What is a Venlo greenhouse?

The Dutch multi-ridge glass type: a roof of small panes carried on a repeating grid of closely spaced ridges over a gutter-connected steel frame. It exists to solve one problem — every structural member above a crop costs it light — by putting less steel in the light path per square metre of floor than large-span alternatives.

What are the standard Venlo dimensions?

Spans of 8, 9.6 or 12.8 metres between column rows, trusses at roughly 4 to 5 metre bays along the gutter, a roof pitch near 22 to 23 degrees, and 6 to 8 metres to the gutter in a modern production house. The grid is then dimensioned around the cultivation system rather than the reverse.

The widespan trades some of the Venlo's light advantage for fewer gutters and larger vent openings. That is the right exchange where snow loads are heavy or roof ventilation has to be maximised. Where light governs and snow does not, the Venlo's lower structural shadow wins.

What makes the Venlo gutter unusual?

It does three jobs at once: it ties the trusses together as a structural member, collects rainwater from the roof, and drains the condensation running down the inside of the glass. The glazing bars carry grooves that deliver that condensation to it rather than letting it fall on the crop.

Venlo Greenhouse — DutchGreenhouses

Maximum light, minimum shadow

The Venlo is the glass greenhouse type that modern horticulture is built on, and it exists because of one problem: every structural member above a crop costs it light. Named for the Dutch region where it was developed, the Venlo answers that by carrying the roof on a repeating grid of small, closely spaced ridges instead of a few large spans — a geometry that puts less steel in the light path per square metre of floor than the alternatives. It is the reason Dutch glasshouse horticulture set the international benchmark for production per square metre, and the reason growers in very different climates still specify a Dutch roof.

Structurally it is a multi-ridge roof of small glass panes on a gutter-connected steel grid. Columns stand on a regular span — commonly 8, 9.6 or 12.8 metres between column rows — with trusses at roughly 4 to 5 metre bays along the gutter, and a roof pitch near 22 to 23 degrees that balances light incidence against condensation run-off and snow shedding. Modern production houses run 6 to 8 metres to the gutter, which buys the climate buffer above the crop and the headroom that screens, lighting and high-wire cultivation need.

Its multi-purpose detailing is what distinguishes it from a glasshouse that merely looks similar. The aluminium gutter between roof sections is simultaneously a structural tie between trusses, the rainwater collection channel and the drain for condensation running off the inside of the roof; the glazing bars carry grooves that take that condensation to the gutter rather than letting it fall on the crop. The alternative type, the widespan, trades some of that light advantage for fewer gutters and larger vent openings, which is the right choice where snow loads are heavy or roof ventilation has to be maximised.

The grid is then dimensioned around the cultivation system rather than the reverse: row spacing, crop height and internal transport set the geometry, and the steel follows. DutchGreenhouses® engineers the Venlo structure together with the screening, climate, irrigation and lighting it has to carry, so span, gutter height and vent area are settled against the crop and the local wind and snow loads. Get in touch to discuss a Venlo greenhouse for your project.

From the knowledge base