It is here, blindfolded and held down on a plastic sheet by as many as five women, that girls as young as eight are brought to be mutilated, in the name of female circumcision.
Mother and daughter Hawa and Fatima (not their real names) are backstreet "cutters," secret practitioners of Female Genital Mutilation (FGM) in the Kenyan capital, Nairobi.
Speaking to CNN on condition of anonymity, the pair explained how they carry out their grisly -- and illegal -- trade, using a razor blade and a bottle of alcohol.
"We sit down the girl, someone blindfolds her and lays her on the ground, then we cut, we cut three times, then you put the [alcohol], you ... pour it on the wound; the [alcohol] is a bit painful but it stops the bleeding."
FGM, the partial or complete removal of the external female genitalia to inhibit a woman's sexual desires, was outlawed in Kenya in 2011, alongside early marriage.
Despite the fact it is now illegal, FGM has continued in some communities, where CNN discovered it is deeply ingrained in cultural traditions.
The practice is often handed down from generation to generation, through the same family.
It is extremely dangerous; many procedures end in tragedy because of infections caused by a lack of hygiene.
But Fatima told CNN that she and her mother see themselves as the enforcers of a moral code, on behalf of the whole community.
"It is important, because when girls don't get cut when they are young, they go after boys while they are still young and we don't want that. We don't want them to get spoiled, that's why we do it."
The "cutting room" forms part of the pair's ramshackle home in a predominantly Kenyan-Somali neighborhood. Girls are kept immobile here for weeks after their ordeal.
"You tie the legs ... this way, a traditional way, then you lay her down and cover her up with a blanket and give her some hot tea -- she should not be exposed to cold or feel cold.
"We clean up the wound every morning with the ethanol spirit, then after two weeks we untie [her] and see whether the wound is healed, and allow her to walk around the house a little bit.
"By the third week she should be fine but not do lots of activities, till it is one month and then she would be fine and good to go back to her daily routine."
The women say their neighbors all know that they are FGM practitioners, and insist that female circumcision is a cultural norm in their community.
And it isn't only local girls who find themselves at the mercy of the pair's razor blades -- British girls with family ties to Kenya are also brought here during the school holidays.
Both women say they were genitally mutilated when they were aged eight or nine; they admitted it had hurt -- almost unimaginably -- but they claim it was the "right thing."
They say social pressure on the girls they cut means many don't even cry out while they are being mutilated.
"We blindfold them and put hands over their mouths, they don't even scream because if they do, their age mates will despise them," says Fatima. "So they hold it back and endure the pain, they can't make noise because of what other girls might think of them."
What these women are doing is vile and illegal. But they claim they are serving a need and -- unless someone stops them -- they will continue carrying out this barbaric procedure, in their grim, grubby room.