Newer public housing estates are not the "walled cities" one Straits Times reader called them.
Instead, interspersed among high-rise blocks are low-rise developments such as parks.
This was the Housing Board's reply to a letter published in The Straits Times on Dec 18 complaining about the quality of newer towns such as Sengkang, Sembawang and Punggol.
"The spaces between blocks have been reduced significantly, leading to a pervasive 'walled-city' look," architectural designer Liu Zhenghao, 30, had written.
While HDB could not confirm whether blocks are built closer together now, it did say that towns are planned with a "checkerboard concept", in which low-rise areas break up high-rise stretches.
HDB added it will maintain "reasonable" spaces between buildings "to achieve some privacy and visual relief for our residents". Even the heights of blocks within an estate are varied.
Singapore Institute of Architects chairman Theodore Chan said given land constraints, "HDB is doing an excellent job". Pointing to older estates' surface parking as an example, he said: "If you look at new precincts - it can never be as luxurious as before."
Mr Liu also complained about the lack of low-rise markets and shopping streets in new estates.
In older towns, "there was a conscious effort to make the centre low-rise, to create a village-feel with open squares", he told The Straits Times last week. "It made the place welcoming."
He also believes facilities in newer estates tend to be concentrated in a hub, not spread out.
Disputing that point, HDB noted that newer towns do have neighbourhood centres away from the heart of the town. These include Rivervale Mall, Sembawang Mart and Punggol Plaza.
And in Punggol, for instance, upcoming areas such as the Northshore district will include low-rise shopping stretches.
Mr Liu, who has been with Formwerkz Architects for three years, also took issue with the design of blocks, which he deemed bland. Heavy use of prefabricated concrete "makes blocks look like factory units".
He later told The Straits Times that contractors here "don't seem to want to make a variety of moulds" for the prefab concrete components. "So with a limited palette, architects design according to existing components."
Concrete also results in higher carbon dioxide emissions than other materials, he added.
Defending prefab technology, the HDB said it improves both productivity and building quality.
Carbon dioxide is released when cement is made. But the same amount of cement is used when making concrete on-site and during prefabrication. The prefab method is also more environmentally friendly as it wastes less material and requires shorter construction time, said HDB.
The use of prefab components does not hold back design, added HDB. It has a team of in-house designers and architects and appoints "a range of private consultants" to design flats.
It pointed to how upcoming housing along the Punggol waterway will have a terraced look and courtyard spaces. But the Punggol Matilda district will have verandahs, colonnaded walkways, open lawns and groves of trees.
Mr Chan said the use of prefab "really depends on the architect". He noted that the Pinnacle @ Duxton flats, for instance, were made from prefab parts.
But he agreed that "prefab components must be used in a more interesting manner. There isn't a national effort in this yet."