Why building up makes sense on the Fens
Boston sits on drained fen, and the county's own survey of the town notes that much of the land is below sea level. On 5 December 2013 a tidal surge got over or through the defences and flooded more than 800 properties across 55 streets. The Boston Barrier has been working since 2020 and protects the town far better than before. The land is still as low as it ever was.
So think about where the extra room goes. A rear extension that needs planning permission here comes with a flood risk assessment, because the whole town is in the floodplain. A loft conversion adds no footprint. If it falls under permitted development it doesn't go through planning at all, and the new room is the highest one in the house. For most Boston families short of a bedroom, we'd look up before looking out.
Railway terraces, Spilsby Road villas and a lot of bungalows
Lincolnshire County Council's survey splits the town into ten character areas, and the roofs follow them. West of the centre, round Tower Street, James Street and Lincoln Lane, are two-storey red brick terraces put up for railway workers after the line arrived in 1848. East of Wide Bargate you get Victorian terraces around Pen Street and Grove Street and big Victorian villas on Spilsby Road. Older roofs like these were built by hand and usually open up well.
Further out it's mostly twentieth century. Interwar council estates in brick and white render, then post-war estates to the north-west and planned estates from 1950 to 1975 out east. Bungalows turn up all over. A bungalow can make a good loft, but it lives or dies on the ridge height, so get it measured before you get excited. Newer houses such as those on the Quadrant at Wyberton will mostly have factory trusses, which means a steel frame and a higher quote.
Picking the right type for your roof
Hip to gable. Detached and semi-detached houses far outnumber terraces in Boston, and plenty of them, bungalows included, have a sloping end roof. Squaring that end off into a gable is often the move that turns a cramped loft into a usable floor.
Read our full guide: Hip-to-Gable Loft Conversions: What It Involves and Which Houses It Suits →
Rear dormer. The usual choice on the railway terraces west of the centre and on interwar semis. Outside a conservation area it normally goes ahead under permitted development, within 40 cubic metres on a terrace and 50 on anything else.
Rooflights only. The gentlest option for the town centre, Skirbeck and Spilsby Road conservation areas, where any dormer needs permission. It only works where the roof already gives you standing room, which a steep old roof like those on Wide Bargate may.
L-shaped dormer. Worth asking about if your Victorian terrace has a two-storey back addition. A second dormer over it gives room for a shower room without eating into the bedroom.
Mansard. Nearly always a planning application. Near the Stump or in the historic core you'd want an architect who knows the conservation officers before anything is drawn.
Extra bedroom. This is what most Boston lofts become. Building control checks the stairs and fire protection before it signs off, so make sure the quote covers them.
En-suite. Decide early. On a bungalow conversion the soil pipe has the furthest to drop and the fewest places to go, and that decides where the shower can sit.
Home office. A room up in the roof, away from the street and the rest of the household, is the quietest in the house. Have the data cable pulled up while the floor is open.
Read our full guide: Loft Home-Office Conversion: What Works Well Up There and What to Specify →
Planning. Outside the conservation areas, most rear dormers and hip to gables here are permitted development. Inside one, any roof enlargement needs an application. Building Regulations approval is needed either way.
Cost. We don't put a Boston price on this page. A hand-built Victorian roof and a trussed new-build roof are different jobs, and a printed figure would only mislead. Three site visits will tell you more.
Pantiles, slate and the conservation areas
Boston Borough Council has 11 conservation areas. Three are in the town itself: the town centre, designated in 1969, Skirbeck around St Nicholas church, and Spilsby Road. The rest cover villages such as Kirton and Swineshead. Inside any of them, permitted development for loft conversions doesn't apply, so a dormer on the back needs permission just as much as one on the front.
The old roofs mix their materials. Wide Bargate has early eighteenth-century houses under steep pantiles, Fydell House on South Square has plain clay tiles, and the early nineteenth-century South Terrace was built in Gault brick under Welsh slate, though only one house there still has its original slate. Expect the planners to want new work that matches the roof you've got.
Since 2021 Boston has shared staff with East Lindsey and South Holland through the South and East Lincolnshire Councils Partnership. Building control is still run from Boston's own office at Municipal Buildings on West Street, and its email address is buildingcontrol@boston.gov.uk. Look up your street on the council's planning register first. What the neighbours got approved is the best clue to what you'll get.
Where these facts come from
- Boston Borough Council: conservation areas
- Boston Borough Council: building control forms and contact
- Boston Borough Council: South and East Lincolnshire Councils Partnership
- Lincolnshire County Council: Boston Extensive Urban Survey
- Environment Agency: Boston Barrier flood defence
- Environment Agency: Boston Barrier gate fully operational
- Planning Portal: loft conversion permitted development
- Lincolnshire Heritage Explorer: listed terrace on South Terrace
How FirQuote works in Boston: We connect you with local specialists who visit your property before giving you a price. You get up to 3 written quotes — no call centres, no estimates from photos, no obligation to accept any quote.
Questions people in Boston ask
Our street flooded in 2013. Does that affect a loft conversion?
Not much, if the work is permitted development. It doesn't go through planning, so there's no flood risk assessment. If you need an application, because you're in a conservation area or the loft comes with a ground-floor extension, expect the flood questions to come with it. Either way, the new room is the one furthest from the water.
I live on Spilsby Road. Can I put a dormer on the back?
Possibly, but not without asking. Spilsby Road is a conservation area, so loft permitted development rights don't apply there and even a rear dormer needs planning permission. Rooflights are the easier route. Several houses on the road are listed too, which brings listed building consent into it.
Is it worth converting the loft in a Boston bungalow?
Often, if the roof is tall enough. Measure from the top of the ceiling joists to the underside of the ridge. Hipped bungalow roofs usually need a hip to gable or a big rear dormer to give real headroom. A builder on site can tell you in ten minutes whether it's worth drawing up.
Has Boston's building control merged with East Lindsey?
Not as a single service. The three councils in the partnership share some staff, but Boston still runs its own building control office. Your builder can also use a private building control company instead.