UK Landlord Forum / Life

I am the owner of a 1940's upper floor (2 storey building) maisonette.
It is a 999 year lease , I rent it out to tenants.
According to the lease I am responsible for the upper floor and roof , lower floor is responsible for supporting walls foundations etc.
On my last visit to the property i noticed a substantial crack in the brickwork of the lower maisonette below my external staircase. 12 bricks have fractured and the crack is 22mm at its widest point. I am concerned to the safety of the parapet wall which is directly above the damage. My section has a few cracks eminating from the main damage.
I have spoken to the downstairs leaseholder , he isn't bothered (he doesn't maintain his property at all)
I am planning on sending an official letter asking him to contact his insurer in order that they send a structural engineer.
I am half expecting him to ignore the letter.
Does anyone know what my options are should this occur?

Very very difficult to provide advice without reading the lease.

The lease will set out how covenants can be enforced.
Normally the landlord has the power to enforce covenants within the lease. This means that you as a leaseholder will need to ask the landlord to enforce the covenants against the other leaseholder [and potentially indemnify the landlord against cost incurred].

In some leases certain covenants may be mutually enforceable. This means that you as a leaseholder could take legal action directly against the other leaseholder for breach of covenant - this is not very common.

Consider contacting the Landlord to get in touch with the other lessee.
Perhaps you could clarify the insurance arrangements...that might an avenue of pursuit.

Again without sight of the lease itself very hard to advise