Should newly added house steps feature insulation?
If the base for your stairs are not at the same level in ground as your foundation for your house, your stairs could or will be subject to frost heave. For that reason a thin layer (1/2&quot;) of insulation between the house and steps will act as a slip sheet so when one moves slightly, one will not affect the other. If there is any concern of wicking it will remedy that as well.
As a mention, all masonry products soak up moisture, some less than others, but all do. Any masonry that is exposed to the weather is supposed to be rated to withstand this exposure and any wood in contact with the masonry, is to be pressure treated, at least in modern times. If it is an older home, it may not have pressure treated material and hopefully other means were used at the time to provide separation between the wood and masonry, whether it be a type of metal or even tar paper...