Keep same roofline or lower, and cut into wall

[arbeyukay]

In the planning stages of a two storey side extension, where it will sit on slightly lower ground (400-900mm) than the main house (live on a hill).
I understand that local authorities sometimes prefer extensions to be subservient to the main house but I've been told by an officer (at a pre-planning meeting) that it shouldn't be a problem due to local precedent.

Anyway, I don't mind too much either way, really just want the cheapest/easiest option. Is it cheaper/easier to join new roof tiles into existing ones, or join them at a lower level to an existing gable end wall?

 

[John D v2.0]

Ideally you want to minimise the amount of detailing. Not sure if it would cost more up front, but in the long term there's less to leak ou crack.
Just my personal opinion.
Regardless of that, surely if you step the whole extension down you'll have a step inside the house between the main house and new part? Is that acceptable to you?

 

[arbeyukay]

Ideally you want to minimise the amount of detailing. Not sure if it would cost more up front, but in the long term there's less to leak ou crack.
Just my personal opinion.
Regardless of that, surely if you step the whole extension down you'll have a step inside the house between the main house and new part? Is that acceptable to you?

Thanks John. No I don't mind a step down - could make a feature of it in the kitchen, and it would be on a landing upstairs.

Sorry, to ask a stupid question, but which one are you suggesting would cost more / require more detailing / be more inclined to leak or crack
?

 

[John D v2.0]

I'm saying regardless of the up front cost, a continuous roof will be more reliable than a flashing into a wall.
It's likely flashing in would be cheaper due to no need to disturb the existing roof but I wouldn't like to speculate as I'm not an expert