Privacy renters understand
A private shower, WC and basin can be a decisive advantage for professionals, couples and longer-term lodgers comparing similar rooms.
Spare room rental potential
Have a spare room? Give renters the private bathroom they are looking for.
We assess whether a bedroom can take a private shower room without ruining the room, then plan the drainage, ventilation, build and finish properly.
Have a spare room?
A private bathroom can change how a room is valued.
For many London renters, an en-suite is not a decorative extra. It means privacy, no queue for the main bathroom and a room that feels more self-contained. A suitable spare bedroom can therefore compete in a different part of the rental market.
Potentially stronger rent
An en-suite may support a higher asking rent where the bedroom remains comfortable and the local market shows a clear premium for private facilities.
Better use of spare space
The project can turn an underused bedroom into a more attractive income-producing room without building a full extension.
A real London example
Around £200 more per month.
In one real London room rented out by our founder, adding an en-suite helped the room achieve around £200 more per month than comparable accommodation with shared bathroom facilities.
That is one individual experience, not a promise or rental valuation. The result for another property could be lower or higher and depends on the postcode, room size, remaining bedroom space, specification, competition and current tenant demand.
£200
example monthly uplift
£2,400
example yearly uplift
£12,000
over five years*
*Simple illustration before voids, costs, tax, maintenance or market changes.
Market evidence
Use the figures as a reason to investigate—not as a guarantee.
Independent evidence supports the principle that additional private bathroom facilities can improve rental appeal, while your own local comparisons should decide whether the project makes financial sense.
6%
Reported rental premium
The Mortgage Works/Nationwide analysis linked a second bathroom with an average rental premium of about 6%, around £60 per month in its typical example.
Read the source£7,500
Rent a Room threshold
Eligible people letting furnished accommodation in their main home may earn up to the government scheme's annual threshold tax-free. It is halved when the income is shared.
Check GOV.UK eligibility8%
Reported BTL value effect
The same research estimated an extra bathroom could add around 8% to buy-to-let property value. This is market analysis, not a valuation for an individual home.
Tax, valuation and licensing advice should be taken separately.
Try the numbers
Spare-room en-suite income calculator
Compare the ordinary room rent you believe is realistic with evidence from similar local en-suite listings. The calculator shows the difference; it does not predict or guarantee a rent.
Use comparable local room listings and allow for tax, bills, maintenance, voids and finance costs.
Illustrative result
£200
extra per month
£2,400
extra per year
£12,000
over five years
6.3 years
simple payback
A simple gross-income comparison only. It excludes finance, tax, running costs, maintenance, void periods and changes in rent.
Before the earnings
The room still has to work as a bedroom.
An en-suite only adds appeal when it is planned properly. If it destroys circulation space, blocks wardrobes, creates noisy pipework or leaves the bedroom feeling cramped, the financial case can disappear.
Usable room size
Bed, storage, door swings and circulation must still work after the enclosure is formed.
Drainage route
The WC, shower and basin need sensible connections, correct waste falls and accessible maintenance points.
Ventilation
Moisture needs a proper extract route to outside, not a shortcut into a ceiling void.
Rules and licensing
Building regulations, electrical zones and HMO or landlord requirements may affect what is suitable.
Who this is for
A different plan for homeowners, landlords and HMOs.
The practical checks overlap, but the reason for creating the en-suite—and the correct specification—can be very different.
Live-in homeowners
Create a more appealing room for a lodger while improving privacy for both the lodger and the household. Check Rent a Room eligibility separately.
Private landlords
Compare likely rent, vacancy risk, durability and maintenance access before deciding how much specification the investment justifies.
HMO owners
Room-size, amenity, fire, licensing and local authority requirements must be checked before reducing the bedroom footprint.
Start with photographs
Could your spare room take an en-suite?
WhatsApp photographs of the room, adjoining walls and any nearby bathroom. We can give an initial view, then arrange a proper survey before making promises about layout, cost or rental potential.
Questions
Frequently asked questions
How much extra rent could an en-suite room achieve?+
There is no fixed figure. In one real London example experienced by our founder, the room achieved around £200 more per month than comparable shared-bathroom accommodation. The Mortgage Works reports a 6% average rental premium for a second bathroom in its wider buy-to-let analysis. Local listings, room size, finish and demand must be checked.
Can every spare bedroom take an en-suite?+
No. We first check the room size, remaining bedroom layout, soil-pipe route, waste falls, water pressure, ventilation, electrics, access and any licensing or building-control requirements.
Does an en-suite reduce the legal bedroom size?+
The enclosure reduces the usable bedroom area, so landlords and HMO owners must check relevant licensing, amenity and minimum-room-size requirements before proceeding.
What does a new en-suite usually cost in London?+
A properly planned new en-suite is a building project, not just three fittings. As a broad guide, many London conversions begin around £12,000–£18,000+, with drainage, access, specification and structural complexity affecting the final price.
Can rental income be tax-free?+
Eligible resident landlords may be able to use the government's Rent a Room Scheme, which currently has a £7,500 annual threshold, halved when income is shared. Eligibility and tax treatment depend on personal circumstances, so take tax advice where needed.
Start with the real room
Let us check what can actually be built.
Send photographs and a rough description, visit our Fulham consultation office, or arrange a home survey. We will assess space, drainage, water, ventilation and the practical build route before the design is finalised.