Your books are fantastic and I really enjoy reading them. I need to have some clarification on period change for house renovation. I bought a period 7 house E3 (1989) and intend to do renovation on the house. I'd rather the period stays at period 7 but because the roof on left side is lower, I need to bump that up, rearrange the old roof tiles and replace some of the patio roofs 1/3 with new roof tiles, the rest of the old roof tiles will be reused just bumped up and rearranged. 

So my question is if only partial roofs are changed and extended for porch, floor tiles and main door changed, would my house now be period 8 house or remain as period 7 since it's only partial roof rather than the whole roof changed? I am moving the door to the left side coz the current door is kinda facing a T junction, quite a minor one not direct and its a quiet road. If I want to retain the period, what should i do, retain the old door and reuse? Please advise. 

Many thanks for your help.

Thanks for reading my books. 

A major renovation like what you have described will change the Period of the house. But do not worry, all you have to do is learn how to use the P8-E3 house's chart appropriately. Every chart has pros and cons. Make the best out of it. 

Warm Regards,

JY