diff --git a/base/array.jl b/base/array.jl
index 8c753b3e3924dc..b9452e62d7e889 100644
--- a/base/array.jl
+++ b/base/array.jl
@@ -682,15 +682,6 @@ function reverse!(v::AbstractVector, s=1, n=length(v))
 end
 
 
-# concatenations of combinations (homogeneous, heterogeneous) of dense matrices/vectors #
-vcat{T}(A::Union{Vector{T},Matrix{T}}...) = typed_vcat(T, A...)
-vcat(A::Union{Vector,Matrix}...) = typed_vcat(promote_eltype(A...), A...)
-hcat{T}(A::Union{Vector{T},Matrix{T}}...) = typed_hcat(T, A...)
-hcat(A::Union{Vector,Matrix}...) = typed_hcat(promote_eltype(A...), A...)
-hvcat{T}(rows::Tuple{Vararg{Int}}, xs::Union{Vector{T},Matrix{T}}...) = typed_hvcat(T, rows, xs...)
-hvcat(rows::Tuple{Vararg{Int}}, xs::Union{Vector,Matrix}...) = typed_hvcat(promote_eltype(xs...), rows, xs...)
-cat{T}(catdims, xs::Union{Vector{T},Matrix{T}}...) = Base.cat_t(catdims, T, xs...)
-cat(catdims, xs::Union{Vector,Matrix}...) = Base.cat_t(catdims, promote_eltype(xs...), xs...)
 # concatenations of homogeneous combinations of vectors, horizontal and vertical
 function hcat{T}(V::Vector{T}...)
     height = length(V[1])
diff --git a/base/sparse/sparsematrix.jl b/base/sparse/sparsematrix.jl
index d8d3fa47d0f424..c0174fe850a1bb 100644
--- a/base/sparse/sparsematrix.jl
+++ b/base/sparse/sparsematrix.jl
@@ -265,6 +265,8 @@ function convert{Tv,Ti}(::Type{SparseMatrixCSC{Tv,Ti}}, S::SparseMatrixCSC)
 end
 # convert'ing from other matrix types to SparseMatrixCSC (also see sparse())
 convert(::Type{SparseMatrixCSC}, M::Matrix) = sparse(M)
+convert{Tv}(::Type{SparseMatrixCSC}, M::AbstractMatrix{Tv}) = convert(SparseMatrixCSC{Tv,Int}, M)
+convert{Tv}(::Type{SparseMatrixCSC{Tv}}, M::AbstractMatrix{Tv}) = convert(SparseMatrixCSC{Tv,Int}, M)
 function convert{Tv,Ti}(::Type{SparseMatrixCSC{Tv,Ti}}, M::AbstractMatrix)
     (I, J, V) = findnz(M)
     eltypeTiI = convert(Vector{Ti}, I)
diff --git a/base/sparse/sparsevector.jl b/base/sparse/sparsevector.jl
index cd002a2574bdbf..e94d34a2afb7e8 100644
--- a/base/sparse/sparsevector.jl
+++ b/base/sparse/sparsevector.jl
@@ -793,27 +793,48 @@ hcat(Xin::Union{Vector, AbstractSparseVector}...) = hcat(map(sparse, Xin)...)
 vcat(Xin::Union{Vector, AbstractSparseVector}...) = vcat(map(sparse, Xin)...)
 
