Contractor Rob Robillard also discusses lally column replacement. For more expert home improvement advice, go to realestate.boston.com.

Q. The outside of the Lally columns in my under-the-house garage have rusted out at the bottom. The inside concrete looks OK, but is the outside steel layer important? GUEST, in Hotton’s chat ...

A: Lally columns are made up of a steel tube filled with concrete. The steel is most important, because any concrete inside the steel tube is too small to hold up without the steel.

A lally column is replaced by a larger ridge beam for an open kitchen and dining area. Great progress is being made on the project house. The primary addition is being framed and the rooms are ...