Builders and Building Contractors in Cardiff
Structural and building work done to specification, with proper materials, by a team that knows what it is doing. Brickwork, groundwork, structural alterations, refurbishments and new builds across Cardiff and South Wales.
Building services
Bricklaying Cardiff
New walls, boundary walls, garden walls, extension brickwork and repair of existing brickwork. Correct mix, correct bonding, correct pointing to match existing work. We don't rush brickwork — it either stands properly or it doesn't stand at all.
Structural alterations Cardiff
Removing load-bearing walls, creating new openings, installing RSJ steel beams, underpinning and structural repairs. All structural work is carried out to Building Regulations and supported by the relevant sign-off documentation.
Building contractors in Cardiff
Structural and building work is the area where shortcuts cause the most damage. A wall built without correct footings. Brickwork that is not tied properly. A refurbishment that saves money on materials. These problems are not visible immediately — they show up six months or six years later, and they are expensive to put right.
J&Z Property Maintenance carries out bricklaying, general building and structural refurbishment across Cardiff to written specifications, with proper materials and a team that knows what it is doing. We specify for the building, not for the invoice.
South Wales weather — high rainfall and freeze-thaw cycles through winter — is particularly hard on incorrectly specified materials. Concrete poured without the right mix will not carry load. Brickwork pointed in the wrong mortar fails in frost. We get the specification right from the start so the work lasts.
Building services in Cardiff
Brickwork & repointing
New walls, boundary walls, garden walls, extension brickwork and repointing of existing masonry. Correct mix, correct bonding, pointing matched to the original. We do not rush brickwork — it either stands properly or it does not stand at all.
Structural alterations
Removing load-bearing walls, forming new openings, installing RSJ steel beams and structural repairs. All carried out to Building Regulations with the relevant inspections and sign-off from Cardiff Council building control or an approved inspector.
Groundwork & foundations
Foundations, footings, drainage, concrete slabs and site preparation. Groundwork is where most building problems start. We establish what is actually in the ground before designing anything onto it rather than assuming.
Structural refurbishments
Stripping back to brick, repointing, damp treatment, replacing failed lintels, replastering and structural repair. Common across Cardiff's older terraced stock where decades of patching have hidden what is going on underneath.
New builds & outbuildings
Garden rooms, annexes, outbuildings, garages and small new builds. Full project management from foundation through to watertight structure and first fix, with a written quote covering every stage before work starts.
General building work
The broader range that does not fit one category — chimney repairs, parapet walls, steps and thresholds, concrete repairs, stonework and site-specific structural fixes. If it involves masonry, concrete or structure, we cover it.
Two things about Cardiff buildings worth knowing before you start
The ground varies enormously across the city. Much of southern Cardiff — Grangetown, Butetown, Splott, Adamsdown and the areas around the docks — sits on softer alluvial and reclaimed ground associated with the Taff and Ely floodplains and the historic dock development. Northern Cardiff generally sits on firmer ground. That difference matters as soon as you start digging foundations or adding load to an existing structure, and it is why we establish what is actually beneath a site rather than working from an assumption about the area.
Rear outriggers are the weak point in most Cardiff terraces. The two-storey back addition on a Victorian terrace — the wing containing the original scullery and bathroom — was frequently built to a lower standard than the main house. Thinner walls, poorer foundations, and often inadequately tied into the main structure. That junction between the outrigger and the main house is where cracking most commonly appears, and it is regularly misdiagnosed as general settlement when it is actually a tying problem.
We see both of these constantly. Neither is a reason not to build — but they change what the correct specification is, and getting that wrong is expensive.
Signs your Cardiff property needs a builder
Structural signs
- Cracks wider than a few millimetres
- Diagonal cracking, especially around openings
- Cracking where a rear outrigger meets the main house
- Walls bowing or bulging outward
- Lintels showing rust staining or movement
- Floors sloping or springing underfoot
Masonry & damp signs
- Mortar crumbling or missing from joints
- Brick faces spalling or flaking away
- Render cracked, hollow or detaching
- Damp patches on internal walls
- White salt deposits on brickwork
- Vegetation growing from joints or chimney stack
If you have noticed any of these, call us for a free inspection. We assess it, explain what is happening and quote in writing for the remedial work. No charge for the visit.
Building Regulations in Cardiff — what applies
Most structural building work requires Building Regulations approval. This is separate from planning permission and applies even where planning consent is not needed. In Wales the regulations are administered under the Building Regulations 2010 as amended for Wales, and overseen by Cardiff Council building control or an approved inspector.
Work that typically requires approval includes:
- Removing or altering load-bearing walls
- Installing structural steel beams
- Underpinning or foundation work
- Extensions over a certain size
- Alterations affecting the thermal envelope
- New drainage connections
- Converting a garage to habitable space
We advise on what applies to your project at the initial visit and manage the applications, inspections and sign-off where required. This is general guidance rather than formal advice — for anything unusual or contested we will tell you to speak directly to building control.
