diff --git a/festim/boundary_conditions/dirichlet_bc.py b/festim/boundary_conditions/dirichlet_bc.py
index cd334c483..6b31ab22e 100644
--- a/festim/boundary_conditions/dirichlet_bc.py
+++ b/festim/boundary_conditions/dirichlet_bc.py
@@ -99,7 +99,7 @@ def create_value(
             if "t" in arguments and "x" not in arguments and "T" not in arguments:
                 # only t is an argument
                 self.value_fenics = F.as_fenics_constant(
-                    mesh=mesh, value=self.value(t=t.value)
+                    mesh=mesh, value=self.value(t=float(t))
                 )
             else:
                 self.value_fenics = fem.Function(function_space)
@@ -119,19 +119,6 @@ def create_value(
                 )
                 self.value_fenics.interpolate(self.bc_expr)
 
-    def create_formulation(self, dofs, function_space):
-        """Applies the boundary condition
-        Args:
-            dofs (numpy.ndarray): the degrees of freedom of surface facets
-            function_space (dolfinx.fem.FunctionSpace): the function space
-        """
-        form = fem.dirichletbc(
-            value=self.value_fenics,
-            dofs=dofs,
-            V=function_space,
-        )
-        return form
-
     def update(self, t):
         """Updates the boundary condition value
 
diff --git a/festim/hydrogen_transport_problem.py b/festim/hydrogen_transport_problem.py
index a90f5eb3d..3a45adec7 100644
--- a/festim/hydrogen_transport_problem.py
+++ b/festim/hydrogen_transport_problem.py
@@ -246,45 +246,67 @@ def define_boundary_conditions(self):
                 # if name of species is given then replace with species object
                 bc.species = F.find_species_from_name(bc.species, self.species)
             if isinstance(bc, F.DirichletBC):
-                if (len(self.species) > 1) and (
-                    not isinstance(bc.value, (int, float, fem.Constant))
-                ):
-                    bc_dofs = bc.define_surface_subdomain_dofs(
-                        facet_meshtags=self.facet_meshtags,
-                        mesh=self.mesh,
-                        function_space=(
-                            bc.species.sub_function_space,
-                            bc.species.collapsed_function_space,
-                        ),
-                    )
-                    bc.create_value(
-                        mesh=self.mesh.mesh,
-                        temperature=self.temperature,
-                        function_space=bc.species.collapsed_function_space,
-                        t=self.t,
-                    )
-                else:
-                    bc_dofs = bc.define_surface_subdomain_dofs(
-                        facet_meshtags=self.facet_meshtags,
-                        mesh=self.mesh,
-                        function_space=bc.species.sub_function_space,
-                    )
-                    bc.create_value(
-                        mesh=self.mesh.mesh,
-                        temperature=self.temperature,
-                        function_space=bc.species.sub_function_space,
-                        t=self.t,
-                    )
-                if (len(self.species) == 1) and (
-                    isinstance(bc.value_fenics, (fem.Function))
-                ):
-                    form = bc.create_formulation(dofs=bc_dofs, function_space=None)
-                else:
-                    form = bc.create_formulation(
-                        dofs=bc_dofs, function_space=bc.species.sub_function_space
-                    )
+                form = self.create_dirichletbc_form(bc)
                 self.bc_forms.append(form)
 
+    def create_dirichletbc_form(self, bc):
+        """Creates a dirichlet boundary condition form
+
+        Args:
+            bc (festim.DirichletBC): the boundary condition
+
+        Returns:
+            dolfinx.fem.bcs.DirichletBC: A representation of
+                the boundary condition for modifying linear systems.
+        """
+        # create value_fenics
+        function_space_value = None
+
+        if callable(bc.value):
+            # if bc.value is a callable then need to provide a functionspace
+
+            if len(self.species) == 1:
+                function_space_value = bc.species.sub_function_space
+            else:
+                function_space_value = bc.species.collapsed_function_space
+
+        bc.create_value(
+            mesh=self.mesh.mesh,
+            temperature=self.temperature,
+            function_space=function_space_value,
+            t=self.t,
+        )
+
+        # get dofs
+        if len(self.species) > 1 and isinstance(bc.value_fenics, (fem.Function)):
+            function_space_dofs = (
+                bc.species.sub_function_space,
+                bc.species.collapsed_function_space,
+            )
+        else:
+            function_space_dofs = bc.species.sub_function_space
+
+        bc_dofs = bc.define_surface_subdomain_dofs(
+            facet_meshtags=self.facet_meshtags,
+            mesh=self.mesh,
+            function_space=function_space_dofs,
+        )
+
+        # create form
+        if len(self.species) == 1 and isinstance(bc.value_fenics, (fem.Function)):
+            form = fem.dirichletbc(
+                value=bc.value_fenics,
+                dofs=bc_dofs,
+                # no need to pass the functionspace since value_fenics is already a Function
+            )
+        else:
+            form = fem.dirichletbc(
+                value=bc.value_fenics,
+                dofs=bc_dofs,
+                V=bc.species.sub_function_space,
+            )
+        return form
+
     def create_formulation(self):
         """Creates the formulation of the model"""
         if len(self.sources) > 1:
diff --git a/test/test_dirichlet_bc.py b/test/test_dirichlet_bc.py
index 065a97b25..c73742c15 100644
--- a/test/test_dirichlet_bc.py
+++ b/test/test_dirichlet_bc.py
@@ -130,12 +130,13 @@ def test_value_callable_x_t_T():
         assert np.isclose(computed_value, expected_value)
 
 
-def test_callable_t_only():
+@pytest.mark.parametrize("value", [lambda t: t, lambda t: 1.0 + t])
+def test_callable_t_only(value):
     """Test that the value attribute can be a callable function of t only"""
 
     subdomain = F.SurfaceSubdomain1D(1, x=1)
     vol_subdomain = F.VolumeSubdomain1D(1, borders=[0, 1], material=dummy_mat)
-    value = lambda t: 1.0 + t
+    # value = lambda t: 1.0 + t
     species = F.Species("test")
 
     bc = F.DirichletBC(subdomain, value, species)