Harlow carries an unusually high proportion of flat-roofed homes because it was planned and built as a post-war new town, and the architects of the late 1940s and 1950s favoured flat roofs for terraces, maisonettes and low-rise blocks. Many of those original coverings have now reached or passed the end of their service life, which is why flat-roofing renewal is a recurring project across the town's residential neighbourhoods.
The post-war origins of Harlow's flat-roof stock
Harlow was designated a new town in 1947 and built out rapidly under a single master plan. The design teams of that era drew on modernist principles, where the flat roof was treated as a deliberate aesthetic and practical choice rather than a compromise. It allowed simpler, cheaper construction at scale and gave the terraces and apartment blocks their clean, horizontal lines.
Speed mattered too. The country faced a severe housing shortage, and flat roofs were quicker to erect over long terraces and grouped maisonettes. The result is a building stock where flat and shallow-pitched roofs are normal rather than exceptional, concentrated in the neighbourhood units that make up much of central and northern Harlow.
How the terraces and maisonettes are built
The post-war origins of Harlow's flat-roof stock Harlow was designated a new town in 1947 and built out rapidly under a single master plan.
The typical new-town terrace runs as a continuous block, often with a flat or near-flat roof spanning several dwellings. Maisonettes — flats arranged over two floors — were widely used here, frequently stacked or set above ground-floor units, and these too tend to carry flat roofs over the upper level.
This matters for any renewal. A flat roof above a maisonette may cover more than one home, and the deck structure can be timber, concrete or a mix depending on the build phase. Anyone assessing such a roof will usually need to establish the deck type, the insulation arrangement and whether the upstand and parapet details are original.
Renewing the original mid-century coverings
The earliest coverings were generally built-up felt — layers of bitumen felt bonded together. Felt of that age does not last indefinitely. Decades of weathering, thermal movement and ponding water break down the surface, leading to splits, blistering and water ingress.
When these roofs are replaced today, several modern options are commonly used:
- Single-ply membranes — sheet materials such as PVC or TPO, heat-welded at the joints.
- Liquid-applied systems — cold-applied coatings that cure into a seamless layer, useful around awkward detailing.
- Modern reinforced bitumen membranes — the contemporary successor to traditional built-up felt.
Renewal is also an opportunity to address insulation. Original mid-century roofs were poorly insulated by current standards, and Building Regulations now expect a "warm roof" build-up to be considered when a covering is replaced, which raises the roof level and changes the upstand heights. The deck itself may need attention where long-term leaks have caused decay.
Shared and communal roof areas
A large share of Harlow's flat roofs sit above more than one household. Where terraces and maisonette blocks are leasehold or part-managed, the roof can be a communal area, meaning responsibility for it does not rest with a single occupier.
For leaseholders, the roof is typically maintained by the freeholder or managing agent, with costs recovered through service charges. This affects how and when renewal happens, because work spanning several homes has to be coordinated and funded collectively. Council-owned and housing-association blocks follow their own planned maintenance programmes.
Before any communal flat roof is renewed, it is worth confirming who holds responsibility, how the work will be specified across the whole roof rather than one section, and whether scaffolding or access affects neighbouring properties. Patch repairs to a single dwelling's portion of a shared roof rarely solve a problem that runs across the full span.
Last reviewed: June 2026