What is a double-storey extension?
A double-storey extension (also called a two-storey extension) adds rooms on both the ground and first floor in one build. It typically gives a larger kitchen or living space downstairs and an extra bedroom or bathroom above.
How much does a double-storey extension cost in Barrhead?
In Barrhead, a double-storey extension typically costs £1,600–£2,400 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £57,500–£86,500. Prices in Scotland sit near the national average for this kind of work, and the range for Barrhead reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £40,000–£60,000 |
| Typical project (36 m²) | £57,500–£86,500 |
| Larger project (50 m²) | £80,000–£120,000 |
| Rate per m² | £1,600–£2,400 |
Your quote will depend mainly on:
- Brick matching and external finishes
- Steel beams where walls are opened up
- Roof design and how it joins the existing roof
- Scaffolding and access to the rear
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a double-storey extension in Barrhead?
Here is how the rules work for a double-storey extension in Scotland. In Scotland an extension of more than one storey is only permitted development if it is at least 10 metres from every boundary and no higher than the existing ridge, so most need planning permission. A building warrant is needed before work starts.
Scotland has no Party Wall Act. Work on shared walls is governed by your title deeds, the Tenements (Scotland) Act 2004 for flats, and common law, so we agree arrangements with neighbours in writing before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
What we take care of:
- Windows, doors and staircase alterations
- Electrics, heating, plumbing and plastering
- Foundations, drainage and scaffolding
- Structural engineer’s calculations
- Design drawings and planning application
- Opening up at both levels with steel beams
How long does it take?
Allow 14 to 20 weeks on site, after planning and building control approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Barrhead
Scotland’s housing ranges from sandstone tenements and villas to post-war and modern estates, and the building warrant system shapes how projects are planned.
Our Barrhead coverage includes postcode districts G78, and we also work in nearby places such as Paisley, Newton Mearns and Renfrew.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about double-storey extensions in Barrhead
How long does a double-storey extension take in Barrhead?
Typically 14 to 20 weeks on site, after planning and building control approval. Design and approvals beforehand usually take 3 to 4 months.
Do I need planning permission for a double-storey extension in Barrhead?
In Scotland an extension of more than one storey is only permitted development if it is at least 10 metres from every boundary and no higher than the existing ridge, so most need planning permission. A building warrant is needed before work starts.
Can I live at home during the work?
Most families stay put. The shell is built first and the house is opened up late in the job, so disruption inside is limited to a few weeks.
What drawings do I need?
Planning drawings for the application, then more detailed building regulations drawings and structural calculations for building control. We prepare both.
How close can it be to my neighbour?
Councils look at loss of light and outlook for neighbours. Many apply a 45-degree guideline from the nearest neighbouring window. We design to the council’s published guidance to give the application the best chance.
How much does a double-storey extension cost in Barrhead?
In Barrhead, a double-storey extension typically costs £1,600–£2,400 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £57,500–£86,500. Your fixed price depends on the survey and drawings.