One of the most impressive churches built in the UK in the mid 20th century, the redbrick fortress of St Bride’s Roman Catholic church, has been awarded a £40,000 grant to help restore it to its original appearance.

The church has been described as a Scottish version of the then fashionable “brutalist” style, usually in concrete, but executed in red brick in 1962-3 by the influential architectural firm Gillespie, Kidd and Coia in the post-war new town of East Kilbride.

It has won many architecture awards and has the highest Scottish Category A listing. But the roof, which will now be completely resurfaced, has been leaking badly , many of the original windows have been blocked up or obscured, and mismatched bricks have been used in repairs.

It is among 29 churches and chapels sharing grants totalling £400,000, to be announced by the National Churches Trust.

Six of the churches are in such poor state that they are on the Historic England “At Risk” register, including the huge Grade II listed St John the Evangelist in Upper Norwood in south London, described as “the most beautiful parish church of modern days” when it was consecrated in 1887. The church, damaged in the Blitz, is now suffering severe structural problems from subsidence, and has also been awarded £40,000.

• This article was amended on 14 December 2015. It originally said St Bride’s had a Scottish Grade A listing. The Scottish listed building system uses categories, not grades. This has been corrected.