For positive integers p = k + 2, we construct a logarithmic extension of the b s (2) k conformal field theory of integrable representations by taking the kernel of two fermionic screening operators in a butterfly resolution of a three-boson realization of b s (2) k . The currents W − (z) and W + (z) of a W -algebra acting in the kernel are determined by a highest-weight state of dimension 4p − 2 and charge 2p − 1 and by a (θ=1)-twisted highest-weight state of the same dimension 4p−2 and opposite charge −2p+1. We construct 2p W -algebra representations, evaluate their characters, and show that together with the p−1 integrable representation characters, they generate a modular group representation whose structure is described as a deformation ofs (2) k integrable-representation characters and Rp+1 is a (p+1)-dimensional SL(2, Z)-representation known from the logarithmic (p, 1) model. The dimension 9p − 3 is conjecturally the dimension of the space of torus amplitudes, and the C n with n = 2 and 3 suggest the Jordan cell sizes in indecomposable W -algebra modules. We show that under Hamiltonian reduction, the W -algebra currents map into the currents of the triplet W -algebra of the logarithmic (p, 1) model.