Extension Builders In Belfast
House Extensions Belfast
More kitchen, another bedroom, somewhere the family can actually sit together. CSW builds rear, side and two storey extensions across Belfast, and handles the district council side of it so you are not guessing.
Extending A Belfast House, Properly
Most of the extensions we build in Belfast are on houses that were never designed to be extended. Red brick terraces off the Ormeau and Lisburn Roads with a narrow return and a yard behind. Nineteen thirties semis in east Belfast with a side passage just wide enough to be worth claiming. Nineteen sixties and seventies estate houses out towards Dundonald and Carryduff with a decent back garden and a kitchen the size of a corridor. Each of those starts from a different place, and the honest answer to what is possible only comes after somebody has stood in the room and looked at where the drains run.
We take extensions from the first sketch through to the last coat of paint. Foundations, blockwork, roof, windows and doors, plastering, first and second fix joinery, and the landscaping to put the garden back together afterwards. Because the same family firm does the joinery and the groundwork, you are not managing three sets of tradesmen who each blame the last one for the mess.
The part homeowners find hardest is not the building. It is knowing which permissions actually apply, because most of what you will read online about extensions is written for England and Wales, and a good deal of it is simply wrong here. Northern Ireland runs its own building control and its own planning system, and it does not have some of the legislation English guidance assumes.
Rear Extensions
The most common job we do. A single storey across the back of the house to open the kitchen into a dining and living space, with bifold or patio doors onto the garden and rooflights where the depth would otherwise leave the middle of the room dark.
Side Returns
Filling in the alleyway or side passage on a terrace or semi. It is often the cheapest square metre you will ever add, because two of the walls are already there, though it usually needs the most careful thought about your neighbour's boundary.
Two Storey Extensions
Adding a bedroom or bathroom above the new ground floor space. More expensive per square metre than a single storey, but a far better return where the family needs the sleeping accommodation rather than the living space.
Why Belfast Homeowners Use CSW For Extensions
One Team, Start To Finish
Groundwork, blockwork, roofing, joinery and landscaping are all in house. Nobody is waiting on a subcontractor who has taken another job.
50 Years Of Combined Experience
Skilled tradesmen who have seen what Belfast housing stock hides behind the plaster, from shallow Victorian foundations to cavity walls that were never tied properly.
We Handle The Council Side
We are used to district council building control in Northern Ireland, the inspection stages and what an officer will want to see opened up before it gets covered.
Quality Materials
Specified for the job rather than for the quote. Blockwork, insulation and timber that will still be doing their job in thirty years.
Local, Not National
A family run business based in Belfast. If something needs looking at after we finish, we are half an hour away rather than a call centre.
Your Garden Put Back
An extension wrecks a garden. Because we also do landscaping, the fencing, paving and turf go back as part of the job rather than as an afterthought you have to arrange yourself.
Extensions And The Rules In Northern Ireland
This is where most of the confusion sits, and it is worth reading properly before you commit to anything. Planning permission and building control are two separate consents from your district council, and needing one does not mean you need the other. What follows is general guidance for Northern Ireland, not advice about your particular property, and your council's building control office is always the final word.
Building Notice Or Full Plans
Building control in Northern Ireland is administered by your district council under the Building Regulations (Northern Ireland) 2012. For a Belfast address that is Belfast City Council Building Control. There is no private approved inspector route here, which is one of the first things English guidance gets wrong about Northern Ireland: the council is the only route.
There are two ways in. A Full Plans application means drawings are submitted and assessed, and if they satisfy the regulations the council issues a Notice of Passing of Plans for that design. A Building Notice lets work start without full drawings, but it can only be used for minor planned work to a single domestic property, and the council can still ask for plans once it sees what is involved.
- A Full Plans approval leaves you with a document. A Building Notice does not.
- That document is what a solicitor or a purchaser tends to look for when the house is sold.
- For anything the size of a genuine extension we would normally expect a Full Plans application rather than a notice.
There Is No Party Wall Act Here
The Party Wall etc. Act 1996 does not extend to Northern Ireland. There is no statutory party wall notice to serve, no statutory timetable, and no surveyors' award mechanism. If you have read that you must give your neighbour two months' notice before working on a shared wall, that is English law and it does not apply to your Belfast terrace or semi.
