Extra bedroom and en-suite extensions in Renfrew
Adding an extra bedroom and en-suite extension in Renfrew gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in Scotland.
Before you start in Renfrew, here's what applies.
- Postcode districts
- PA4
- County / area
- Renfrewshire and Inverclyde, Scotland
- Price region
- Scotland
- Guide price
- £52,500–£71,000 (£1,880–£2,540 per m²), plus £5,500–£11,000 for the en-suite
- Approval route
- Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
- Nearest towns
- Clydebank (2.1 miles), Erskine (3 miles), Dalmuir (3 miles)
- Distance to Paisley
- about 3.2 miles
- First visit
- Free, no obligation
About an extra bedroom and en-suite extension
This service suits you if you need another bedroom, or want a main bedroom with its own bathroom, without converting the loft or moving. You get a first-floor layout that connects well to your landing, an en-suite designed for plumbing and ventilation, a useful room downstairs, the approvals your nation needs and the build, managed by us and carried out by vetted teams working under S&K.
Around Renfrew we also work in Clydebank, Erskine and Dalmuir, and across the rest of Renfrewshire and Inverclyde. Postcode district in and near Renfrew: PA4.
What it costs in Renfrew
In Scotland, which includes Renfrew, we'd expect an extra bedroom and en-suite extension to cost around £52,500–£71,000 (plus £5,500–£11,000 for the en-suite) for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), or £1,880–£2,540 per m² including VAT. Keep a contingency of around 10% for things nobody can see until the ground is opened up.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,730–£2,330 per m² | £48,500–£65,500 |
| Standard | £1,880–£2,540 per m² | £52,500–£71,000 |
| Premium | £2,260–£3,050 per m² | £63,000–£85,500 |
Planning and building standards in Renfrew
In Scotland, an extra bedroom on a new first floor makes the extension more than one storey, so Class 1B applies, needing at least 10 m to every boundary. Most plots need a householder application, which costs £371 and is decided within two months. The building warrant then covers the escape window, ventilation and drainage.
Approval in Scotland: Householder planning application: £371. Councils have two months to decide a local planning application.
Building standards: A building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks.
Design points for Renfrew homes
Connecting to the landing
The new bedroom must be reached from the existing landing, usually through a new opening in the outside wall or by taking part of an existing bedroom as a corridor. We look at the stairs and landing first, because a poor connection can waste much of the new space.
Escape window and fire safety
A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and high, and the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs. We design the windows to meet this.
How we'd run your project
Measure and listen
A visit to Renfrew to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Drawings, then consent
We draw the scheme, check it against the rules in Scotland, and take it through the right consent with the council.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about extra bedroom and en-suite extensions in Renfrew
Which postcodes do you cover around Renfrew?
We cover Renfrew (PA4) and nearby places including Clydebank, Erskine and Dalmuir, plus the rest of Renfrewshire and Inverclyde. The first site visit is free.
Do I need planning permission for an extra bedroom and en-suite extension in Renfrew?
Renfrew is in Scotland. Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
How much does an extra bedroom and en-suite extension cost in Renfrew?
Our guide for Scotland, which covers Renfrew, is £1,880–£2,540 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £52,500–£71,000 (plus £5,500–£11,000 for the en-suite). Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Does an extra bedroom add value to my house?
It usually does, though not always by the full cost. Nationwide's 2025 research found that adding a double bedroom to a two-bed house was linked to about 13% higher value, and a double bedroom and bathroom on a three-bed, one-bathroom house up to 24%. Local ceiling prices still apply.
How big should a new double bedroom be?
There is no legal minimum size for a bedroom in a house you own, so the test is whether it works. A comfortable double needs room for the bed with space to walk round it, wardrobes and a door that opens freely. We draw furniture on the plans so you can judge the space before anything is built.
Nearby
The same service in neighbouring towns:
Other extensions in Renfrew
All two-storey extension services in Renfrew · Extra bedroom and en-suite extensions across Renfrewshire and Inverclyde
Tell us about your house in Renfrew and we'll call you back to arrange a free, no-obligation visit.