Skylight Installation in Hollesley
- Fixed quote before we start
- Roof never left open overnight
- 10-year workmanship guarantee
- Fixed quote before we start
- 10 years workmanship guarantee
- 25 years fitting rooflights
- Skylights only, not a general roofer
Hollesley is 11.6 miles from Ipswich and roughly thirty-five minutes down through the Deben villages. It sits on the coastal plain a short way inland of Shingle Street, which is about as open as the Suffolk coast gets, and there is nothing between the two worth calling shelter. Flat ground, then shingle, then the North Sea.
Nearly every rooflight leak we get called to look at around here comes in at the head or the sides of the upstand, not through the unit. The glass is fine. The seals are fine. Water simply got over the top of the kerb, and it did so because the kerb was built to a number that was never meant for this coast.
Where 150mm comes from, and what it assumes
The 150mm upstand is close to a default in this trade. It is a sensible figure and it appears widely in flat roofing guidance as a minimum height for a kerb above the finished waterproofing level. The important word is minimum.
It assumes something specific: that rain falls broadly downwards, lands on the roof surface, and drains away as a shallow film that never gets near the top of the kerb. On a sheltered site in central Suffolk that holds nearly all the time.
On the Hollesley plain it does not. In a proper easterly, rain does not fall so much as travel. It arrives at a shallow angle with real velocity, driven across the roof surface rather than settling on it, and it climbs vertical faces instead of running down them. Add wind pressure into the roof build-up, add water already ponding at a low point, and 150mm of vertical face is not much of an obstacle. Water goes over the upstand and enters behind the flashing, a route the detail was never designed to defend.
How to tell that is what is happening: the leak is intermittent and it only appears in wind-driven rain, not in steady heavy rain with no wind. If a still, wet day causes no problem at all and a gusty one soaks the ceiling, you are almost certainly looking at water going over the upstand rather than through anything.
What we build instead
On exposed sites near this coast we raise the upstand well above the inland minimum. The exact figure comes out of the survey rather than a rule of thumb, because it depends on the roof size, where the unit sits relative to the falls, how much open ground lies upwind and whether anything nearby funnels water towards it. What does not vary is that 150mm is a floor, not a target.
Height alone is not the whole answer. Three other things go with it.
- Falls that actually work. Current flat roofing practice targets a minimum finished fall of 1 in 80, and because deflection and workmanship eat into any design figure, designing to 1 in 40 is what gets you there. Water that never stands near the kerb cannot be driven over it. On rear extensions with a long-standing ponding problem, that gets fixed as part of the job or the new unit inherits the old one’s fate.
- Drainage away from the upstand. A rooflight sitting in the path of the roof’s drainage is asking for trouble. Where we can, the unit is positioned so water is shed around it rather than arriving at its upwind face.
- The head detail. The membrane is dressed fully up the kerb face and over the top, mechanically retained rather than relying on adhesion at the vulnerable edge, with the frame’s weathering skirt lapping over it properly rather than token. Laps face away from the prevailing driven rain where the geometry allows.
None of this is unusual work. It is simply not what a standard specification produces, and a standard specification is what most units around here were fitted to.
Flat-roof rear extensions and low-pitch outbuildings
Most of the work in Hollesley falls into two categories.
The first is flat-roof rear extensions on village houses. Deep plans, a kitchen or dining room added at the back, very little daylight reaching the middle of it. A flat roof rooflight is usually the right answer, and on a wide extension a roof lantern gets light considerably further into the plan, though it presents more coated aluminium to the weather and the coating specification has to reflect that.
The second is low-pitch outbuildings. Garden rooms, converted outbuildings, workshops and garages with slopes genuinely too shallow for a standard roof window. Most pitched roof windows carry a minimum pitch rating of around 15 degrees, and below it water does not clear the flashing fast enough, sits at the lap, and gets drawn back under by capillary action. We either use a unit certified for low pitch with its specific collar and flashing kit, or build a kerb and fit a flat-roof-type unit on top to create the fall independently of the roof. On an exposed site the kerb route is often better anyway, because it lets us set the upstand height we actually want.
Work in the main house slope is pitched roof skylight installation, with the covering deciding the flashing kit. Where an existing roof window is being swapped, VELUX, Keylite and Roto units are all straightforward for us.
The coastal specification, throughout
Everything we fit in Hollesley uses marine-grade 316L stainless fixings as standard. A2 stainless pits under chloride attack rather than corroding evenly, so a fixing can lose most of its section while the head still looks acceptable from the ground. Aluminium components carry a marine-specification powder coating, because standard architectural polyester chalks and then lifts in salt-laden air. Both decisions are made once, at specification, and they are the difference between a unit reaching its expected life and falling several years short.
