# Conversion Use and Value

> The Conversion Use and Value carries 18 published figures read from 3 sources' own pages, from 4,000 to 60,000 GBP, read 12 October 2026.

Roofing Quotes UK · https://roofingquotesuk.com/datasets/conversion-use-and-value/ · computed 2026-10-21

**Range of the published figures:** 4,000 to 60,000 GBP (range 4,000 to 60,000 GBP; 17 published figures; 3 of 18 sources read publish one).

3 of the 18 named sources read in full publish a figure; 15 publish none, read 12 October 2026.

## By use

| Breakdown | Median | Range | Sources |
|---|---|---|---|
| use office | 8,000 GBP | 7,000 to 14,000 GBP | 3 |
| use gym | 10,000 GBP | 5,000 to 15,000 GBP | 2 |
| use bedroom | 16,000 GBP | 15,000 to 18,000 GBP | 3 |
| use entertainment | 10,000 GBP | 10,000 to 10,000 GBP | 1 |
| use playroom | 8,500 GBP | 6,000 to 11,000 GBP | 2 |
| use utility | 4,000 GBP | 4,000 to 4,000 GBP | 1 |
| use annexe | 35,000 GBP | 28,000 to 60,000 GBP | 3 |
| use guest suite | 25,000 GBP | 25,000 to 25,000 GBP | 1 |
| use living room | 13,000 GBP | 13,000 to 13,000 GBP | 1 |

## Every figure, with its source

One row per source: the figure the source's own page publishes, the page, and the day it was read.

| Source | Figure | Breakdown | Read |
|---|---|---|---|
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 60,000 GBP | annexe | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 35,000 GBP | annexe | 2026-10-12 |
| [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs) | 28,000 GBP | annexe | 2026-10-12 |
| [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs) | 28,000 GBP | annexe | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 25,000 GBP | guest suite | 2026-10-12 |
| [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs) | 18,000 GBP | bedroom | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 16,000 GBP | bedroom | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 15,000 GBP | gym | 2026-10-12 |
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 15,000 GBP | bedroom | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 14,000 GBP | office | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 13,000 GBP | living room | 2026-10-12 |
| [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) | 11,000 GBP | playroom | 2026-10-12 |
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 10,000 GBP | entertainment | 2026-10-12 |
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 8,000 GBP | office | 2026-10-12 |
| [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs) | 7,000 GBP | office | 2026-10-12 |
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 6,000 GBP | playroom | 2026-10-12 |
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 5,000 GBP | gym | 2026-10-12 |
| [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) | 4,000 GBP | utility | 2026-10-12 |

## The sentence each figure was read from (18)

- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "ADU or Self-Contained Suite £60,000+ 12–20 weeks Planning + regs Excellent"
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "Costs start at £35,000 and can exceed £65,000 for a full design-and-build project."
- [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs), read 2026-10-12: "These can range anywhere from £28,000 upwards depending on how much you include in the project, this can include:"
- [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs), read 2026-10-12: "Annexe spaces, which include extensions and additional amenities, can start from £28,000 and go upwards, depending on the project scope."
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "Total cost typically £25,000 to £40,000."
- [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs), read 2026-10-12: "Garages can be a fantastic opportunity to provide an extra bedroom to your property as long as you are aware of the planning permission requirements. Bedrooms will normally come in at a higher bracket of £18,000 - £28,000 assuming the following:"
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "Costs start at around £16,000 for a basic bedroom; a full en suite bedroom will push closer to £22,000 to £28,000."
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "Budget from £15,000 for a functional fit-out; add mirrors, cable management, and specialist flooring for a high-end result."
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "Guest Bedroom £15,000–£40,000 6–10 weeks Building regs Excellent"
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "A simple single-garage office conversion can be done for £14,000 to £20,000 at a comfortable finish."
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "Costs from £13,000 to £22,000 depending on finish."
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas), read 2026-10-12: "Rubber or vinyl flooring, built-in toy storage, and a half-glazed stable-style external door that lets in light while keeping small children contained are practical choices. Budget £11,000 to £18,000."
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "Entertainment Room £10,000–£30,000 4–8 weeks Building regs Good"
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "Room Type Typical Cost Build Time Permit Needed Value Impact Home Office £8,000–£25,000 4–8 weeks Building regs Good"
- [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs), read 2026-10-12: "A garage-to-office conversion can be an extremely affordable option with a budget of £7,000 to £12,000 and can be much less if you are resourceful and partake in some DIY."
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "Playroom or Hobby Room £6,000–£18,000 3–6 weeks Building regs Moderate"
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "Home Gym £5,000–£15,000 2–5 weeks Usually not Moderate"
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/), read 2026-10-12: "Boot Room or Utility £4,000–£10,000 2–4 weeks Often not Moderate"

