Decks Built To Last
Decking Installation Belfast
The boards are the cheap bit. CSW builds decks in Belfast on a frame and a ventilation gap designed for a climate that is wet for most of the year.
Everything Important Is Under The Boards
Decking gets sold on the boards, which is the wrong way round. What decides whether a deck is still solid in fifteen years is the frame under it, the way it is fixed and supported, and whether air can move underneath. Belfast is wet, often for weeks at a time, and any timber structure sitting on damp ground with no airflow will rot from beneath while looking perfectly fine on top, right up until somebody puts a foot through it.
The second thing that decides it is what the deck sits on. A frame bearing directly onto soil, or onto a few slabs pressed into the grass, will settle unevenly and start to move within a couple of seasons. Proper pads or posts on a firm bearing cost very little more at build stage and are impossible to retrofit.
We build both timber and composite decks, along with the steps, balustrades and screens that usually come with them. Composite has genuinely improved and is a reasonable answer for a lot of Belfast gardens. It is not maintenance free, whatever the brochure says, and it still needs exactly the same frame underneath.
Timber Decking
Treated softwood or hardwood boards on a treated frame. Warmer underfoot, cheaper to build, and it needs cleaning and treating to stay looking like something you want to sit on.
Composite Decking
Wood and polymer boards that do not need annual treating and do not splinter. More expensive, low maintenance rather than no maintenance, and it still sits on a timber or aluminium frame that has to be built properly.
Steps, Balustrades And Screens
Getting down to the garden safely, guarding a raised deck, and privacy screening. Made by our joiners rather than bought as kit parts that never quite line up.
Why CSW For Decking
Frame First
Joist spacing to suit the board, proper bearings, and everything treated. The part nobody photographs is the part that decides the lifespan.
Ventilation Underneath
A gap that lets air move under the deck. Without it a Belfast deck rots from below while the surface still looks new.
Falls And Drainage
Water taken away from the house and from the deck rather than allowed to pond under it. Standing water under decking is how frames fail.
Joinery Standards On Steps
Steps and balustrades made rather than assembled from kit, so risers are consistent and handrails are actually solid.
Groundwork Included
Levels, bases and any retaining needed for a raised deck are our work too, so the deck is not built onto whatever happened to be there.
Honest About Composite
It is low maintenance, not no maintenance, and it gets slippery in shade like everything else. We would rather say so than sell the brochure.
Decking, Planning And Drainage
Most garden decking sits below the thresholds that trigger anything, but raised decks and decks near drainage are the two exceptions. This is general guidance for Northern Ireland rather than advice about your garden, and your district council and NI Water are the authorities on your own case.
Raised Platforms And Permitted Development
Permitted development rights for a dwellinghouse in Northern Ireland come from the Planning (General Permitted Development) Order (Northern Ireland) 2015 and are decided by your district council. A low deck sitting close to ground level is a very different proposition in planning terms from a raised platform that overlooks a neighbour's garden.
The height of the platform is the thing to establish, and so is whether any balustrade around it counts as a means of enclosure. A fence, wall, gate or other means of enclosure is permitted up to two metres generally and only one metre where it adjoins a road or a footpath.
- The higher the deck, the more likely a planning question arises, particularly where it overlooks.
- Open plan and shared surface estates often have enclosure rights restricted altogether.
- An Article 4 direction removes permitted development rights. Belfast City Council has made them, Malone Park being a published example.
Decking Over Drains And Sewers
Decks go across the back of houses, which in Belfast is frequently exactly where the drainage runs. Building over or near a public sewer, water main or associated works without NI Water's prior consent is an offence under Article 236 of the Water and Sewerage Services (Northern Ireland) Order 2006, and the protected strip is three metres or one and a half times the depth, whichever is greater.
Even where it is a private drain rather than a public sewer, covering an inspection chamber with a fixed deck is a decision you will regret the first time something blocks. Access has to be designed in, not sacrificed.
- Establish what is under the proposed deck before the frame is set out.
- Where a chamber falls within the deck, a properly made lifting hatch is the answer.
- Where building near a non critical public sewer is unavoidable, the NI Water application goes in on form SBO A236.
Building Control Is Usually Not Involved
An ordinary garden deck is not generally a building control matter. For comparison, Schedule 2 to the Building Regulations (Northern Ireland) 2012 exempts small detached single storey buildings not exceeding thirty square metres standing at least one metre from a dwelling, road or boundary, and a carport up to thirty square metres open on at least two sides.
A deck is not a building in that sense, but the comparison is useful because it shows where the thresholds sit if the project grows into a covered structure or a garden room.
- Adding a roof over a deck changes what it is, and the question is worth asking before it is built.
- Where a deck is attached to the house at first floor level it is a structure carrying people at height and deserves proper design.
- Building control in Northern Ireland is your district council. There is no private approved inspector route here.
How A Deck Is Built To Survive Here
The Base And The Bearing
A frame resting on soil, or on a handful of slabs bedded into the grass, will settle unevenly. Within two seasons the deck rocks in one corner and the boards start opening at the joints. The fix is not achievable without lifting the whole thing.
So we set the deck on pads or posts bearing onto firm ground, spaced to suit the joist span, and levelled properly. It is unglamorous and it is the reason a deck is still solid a decade later.
