Where the risk actually sits
A rooflight high on a main roof is rarely the way anyone gets into a house; the rooflights worth thinking about are the ones someone can reach.
On a pitched slate or tile roof two storeys up, reaching a conservation skylight means a ladder, a roof ladder and time in full view of the street or the neighbours. The picture changes when a rooflight sits low on a slope that can be reached from a lower roof. In the Victorian terraces around Romsey, Petersfield and Mill Road, many houses have a single storey rear outshot or a side return extension, and its flat or shallow roof can put the lower edge of a loft rooflight within easy reach. The same is true of a rooflight on a garage, a garden studio or a barn with a low eaves line, and of units above a first floor flat roof or balcony.
So the first security question at a survey is not about the product at all. It is where the unit sits and what can be climbed to reach it. We note that on the light plan alongside the orientation and sun path, because moving an opening up the slope by a few courses can change both the light and the exposure. The trade-off with how the slope looks from the street is covered in how far from the ridge a rooflight should be.
The frame and the glass
The slim steel frame that makes a conservation rooflight look right on a historic roof is also its strongest security feature.
Steel is much stiffer than timber or uPVC section for section, so the thin frame and glazing bar of a conservation unit do not flex easily under a lever. Many ranges glaze from the inside or bond the sealed unit into the sash, so there is no external bead or putty line that can be prised out from the roof. Whether a given range works this way is a maker's detail, and we check it on the specification rather than assume it. The material question in more depth is in steel vs aluminium conservation rooflights.
The glass matters as much as the frame. Approved Document K expects overhead glazing in a home to be safe if it breaks, which in practice means a laminated inner pane in the double glazed unit. Laminated glass has a plastic interlayer that holds the pieces together when it cracks, so a broken pane stays in the frame as a single sheet rather than falling into the room. That same interlayer makes it slow and noisy to get through, which is why laminated glass is also the standard answer for security glazing. A toughened outer pane over a laminated inner one is the usual make up.
Locks, handles and vent positions
Fixed conservation rooflights have nothing to lock; on opening units the handle and the stay decide how secure the sash is.
A fixed unit has no opening sash, so its security rests on the frame, the glass and the fixings. On top hung opening units the sash is held shut by a handle or catch at the bottom edge, and opened on a stay. Security features vary widely between ranges, and it is sensible to check them against the maker's specification:
- Lockable handles. Some makers state a key locking handle, so the sash cannot be opened from inside without the key, which also matters in a child's bedroom.
- Locking night vent. Some makers state a restricted ventilation position that locks, so the sash can stay slightly open without being lifted further from outside.
- Multi-point closing. Larger sashes in some ranges close on more than one point along the frame.
- Electric control. Motorised units close on a rain sensor and some can link to an alarm contact; see can a conservation rooflight be electric.
The opening types themselves are set out in can conservation rooflights open. A rooflight that doubles as a loft escape route has a separate rule to meet: it must open easily from inside without a removable key, so a key lock on that sash needs thought. That is covered in can a conservation rooflight be an escape window.
Security standards and what to ask
Some makers state that particular conservation ranges have been tested against a recognised security standard, but this is range specific and should be read on the product's own documents.
The standard most often quoted for doors and windows in UK homes is PAS 24, and Secured by Design is the police backed scheme that refers to it. Some makers state that certain rooflight ranges, or certain sizes within a range, meet PAS 24 or carry Secured by Design status; others make no security claim at all. Because the claim can apply to one configuration and not another, the useful questions are these:
| Ask | Why it matters |
|---|---|
| Which standard, and which sizes? | A claim may cover some sizes only |
| Is the inner pane laminated? | Safety and security in one layer |
| Does the handle lock? | Stops the sash being opened casually |
| Is there a locking vent position? | Air without leaving the sash free |
If your home insurer asks for a particular standard on accessible windows, it is worth telling us at the survey so we can match it to a range that states it. The unit's own paperwork is what an insurer will want to see.
How fitting affects security
A secure rooflight still has to be fixed securely into the roof, and on a conservation installation that happens mostly out of sight.
The frame is screwed to a timber trimmer frame between the rafters, and the fixings sit inside the roof void, not on the weather face. Flashings and the slate or tile around the unit cover the edge, so there is nothing on the outside that unscrews. An older roof on a village cottage or a converted barn can have irregular rafters, and packing the frame square and fixing it fully is part of what makes it hold. The detail on different coverings is in conservation rooflights on slate and tile, and the wider service is described on conservation rooflight installation in Cambridge. Every installation is done to current Building Regulations and carries our 10-year workmanship guarantee.
Questions people also ask
Are old cast iron rooflights secure?
Original Victorian cast iron rooflights usually have single glazing held in putty and a simple catch, so they are much easier to get through than a modern unit. Replacing one with a conservation rooflight with a laminated inner pane is a real step up; see replacing cast iron rooflights.
Does laminated glass change the light in the room?
Very little. Clear laminated glass lets through almost the same visible light as ordinary glass, and it is the glazing bars and frame that cost a little light, as explained in does a conservation rooflight let in less light.
Is a fixed conservation skylight more secure than an opening one?
A fixed unit has no sash to force, so on a low, reachable slope it is the simplest secure choice. It gives no ventilation, though, so it suits landings and stairwells better than bedrooms or bathrooms.
Can you check security on the survey?
Yes. At the light survey we look at what can be climbed to reach each proposed opening and note the lock and glass specification on the written light plan. Book a light survey and we will walk the roof with you.
