diff --git a/src/domains/common/boundary_conditions.jl b/src/domains/common/boundary_conditions.jl
deleted file mode 100644
index 1356faa..0000000
--- a/src/domains/common/boundary_conditions.jl
+++ /dev/null
@@ -1,192 +0,0 @@
-# This file is a part of JuliaFEM.
-# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
-
-"""
-Generic boundary condition application for all domain types.
-
-This file provides BC application functions that work with any kernel implementing
-the generic kernel interface (continuum, beams, shells, plates, trusses, heat, etc.).
-
-# Explicit Workflow (Recommended)
-
-```julia
-# Setup (example with continuum mechanics)
-mesh = create_cantilever_mesh(50, 10, 10)
-material = LinearElastic(E=210e9, ν=0.3)
-kernel = ContinuumKernel(
-    ContinuumFormulation{FullThreeD}(),
-    material,
-    Displacement{3}()
-)
-
-# Choose assembler explicitly
-assembler = CSCAssembler()  # or COOAssembler()
-
-# Create cache (reusable!)
-cache = create_cache(assembler, mesh, kernel)
-
-# Assembly and solve
-assemble!(cache, assembler, kernel, mesh)
-K, f = extract_system(cache)
-
-# Apply BCs explicitly
-apply_neumann_bcs!(f, kernel, mesh, bc_neumann)
-apply_dirichlet_bcs!(K, f, kernel, mesh, bc_dirichlet)
-
-# Solve
-u = K \\ f
-```
-
-# Nonlinear Loop Example
-
-```julia
-cache = create_cache(CSCAssembler(), mesh, kernel)
-
-for iter in 1:max_iter
-    assemble!(cache, assembler, kernel, mesh)  # Zero allocations!
-    K, f = extract_system(cache)
-    apply_neumann_bcs!(f, kernel, mesh, bc_neumann)
-    apply_dirichlet_bcs!(K, f, kernel, mesh, bc_dirichlet)
-
-    Δu = K \\ f
-    u .+= Δu
-
-    if norm(Δu) < tol
-        break
-    end
-end
-```
-"""
-
-"""
-    apply_neumann_bcs!(
-        f::Vector{Float64},
-        kernel::AbstractKernel,
-        mesh::AbstractMesh,
-        bc_neumann::NeumannBC
-    ) -> Nothing
-
-Apply Neumann (natural) boundary conditions to force vector **in-place**.
-
-Works with any kernel type (continuum, beams, shells, heat, etc.) that implements
-the `dofs_per_node(kernel)` interface.
-
-For now, interprets `surface_ids` as node IDs (simplified).
-TODO: Proper surface force integration over element faces.
-
-# Arguments
-- `f`: Global force vector (modified in-place)
-- `kernel`: Domain kernel (provides dofs_per_node)
-- `mesh`: Finite element mesh
-- `bc_neumann`: Neumann BC data structure
-
-# Usage
-
-```julia
-# Define Neumann BCs
-bc_neumann = NeumannBC()
-push!(bc_neumann.surface_ids, 100)  # Node ID (simplified)
-push!(bc_neumann.values, Vec{3}((0.0, 0.0, -1000.0)))  # Force vector
-
-# Apply to force vector
-apply_neumann_bcs!(f, kernel, mesh, bc_neumann)
-```
-
-# See Also
-- [`apply_dirichlet_bcs!`](@ref)
-"""
-function apply_neumann_bcs!(
-    f::Vector{Float64},
-    kernel::AbstractKernel,
-    mesh::AbstractMesh,
-    bc_neumann::NeumannBC
-)
-    nnodes = nnodes_total(mesh)
-    ndofs_per_node = dofs_per_node(kernel)
-
-    for (surf_id, force) in zip(bc_neumann.surface_ids, bc_neumann.values)
-        # Simplified: treat surface_id as node_id
-        # TODO: Implement proper surface integration
-        node = surf_id
-        if node <= nnodes
-            for α in 1:ndofs_per_node
-                f[ndofs_per_node*(node-1)+α] += force[α]
-            end
-        end
-    end
-
-    return nothing
-end
-
-"""
-    apply_dirichlet_bcs!(
-        K::SparseMatrixCSC{Float64,Int},
-        f::Vector{Float64},
-        kernel::AbstractKernel,
-        mesh::AbstractMesh,
-        bc_dirichlet::DirichletBC
-    ) -> Nothing
-
-Apply Dirichlet (essential) boundary conditions **in-place**.
-
-Works with any kernel type (continuum, beams, shells, heat, etc.) that implements
-the `dofs_per_node(kernel)` interface.
-
-Uses elimination method:
-1. Zero out row and column for constrained DOF
-2. Set diagonal to 1.0
-3. Set force vector entry to prescribed value
-
-# Arguments
-- `K`: Global stiffness matrix (modified in-place)
-- `f`: Global force vector (modified in-place)
-- `kernel`: Domain kernel (provides dofs_per_node)
-- `mesh`: Finite element mesh
-- `bc_dirichlet`: Dirichlet BC data structure
-
-# Usage
-
-```julia
-# Define Dirichlet BCs (fix all DOFs at node 1)
-bc_dirichlet = DirichletBC()
-push!(bc_dirichlet.node_ids, 1)
-push!(bc_dirichlet.components, [1, 2, 3])  # All components
-push!(bc_dirichlet.values, 0.0)
-
-# Apply to system
-apply_dirichlet_bcs!(K, f, kernel, mesh, bc_dirichlet)
-```
-
-# See Also
-- [`apply_neumann_bcs!`](@ref)
-"""
-function apply_dirichlet_bcs!(
-    K::SparseMatrixCSC{Float64,Int},
-    f::Vector{Float64},
-    kernel::AbstractKernel,
-    mesh::AbstractMesh,
-    bc_dirichlet::DirichletBC
-)
-    nnodes = nnodes_total(mesh)
-    ndofs_per_node = dofs_per_node(kernel)
-    ndofs = ndofs_per_node * nnodes
-
-    for i in 1:length(bc_dirichlet.node_ids)
-        node = bc_dirichlet.node_ids[i]
-        components = bc_dirichlet.components[i]
-        value = bc_dirichlet.values[i]
-
-        for comp in components
-            dof = ndofs_per_node * (node - 1) + comp
-            if dof <= ndofs  # Safety check
-                # Elimination method
-                K[dof, :] .= 0.0
-                K[:, dof] .= 0.0
-                K[dof, dof] = 1.0
-                f[dof] = value
-            end
-        end
-    end
-
-    return nothing
-end