That cuts both ways. There is nothing to serve, but there is also no statutory protection for either side if something goes wrong. What actually governs it is the deeds, the common law, and whatever you and your neighbour agree between you.
- Talk to the neighbour before the digger arrives, not after.
- Take a dated photographic record of their side of the wall, their ceilings and their garden before any work starts. It is the sensible substitute for the English schedule of condition.
- Where the deeds say something about the boundary or a shared wall, read them, because here they carry the weight the statute carries in England.
Sewers, And Why They Move An Extension
Under Article 236 of the Water and Sewerage Services (Northern Ireland) Order 2006 it is an offence to build over or near a public sewer, water main or associated works without NI Water's prior consent. The protected strip is three metres, or one and a half times the depth of the sewer, whichever is greater.
If a public sewer runs through your back garden, and in a lot of Belfast terraces it does, that strip may be the single thing that decides how far back your extension can go. Where the only realistic option is to build over or near a non critical sewer, the application goes to NI Water on form SBO A236, and they may ask for a structural engineer's report at your expense.
- We check the sewer position before the design is finalised, not after the foundations are set out.
- NI Water will not consider building over a public sewer for a new building at all.
- Retrospective consent is never given for work built directly over a critical sewer, a manhole or a pumping main.
Planning Permission And Permitted Development
Planning in Northern Ireland is decided by the eleven district councils, and permitted development rights for houses come from the Planning (General Permitted Development) Order (Northern Ireland) 2015. Some extensions fall inside those rights and some do not, and the answer depends on the size, the position and what has already been added to the house.
Two things catch Belfast homeowners out. If your street sits under an Article 4 direction, permitted development rights have been removed and work that would normally be allowed needs a planning application: Belfast City Council has made Article 4 directions, Malone Park being a published example. And an extension that needs no planning permission at all may still need full building control approval, because they are separate consents.
- If the property is listed or sits in a conservation area, assume a separate consent is needed and check before you design around it.
- Permitted development is a right, not a certificate. Some homeowners still apply for confirmation in writing before selling.
What An Extension Actually Involves
Groundwork And Foundations
The first week is the messiest and the most important. We dig, the council's building control officer inspects the trench before anything is poured, and the depth is decided by what is actually in the ground rather than by what was assumed on paper. Belfast has plenty of soft ground and plenty of old fill, and it is not unusual for a trench to have to go deeper than the drawing shows.
Drains get located and, where they need to be, diverted properly with new inspection chambers rather than boxed around and hoped for. This is also the point at which any sewer question has to already have been settled with NI Water.
Shell, Roof And Weathertight
Blockwork goes up, the cavity is insulated and the wall ties go in at the correct centres. Steels are craned or carried in where an opening is being formed into the existing house, and the calculations for those come from an engineer, not from a rule of thumb.
Getting the roof on and the windows and doors in is the point where the job stops being weather dependent and your house stops feeling like a building site. We aim to reach it as early in the programme as the inspections allow.
Opening Into The Existing House
Knocking through is the day everyone remembers. It is also the dustiest, so we sheet and seal the rest of the house first and keep a route in and out that does not run through your living room.
Where a load bearing wall is coming out, the opening is propped, the beam is set on properly sized padstones and the whole thing is inspected before it is closed in. That inspection is not optional and it is not something to let a builder talk you out of.
First Fix, Second Fix And Finishing
Electrics and plumbing are run before the plaster. Worth knowing at this stage: Northern Ireland has no equivalent of the England and Wales Part P self certification regime, and there are currently no statutory requirements for domestic electrical installation work here. Nobody is legally obliged to certify your new circuits, so ask for an installation certificate from an electrician registered with a recognised body, and do not assume it will arrive by itself.
Then plastering, joinery, skirtings, architraves, internal doors and decoration. Our own joiners do the second fix, which is why the trim tends to look like it belongs to the house rather than to the extension.
How We Run An Extension
Free Site Visit And Estimate
We come out, look at the house, the garden, the access and where the drains run, and talk through what is realistic. The visit and the written estimate cost you nothing.
