HI, I own a part share of a nice recently renovated house in North London, with other members of my family owning the rest, left to me in my fathers estate, with probate granted in 1999, as a tenant in common.

The vast majority of contractors won't want to give bids on properties while under contract unless they have a relationship with that person from prior jobs.

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.

However, actually about 83% of federal jobs are not in Washington D.C. 

Should I try to make the deck on the second floor a common space or as part of a large bedroom?

If you have a flat roof with drains, or a pitched roof with gutters I would ensure either way that the flow of water is un-obstructed most commonly by leaves or pine needles from trees.

A lot of investors provide comps (residential RE) but I avoid doing it because it's like telling them how to do there job.

I recognize there are other ways I could invest this cash (including another property) but I am being mindful of levering myself out too much in the current environment where job losses are more common in my industry (tech).

@Aaron Raffaelli what did you do before this job?

Quote from @Erick Pena: A "good" rental property is one that covers all expenses (mortgage, taxes, insurance, maintenance, property management fees, and any other costs) and still leave a surplus (commonly referred to as cash flow).Calculate cash flow as: Cash Flow = Rental Income − Operating Expenses − DebtThere's much more to it, but that's the basic idea.