Plastic windows and extra parking places among threats to historical and architectural character
English Heritage has urged councils to put more work into preserving the character of the UK’s suburbs where more than eight out of ten people live.
It said that special historical and architectural character was at risk of being destroyed by developments that were replacing green space.
It added that other threats included plastic windows, badly designed extensions and converting front gardens into additional area for parking cars.
The Greater London Assembly estimates that two thirds of the capital's front gardens have been converted for parking, reducing wildlife habitat and increasing water run-off.
Simon Thurley, the chief executive of English Heritage, said: "Higher density living is a good idea but it can have unintended consequences.
"Some of our best-loved suburbs are blighted by ill-planned incremental changes and inappropriate development.
"I don't believe that heritage is somewhere you visit, like going to a stately home. It is all around us, it is where we live. And for very many of us that is a suburb.
"Change won't go away but we can work together to drive it towards the values and goals we believe in, enhancing local character and adding to the best of what is already there."
English Heritage has now published a guide, Suburbs and the Historic Environment, to help residents and their councils to protect the suburbs, which are not always listed and therefore do not come under legislation that English Heritage can enforce directly.
It gives the example of Wycombe and Solihull councils, which have both used a planning document to set guidelines about aspects of design and location that have to be given special consideration.