According to data from HM Land Registry, 40, Allen Street, Mountain Ash sits on a plot of 92 m².

We have plot size data on 25 out of 31 other houses in the postcode and 40, Allen Street, Mountain Ash sits on the 22nd largest plot.

40, Allen Street, Mountain Ash has an Energy Performance Rating (EPC) of D. This is based on the most recent assessment, dated 30 Jan 2026.

The property is connected to mains gas and has fully double glazed windows. It is heated using a boiler and radiators (mains gas).

According to HM Land Registry, 40, Allen Street, Mountain Ash was last sold on 11th October 2001 for £40,000 and was recorded as a freehold house.

The property has had 3 sales since 1995.

• Sold Oct 2001£40,000
• Sold Jun 2000£14,000
• Sold May 2000£12,000

According to the Land Registry and our network of Estate Agents, there have been 96 sales of properties similar to 40, Allen Street, Mountain Ash within a radius of 670 metres since 2019.

The most recent example is 12, Beckett Street, Mountain Ash, CF45 4AW, a freehold house which sold for £150,000 on the 8th May 2026.

Read more about house prices in CF45.

• Sold May 2026£150,000 | 3 Bed House12, Beckett Street, Mountain Ash, CF45 4AW12, Beckett Street, Mountain Ash, CF45 4AW
• Sold Mar 2026£189,998 | 3 Bed House59, Allen Street, Mountain Ash, CF45 4BB59, Allen Street, Mountain Ash, CF45 4BB
• Sold Feb 2026£160,000 | 3 Bed House10, The Triangle, Mountain Ash, CF45 4BA10, The Triangle, Mountain Ash, CF45 4BA
• Sold Feb 2026£158,000 | 3 Bed House24, Richmond Road, Mountain Ash, CF45 4AN24, Richmond Road, Mountain Ash, CF45 4AN
• Sold Oct 2025£130,000 | 3 Bed House26, The Triangle, Mountain Ash, CF45 4BA26, The Triangle, Mountain Ash, CF45 4BA
• Sold Jul 2025£210,000 | 4 Bed House18, Richmond Road, Mountain Ash, CF45 4AN18, Richmond Road, Mountain Ash, CF45 4AN
• Sold Oct 2024£148,500 | 3 Bed House33, Phillip Street, Mountain Ash, CF45 4BE33, Phillip Street, Mountain Ash, CF45 4BE
• Sold Sep 2024£180,000 | 3 Bed House7, Campbell Terrace, Mountain Ash, CF45 4AE7, Campbell Terrace, Mountain Ash, CF45 4AE
• Sold May 2024£143,000 | 3 Bed House8, Copley Street, Mountain Ash, CF45 4AS8, Copley Street, Mountain Ash, CF45 4AS
• Sold Mar 2024£144,000 | 3 Bed House24, The Triangle, Mountain Ash, CF45 4BA24, The Triangle, Mountain Ash, CF45 4BA
• Sold Feb 2024£125,000 | 4 Bed House76, Phillip Street, Mountain Ash, CF45 4BG76, Phillip Street, Mountain Ash, CF45 4BG
• Sold Oct 2023£185,000 | 3 Bed House3, Richmond Road, Mountain Ash, CF45 4AN3, Richmond Road, Mountain Ash, CF45 4AN
• Sold Aug 2023£180,000 | 3 Bed House3, Beckett Street, Mountain Ash, CF45 4AW3, Beckett Street, Mountain Ash, CF45 4AW
• Sold Jul 2023£70,000 | 4 Bed House26, Copley Street, Mountain Ash, CF45 4AS26, Copley Street, Mountain Ash, CF45 4AS
• Sold Feb 2023£150,000 | 3 Bed House12, Richmond Road, Mountain Ash, CF45 4AN12, Richmond Road, Mountain Ash, CF45 4AN
• Sold Sep 2022£120,000 | 4 Bed House14, Phillip Street, Mountain Ash, CF45 4BE14, Phillip Street, Mountain Ash, CF45 4BE
• Sold Aug 2022£185,000 | 3 Bed House19, Campbell Terrace, Mountain Ash, CF45 4AE19, Campbell Terrace, Mountain Ash, CF45 4AE
• Sold Jul 2022£164,000 | 4 Bed House30, Richmond Road, Mountain Ash, CF45 4AN30, Richmond Road, Mountain Ash, CF45 4AN
• Sold Apr 2021£146,000 | 3 Bed House8, Campbell Terrace, Mountain Ash, CF45 4AE8, Campbell Terrace, Mountain Ash, CF45 4AE
• Sold Feb 2019£98,800 | 3 Bed House56, Allen Street, Mountain Ash, CF45 4BB56, Allen Street, Mountain Ash, CF45 4BB

Allen Street, Mountain Ash, CF45 has a total of 63 addresses. According to our analysis of all the public data, 40, Allen Street, Mountain Ash is the 18th largest and the 19th most expensive property on the street.

When compared to the postcode district it is £15k more expensive than the average property in CF45.

• Mountain Ash

  |

  500 m away
• Fernhill

  |

  1.3 km away
• Penrhiwceiber

  |

  2.1 km away

According to data from the Environment Agency, the flood risk in this area is considered to be Very Low.