Rooflights and skylights in Letchworth Garden City

Because the town was designed as a whole rather than grown street by street, its roofscape reads as a deliberate composition: cottages set back behind their hedges, roofs pitched to a shared rhythm, chimneys and dormers placed for effect as much as for the room beneath. Cutting into that roofline, whether for a loft room, a kitchen extension or a replacement window, is a smaller version of the same question the original planners asked: where does the light fall, and what does the street see. Our rooflight and skylight installation across Cambridge and the surrounding towns answers that question wherever we work, and in Letchworth Garden City it carries more weight than usual.

We say this in general terms because the scheme's reach and requirements vary by property and by the specific alteration proposed, and only the Foundation can confirm what applies to a particular cottage or plot. Before we draw a light plan for a home here, we ask the homeowner to check their position directly with the Letchworth Garden City Heritage Foundation, alongside the usual planning check, so the design we propose is one that can actually go ahead.

Orientation still does most of the work once that outlook is clear, and it behaves here exactly as it does everywhere: a slope facing due south takes the sun from mid-morning through to early evening in high summer, bright enough that we would rarely specify it without solar control glass and a way of shading the room beneath, most often a blind rather than external louvres on a domestic roof. Face the same cottage roof north instead and the light arriving is softer and cooler through every season, which lets us go larger on the glass without the room overheating on a July afternoon; a bedroom or home office often does best here. East catches the cottage before the household is properly awake, a short, low burst worth screening in a bedroom; west repeats that low, glancing sun into the evening, welcome in a sitting room but worth controlling behind a screen or workspace. Our guide to skylight orientation goes further into how each direction shifts through the seasons, and at survey we test all of it against the real garden, not a compass reading taken off a plan.

The existing hole is usually kept as it is: a new unit sized to match sits in it, with flashing dressed to the surrounding tiles, and on a flat extension roof the shallow kerb an older build is likely to have gets built up to a current insulation depth rather than left as it was. On a slope facing the street, where the Heritage Foundation's position and any conservation designation both need checking before anything else, a conservation-style rooflight with a slim central bar keeps the flush, low profile a period roof calls for.

A replacement is also the point to put right a specification that never quite worked: swap a fixed pane for an opening one so a bathroom can clear its own steam, or drop clear glass on a south slope in favour of solar control glazing if the room below has run too warm through summer since it was fitted. Our energy efficient rooflights page covers the glass side of that decision, and an electric opening rooflight suits a unit set too high on a steep cottage roof to reach by hand.

Does the Heritage Foundation's scheme of management apply on top of planning permission?

Yes, in the parts of the town it covers: it is a separate consent from the Letchworth Garden City Heritage Foundation for external alterations, alongside whatever planning permission or permitted development applies through North Hertfordshire District Council. One does not replace the other, and both are worth checking before a design is fixed.

Will a rooflight need anything beyond the usual permitted development check here?

Possibly two things beyond it: a conservation area designation on some streets, and the Heritage Foundation's own consent under its scheme of management, neither of which the national permitted development rules touch on. We confirm both against the property before the design is settled rather than assume from its age or style.

Does a hand-cut cottage roof limit what size rooflight I can fit?

It shapes the choice rather than limiting it. Rafter spacing on an early twentieth-century cut roof is rarely as even as a modern truss layout, so a wider opening sometimes needs a rafter trimmed and its load carried on new timbers either side, agreed with an engineer and checked through Building Control. We settle that in the roof space at survey.