Good ways of calculating Deferred Maintenance into value

[Kurt E.]

I have only been an agent for a few months now and my main focus is on Multi-Family properties (only agent in the office in Multi-Family). I was wondering if there is a rule of thumb when it comes to deferred maintenance and how it affects the market value of the property?

Simple Example:
8 unit property in secondary market
$30,500 NOI
Market Cap 8%
Value = $380,000
Estimated Deferred Maintenance = $20,000 (Siding and a little work on the roof)

The work hasn't been done because the current owner feels it has no effect on the occupancy rate. How heavy should this deferred maintenance weigh on the value of the property?

Kurt