Air Under The Deck
This is the Belfast specific point. In a climate where the ground is damp for most of the year, a deck built tight to the soil has no way of drying out underneath. The frame rots from the top of the soil upwards while the surface still looks fine.
A ventilation gap under the frame, and clear air paths at the edges rather than boxing the whole thing in with solid fascia, is what prevents that. If a deck is going to be enclosed at the sides for appearance, the ventilation has to be designed back in rather than forgotten.
Falls, Gaps And Where Water Goes
Boards get a small gap between them so water passes through rather than sitting on the surface, and the ground beneath is graded so that water leaves rather than ponding. A deck over a permanent puddle has a limited life however well it is framed.
Where the deck meets the house, water must be taken away from the wall, and the deck surface should sit below the damp proof course rather than bridging it. Bridging a damp proof course with a deck is a common and genuinely damaging mistake.
Timber Or Composite, Honestly
Timber is cheaper to build, warmer underfoot and can be sanded and retreated. It needs cleaning and treating to stay looking good, and in a Belfast garden that means real annual work rather than an intention.
Composite does not need treating and does not splinter, which matters with children. It is not maintenance free, it needs washing, and like every deck surface it will get slippery where it is permanently shaded. Both are legitimate choices. The frame underneath is identical in importance either way.
How A Decking Job Runs
Look At Levels And Drains
Where the deck goes, how much the ground falls, where the damp proof course sits and what drainage runs underneath. All of it before setting out.
Check Height And Enclosure
How raised the platform will be and whether any balustrade counts as a means of enclosure, so any planning question is raised before we build.
Prepare The Ground
Grade the ground so water leaves, clear vegetation, and set out pad or post positions to suit the joist span rather than to suit convenience.
Build The Frame
Treated joists at the correct spacing for the board being used, level, properly bearing, with a ventilation gap underneath and access retained to any chamber.
Lay The Boards
Consistent gaps for drainage, fixings appropriate to the material, and edges finished cleanly rather than cut short and covered with trim.
Steps, Rails And Tidy Up
Steps with consistent risers, balustrade where the height needs it, screens if wanted, and the surrounding garden made good.
Frequently Asked Questions
Do I need planning permission for decking?
It depends mainly on height. A low deck close to ground level is a very different proposition from a raised platform overlooking a neighbour. Permitted development rights come from the Planning (General Permitted Development) Order (Northern Ireland) 2015 and are decided by your district council, and any balustrade may count separately as a means of enclosure.
Why do decks rot from underneath?
Because there is no airflow. In a climate where the ground stays damp for most of the year, a frame built tight to the soil never dries out. It rots from the top of the soil upwards while the boards on top still look perfectly good, which is why failures tend to be discovered by somebody putting a foot through.
Can I build decking over a drain?
Not over a public sewer without consent. Building over or near one is an offence under Article 236 of the Water and Sewerage Services (Northern Ireland) Order 2006, and the protected strip is three metres or one and a half times the depth, whichever is greater. Even for a private drain, access to any inspection chamber must be designed in with a lifting hatch.
Is composite decking maintenance free?
No, and anyone telling you otherwise is selling. It does not need annual treating and it does not splinter, which are genuine advantages, particularly with children. It still needs washing, and like every deck surface it will get slippery where it stays permanently shaded. It is low maintenance, which is a different claim.
What should the deck sit on?
Pads or posts bearing onto firm ground, spaced to suit the joist span and levelled properly. A frame resting on soil, or on slabs pressed into the grass, settles unevenly and starts rocking within a couple of seasons. There is no way to fix that afterwards without lifting the entire deck.
Can decking cause damp in the house?
Yes, if it bridges the damp proof course. The deck surface should sit below the damp proof course, and the ground where the deck meets the wall should take water away rather than towards it. Bridging a damp proof course with a deck is common, genuinely damaging and entirely avoidable at build stage.
How far apart should the joists be?
It depends on the board being used, and composite in particular usually wants closer centres than timber because it is less stiff. Building a frame at generic spacing and then laying whatever boards get delivered is how you end up with a deck that feels bouncy. The board choice comes before the frame gets built.
Timber or composite for a Belfast garden?
Both work. Timber is cheaper to build, warmer underfoot and can be sanded and retreated, but it needs real annual cleaning and treating rather than an intention to do it. Composite costs more and removes that chore. What does not change either way is the frame, which is where the lifespan actually comes from.
Why do the boards have gaps between them?
So water passes through rather than sitting on the surface, and so the boards have room to move. A deck laid tight looks neat on day one and then either holds water or buckles as the boards take up moisture. The gap is deliberate and it is part of why the deck survives.
Can you build steps down to the garden?
Yes, and they are worth having made rather than assembled from kit parts. Consistent riser heights matter enormously for safety, and kit steps rarely land on a consistent riser once the ground is factored in. Our joiners build the steps and any balustrade so the handrail is genuinely solid rather than nominally present.
More Joinery & Carpentry From CSW
Get Your Free Quote Today!
Tell us roughly the size you want and how much the ground falls away, and we will come and look at the levels and what runs underneath. Both decide the design more than the board choice does. No charge for the visit.
- Call us: 07703 433214
- Email: Cswbuild@gmail.com
- Location: Belfast, Northern Ireland