Checking stairs, landings, and entrance doors to flats in a high-rise is at first sight a simple and repetitive task. Whilst there can be considerable differences in the layout of landings and stairs of high-rise buildings, a block-check is in most of the cases carried out by one and sometimes by two concierges. The rhythm of a block-check varies with different buildings [image_2]. For example, in the backstairs of 213/183/153 Petershill Drive (2c) corridors are arranged around the staircase. The concierge walks down one flight, enters the corridor through a door to his left, walks along the small u-shaped corridor and re-enters the stairs through a door opposite of where he just has left the staircase.

The tour of the concierge must 'cover' all publicly shared areas of the block. A block-check that would not consider systematically and in full all parts of the building can have crucial if not fatal consequences. Bulky things, for example, can block an emergency exit, that residence would use to leave the building in a fire emergency.

Usually concierges check blocks by walking down the stairs. It is certainly easier less exhausting and time consuming to walk downstairs, but when asking Steve on a block-check if he would sometimes walk from bottom to top he pointed at the importance of seeing what is coming up on a tour: "I prefer to walk down. Because I see what I am looking at" (RR016 00:23:23:03).

Although walking down the stairs allows easier scanning and assessment of what is happening, the concierge has always only a partial view of the scene he is approaching.[2] For example, when walking down a flight of stairs in the point block at 21 Bernie Court [image_3], concierges get a relatively late view of the main part of the landing and doors of flats. Swinging down the stairway, the concierge get his first glimpse of the next floor when making a turn of 180° on the half space landing (still a and b). From here he looks through a glass panel in the anteroom of the landing and can see to his right the door leading into the anteroom (still c). When arriving at that door he brieflylooks to his right where there is another glass panels through which he can get a glimpse of what is happening in the main are of the landing (still d). Concierges cannot only walk straight forward, but need to sidestep, to look in hidden corners (still e). From the staircase the concierge has to go in total through two doors to reach the main area of the landing, where flats and lifts can be accessed (still e to h). Being able to discern scenes in the block always only in the short-run the concierge assesses forthcoming events also by listening to noise that might occur in the flats, stairs and on landings. Concierges assess the scene with regard to possible encounters and potential confrontation. They can relatively late see and hear if there are other activities or signs present on the landing. For example: prams in front of flat doors, people waiting for lifts or sitting on stairs, bulky things left behind or rubbish lying around.

A scene is never assessed through scanning only, but the concierge might base himself on some sense of the routine of the building, to anticipate events he might come across on his tour. Some residents for instance are active at night and others, mainly elderly people, would only leave their flats during the day. When they are on tour or on duty in the concierge station, concierges spend a lot of time observing people, events and routines in and around a building. They know about illegal activities such as drug dealing and which residents are involved in it. On a block-check particular landings and the connected stairs are well perceived as places where one can run into people that would squat the stairs, hang about and leaving rubbish behind. Such anticipated circumstances can lead the concierge to change the block-check routine for his own safety. In the Bernie Court block [see Figure a in image_2] the concierge can avoid the backstairs by continuing his walk on the frontstairs, or by taking the lift to descend to the next level.

Furthermore, concierges would assess the scene of a landing through information they have received in the workstation before beginning a block-check. Actual events and how they develop are sometimes communicated via walkie-talki. Concierge use also CCTV and intercom in the lift and at entrance doors to talk to the colleague on duty in the station. In this way the concierge would learn, for example, that one of the lifts in the building is out of order because an engineer is doing repair work in the engine room on the rooftop. He would therefore expect to meet more waiting residents on the landings and more people walking up and down the stairs.

An important aspect of checking a block systematically, is the concierges ability to assemble sense circumstantially relevant for every new scene that is opening up. Once the concierge has started his tour, he has some but generally little information on what is going on in the building. He relies on his own observations and assessments of what opens up in front, but also experiences he made earlier on the tour and before starting his walk. Harold Garfinkel has observed that an interview partner of his did not answer single questions but was getting a sense of how to answer "from […] questions, and more importantly from more subtle cues both prior to and after questions, what answers would do"[3]. Similarly, checking a building is not only about systematically looking in every corner, but concierges on block-checks practice a form of anticipatory observation; i.e. the concierge's sense of the building and what he witnesses is closely tied to subtle cues prior and after looking respectively to opening up, passing by and closing scenes.