Flat backs, tunnelbacks and houses built into the hill
Look at the back of a Swansea house before you look at any rulebook. Many of the private terraces were built as tunnelbacks, with a narrow rear wing and a strip of yard running down beside it. The council's own early estates went the other way. When the Townhill estate was built after 1919, the red brick houses went up in blocks without those rear projections, so the back wall is one flat face from end to end.
That difference decides a lot. A tunnelback has a side return waiting to be filled. A flat-backed council house usually doesn't, and the sensible move is straight out from the kitchen wall. Then there's the slope. Streets like Dewi Terrace and Glyndwr Place were stepped up the hillside to follow the contours, so one garden can sit well above the next. Digging out for a level floor and holding back the bank can take more effort than the walls.
The Welsh rules, and the Swansea streets where they stop
Swansea follows the Welsh permitted development order, not England's. A single storey addition at the back can reach 4 metres beyond the original rear wall and 4 metres in height without a planning application, and that figure is the same for a terrace, a semi or a detached house. Within 2 metres of a boundary the eaves must stay at or under 3 metres. Going up a floor brings a 3 metre limit on the upper storey and a 10.5 metre gap to the back boundary, which plenty of hillside gardens can't give.
Those rights shrink across much of the county. Gower became the UK's first Area of Outstanding Natural Beauty in 1956, and the council looks after 31 conservation areas, from Mumbles and Morriston to small Gower villages like Cheriton and Llanmadoc. In any of them, going above one storey is never permitted development. Side additions are held to 3 metres wide, set a metre behind the front elevation, and cladding in render, stone or timber needs consent.
Then there are roughly 270 houses in Ffynone and Uplands. The council's Article 4 direction there lists Class A, the right to extend, among the rights it removes, so on those addresses assume an extension needs a planning application until the council says otherwise.
Where an application is needed, officers work from the council's Placemaking Guidance for Householder Development, adopted on 22 October 2021. Read it before the drawings start.
Which addition suits which house
Single storey rear. The obvious answer for a flat-backed council house on Townhill, and usually possible without an application. Not on the Article 4 houses in Uplands, and check the original consent for a condition that removes the right.
Side return. Belongs to the private tunnelback terraces, where the yard beside the back wing is often the only spare ground. Where the street steps, check the neighbour's floor level against yours before fixing a wall height.
Kitchen. Plenty of hillside houses look over the bay from the back. Glaze towards the view, units against the bank.
Wrap-around. Filling the return and running across the end of the wing gives a tunnelback a proper family room. Expect to apply, since the result rarely fits the Welsh side limits.
Open plan. Taking out the old back wall means steel. Party wall notices apply here too, so serve them before the beams arrive.
Two storey. Most likely to work on the larger semis and detached houses in the suburbs. Anywhere on Gower or inside a conservation area it goes through planning, with no exceptions.
Ground floor bedroom. Getting level access from a steep road can be harder than building the room. Design the path and threshold first.
Home office. A cabin halfway up a sloping garden is a cold walk in January. Attached, the office shares the heating and broadband.
Planning. Inside the Welsh limits, a Lawful Development Certificate gives you proof for when you sell. Look up old conditions on the council's planning search as well.
Cost. We don't quote Swansea prices. Hillside excavation or foundations through made ground can move the figure a long way, so compare what each builder has allowed for.
Old works, peat and the river
Swansea grew on copper and coal, and the British Geological Survey says mining left spoil, subsidence and contaminated ground behind it, with made ground over the old industrial land. Small landslips happen along the valley sides where water seeps out at the foot of the Pennant sandstone. None of that stops you extending. It does make the trial hole worth paying for. If a shaft or old working turns up mid-dig, GOV.UK gives a 24-hour hazard line, 0800 288 4242.
The council lists the lower Swansea Valley, around Swansea Vale and the Beaufort and Plasmarl estates, as at high risk of flooding from the Tawe, the Nant-y-Fendrod and the Nant Bran. Check your address on the Natural Resources Wales Flood Map for Planning. If you're in one of its flood zones and need permission anyway, the application will need a flood consequences assessment.
And find the drains. Building within 3 metres of a public sewer, or over one, needs Dลตr Cymru Welsh Water's agreement.
Where these facts come from
- Welsh Government: planning permission for extensions
- Welsh Government: permitted development for householders, technical guidance
- Swansea Council: Placemaking Guidance for Householder Development
- Swansea Council: Ffynone and Uplands Article 4(2) direction
- Swansea Council: conservation areas
- Swansea Council: Gower AONB
- Swansea Council: Lower Swansea Valley flood risk
- British Geological Survey: geology of the Swansea district
- GOV.UK: planning applications and coal mining risk assessments
- Natural Resources Wales: Flood Map for Planning
- Dลตr Cymru Welsh Water: building over or near sewers
- Municipal Dreams: early municipal housing in Swansea
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Questions people in Swansea ask
Our house in Uplands is on the Article 4 plan. Can we still add a kitchen at the back?
Possibly, but don't rely on permitted development. The direction lists Class A rights for about 270 houses in Ffynone and Uplands. Directions of this type usually target work visible from the street, so ask the council whether a rear kitchen is caught. Talk to the Design and Conservation team on 01792 635794 before you commission drawings.
We live on Gower, outside the villages. Is a two storey extension off the table?
No, but it always needs an application, because two storey additions aren't permitted development anywhere in the AONB. A single storey one at the back, within the 4 metre limit, may not.
Our ex-council house on Townhill has no back wing. How far out can we go?
Up to 4 metres from the original rear wall and 4 metres high under the Welsh rules, keeping the eaves to 3 metres within 2 metres of the boundary. Earlier additions count towards the half-the-plot limit.
Do we need a mining report to extend on the old coalfield?
GOV.UK lists householder development among the applications that don't need a coal mining risk assessment, though the council can still ask for one. Dig a trial hole anyway, and report any mine feature found on 0800 288 4242.