Gutters
A gutter system has one job – to take water off the roof and carry it away from the house. If it is undersized, has no fall or is blocked, water spills over the edge and damages the facade, plinth and foundations. Here is the whole system, with links to the details.
- Sheet
- Gutters
- Revision
- Sources
- 10 items
- Type
- information guide
Parts of a rainwater system
- gutter (half-round or box)
- gutter brackets
- stop end
- hopper and outlet
- two bends (offset round the eaves overhang)
- downpipe
- pipe clips
- shoe, or connection to a drain gully
- Drawing no.
- KV-08
- Title
- Rainwater system, elevation
- Scale
- diagram, not to scale
- Revision
- 14 October 2026
| Part | Function | More |
|---|---|---|
| gutter (žľab) | collects water from the roof covering | Eaves gutters |
| brackets (háky) | carry the gutter and set its fall | Eaves gutters |
| stop ends and angles | close the end, change direction | |
| hopper and outlet (kotlík, hrdlo) | lead water from the gutter into the downpipe | Downpipes |
| bends | take the downpipe round the eaves overhang, change direction | Downpipes |
| downpipe and pipe clips (zvod, objímky) | carry water down the facade | Downpipes |
| rainwater diverter, leaf trap | optional – collecting water, filtering | |
| gully / shoe | connection to the surface water drain or a soakaway |
Half-round or box
The half-round system is the most widespread, is easy to clean and has a long tradition on pitched roofs. Box gutters are chosen mainly for the architecture of more modern houses. KJG makes half-round gutters in girths of 200 / 250 / 280 / 333 / 400 / 500 mm and downpipes with diameters of 60 / 80 / 100 / 120 / 150 mm, box gutters from 200 to 500 mm and square downpipes from 80 × 80 to 150 × 150 mm.
How big a gutter do you need
The size is derived from the area of roof that drains into a given run of gutter. In its nomogram, the manufacturer KJG matches the plan area to a downpipe diameter and gutter size:
| Plan area per downpipe | Downpipe Ø | Gutter (girth) |
|---|---|---|
| up to 37 m² | 60 mm | 200 |
| 37–83 m² | 80 mm | 250 or 280 |
| 83–150 m² | 100 mm | 280 or 333 |
| 150–243 m² | 120 mm | 333 or 400 |
| 243–443 m² | 150 mm | 400 or 500 |
The figures apply to a downpipe placed at the end of the gutter’s fall. If one downpipe cannot cope with the area, another is added. A calculation for your roof, including a check using the relationship from EN 12056-3: gutter and downpipe calculator.
Fall and expansion
- Gutter fall: KJG’s installation guide says to fix the brackets with a fall of 1–5 mm/m. Lindab’s warranty conditions require a minimum gutter fall of 5 mm per 1 m. Where the guides differ, the guide for the system you are installing applies.
- Expansion: KJG specifies an expansion gutter every 15 m for galvanised steel, titanium-zinc, copper and stainless steel with a girth of up to 500 mm (12 m for aluminium). From an external angle or the start of the gutter, half applies (max. 7.5 m); from an internal angle a quarter (max. 3.75 m), because angles are fixed points.
Materials and prices
Gutter, girth 333, KJG recommended retail prices, price list from 11 August 2026, excl. VAT: galvanised steel €4.20 per m, titanium-zinc €13.49 per m, copper €45.59 per m. The full table for six materials and for downpipes: Products and prices. Installation: €8–20 per m for gutters and €6–15 per m for downpipes, excl. VAT (Numiq, 14 May 2026).
Technical sources
The sources this sheet draws on. We checked prices and values from standards on the date shown; for prices, whatever the source currently states always applies. Sources marked “in Slovak” or “in Czech” are only available in that language.
- Prepared by
- KlampiarskeVýrobky.sk
- Revision
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