 
-### Sparse/special/dense vector/matrix concatenation
-
-# TODO: These methods should be moved to a more appropriate location, particularly some
-# future equivalent of base/linalg/special.jl dedicated to interactions between a broader
-# set of matrix types.
-
-# TODO: A similar definition also exists in base/linalg/bidiag.jl. These definitions should
-# be consolidated in a more appropriate location, for example base/linalg/special.jl.
-SpecialArrays = Union{Diagonal, Bidiagonal, Tridiagonal, SymTridiagonal}
-
-function hcat(Xin::Union{Vector, Matrix, SparseVector, SparseMatrixCSC, SpecialArrays}...)
+### Concatenation of un/annotated sparse/special/dense vectors/matrices
+
+# TODO: These methods and definitions should be moved to a more appropriate location,
+# particularly some future equivalent of base/linalg/special.jl dedicated to interactions
+# between a broader set of matrix types.
+
+# TODO: A definition similar to the third exists in base/linalg/bidiag.jl. These definitions
+# should be consolidated in a more appropriate location, e.g. base/linalg/special.jl.
+typealias _SparseArrays Union{SparseVector, SparseMatrixCSC}
+typealias _SpecialArrays Union{Diagonal, Bidiagonal, Tridiagonal, SymTridiagonal}
+typealias _SparseConcatArrays Union{_SpecialArrays, _SparseArrays}
+
+typealias _Symmetric_SparseConcatArrays{T,A<:_SparseConcatArrays} Symmetric{T,A}
+typealias _Hermitian_SparseConcatArrays{T,A<:_SparseConcatArrays} Hermitian{T,A}
+typealias _Triangular_SparseConcatArrays{T,A<:_SparseConcatArrays} Base.LinAlg.AbstractTriangular{T,A}
+typealias _Annotated_SparseConcatArrays Union{_Triangular_SparseConcatArrays, _Symmetric_SparseConcatArrays, _Hermitian_SparseConcatArrays}
+
+typealias _Symmetric_DenseArrays{T,A<:Matrix} Symmetric{T,A}
+typealias _Hermitian_DenseArrays{T,A<:Matrix} Hermitian{T,A}
+typealias _Triangular_DenseArrays{T,A<:Matrix} Base.LinAlg.AbstractTriangular{T,A}
+typealias _Annotated_DenseArrays Union{_Triangular_DenseArrays, _Symmetric_DenseArrays, _Hermitian_DenseArrays}
+typealias _Annotated_Typed_DenseArrays{T} Union{_Triangular_DenseArrays{T}, _Symmetric_DenseArrays{T}, _Hermitian_DenseArrays{T}}
+
+typealias _SparseConcatGroup Union{Vector, Matrix, _SparseConcatArrays, _Annotated_SparseConcatArrays, _Annotated_DenseArrays}
+typealias _DenseConcatGroup Union{Vector, Matrix, _Annotated_DenseArrays}
+typealias _TypedDenseConcatGroup{T} Union{Vector{T}, Matrix{T}, _Annotated_Typed_DenseArrays{T}}
+
+# Concatenations involving un/annotated sparse/special matrices/vectors should yield sparse arrays
+function cat(catdims, Xin::_SparseConcatGroup...)
+    X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
+    T = promote_eltype(Xin...)
+    Base.cat_t(catdims, T, X...)
+end
+function hcat(Xin::_SparseConcatGroup...)
     X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
     hcat(X...)
 end
-
-function vcat(Xin::Union{Vector, Matrix, SparseVector, SparseMatrixCSC, SpecialArrays}...)
+function vcat(Xin::_SparseConcatGroup...)
     X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
     vcat(X...)
 end
-
-function hvcat(rows::Tuple{Vararg{Int}}, X::Union{Vector, Matrix, SparseVector, SparseMatrixCSC, SpecialArrays}...)
+function hvcat(rows::Tuple{Vararg{Int}}, X::_SparseConcatGroup...)
     nbr = length(rows)  # number of block rows
 
     tmp_rows = Array{SparseMatrixCSC}(nbr)
@@ -825,11 +846,16 @@ function hvcat(rows::Tuple{Vararg{Int}}, X::Union{Vector, Matrix, SparseVector,
     vcat(tmp_rows...)
 end
 
-function cat(catdims, Xin::Union{Vector, Matrix, SparseVector, SparseMatrixCSC, SpecialArrays}...)
-    X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
-    T = promote_eltype(Xin...)
-    Base.cat_t(catdims, T, X...)
-end
+# Concatenations strictly involving un/annotated dense matrices/vectors should yield dense arrays
+cat(catdims, xs::_DenseConcatGroup...) = Base.cat_t(catdims, promote_eltype(xs...), xs...)
+vcat(A::_DenseConcatGroup...) = Base.typed_vcat(promote_eltype(A...), A...)
+hcat(A::_DenseConcatGroup...) = Base.typed_hcat(promote_eltype(A...), A...)
+hvcat(rows::Tuple{Vararg{Int}}, xs::_DenseConcatGroup...) = Base.typed_hvcat(promote_eltype(xs...), rows, xs...)
+# For performance, specially handle the case where the matrices/vectors have homogeneous eltype
+cat{T}(catdims, xs::_TypedDenseConcatGroup{T}...) = Base.cat_t(catdims, T, xs...)
+vcat{T}(A::_TypedDenseConcatGroup{T}...) = Base.typed_vcat(T, A...)
+hcat{T}(A::_TypedDenseConcatGroup{T}...) = Base.typed_hcat(T, A...)
+hvcat{T}(rows::Tuple{Vararg{Int}}, xs::_TypedDenseConcatGroup{T}...) = Base.typed_hvcat(T, rows, xs...)
 
