeys_attic">Attic storeys</label>
                             <input className="form-control" type="number" step="1"
-                                   id="size_attic" name="size_attic"
-                                   value={this.state.size_attic}
+                                   id="size_storeys_attic" name="size_storeys_attic"
+                                   value={this.state.size_storeys_attic}
                                    onChange={this.handleChange}
                                    />
 
-                            <label htmlFor="size_core">Core storeys</label>
+                            <label htmlFor="size_storeys_core">Core storeys</label>
                             <input className="form-control" type="number" step="1"
-                                   id="size_core" name="size_core"
-                                   value={this.state.size_core}
+                                   id="size_storeys_core" name="size_storeys_core"
+                                   value={this.state.size_storeys_core}
                                    onChange={this.handleChange}
                                    />
 
-                            <label htmlFor="size_basement">Basement storeys</label>
+                            <label htmlFor="size_storeys_basement">Basement storeys</label>
                             <input className="form-control" type="number" step="1"
-                                   id="size_basement" name="size_basement"
-                                   value={this.state.size_basement}
+                                   id="size_storeys_basement" name="size_storeys_basement"
+                                   value={this.state.size_storeys_basement}
                                    onChange={this.handleChange}
                                    />
                         </div>
diff --git a/app/src/frontend/building-view.js b/app/src/frontend/building-view.js
index 10ce5bba..7b126094 100644
--- a/app/src/frontend/building-view.js
+++ b/app/src/frontend/building-view.js
@@ -64,11 +64,11 @@ const BuildingView = function(props){
                 <h3 className="h3 bullet-prefix size">Size</h3>
                 <dl className="data-list">
                     <dt>Attic storeys</dt>
-                    <dd>{props.size_attic? props.size_attic : '-'}</dd>
+                    <dd>{props.size_storeys_attic? props.size_storeys_attic : '-'}</dd>
                     <dt>Core storeys</dt>
-                    <dd>{props.size_core? props.size_core : '-'}</dd>
+                    <dd>{props.size_storeys_core? props.size_storeys_core : '-'}</dd>
                     <dt>Basement storeys</dt>
-                    <dd>{props.size_basement? props.size_basement : '-'}</dd>
+                    <dd>{props.size_storeys_basement? props.size_storeys_basement : '-'}</dd>
                 </dl>
             </section>
             <section className="data-section">
diff --git a/app/src/tileserver.js b/app/src/tileserver.js
index 6247f1ed..88bcb3e3 100644
--- a/app/src/tileserver.js
+++ b/app/src/tileserver.js
@@ -81,7 +81,10 @@ router.get('/size_storeys/:z/:x/:y.png', function(req, res) {
     // const table_def = 'geometries'
     const table_def = `(
         SELECT
-            (b.size_attic + b.size_core) as size_storeys,
+            (
+                coalesce(b.size_storeys_attic, 0) +
+                coalesce(b.size_storeys_core, 0)
+            ) as size_storeys,
             g.geometry_geom
         FROM
             geometries as g,
diff --git a/migrations/004.location-date-size-like.up.sql b/migrations/004.location-date-size-like.up.sql
index 2e62b36b..97b03bc0 100644
--- a/migrations/004.location-date-size-like.up.sql
+++ b/migrations/004.location-date-size-like.up.sql
@@ -51,11 +51,11 @@ ALTER TABLE buildings ADD CONSTRAINT buildings_facade_source_len CHECK (length(f
 -- Size
 
 -- Attic storeys
-ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_storeys_attic smallint;
+ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_storeys_attic smallint DEFAULT 0;
 -- Core storeys
-ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_storeys_core smallint;
+ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_storeys_core smallint DEFAULT 0;
 -- Basement storeys
-ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_storeys_basement smallint;
+ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_storeys_basement smallint DEFAULT 0;
 
 -- Height to apex (m)
 ALTER TABLE buildings ADD COLUMN IF NOT EXISTS size_height_apex real;