Continuing cavity into porch?

[syne]

Is it the done thing to continue a cavity into adjoining walls? The main extension has a porch and originally I was just going to build the house wall then 'attach' the porch with wall starters or brick bond to the porch walls and have two separate cavities.

But now I'm wondering if I should make the cavity a T Shape?/continuous?

 

[^woody^]

No, but you should insert a physical vDPC where an external leaf becomes an inner leaf.

 

[syne]

That's interesting.
So the main house wall should have a vdpc where the porch begins.
Does this mean the wall would have a vertical line (much like an expansion joint) or would you 'back an forth' the dpc up the normal bond...

 

[Mr Chibs]

That's interesting.
So the main house wall should have a vdpc where the porch begins.
Does this mean the wall would have a vertical line (much like an expansion joint) or would you 'back an forth' the dpc up the normal bond...

No, a vertical DPC is cut into the cavity in-between your wall starter not like an expansion joint.

Some cut a 50mm sliver all the way down to house DPC, some just cut a slit with grinder and slide in the DPC.

 

[Mag2.0]

I had a porch with cavity built onto an existing building.
I fitted a DPC behind the wall starter to the inner leaf of blockwork.
I wasn't a fan of cutting into the existing building and potentially weakening structurally.

 

[^woody^]

 

[syne]

That pictures getting pretty famous theese days woody..
Not sure if its the answer to my question but suspect it probably is.

This is all new brickwork. I never considered this junction detail when drawing the plans.

 

[23vc]

I believe the majority of people don’t do this nowadays nor the building inspectors require it. Not saying it’s not the right thing to do though

 

[syne]

I'm still unsure about this detail.
Should it be like a or b ?
Any opinions..