The old page chased a neat “ideal gap” answer. Real bathrooms are messier. A shower can leak with a small gap if the spray hits the hinge line, and it can stay dry with a visible clearance if the seal, fall and screen position are correct.
Shower door gap diagnosis table
| What you see | Likely cause to check | Better next step |
|---|---|---|
| Gap wider at top than bottom | Wall or fixed panel out of plumb, hinge adjustment, door sag | Measure vertically before changing seals. A tapered gap points to alignment. |
| Water escaping under the door | Bottom seal, tray fall, missing deflector or spray direction | Check the seal profile and whether water is being driven directly at the opening. |
| Door rubs or seal drags | Clearance too tight, wrong seal, hinge drop, track issue | Do not force it. Dragging seals can pull loose and stress fittings. |
| Leak only during powerful showers | Spray angle, screen size or open-walk-in design issue | Check shower head position and whether the screen length contains splash. |
| Gap returns after resealing | Movement in tray, panel, hinges or loose fixings | Stabilise the enclosure before applying more silicone. |
Shower door gap checker
Use this before buying seals, adding silicone or blaming the door size.
How to measure before fixing the gap
- Measure the gap at the top, middle and bottom, not just where water appears.
- Check the fixed panel and door edge with a level if the gap changes height.
- Look at the tray or tiled floor fall: water should not be pushed towards the door line.
- Inspect the seal profile. Bottom seals, side seals and magnetic strips are not interchangeable.
- Test with normal shower pressure before deciding the enclosure itself is too small.
When a seal is enough and when it is not
The door is plumb, the tray is level, the gap is even and the old seal is visibly worn or missing.
The gap is tapered, the door has dropped, the hinge line is loose or a sliding door does not overlap correctly.
Spray hits the opening, the screen is too short, or the walk-in entry cannot contain water at the current shower position.
The tray moves, silicone keeps splitting, or the wall is badly out of plumb. The enclosure may need proper resetting.
If a shower door gap is part of a wider leak, tray or enclosure problem, ABC Home can check alignment, seals, tray fall and screen position during a bathroom fitting project in Aberdeen.
Sources and practical checks used
- Mira Ascend frameless sliding door installation guide: manufacturer guidance showing why door position, wall/tray sealing and not directing spray at the door matter.
- Scottish Government technical handbook 2022: sanitary facilities: domestic sanitary background for showers and bathroom provision.
- Scottish Government technical handbook 2022: ventilation: bathroom extraction context; leaks and poor ventilation often show up together as damp problems.
- Energy Saving Trust: damp and condensation: background on moisture signs to separate splash leaks from wider condensation issues.
FAQ
What gap should be around a shower door?
It depends on the enclosure, hinge or runner type, seals and manufacturer adjustment range. The safest answer is to follow the installation guide and measure the actual top, middle and bottom gaps, not copy a generic number.
Why is my shower door leaking at the bottom?
Common causes include a wrong or worn bottom seal, tray not level, door not plumb, spray aimed at the opening, missing silicone line or a gap outside the enclosure adjustment range.
Can I fix a shower door gap with a bigger seal?
Sometimes, but a bigger seal can drag, twist or trap water if the screen is out of alignment. Check plumb, tray level and hinge/runner adjustment before adding a seal.
Is a frameless shower door more likely to show gaps?
Frameless doors can be more sensitive to wall and tray alignment because there is less frame to hide tolerance. They can work well, but measurement and installation quality matter.
