I putty to try to get an even hull. I have seen several construction logs with hulls that are not quite smooth but also ones that are smooth. Unfortunately, the builders rarely write how they build the hull, whether they putty or not. Will try to get a construction log but I am in the middle of a renovation of our hall which is 20 square meters with nine doors. I have steamed down four layers of wallpaper and will start puttingty there too!