Layered decoding is known to provide ef- ficient and high-throughput implementation of LDPC decoders. In the practical hardware implementation of layered decoders, the performance is strongly affected by quantization. The finite precision model determines the area of the decoder, which is mainly composed of memory, especially for long frames. To be specific, in the DVB-S2,-T2 and -C2 standards, the memory can occupy up to 70% of the total area. In this paper, we first focus our attention on the optimization of the num- ber of quantization bits. The effect of quantification on the channel values, Extrinsic and A-Posteriori Proba- bilities are studied separately. We propose solutions to optimize the quantification by an efficient saturation considering the case of a DVB-S2 decoder. We show that the memory area can be reduced by 28% compared to the state-of-the-art, without performance loss. Then, we optimize the size of the extrinsic memory considering implementation constraints when decoding multiple code rates. Finally, fixed point architecture is presented with implementation results.