Rooflight installation in Springfield

The older streets around Springfield Green

The oldest part of the district sits around the church and the Green, and a conservation area covers a portion of it. Within that boundary the expectation on any street-facing slope is that new glazing sits flush and reads as historically plausible: a slim cast frame, a central bar, no white plastic surround standing proud of the slates.

Rear slopes are usually treated more pragmatically, because they are not visible from public ground. That distinction is worth checking before the design is fixed rather than assumed, since the boundary line does not always follow the road you would expect.

Rear outriggers and side returns off the older streets

The Victorian houses here mostly have a two-storey rear outrigger with a narrow side return beside it, and that return is the darkest strip of the plan. Roofing it over to make a wider kitchen is the single commonest project on those streets.

The resulting roof is narrow, often two metres or less across, and it usually runs against a party wall on one side. A flush flat rooflight suits it far better than a raised structure, because a lantern in a two metre width reads as a lid rather than as height. A long slim unit running with the length of the return delivers light along the whole strip rather than in one bright pool.

The nineteen eighties estates and their trussed roofs

The large estates east and north of the older streets are trussed rafter construction throughout. The webs and the bottom chord carry load in tension and compression, and cutting one changes how the whole truss behaves.

So the width available for a roof window is the clear gap between trusses, which at 600mm centres leaves room for a unit of roughly 550mm. Two units in adjacent bays, with the truss between them left untouched, is the standard solution. It looks deliberate from outside and it lights a room more evenly than a single opening would.

Hipped roofs, and the room a hip leaves you

Interwar and post-war Springfield houses often have hipped roofs, where all four sides slope in towards a short ridge. That geometry eats loft space at both ends and it also constrains where a rooflight can go.

The usable area is the middle third of the slope, away from the hip rafters and clear of the ridge. Manufacturers generally want a minimum distance below the ridge and above the eaves so the flashing has somewhere to terminate. On a shallow hip that window of opportunity can be under a metre of slope depth, which is exactly why the position is measured on the roof before a size is agreed.

Party walls on a Springfield terrace

On a terrace or a semi, an opening near the party wall line raises a question that has nothing to do with weathering. Where structural work is proposed within three metres of a neighbouring structure, or where the work touches the party wall itself, the Party Wall etc. Act may apply.

Most rooflight work does not go near that threshold, because trimming between rafters in the middle of a slope touches nothing shared. Where a steel is needed for a wide opening and it bears on a party wall, it does. Establishing which of the two you have at survey means notices go out early rather than holding up a booked start date.

Orientation across the Springfield street grid

The Victorian streets run in a fairly consistent grid, which means whole rows share an orientation. If a neighbour’s rear extension overheats in July, yours will too.

South and west facing rears want solar control glass with a low g-value, which limits how much solar energy comes through the unit. North facing rears can take a larger area of neutral glass and gain steady shadowless light all day. The estates are laid out on curves, so orientation there is house by house rather than street by street, and it is checked with a compass at survey rather than guessed from the map.

Getting a price for a Springfield roof

The first figure is a range and it comes by email. What makes it useful rather than a guess is the detail supplied with the enquiry: which part of Springfield the house sits in, what the roof is covered with, roughly which way the relevant slope faces, and the approximate size of the room below. Those four answers narrow a broad range considerably, because they settle the flashing kit, the likely glazing specification and whether the structure is cut or trussed.

A photograph helps more than a description. One of the roof from the garden and one of the ceiling from inside the room usually tells us more than a paragraph, particularly on the Chelmer Village and Beaulieu Park side where the estate roofs are consistent enough to recognise on sight.

The second figure is fixed, written and itemised, and it follows a survey. It names the unit, the glazing specification with its U-value, what structural work is included, who forms the opening, who makes the plaster good, and confirms the Building Control notification. The figure does not move once the work starts. Where the survey turns something up inside the roof that changes the job, and on older Springfield terraces it occasionally does, you hear about it before anybody proceeds rather than as a line on a final invoice.