Last year I listed my spare room on Air BNB and enjoyed a few weekends with paying guests. However toward the end of the summer, new fire regulations were introduced with more stringent fire regulations. For me to comply, I need to change the door on my spare room to an F30 Fire Door. The current door is a hollow panel door and measures 180x60x 3cm. The bedroom was an addition to the house by a previous owner and is a large room under the eaves of the roof - hence the door being smaller than standard size. The internal walls are partition, stud walls I believe. I understand that if I can find a solid door I can paint it with an intumescent coating paint which is fire resistant. This is the only door which needs to be changed to comply with the regulations. My query is - how can I strengthen the door frame - particularly the hinged side - to allow for the additional weight of a solid door?