 
 ### math functions
diff --git a/test/linalg/special.jl b/test/linalg/special.jl
index 05105acd149a86..fc8e4c67d6d84b 100644
--- a/test/linalg/special.jl
+++ b/test/linalg/special.jl
@@ -166,3 +166,86 @@ let
         end
     end
 end
+
+# Test that concatenations of annotated sparse/special matrix types with other matrix
+# types yield sparse arrays, and that the code which effects that does not make concatenations
+# strictly involving un/annotated dense matrices yield sparse arrays
+#
+# TODO: As with the associated code, these tests should be moved to a more appropriate
+# location, particularly some future equivalent of base/linalg/special.jl dedicated to
+# intereactions between a broader set of matrix types
+let
+    N = 4
+    # The tested annotation types
+    utriannotations = (UpperTriangular, Base.LinAlg.UnitUpperTriangular)
+    ltriannotations = (LowerTriangular, Base.LinAlg.UnitLowerTriangular)
+    annotations = (utriannotations..., ltriannotations..., Symmetric, Hermitian)
+    # Concatenations involving these types, un/annotated, should yield sparse arrays
+    spvec = spzeros(N)
+    spmat = speye(N)
+    diagmat = Diagonal(ones(N))
+    bidiagmat = Bidiagonal(ones(N), ones(N-1), true)
+    tridiagmat = Tridiagonal(ones(N-1), ones(N), ones(N-1))
+    symtridiagmat = SymTridiagonal(ones(N), ones(N-1))
+    sparseconcatmats = (spmat, diagmat, bidiagmat, tridiagmat, symtridiagmat)
+    # Concatenations involving strictly these types, un/annotated, should yield dense arrays
+    densevec = ones(N)
+    densemat = ones(N, N)
+    # Annotated collections
+    annodmats = [annot(densemat) for annot in annotations]
+    annospcmats = [annot(spcmat) for annot in annotations, spcmat in sparseconcatmats]
+    # Test that concatenations of pairwise combinations of annotated sparse/special
+    # yield sparse matrices
+    for annospcmata in annospcmats, annospcmatb in annospcmats
+        @test issparse(vcat(annospcmata, annospcmatb))
+        @test issparse(hcat(annospcmata, annospcmatb))
+        @test issparse(hvcat((2,), annospcmata, annospcmatb))
+        @test issparse(cat((1,2), annospcmata, annospcmatb))
+    end
+    # Test that concatenations of pairwise combinations of annotated sparse/special
+    # matrices and other matrix/vector types yield sparse matrices
+    for annospcmat in annospcmats
+        # --> Tests applicable to pairs including only matrices
+        for othermat in (densemat, annodmats..., sparseconcatmats...)
+            @test issparse(vcat(annospcmat, othermat))
+            @test issparse(vcat(othermat, annospcmat))
+        end
+        # --> Tests applicable to pairs including other vectors or matrices
+        for other in (spvec, densevec, densemat, annodmats..., sparseconcatmats...)
+            @test issparse(hcat(annospcmat, other))
+            @test issparse(hcat(other, annospcmat))
+            @test issparse(hvcat((2,), annospcmat, other))
+            @test issparse(hvcat((2,), other, annospcmat))
+            @test issparse(cat((1,2), annospcmat, other))
+            @test issparse(cat((1,2), other, annospcmat))
+        end
+    end
+    # The preceding tests should cover multi-way combinations of those types, but for good
+    # measure test a few multi-way combinations involving those types
+    @test issparse(vcat(spmat, densemat, annospcmats[1], annodmats[2]))
+    @test issparse(vcat(densemat, spmat, annodmats[1], annospcmats[2]))
+    @test issparse(hcat(spvec, annodmats[3], annospcmats[3], densevec, diagmat))
+    @test issparse(hcat(annodmats[4], annospcmats[4], spvec, densevec, diagmat))
+    @test issparse(hvcat((5,), diagmat, densevec, spvec, annodmats[1], annospcmats[5]))
+    @test issparse(hvcat((5,), spvec, annodmats[2], diagmat, densevec, annospcmats[6]))
+    @test issparse(cat((1,2), annodmats[3], diagmat, annospcmats[7], densevec, spvec))
+    @test issparse(cat((1,2), spvec, diagmat, densevec, annospcmats[8], annodmats[4]))
+    # Test that concatenations strictly involving un/annotated dense matrices/vectors
+    # yield dense arrays
+    for densemata in (densemat, annodmats...)
+        # --> Tests applicable to pairs including only matrices
+        for densematb in (densemat, annodmats...)
+            @test !issparse(vcat(densemata, densematb))
+            @test !issparse(vcat(densematb, densemata))
+        end
+        # --> Tests applicable to pairs including vectors or matrices
+        for otherdense in (densevec, densemat, annodmats...)
+            @test !issparse(hcat(densemata, otherdense))
+            @test !issparse(hcat(otherdense, densemata))
+            @test !issparse(hvcat((2,), densemata, otherdense))
+            @test !issparse(hvcat((2,), otherdense, densemata))
+            @test !issparse(cat((1,2), densemata, otherdense))
+            @test !issparse(cat((1,2), otherdense, densemata))
+        end
+    end
+end