diff --git a/src/ansys/acp/core/_tree_objects/stackup.py b/src/ansys/acp/core/_tree_objects/stackup.py
index 54fe69b6d6..3b68c62670 100644
--- a/src/ansys/acp/core/_tree_objects/stackup.py
+++ b/src/ansys/acp/core/_tree_objects/stackup.py
@@ -222,8 +222,12 @@ def _create_stub(self) -> stackup_pb2_grpc.ObjectServiceStub:
 
     locked: ReadOnlyProperty[bool] = grpc_data_property_read_only("properties.locked")
     status = grpc_data_property_read_only("properties.status", from_protobuf=status_type_from_pb)
-    thickness: ReadOnlyProperty[float] = grpc_data_property_read_only("properties.thickness")
-    area_weight: ReadOnlyProperty[float] = grpc_data_property_read_only("properties.area_weight")
+    thickness: ReadOnlyProperty[float] = grpc_data_property_read_only(
+        "properties.thickness", check_optional=True
+    )
+    area_weight: ReadOnlyProperty[float] = grpc_data_property_read_only(
+        "properties.area_weight", check_optional=True
+    )
 
     symmetry = grpc_data_property(
         "properties.symmetry",
diff --git a/tests/unittests/test_stackup.py b/tests/unittests/test_stackup.py
index 0bbbae7ab0..8e8123aadc 100644
--- a/tests/unittests/test_stackup.py
+++ b/tests/unittests/test_stackup.py
@@ -190,9 +190,22 @@ def test_add_fabric(parent_object):
     assert stackup.fabrics[-1].angle == 45.0
 
 
-def test_fabric_wit_angle(parent_object):
+def test_fabric_with_angle(parent_object):
     fabric1 = parent_object.create_fabric()
     fabric_with_angle = FabricWithAngle(fabric=fabric1, angle=45.0)
     assert fabric_with_angle != FabricWithAngle(fabric=parent_object.create_fabric(), angle=45.0)
     assert fabric_with_angle != FabricWithAngle(fabric=fabric1, angle=55.0)
     assert fabric_with_angle == FabricWithAngle(fabric=fabric1, angle=45.0)
+
+
+def test_fabric_without_material(parent_object, skip_before_version):
+    """Verify that a fabric without material can be added to a stackup.
+
+    Checks that the properties which should not be computable are 'None'.
+    """
+    skip_before_version("26.1")
+    fabric = parent_object.create_fabric()
+    stackup = parent_object.create_stackup()
+    stackup.add_fabric(fabric)
+    assert stackup.thickness is None
+    assert stackup.area_weight is None