01Glass type
What laminated means, and where VELUX uses it
Laminated glass is two sheets bonded to a plastic layer between them. Whether your window has it depends on the build, so read the data, not the brochure.
Your car windscreen and your shower door are both safety glass, but of two different kinds. Laminated glass is a sandwich: two sheets with a thin interlayer of tough plastic bonded in the middle. When it breaks, the pieces stay stuck to the layer, so the pane cracks like a spider's web instead of falling out. Toughened glass is different. It is heat-treated to be several times stronger than ordinary glass, and when it does break it crumbles into small blunt pieces.
A double glazed roof window has an outer pane facing the weather and an inner pane facing the room. VELUX has, in its standard double glazing for roof windows, used a toughened outer pane and a laminated inner pane, and says so in its published product information. Specifications change between ranges and over the years, so we will not tell you what yours has without seeing the code on its label. If you want to find the code, our guide on finding your VELUX window code shows where it sits.
A skylight is overhead glazing, which is why the inner pane matters. Anything that cracks above your head has a long way to fall, and a laminated inner pane is meant to keep a broken sheet in place.
| Glass | How it is made | When it breaks |
|---|---|---|
| Annealed (ordinary) | Standard float glass | Long sharp shards |
| Toughened | Heat-treated for strength | Small blunt pieces fall |
| Laminated | Two sheets plus plastic layer | Cracks, but pieces stay held |
02The rules
Do the Building Regulations demand it?
No. Laminated glazing overhead is good practice, not a legal requirement of Part K.
Part K of the Building Regulations covers protection from falling, collision and impact. Its glazing rules deal with glass in doors and low windows, and they do not require laminated or overhead glazing for a rooflight. So a window without a laminated pane is not breaking the rules by that fact alone.
That does not make the choice a toss-up. Good practice for overhead glass is a laminated inner pane, because the failure mode is kinder. We fit to current Building Regulations, and where we have a choice of glass we choose the one that holds together. A complete rooflight swap is a controlled fitting under Part L and is notified to Building Control. We take care of that notification whenever the job requires one.
03Warmth
Does laminated glass change how warm the room is?
Not much on its own. The coatings, gas and spacer decide how well the unit holds heat.
A laminated inner pane is about safety. Heat performance comes from the low-e coating (a thin invisible metal oxide layer that keeps warmth in the room), the argon in the cavity and the warm-edge spacer that holds the panes apart. A unit can have a laminated inner pane and still be warm or cold depending on those. We specify warm-edge glazing as standard, and our warm specification page lists what goes into each opening.
Laminated glass has one bonus that people notice. The plastic layer blocks a good part of ultraviolet light, which is what fades fabric and floors. It is a useful side effect, though not a reason to buy on its own, and it does not replace a blind on a south-facing roof.
- Read the glazing line on the maker's data sheet for your window code
- Ask whether the inner pane is laminated, and whether the outer pane is toughened
- Check the U-value too, because safety and warmth are separate questions
- If a unit has misted, ask for a like-for-like or better glass build
04Replacing glass
Choosing glass when you replace
A new pane should be at least as safe as the one it replaces, and a good moment to improve the heat side too.
If your window has misted, you may only need a new sealed unit in the existing frame. Our page on triple glazed VELUX windows sets out what other glazing builds exist, and double versus triple glazed rooflights compares the warmth. A whole new window brings whatever glass its range uses today.
Ask us at the free survey to show the glass build in writing on the quote. If you have a loft room or a bed under the glass, mention it, since that makes a laminated inner pane even easier to justify. Our VELUX window installation page describes the full service, from survey to finished lining, with one fitting team and protected floors throughout. We would rather you spend a few minutes on glass choice now than wonder about it every time the wind gets up. Bring any paperwork you have for the window and we will compare it against the label.
Over a bed or a desk
A laminated inner pane is the sensible choice, because broken glass stays in the frame instead of falling.
Over a landing
Same advice applies. The pane is still overhead, so choose the build that holds together if it fails.
Is laminated glass worth choosing for your roof window?
Is every VELUX window laminated?
No one answer fits every window. Builds differ between ranges and between older and newer products, so check the data for your window code or ask us to check at the survey.
Is toughened glass safe in a roof?
Toughened glass is strong and breaks into small blunt pieces, which makes it a safety glass. Overhead, laminated is better practice for the inner pane because it holds the pieces in place.
Can I swap a toughened inner pane for laminated?
Usually you change the whole sealed unit or the sash, not one pane. Our page on replacing just the glass in a VELUX explains what is possible.
Does laminated glass cost more?
It can add to the price of a unit. We give the glass build and the cost together in the free written quote, so you can compare like with like.