Design And Drawings
The layout is agreed and drawings are prepared for the council. This is where the sewer position, the boundary and any Article 4 or conservation issue has to be settled, before anything is built.
Council Applications
Building control goes in, and planning too where it is needed. We are used to what a district council building control officer wants to see and at which stage.
Start Date And Programme
You get a start date and a realistic sequence, including the two or three weeks where the house is genuinely disrupted, so you can plan around it rather than discover it.
Build, With Inspections
Foundations, shell, roof, openings and drainage, each inspected at the right point rather than opened back up afterwards.
Finish And Hand Back
Second fix joinery, decoration, the site cleared, and the garden and boundary put back. You get the paperwork from the council, not just a handshake.
Frequently Asked Questions
Do I need planning permission for an extension in Belfast?
Sometimes. Permitted development rights under the Planning (General Permitted Development) Order (Northern Ireland) 2015 cover a lot of ordinary extensions, but the answer depends on size, position, what has already been added and whether an Article 4 direction applies to your street. Belfast City Council has made Article 4 directions in some areas, which remove those rights. We check it before the design is finalised rather than after.
Is planning permission the same thing as building control approval?
No, and this is the single most common misunderstanding. They are two separate consents from your district council. An extension can need building control approval and no planning permission, or occasionally the other way round, and it is quite normal to need both. Getting one does not get you the other.
Do I have to serve a party wall notice on my neighbour?
No. The Party Wall etc. Act 1996 does not extend to Northern Ireland, so there is no statutory party wall notice, no timetable and no surveyors' award here. That also means there is no statutory protection for either side, so we recommend talking to the neighbour early and taking a dated photographic record of their side before work starts.
Should I go for a Building Notice or a Full Plans application?
A Building Notice can only be used for minor planned work to a single domestic property, and it leaves you with no approved design to point at later. A Full Plans application produces a Notice of Passing of Plans, which is the document a solicitor or a purchaser tends to look for when the house is sold. For a genuine extension we would normally expect Full Plans.
There is a sewer in my back garden. Can I still extend?
Often yes, but it changes the design. NI Water's protected strip is three metres or one and a half times the depth of the sewer, whichever is greater, and building over or near a public sewer without consent is an offence under Article 236 of the Water and Sewerage Services (Northern Ireland) Order 2006. Where building near a non critical sewer is the only option, the application goes in on form SBO A236 and a structural engineer's report may be required.
How long does a single storey rear extension take?
It depends on the size, the ground and the weather, and any builder who gives you a number before seeing the site is guessing. What we will do is give you a programme with the disruptive stages marked, so you know which weeks are the awkward ones. Groundwork and knocking through are the two that affect daily life most.
Will I be able to live in the house while you build?
For most single storey rear extensions, yes. The shell goes up outside the existing wall, so the house stays sealed until the day we knock through. We sheet and seal before that and keep our route in and out away from your living space. A two storey extension is more disruptive and we will say so honestly at the estimate stage.
Do I need to think about the foundations of my existing house?
Yes, particularly on older Belfast property. Victorian and Edwardian houses often sit on shallow foundations, and new work next to them has to be designed so it does not undermine what is there. The trench is inspected by building control before anything is poured, and the depth is decided by what is actually in the ground.
Who certifies the electrical work in the extension?
Ask for it explicitly. Northern Ireland has no equivalent of the England and Wales Part P regime, and there are currently no statutory requirements for domestic electrical installation work here, so nobody is obliged to notify or certify it. We use electricians registered with a recognised body and you should ask for an installation certificate on completion.
Can you put the garden back afterwards?
Yes, and it is worth planning it in rather than bolting it on. Extensions destroy gardens, and because CSW does landscaping and fencing as well as building, the paving, boundary and turf can go back as part of the same job. It costs less than bringing in a separate landscaper after the fact, and there is no argument about who damaged what.
More Building & Construction From CSW
Get Your Free Quote Today!
Tell us what you are hoping to add and we will come out, look at the house and the ground, and give you a written estimate with the council side spelled out. No charge for the visit and no obligation afterwards.
- Call us: 07703 433214
- Email: Cswbuild@gmail.com
- Location: Belfast, Northern Ireland