## Read in full, publishes no figure

- [North East Garage Conversions, house valuation](https://northeastgarageconversions.co.uk/increase-house-valuation/), read 2026-09-12: read in full and no accepted figure on the page
- [Horts (estate agent), garage conversions and value](https://www.horts.co.uk/news/how-to-add-value-to-your-home-garage-conversions.html), read 2026-09-12: every candidate on the page was refused
- [Designer Garden Rooms, value added](https://www.designergardenrooms.co.uk/blog/how-much-does-a-garage-conversion-add-to-house-value), read 2026-10-12: every candidate on the page was refused
- [House of Construction, loft against garage](https://www.houseofconstruction.uk/loft-conversions-vs-garage-conversions/), read 2026-10-12: every candidate on the page was refused
- [HM Land Registry, UK House Price Index](https://landregistry.data.gov.uk/app/ukhpi/), read 2026-10-17: every candidate on the page was refused
- [HM Land Registry, open data](https://landregistry.data.gov.uk/), read 2026-09-12: read in full and no accepted figure on the page
- [HM Land Registry, Price Paid Data standard reports](https://landregistry.data.gov.uk/app/standard-reports/), read 2026-09-12: read in full and no accepted figure on the page
- [ONS, housing](https://www.ons.gov.uk/peoplepopulationandcommunity/housing), read 2026-10-12: every candidate on the page was refused
- [ONS, median price paid by ward (HPSSA dataset 37)](https://www.ons.gov.uk/peoplepopulationandcommunity/housing/datasets/medianpricepaidbywardhpssadataset37), read 2026-09-12: read in full and no accepted figure on the page
- [MyBuilder, garage conversion ideas](https://www.mybuilder.com/conversions/articles/garage-conversion-ideas), read 2026-09-12: every candidate on the page was refused
- [More Living Space, garage conversion case studies](https://morelivingspace.co.uk/case-studies/page/2/), read 2026-10-12: read in full and no accepted figure on the page
- [DJL Home Improvements, garage conversion ideas](https://www.djluk.co.uk/garage-conversion-ideas/), read 2026-10-12: read in full and no accepted figure on the page
- [The Garage Conversion Specialist (Nottingham, Derby, Leicester), ideas](https://thegarageconversionspecialist.com/10-garage-conversion-ideas-to-inspire-your-next-project/), read 2026-09-12: read in full and no accepted figure on the page
- [All Well Property Services, office, gym or annexe](https://allwellpropertyservices.co.uk/blog/garage-conversion-ideas), read 2026-10-12: every candidate on the page was refused
- [Designs in Detail, architect design inspiration](https://www.designsindetail.com/articles/garage-conversion-ideas-uk-architect-design-inspiration), read 2026-09-12: read in full and no accepted figure on the page

## Methodology

Every row is a verbatim sentence read from the named source's own page through our fetch service on the date shown, hash-pinned to the stored read (the sha of the page's visible text; the raw page is mirrored to R2). 3 of the 18 named sources that could be read published a usable figure; 15 published none and are recorded as not published, never filled in; 1 could not be read (blocked, dead or unreachable) and count nowhere. The headline figures (median, minimum, maximum, quartiles) are over ONE figure per source for each breakdown it prices, in GBP (a source's median where its page yielded several accepted sentences for one breakdown), so a page that gives figures for several breakdowns gives one for each and N counts 17 figures, never sentences; 75 candidate sentence(s) were refused by a reviewer with the reason recorded. The fuller derivation this dataset is chartered to grow into (not yet what the figures above are; they are each source's own published figure as read): the mix of USES across every completed project a converter publishes (bedroom, home office, gym, annexe, utility, studio, playroom), counted rather than listed, with the median published cost of each use from the cost index; joined to HM Land Registry price paid per postcode district, the value of the square metres gained, so the 'adds 10-20%' claim every estate agent repeats is replaced by a local, computed number with its denominator shown.

