Guide
Measure once, fit first time.
Toughened glass cannot be cut once it is made. Ten careful minutes with a tape stops the wrong size arriving.
Our sizes
Every size we list is the outside of the kerb, width by length, in millimetres.
- Steel tape in millimetres60 cm is 600 mm
- Pen and paper, or your phoneWrite every size down
- A safe way onto the roofLadder or scaffold
You already have a kerb
Measure the outside of itTake the outside width and length of the kerb, and the inside of the opening. Then find the matching size below.
Your builder is making the kerb
Choose the size firstPick a standard size and build the kerb to that outside size. Or send us your plan and we check it with you before anything is made.
How to
Four checks before you order
- 01Inside and outside
Outside width and length of the kerb, and the inside of the opening. Measure each at both ends and in the middle; write down the smallest.
- 02Check it is square
Measure corner to corner across both diagonals. If they differ by more than a few millimetres, tell us, or ask your builder to correct the kerb first.
- 03Fall and height
The kerb needs a fall so rain runs off; many installers work to around 5 degrees. Upstands of around 150 mm above the finished roof are common. Ask your roofer.
- 04Plan the lift
Glass weighs about 2.5 kg per square metre for each millimetre of thickness. Agree how it gets onto the roof before delivery day.
Mistakes we see most often
- Measuring the plan, not the kerbBuilders adjust on site. Measure what was built.
- Mixing inside and outside sizesOur sizes are the outside of the kerb. Send us both if unsure.
- A level kerbWithout a fall, water sits on the glass.
- Measuring in one place onlyKerbs are rarely perfectly square. Measure at both ends and the middle.
1200 wide
1200 × 12001500 wide
1500 × 1500Your sizes
Give us the size of the glass, not the opening.
Smallest opening size, minus any gap your fitter needs for fixings. Ask your fitter if you are not sure.
- Steel tape in millimetres60 cm is 600 mm
- Pen and paper, or your phoneWrite every size down
- A photo of the spaceHelps us check it with you
How to
Four checks before you order
- 01Width in three places
Top, middle and bottom. Write down the shortest.
- 02Height in three places
Left, middle and right. Write down the shortest.
- 03Check corner to corner
Measure both diagonals. If they match, the space is square. If not, tell us the difference.
- 04Take off your fitter's gap
The glass has to fit inside the space with room for fixings. If you are not sure how much to allow, ask your fitter.
Mistakes we see most often
- Measuring in centimetres or inchesWe make glass in millimetres. 60 cm is 600 mm.
- Measuring the old glassOld glass can be chipped or cut short. Measure the space.
- Measuring before tiles or worktopsMeasure finished surfaces only.
- Sending the opening sizeGive us the glass size, after any gap for fixings.
Write your list like this
| Width (mm) | Height (mm) | How many | Glass | For |
|---|---|---|---|---|
| 1200 | 800 | 4 | 6 mm toughened | Shelves |
| 900 | 2000 | 1 | 10 mm toughened | Shower screen |
Example only. Width first, then height, every time.
Not sure about a size?
Send it to us with a photo. We check every size with you before anything is made.