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Deck Access

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This building has a single flight staircase that passes by two entrance doors and two kitchen windows, one of slightly reduced height. It’s deck access because the stairwell and access balcony is open and can therefore ventilate and illuminate the inner rooms.

This is important. People are trying to use a single configuration to solve access, illumination and ventilation. Solving those three for a repeatable unit is a working definition of a mat building but mat buildings only repeat the solution horizontally, not vertically as well.

This is a contemporary example of what this blog always refers to as “The Type A” with two apartments accessed from a landing. This arrangement makes dual-aspect apartments possible but fell out of favour when elevators were relatively expensive and needed to service more than two apartments. [This may not hold any more. If, say, an elevator costs $8,000/floor, then it’s a question of whether it’s cheaper to buy more elevators rather than construct corridor to pass by apartments in order to access one or more others.]

The Type A is not deck access because whether or not there’s the elevator, the staircase is for access only and doesn’t ventilate or illuminate any rooms.

These single-loaded corridors look like they might be deck access but they’re enclosed and, because of that windows don’t open onto it.

It’s simply not possible to use one staircase and/or one elevator to access more than two double-sided apartments without having an open corridor pass by the windows of the two inner ones. This next building is unusual in having the living room windows of the inner apartments open onto the corridor – or rather, the open balcony space that also accesses the outer apartments. That outside space with the railing is almost square, which means the living room windows of the inner apartment receive less light but it does mean there’s about three metres between them and the neighbours’ comings and goings.

A more common compromise is to not have that excess space and to place rooms such as bathrooms, kitchens, and secondary bedrooms up against the corridor, often with some sort of security grille in-between. Feelings about this differ according to time and place. What was revolutionary in Germany 1930 and necessary in London in 1938 was undesirable in London in 1970 but unremarkable in Tokyo 1980.

Deck access apartments are still being built, especially in the warmer countries such as Spain where open corridors aren’t a problem, there’s no dependence on air conditioning, and where there’s also a history of grilles on windows. Here’s a recent example from Spain. It has internal bathrooms but the kitchen has a window.

Not having the corridor pass by habitable rooms is the preferred way to go and one way of achieving this involves split level planning so the entrance level is used for a hallway and perhaps a bathroom, while the first half level up and down will usually have the kitchen and living areas and the floors above and below the access corridor will have two bedrooms. Here’s one of my attempts.

But what if you don’t want or can’t extend to a 1+1/2 storey high living room? Or don’t need four bedrooms? There are ways around this too, and one of the best I’ve seen is Kate Macintosh’s 1972 Dawson’s Heights [and thank you Sam for alerting me to it!]

The variable use of the middle bay is inspired. Once again, bathrooms are internal and kitchens not but, wind being wind, it can still pass through both levels of the apartment, unobstructed by half flights of stairs. It’s one of the most well thought-out arrangements I‘ve ever seen.

Corridors aren’t double-loaded but don’t really need to be as there’s still four doors off a very short length of corridor. It’s only a shame there’s nothing left for them to ventilate except entrance halls. Bathrooms can’t be anywhere else but where they are.

If you don’t want to build split levels, then your single level plan had better have some compensating benefit.

These Hong Kong Housing Authority towers are designed to be joined together so those bathrooms ventilate into an air shaft/light well and, should four towers be joined to make a square, the kitchens and all habitable rooms would open onto what is essentially a much larger one with habitable rooms facing each other and kitchens tucked into the corners on the diagonal, distanced from the windows of habitable rooms. It’s a beautiful arrangement and it’s ready should we ever need it. The elevator lobby is naturally lit and ventilated, distances between habitable room windows are maintained, and fire escape is of course not compromised. When towers join, ventilating the bathrooms depends upon wind passing over the top of the buildings generating a negative pressure and resultant updraft in those shafts.

This may not be deck access but it is intense passive design. I only mention this because of the how the air must obviously move in and around the building.

It’s also a configuration that’s extremely difficult to improve upon or further rationalize. The position of these kitchens may or may not be an improvement. The now internal corridor definitely isn’t.

The goal is a spatially efficient plan with

  • the daylighting and ventilation benefits of deck access
  • dual-loaded corridor to access the greatest number of apartments – maybe
  • open space between the access corridor and any windows facing it
  • the option of having all living rooms on the same side of the building (despite the double-sided corridor)
  • the possibility of apartments with different numbers of bedrooms.

The problem becomes one of putting some space between the access corridor and any windows it passes.

At the bottom left of this next image are the shared equity apartments attached to Foster+Partners’ Albion Riverside development in London.

It’s clearly deck access but having all bedrooms face those decks across a gap isn’t great.

