12 Thomas Street, Mountain Ash, CF45 3BU is a freehold terraced property built before 1900. The property offers approximately 818 square feet of living space. In this location, properties of similar size usually have two bedrooms.

The estimated current market value of the property is £143,769 , which equates to approximately £176 per square foot. It was last sold on 20 Feb 2026 for £145,000. Since then, the value has decreased by £1,231, representing a 0.8% decrease, or approximately 2.7% per year.

The current estimated value of £143,769 is:

  • 31.0% higher than the average property price on Thomas Street
  • 45.9% higher than the average in the CF45 3BU postcode area
  • and 6.4% higher than the average price for Mountain Ash as a whole

This property has had 2 EPC inspections with recorded tenure information. It was recorded as owner-occupied both times. This suggests the property has typically been lived in by its owners, which often reflects longer-term residency and more consistent maintenance.

At the most recent EPC inspection on 15 December 2025, the property was recorded as owner-occupied.

View sold house prices in CF45 3BU

Building approximate location

About Property

Type
Terraced House
Built
before 1900
Interior Size
818 sq ft
Tenure
Freehold
Price (estimate)
£143,769
Price Per sq ft (estimate)
£176
Bedroom Count (estimate)
2 bedrooms

EPC Summary

12 Thomas Street, Mountain Ash, Rhondda Cynon Taff, CF45 3BU has an Energy Performance Certificate (EPC) rating of C, based on the latest assessment carried out on 15 Dec 2025.

This property uses a gas-fired boiler and radiators, connected to the mains gas supply, as its main heating source. Hot water is provided from main heating system. The windows are fully double glazed.

The previous EPC assessment was conducted on 27 Oct 2017, when the property was rated E. Since then, the rating has improved to C, with the energy efficiency score increasing by 56.8%.

Since the previous assessment, several changes were observed:

  • The roof construction or insulation changed from pitched, no insulation (assumed) to pitched, unknown loft insulation, improving energy efficiency from very poor to average.
  • The wall construction or insulation changed from granite or whinstone, as built, no insulation (assumed) to sandstone, as built, no insulation (assumed), improving energy efficiency from very poor to poor.
  • The lighting was updated from low energy lighting in 38% of fixed outlets to good lighting efficiency, with efficiency improving from average to good.
Heating Type
Boiler and radiators, mains gas
Good
Hot Water
From main system
Good
Roof
Pitched, Unknown loft insulation
Average
Walls
Sandstone, as built, no insulation (assumed)
Poor
Windows
Fully double glazed
Average
Lighting
Good lighting efficiency
Good

Compared to CF45 3BU

8 th / 26
Price Rank
46% higher than average
15 th / 22
Size Rank
5% smaller than average
3 rd / 22
Price Per Sq FT Rank
54% higher than average

Sale History

Today
£143,769
streetscan.co.uk estimate
-1 %
20 Feb 2026
£145,000
Freehold
+141.7 %
26 Jun 2025
£60,000
Freehold

Flood Risk for this Property

Flood risk from rivers and the sea
Very low flood risk
Flood risk from surface water
Very low flood risk
Surface water flood hazard
No mapped risk

* Results are based on Environment Agency flood risk mapping for the property UPRN where available. They are indicative and should not be treated as a site-specific flood survey.

Flood risk from rivers and the sea

This property has very low flood risk from rivers and the sea.

River and sea flooding includes flooding caused by overflowing rivers, estuaries, tidal waters and coastal surges.

Flood risk from surface water

This property has very low surface water flood risk.

Surface water flooding can happen when heavy rainfall overwhelms drains, roads, gardens or other hard surfaces.

Flood depth indicators

Rivers and Sea
  • 0.2m depth No mapped risk
  • 0.3m depth No mapped risk
  • 0.6m depth No mapped risk
  • 0.9m depth No mapped risk
  • 1.2m depth No mapped risk
Surface Water
  • 0.2m depth No mapped risk
  • 0.3m depth No mapped risk
  • 0.6m depth No mapped risk
  • 0.9m depth No mapped risk
  • 1.2m depth No mapped risk

Area Insights

Similar Properties Sold Nearby

rooms: 4
size: 829 sq ft
sale price: £75,000
sale date: 13 May 2022
rooms: 4
size: 818 sq ft
sale price: £125,000
sale date: 29 Apr 2022
rooms: 4
size: 915 sq ft
sale price: £85,000
sale date: 27 Jan 2022
rooms: 4
size: 700 sq ft
sale price: £87,000
sale date: 7 May 2021
rooms: 4
size: 797 sq ft
sale price: £96,000
sale date: 19 Dec 2019

Data Sources

The property at 12 Thomas Street, Mountain Ash, CF45 3BU appears two times in HM Land Registry records, with the latest transaction recorded on 20 Feb 2026. It also has two Energy Performance Certificate (EPC) records, the earliest dating back to 15 Dec 2025. We use this information to estimate the property's characteristics, flood risk profile and current market value.

This website uses public sector information from:

These datasets are licensed under the Open Government Licence v3.0 .

StreetScan.co.uk is not affiliated with, endorsed by, or associated with HM Land Registry, DESNZ, MHCLG, Defra or the Environment Agency.


Disclaimer: StreetScan.co.uk makes all reasonable efforts to ensure that the information provided on this website is current and accurate. However, no warranties or representations are made regarding its completeness, accuracy, suitability or reliability. Property values, flood risk assessments and other derived information are estimates based on publicly available datasets and should not be relied upon as professional, legal, surveying, environmental, financial or insurance advice. StreetScan.co.uk expressly disclaims all liability for any loss, damage, cost or expense arising directly or indirectly from the use of, or reliance upon, information provided on this website.