## Sources

- [Checkatrade, does a garage conversion add value](https://www.checkatrade.com/blog/expert-advice/garage-conversion-add-value/) (the publisher's own terms; quoted for reporting and comment)
- [North East Garage Conversions, house valuation](https://northeastgarageconversions.co.uk/increase-house-valuation/) (the publisher's own terms; quoted for reporting and comment)
- [Horts (estate agent), garage conversions and value](https://www.horts.co.uk/news/how-to-add-value-to-your-home-garage-conversions.html) (the publisher's own terms; quoted for reporting and comment)
- [Designer Garden Rooms, value added](https://www.designergardenrooms.co.uk/blog/how-much-does-a-garage-conversion-add-to-house-value) (the publisher's own terms; quoted for reporting and comment)
- [House of Construction, loft against garage](https://www.houseofconstruction.uk/loft-conversions-vs-garage-conversions/) (the publisher's own terms; quoted for reporting and comment)
- [HM Land Registry, UK House Price Index](https://landregistry.data.gov.uk/app/ukhpi/) (the publisher's own terms; quoted for reporting and comment)
- [HM Land Registry, open data](https://landregistry.data.gov.uk/) (the publisher's own terms; quoted for reporting and comment)
- [HM Land Registry, Price Paid Data standard reports](https://landregistry.data.gov.uk/app/standard-reports/) (the publisher's own terms; quoted for reporting and comment)
- [ONS, housing](https://www.ons.gov.uk/peoplepopulationandcommunity/housing) (the publisher's own terms; quoted for reporting and comment)
- [ONS, median price paid by ward (HPSSA dataset 37)](https://www.ons.gov.uk/peoplepopulationandcommunity/housing/datasets/medianpricepaidbywardhpssadataset37) (the publisher's own terms; quoted for reporting and comment)
- [houseUP, 20 garage conversion ideas](https://www.houseup.co.uk/news/garage-conversion-ideas) (the publisher's own terms; quoted for reporting and comment)
- [MyBuilder, garage conversion ideas](https://www.mybuilder.com/conversions/articles/garage-conversion-ideas) (the publisher's own terms; quoted for reporting and comment)
- [More Living Space, garage conversion case studies](https://morelivingspace.co.uk/case-studies/page/2/) (the publisher's own terms; quoted for reporting and comment)
- [DJL Home Improvements, garage conversion ideas](https://www.djluk.co.uk/garage-conversion-ideas/) (the publisher's own terms; quoted for reporting and comment)
- [The Garage Conversion Specialist (Nottingham, Derby, Leicester), ideas](https://thegarageconversionspecialist.com/10-garage-conversion-ideas-to-inspire-your-next-project/) (the publisher's own terms; quoted for reporting and comment)
- [All Well Property Services, office, gym or annexe](https://allwellpropertyservices.co.uk/blog/garage-conversion-ideas) (the publisher's own terms; quoted for reporting and comment)
- [Complete Property, garage conversion room ideas](https://complete-property.co.uk/garage-conversion-room-ideas-your-2026-guide/) (the publisher's own terms; quoted for reporting and comment)
- [Fifi McGee, architect explains garage conversion costs](https://fifimcgee.co.uk/blog/garage-conversion-costs) (the publisher's own terms; quoted for reporting and comment)
- [Designs in Detail, architect design inspiration](https://www.designsindetail.com/articles/garage-conversion-ideas-uk-architect-design-inspiration) (the publisher's own terms; quoted for reporting and comment)

## Cite or embed

- The Conversion Use and Value carries 18 published figures read from 3 sources' own pages, from 4,000 to 60,000 GBP, read 12 October 2026.
- 3 of the 18 named sources read in full publish a figure; 15 publish none, read 12 October 2026.
- Conversion Use and Value, use office: median 8,000 GBP across 3 sources, read 12 October 2026.
- Conversion Use and Value, use gym: median 10,000 GBP across 2 sources, read 12 October 2026.
- Conversion Use and Value, use bedroom: median 16,000 GBP across 3 sources, read 12 October 2026.
- Conversion Use and Value, use entertainment: median 10,000 GBP across 1 source, read 12 October 2026.
- Conversion Use and Value, use playroom: median 8,500 GBP across 2 sources, read 12 October 2026.
- Conversion Use and Value, use utility: median 4,000 GBP across 1 source, read 12 October 2026.
- Conversion Use and Value, use annexe: median 35,000 GBP across 3 sources, read 12 October 2026.
- Conversion Use and Value, use guest suite: median 25,000 GBP across 1 source, read 12 October 2026.
- Conversion Use and Value, use living room: median 13,000 GBP across 1 source, read 12 October 2026.

Cite as: "Roofing Quotes UK Conversion Use and Value", updated 2026-10-21, https://roofingquotesuk.com/datasets/conversion-use-and-value/.

CSV: https://roofingquotesuk.com/datasets/conversion-use-and-value.csv
JSON: https://roofingquotesuk.com/datasets/conversion-use-and-value.json
Embed (plain HTML, static link back): see https://roofingquotesuk.com/datasets/conversion-use-and-value/#median