Here’s how they do it in India. Everything’s naturally daylit and ventilated but with no regard to the direction of that light and airflow.

The middle space is basically an open airshaft and light well with open sides and horizontal airflow as well.

The example below – we’re back in China now – also uses a discontinuous deck between window wall and access surface, and for the same reasons.

The note in red on the right refers to the dashed outline and makes special mention of the master bedroom suite having a north-south orientation and cross ventilation.

The access corridor outside the bathroom and kitchen windows and the window of that room with the desk has a break line where it continues to the adjacent and outer apartment. The entrance door to that apartment is in in the same line as the party wall.

What we have here is all those secondary spaces opening onto space open to the open corridor on all levels. Access does not conflict with ventilation.

These next plans are for a building in London called Aragon Towers – cheers Paul! I’m providing two plans for it as it’s a double-sided scissor layout and we need all the help we can get to work out how these things fit together. The plan on the right helpfully has a break line along the corridor.

The bedroom landing here can’t be any smaller and the living room landing is part of the room. Sophisticated as this layout it, it has internal bathrooms and the kitchen ventilation is not great. It’s corridor access.

With double-sided scissor apartments, the bathroom is usually placed on the bridge across/under the access corridor and is accessed by half flights of stairs either side. These stairs determine the length of the apartment (and thus the width of the building) so they need to start and finish as close to the corridor wall as possible. This means the narrow entry hall at one end and a fire exit door right at the end of the stair at the other. The other parts of that sliver of space are well used for a boiler, washing machine, and hallway cupboard. The astonishing thing about the scissor apartment plan is that nothing can be moved. It simply can’t be anything else but what it is.

So then, where’s left to go? What’s left to do? The cross-ventilated master bedroom apartment of the Chinese example reminded me of this proposal from 2010 and the beginnings of this blog. Much like the image with which this post began, it attempts to integrate access, daylighting and ventilation both horizontally and vertically, along with a few other things. At fourteen or so storeys and with a central and not a side corridor, that updraft becomes important.

My first thought was to use the generic apartment type second from the right, and have apartments on one side of the corridor with the bedrooms upstairs, and those on the other side of the corridor with the bedrooms downstairs, a bit like Le Corbusier’s Marseille Unité but more like the Andrei Ohl team entry for the 1926 “Comradely Competition for Communal Housing” organized by the Soviet architectural journal Sovremennaia Arkhitektura (SA, “Contemporary Architecture”)).

Such a reconfiguration would’ve worked but the apartments were huge and the bedrooms disproportionately large compared with the living area. I tried reconfiguring it as a scissor apartment but quickly bumped up against the same stair problem that scissor apartments only just solve. A one-and-a-half or a double-height living room is cheating. Rotating the stairs 90° still leaves you the problem of crossing the corridor.

If the stair isn’t going to determine the apartment length then a full flight stair parallel to the corridor is the only choice. It’s simply a better way of doing it and French architect André Devin was first to realize this.

In June 2016 I could make only marginal improvements to this arrangement by changing the enclosed corridor to an semi-open deck onto which non-habitable room windows could open a minimal distance from a detached deck. [c.f. Detective Story] However, all apartments had four bedrooms so, looking at that configuration in the light of the adaptable spaces in Kate Macintosh’s Dawson’s Heights and my 2018 Streets in the Sky proposal, this is what happened next. There’s a couple more things I’d still like to try but this seems a good place to stop and take stock. Average plan efficiency 20% incl. stairs, 15.6% not.

  • All living areas are on the same side of the building but some are larger than others. One apartment has what would be a conventional arrangement while the use of the rooms in the other three apartments may be more suitable for alternative forms of tenure and occupation.
  • How to cross the corridor is crucial with double-sided apartments but here it’s just a crossing and no more, and the price one pays. It doesn’t have to be 1.5m wide as it’s drawn here. The aim is to make the access corridor between the two buildings as light and airy as possible.
  • For this reason, I imagine downpipes, soil pipes, water supply pipes, and electrical supply conduits simply running down the walls outside bathrooms and kitchens rather than enclosing some of that area.
  • The space between the two halves of the building is about 3.3m, two metres of which is the actual corridor.
  • This building is likely to be in the more temperate climates. I haven’t given any thought to heating. Because a temperate climate is assumed, shelves for reverse–cycle A/C compressors will probably be needed.
  • I’ve added laundry drying balconies to the living areas and expect the washing machine to be placed there but this will means it will likely discharge into the rainwater system. Or it could go nearest the entrance and discharge into the sewer system. Somebody else will make that decision.


  • Great post. The Chinese, Indian, and your personal model certainly give one a lot to think about when delving into multi-family. I dig the solar collector plate option (guessing), structured above to still allow air flow.