House extensions · Caerphilly
House extensions in Caerphilly
Rear, side and over-garage extensions for Caerphilly homes, with the ground, the drains and the permissions checked before anything is drawn.
The room your house is missing
Most of the houses in Caerphilly were built with a small kitchen at the back and little thought for how families live now. An extension puts that right without the cost and upheaval of moving: a kitchen everyone fits in, a downstairs shower room, or a bedroom over the garage.
We handle the whole job, from groundworks and structure to glazing and finishes, with one team from start to finish. We are fully insured and qualified, and you get a free, no-obligation quote before any work is agreed.
- Single-storey
- Two-storey
- Side returns & wrap-arounds
- Steel beams & openings
- Bi-folds, sliding doors & rooflights
- Building control sign-off
Extending a Caerphilly house
Three kinds of house make up most of the town, and one thing lies under all of them.
Stone terraces
In the older streets and in Bedwas, Llanbradach and the Aber Valley, terraces are narrow, with a lean-to kitchen at the back. Replacing the lean-to with a full-width extension is the usual answer, built with access through the house or from a rear lane.
Post-war semis
The estates of Penyrheol, Trecenydd and Energlyn are mostly semi-detached, with space down one side. A side extension, a wrap-around or a second storey over an existing one all suit them.
Later estate houses
Detached homes on estates such as Castle View and Churchill Park usually have an attached garage. Building over it, or converting it and extending behind, adds a room without using up the garden.
Drains under the garden
On many estates a shared sewer crosses the back gardens. Building over or close to one needs the agreement of Dŵr Cymru Welsh Water, so we find the drains before the design is drawn.
Local knowledge
Planning, building control and the ground in Caerphilly
Planning applications go to Caerphilly County Borough Council. Many single-storey rear extensions fall within Wales’s permitted development rules and need no application, though on newer estates those rights were sometimes removed when the houses were built, and we check before you pay for drawings.
The ground matters as much as the permission here. We obtain a coal mining report for the plot before the foundations are designed, and where the garden slopes, as it does on the sides of the basin, a structural engineer designs any retaining wall as part of the same job.
- Planning authority
- Caerphilly County Borough Council
- Before the design
- Mining report and drain survey
- Often needed
- Welsh Water agreement to build near a sewer
Extensions from our gallery
Finished rooms and the walls that hold them up.
Brick extension with sliding doors 
Dining space under a rooflight 
Two-storey rear extension
Why choose Orange Stone Construction
We offer more than construction services: we offer peace of mind, from the first conversation to the day the work is handed over.
Fully licensed & insured
Your project is in safe and professional hands, with the cover to prove it.
Free consultation & quote
A free initial consultation, then a competitively priced quote with no obligation.
On time and within budget
The price and the programme are agreed before we start, and we keep to both.
Professionally trained
Qualified tradespeople and top-quality materials on every stage of the work.
Where we work in Caerphilly
We reach Caerphilly from our base in Llandough by way of Cardiff and the A470.
- Penyrheol
- Trecenydd
- Energlyn
- Churchill Park
- Castle View
- Watford
- Bedwas
- Trethomas
- Machen
- Llanbradach
- Abertridwr
- Senghenydd
FAQs
House extensions in Caerphilly: your questions
Anything else you want to know, call 029 2264 2498 and ask — we would rather have the conversation than have you guess.
Often not for a single-storey rear extension, which is usually permitted development. Two-storey extensions near a boundary, extensions to the side facing a road, and houses on estates where the rights were removed normally need an application to Caerphilly County Borough Council. We confirm which applies first.
Usually, yes. The drain can often be built over with protection, or diverted around the new foundations. If it is a public sewer, Welsh Water has to agree the details, and we deal with that application for you.
Rarely in practice. The mining report tells the engineer what is recorded under the plot, and in most cases standard foundations are suitable. Where something is recorded nearby, the foundations are designed to suit, and it is far cheaper to know at the start.
Yes. The extension is designed with the levels: cut into the slope behind a retaining wall, or stepped down from the house. We price the walls, steps and drainage with the extension, so the garden is usable when we leave.
Free, no-obligation quote
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