peter: i've got 30 houses here in mathare.ing them since i came here and i want to expand. my big goal is to have 40 houses. it's good to be a landlord. when you're getting money from all these households you can make a lot and expand faster. the income lets you ild a lot . reporter: the housing market is not regulatehere. nants haveo pay whater the landlord demands. people share living space to make it affordable. an average 2.6 people live in a one room shack, which costs the equivalent of 30 euros a month. peter chege usually collects the rent himself. on camera, he makes an efft to be friendlypeter: hi. how are you? you got something for me? >> sure, i'll fetch it. peter: ok. is your husband home? >> no, he's not there. peter: no problem. when he gets in, tell him hello from me. reporter: when tenants don't pay the rent on time, the slumlords hire gangs to collect it. gangs who can be quick to resort to violce. for about 10 eos, they'l rongarm the tenants, or throw them out. >> mostly we use machetes and some knives, you k