Q: Should we have an underlayment installed over the plywood subfloor before an unfinished solid wood floor is installed in our kitchen, as well in all the other rooms (not bathrooms of course)? Should any drainage pan be installed by a plumber underneath the dishwasher and refrigerator in case of flooding?
The entire unit (all rooms) will be gutted and all the baseboards will be ripped out.
Also, how much expansion space between the walls and wood flooring should be allowed, before the new baseboard is installed?
A: A drainage pan under the dishwasher won’t help. If you have a leak or blow a hose a pan won’t help. Your refrigerator should already have a pan as it is likely automatic defrost.
Expansion space along outside walls is partly determined by the width of the planks installed. I’d leave up to 1/2″. Is the plywood subfloor 3/4″ thick. Most building codes I’m aware of allow no less than 5/8. If you have either of these you will be fine.