Crack next to new lintel

[m0t]

Had a timber frame extension built on top of our single story brick ground floor.

The lintel over this window was rotten timber and was cut out from the inside and replaced with a concrete lintel. This was done according to the structural engineers drawings.

I've noticed a crack has appeared today in line with the end of the lintel, do I need to worry or is it likely to be settlement?

The wall is solid brick, there is a timber wall plate above and the joists run at 90 degrees from the wall. There's nothing to see from the outside as it's clad in EWI.

 

[jeds]

The crack doesn't say anything about what's happening structurally. It could be a stress crack or it could just be poorly prepared plastering or a combination of the two.
It looks cosmetic and nothing to worry about. If the wall looks ok externally don't worry - just keep an eye on it.

 

[^woody^]

An existing ground floor extension would not settle

 

[m0t]

An existing ground floor extension would not settle

I thought there might have been some as the mortar under the new lintel dried out plus the weight of the new stuff on top?

I might just caulk it and paint over it and see what happens