Fire barriers are to be installed in roof spaces at almshouses in The Square, off Church Street, Spalding.
The three blocks, which make up the grade II listed building, will also be protected by fire blankets and fireproof paint.
South Holland District Council’s planning committee heard the steps are needed to stop fire spreading through the roof voids and granted planning consent at a meeting on Wednesday.
The application was submitted by the council.
Coun Howard Johnson told the meeting: “This is clearly required on fire safety grounds, apart from anything else.”
The homes are arranged in a U-shape around a grassed area.