Hollesley stock, and the outbuildings that come with it
Hollesley is a scattered coastal-plain village rather than a tight core, and the stock is mixed: older brick and pantiled cottages, interwar and post-war houses, agricultural buildings, and a good number of large gardens with outbuildings that have been or want to be converted. That last category is where a lot of the rooflight work sits. Garden rooms, home offices and converted stores tend to have shallow, simply built roofs, and a rooflight is the natural way to light them. The catch is that a shallow, lightly built roof is exactly the structure the driven rain here tests hardest, so the upstand question that runs through this page applies to them with full force.
The membrane matters as much as the height
Raising the upstand only works if what dresses over it is up to the job. On an exposed flat roof near Shingle Street we specify the covering with the exposure in mind, not just the budget. A high-performance single-ply or a properly detailed felt system, dressed up the full face of the kerb and mechanically retained at the top rather than stuck and hoped, is what turns a tall upstand into a weathering detail that actually holds. Cheap membrane laid to an inland detail undoes the height advantage the moment an easterly finds the edge. Where an existing flat roof is sound but the old rooflight has failed, we assess whether the covering can carry another twenty years alongside the new unit, or whether it is false economy to fit a good rooflight into a tired roof.
The other detail worth a line is the corner. Driven rain and the pressure eddies around a raised unit concentrate at the top corners of the upstand, which is why coastal leaks so often show there rather than at the sill. We lap and tape those corners as a continuous secondary layer, so anything that does get past the primary detail has a path back out rather than a path into the ceiling.
One more thing about the outbuildings. A converted store or workshop often has no ceiling void to inspect from, so the structure has to be read from inside the room or by lifting a section of covering, and that is a survey job rather than a photograph job. Where the roof is genuinely too shallow for an in-plane unit, a kerb-mounted flat rooflight solves the pitch problem and lets us set the upstand height the exposure near Shingle Street actually calls for, which is usually taller than anyone expects.
Getting a price in Hollesley
Skylight installation in Hollesley is surveyed on the roof and priced once in writing. The figure holds unless you change the specification. Installed to current Building Regulations, with a 10-year workmanship guarantee, by installers with 25 years in the trade.
We replace failing units rather than patching them. Resealing around a unit that is letting water over the upstand does not address why the water got there, and the leak returns in the next easterly.
We cover the neighbouring villages on the same run, so Alderton, Bawdsey and Orford are easy trips. The full list is on areas we cover.
Request a fixed quote. If the leak only shows up when it is blowing, say so, because that narrows the diagnosis considerably before anyone climbs a ladder.
My rooflight only leaks when it is windy. Why?
Because the water is being driven over the top of the upstand rather than passing through anything. In wind-driven rain, water travels almost horizontally and climbs vertical faces instead of running down them, and a kerb built to an inland minimum height is not tall enough to stop it near this coast. Steady rain with no wind causing no problem is exactly the pattern that points at upstand height rather than a failed seal.
How tall should the upstand be on a Hollesley flat roof?
Taller than the 150mm quoted as standard, with the exact figure coming from the survey. It depends on roof size, where the unit sits in relation to the falls, how much open ground lies upwind and whether anything nearby funnels water towards it. Height is only part of it, because falls and the head detail have to be right or a tall kerb still lets you down.
My roof ponds after rain. Does that need sorting first?
Yes. Standing water near a kerb is the water most likely to be driven over it, and a unit installed into a roof that already ponds inherits that problem on day one. Current practice aims at a minimum finished fall of 1 in 80, which means designing to 1 in 40 so deflection and workmanship do not eat it away. We will tell you at survey whether the falls need correcting and price it in rather than fitting around a fault.
Can I put a rooflight in a shallow-pitched outbuilding here?
Usually, but not with a standard roof window. Most are rated to a minimum pitch of around 15 degrees, and below that water sits at the flashing lap and gets drawn back under by capillary action. The options are a unit certified for low pitch with its specific collar and flashing kit, or a kerb with a flat-roof-type rooflight on top creating its own fall. Near Shingle Street the kerb route is often better anyway, because it lets us set the upstand height the exposure calls for.
Can you light a converted outbuilding at Hollesley without it leaking in the winter storms?
Yes, provided the upstand and the covering are specified for this coast rather than an inland minimum. Shallow outbuilding roofs take driven rain hard, so we raise the kerb well above the standard 150mm, dress a suitable membrane up the full face and retain it mechanically, and tape the corners as a continuous layer. Where the existing roof covering is tired, we will tell you whether it is worth renewing it at the same time rather than fitting a new unit into an old roof.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.