How much does building work cost in Cardiff?
| Work type | Typical range | Key variables |
|---|---|---|
| Repointing (per square metre) | £40 – £90/m² | Access, mortar type, raking out required |
| Garden or boundary wall (per metre) | £150 – £350/m | Height, foundation depth, coping specification |
| Load-bearing wall removal | £1,500 – £4,500 | Beam span, structural engineer fee if required |
| Structural steel beam installation | £800 – £2,500 | Beam size, access, number of supports needed |
| Groundwork & foundations | £3,000 – £12,000 | Area, depth, ground conditions, drainage |
| Structural refurbishment (per room) | £2,500 – £8,000 | Extent of structural work, damp treatment, replastering |
| Garden room or outbuilding | £15,000 – £35,000 | Size, specification, groundwork, finish level |
All figures are indicative for typical Cardiff residential and commercial projects. Every job is quoted individually following a free site visit. Your written quote covers labour, materials and project management with no hidden costs.
Why Cardiff customers choose J&Z for building work
The mortar mix, the foundation depth, the beam size — these are determined by what the job needs. We do not substitute cheaper materials to win a quote and leave you with a repair that fails in five years.
Cardiff's terraced stock needs breathable materials and an understanding of how solid walls and rear outriggers behave. Modern products used carelessly on a Victorian building cause damp problems that were not there before.
Where approval is required we handle the application, the inspections and the sign-off with Cardiff Council building control. You do not need to understand the process — that is our job.
Every project is quoted in full before work starts and the scope is agreed in writing. If something unexpected turns up on site — hidden damp, poor ground, a failed lintel — we discuss it before it affects your cost.
Frequently asked questions — builders Cardiff
What building work do you carry out in Cardiff?
We cover bricklaying and repointing, structural alterations including load-bearing wall removal and steel beam installation, groundwork and foundations, structural refurbishments, general building work, and new builds including garden rooms and outbuildings. If it involves masonry, concrete or structural work, call us and describe the job — we will tell you honestly whether it is within our scope.
Do I need Building Regulations approval for structural work in Cardiff?
In most cases yes — removing load-bearing walls, installing steel beams, underpinning, significant extensions and garage conversions all require approval. In Wales this is administered under the Building Regulations 2010 as amended for Wales and overseen by Cardiff Council building control or an approved inspector. It is separate from planning permission and applies even where planning consent is not needed. We advise on what applies and manage the process.
How do I know if a wall is load-bearing?
Indicators include walls running perpendicular to the floor joists, walls present on more than one storey, walls sitting directly over a foundation, and walls supporting roof structure or a beam above. None of these is conclusive on its own. The reliable way to confirm is a structural survey or opening up to inspect what sits above and below. We assess this at the free site visit before quoting any structural alteration — we will not guess at it.
Why is there cracking where my rear extension meets the main house?
On Cardiff's Victorian terraces this is very often the original rear outrigger rather than a modern extension. Those two-storey back additions were frequently built to a lower standard than the main house — thinner walls, shallower foundations, and sometimes inadequately tied into the main structure. Movement at that junction is common and is regularly misdiagnosed as general subsidence. The correct fix depends on whether it is a tying issue, a foundation issue or thermal movement, which is what an inspection establishes.
Do ground conditions vary across Cardiff?
Considerably. Much of southern Cardiff around the docks, Grangetown, Butetown and Splott sits on softer alluvial and reclaimed ground associated with the Taff and Ely floodplains, while northern parts of the city generally sit on firmer material. This affects foundation design, excavation and how much additional load an existing structure can safely take. We establish what is actually beneath a site rather than working from an assumption about the postcode.
How much does building work cost in Cardiff?
Repointing runs roughly £40–£90 per square metre. A garden or boundary wall is typically £150–£350 per metre. Load-bearing wall removal ranges £1,500–£4,500 depending on span and whether a structural engineer is required. Groundwork and foundations run £3,000–£12,000. Every project is quoted individually after a free site visit, with labour, materials and project management all included in the written figure.
Which areas of Cardiff do you cover?
All Cardiff postcodes CF1 through CF24 and surrounding areas including Barry, Penarth, Caerphilly and Pontypridd. We work across the full range of Cardiff housing — Victorian terraces in Roath, Canton and Grangetown, interwar semis in Whitchurch and Rhiwbina, and newer stock in the north of the city.
Other services we offer in Cardiff
Extensions & conversions
Extensions & conversions Cardiff →Garage conversions
Garage conversions Cardiff →Home renovations
Home renovations Cardiff →Property maintenance
Property maintenance Cardiff →Handyman services
Handyman services Cardiff →Garden & landscaping
Garden services Cardiff →Builders across Cardiff and South Wales
Cardiff · Canton · Roath · Cathays · Pontcanna · Grangetown · Llandaff · Whitchurch · Rhiwbina · Pontprennau · Barry · Penarth · Caerphilly · Pontypridd · Newport
Get a free building estimate in Cardiff
Call us or send your details and we will arrange a free site visit — evenings and weekends available, no charge, no obligation.
Building Contractor Cardiff
Building refurbishments Cardiff
Full structural refurbishment of older Cardiff properties — stripping back to brick, repointing, damp treatment, new lintels, replastering and structural repairs. Common across Cardiff's Victorian and Edwardian terraces where decades of patching have obscured underlying problems.
General building work Cardiff
The broader range of building tasks that don't fit neatly into one category — chimney repairs, parapet walls, steps and thresholds, concrete repairs, heritage stonework and site-specific structural fixes. If it involves masonry, concrete or structural work, we cover it.