U-channel vs Spider: which to pick for a glass railing
The two main mounting systems. Aesthetics, loads, prices, install, maintenance. Real Petersburg balcony and terrace cases.
A glass railing mounts three ways: U-channel (bottom profile), spider (4-point through glass), side-mount (to parapet). First two cover 90% of the market.
01U-channel: classic
Aluminium U-profile at the bottom, glass slots in with wedges and sealant. Level-adjustable. No visible fixings from inside.
Pros: 4-hour install for 5 lin.m, clean look, easy levelling, single-panel replacement in an hour.
Cons: base load on slab, snow can clog drains, needs reinforcement on high-wind terraces.
02Spider: premium
4 holes through glass, anchored to spider arms in slab or stringer. Each point is independent.
Pros: any geometry, distributed load, "floating" aesthetic, public-space rated.
Cons: 30–35% more, holes are pre-temper (can't drill later — full re-make), needs annual fixing check.
032026 prices
| Length | U-channel | Spider | Diff |
|---|---|---|---|
| 3 lin.m | 42 600 ₽ | 55 800 ₽ | +31% |
| 5 lin.m (L) | 71 000 ₽ | 93 000 ₽ | +31% |
| 8 lin.m (terrace) | 113 600 ₽ | 148 800 ₽ | +31% |
Common mistake — cheap U-channel on a parapet that's 25 mm off level over 4 m. Wedges press unevenly, micro-cracks form within a year. If slab is more than 8 mm off — go Spider (doesn't need level base).
04This service at REAL GLASS
If you've read this far, the topic is probably relevant to a real project. We make glass railings in-house in St. Petersburg, with a measure within 1–3 days, 1-year warranty and a fixed contract price. All numbers in this article come from our actual 2026 quotes.
For a project-specific estimate — see the service page or request a free on-site measure.
