Can a wall carry two roofs at different levels?

[Win Hampson]

Hello. I wonder if anyone can help me, please?

 

My house is a little unusual. It comprises a small bungalow and a small two storey house almost side by side with a 2 metre wide flat roof section joining them together.

 

I have planning permission to extend the two storey part over the flat roof. But that would involve extending one of the walls upwards, and that wall is already carrying the bungalow roof. Is it possible to extend the wall upwards with the bungalow roof trusses still embedded in it? I have included a sketch to make things clearer. As you can see, the wall plate for the bungalow is on the “inner” skin but if I extend it upwards to also carry the new two storey roof, the additional wall plate will be on the other skin. I guess I may also have an issue as to whether the foundations can carry the load of two roofs? As you can probably tell, I am not a builder – any advice would be appreciated.

[ToughButterCup]

The answer is really simple.

After doing your Due Diligence, employ a Structural Engineer. We can advise, but we are merely interested onlookers. We'll do our best to help your thinking, but with something as important as this, you need proper professional help.

[nod]

23 minutes ago, ToughButterCup said:

The answer is really simple.

After doing your Due Diligence, employ a Structural Engineer. We can advise, but we are merely interested onlookers. We'll do our best to help your thinking, but with something as important as this, you need proper professional help.

As above 

Se engineer will do a workable design quite cheaply 

[Win Hampson]

Thanks. I guess I may need a structural engineer at some stage. I was just hoping, in the first instance to understand some building principles (like, can I brick upwards from a wall plate, or is that a no-no) and to pick up some experience from the builders on this forum, as I guess some of you guys will have come across this issue before. Cheers

 

[tonyshouse]

Yes?

[Win Hampson]

Thanks! I was hoping that would be the case.

[PeterW]

30 minutes ago, Win Hampson said:

can I brick upwards from a wall plate

Nope. You’ll need to get some element of masonry to masonry bearing which may involve cutting the wall plate between the rafters or inserting a concrete lintel in place of the current wall plate. 
 

you’ll also need a good cavity tray installation and proper planning on how that valley will be formed and waterproofed. 

[Win Hampson]

Thanks. That's very helpful. I wasn't sure if I was allowed to cut the wall plate (I thought I had read somewhere that they should be a minimum of 3m long ie. continuous). But that's great. And thanks for the advice on the valley. Cheers.