When Greenhouse Roof Repairs Can’t Wait for an Empty House

Greenhouse roofs almost never fail at a good time. A leak can start right in the middle of a crop, or a storm can quite easily loosen the glazing right up to harvest. Occasionally a roof vent will break when the greenhouse is full.

Waiting until the greenhouse is completely empty may seem like the sensible thing to do, but that could well mean you’re living with the problem for weeks or months. In that time, water will keep coming in, temperature control will be progressively harder, and the damage is likely to get progressively worse.

The key is to work out what needs urgent fixing, what can wait, and how to go about it without creating any new problems for your crop.

Start With the Roof Damage

Not every roof problem is going to need the same solution.

A loose glazing panel in a high-usage area is far more pressing than a small leak in a corner that’s not in use. Loose glazing, broken glass, damaged structure, and electrical hazards all require the immediate attention of a qualified person. Safety first, of course.

Other issues may well give you a bit more time to plan. A small leak may be OK for a short time if you can keep the area safe and watch it. If, however, the leak is onto electrical equipment, a propagation bench or sensitive young plant, then you need to act pronto. Ask yourself some fundamental questions:

• Where is the damage?
• Is it getting worse?
• What’s underneath it?
• Will it impact people, crops, or equipment?

These answers are going to be of more than just value in terms of ticking off a repair checklist. Also bear in mind that the majority of the repairs will be carried out from outside the greenhouse.

Replacing the glazing will have an effect on the light inside. If you open the roof up at all, you’re going to be letting in cold air, rain, and strong sun. The contractors may end up having to use the production aisles, which will in turn impact the irrigation, the movement of the crops, and so on.

Young plants are far more sensitive to a sudden change in temperature or moisture. Crops that are almost ready to ship can’t take much stress at all. Hanging baskets and tall crops are also very difficult to get to. We’re responsible for that section from the outset. The maintenance manager may well know what has to be done; the grower will tell you the best time to do it with the least amount of disruption.

Sometimes you just need to move a few benches or tweak the working routine. Other times you’ve got to do the repairs in stages.

Inspect the Roof Before Bringing in Contractors

One of the big problems with fixing a greenhouse roof is working out precisely what the extent of the damage is prior to actually getting down to it. Water will often run down the framing or the glazing supports before it eventually drips onto a bench or walkway, which you can’t see from the ground level, so you may not be aware of what’s actually going on until you’ve got some panels off. For a big greenhouse, a drone roof inspection can help document visible damage and flag areas that need to be inspected more closely.

But those methods won’t reveal it all. Loose joints, failed seals, etc., still need to be checked on the ground. Aerial imagery in itself won’t tell you whether a structure is safe to work on or whether the works to repair it are in accordance with the manufacturer’s specifications.

The intention is to give the contractor a better basis to work from rather than to skip a proper inspection.

Label the photos by greenhouse block, bay, or roof section. A photo of damage is of no use weeks down the line if you can’t remember where it was taken.

Once you know what the problem is, then you need to find a good time to do the repairs. In a year-round greenhouse, there may well be no ideal time, so you just have to look for a window.

If you’re about to have crops removed from an aisle, you might get temporary access. On days with low shipping, it may be easier to close an aisle. Some work can also be done prior to staff arrival (as long as the lighting, weather and safety are acceptable).

Contractors must be aware of the greenhouse operating rules prior to their arrival. These include the rules relating to heating, ventilation, crop protection, sanitation and any areas which are off limits to staff and/or equipment.

Keep the dust, the broken glazing, the sealant and all the other associated debris well away from your crops and growing areas. Contractors should, of course, use the appropriate materials and methods for your particular glazing system.

Weather is an issue too. Opening the roof in heavy rain or high winds is likely to make things worse. Good communication between the grower, the maintenance staff and the contractor is key to avoiding any confusion.

Keep a Record of Each Repair

If you’re looking at a number of roof sections to repair, it’s very easy to lose track of which ones you’ve actually got round to.

All you need is a simple repair log.

For each problem record, include the location, date found, photos, what you did, and what further work is required. If you’ve applied a temporary fix, then record when you’re to check it again or when you’re to put in a permanent fix. Check the repaired area against the original photos to ensure you’ve got the right spot and that all the visible problems are sorted. Always inspect the work when required. A roof that looks sorted from the ground may still have a loose panel, a drainage issue or a seal that needs checking.

It’s also worth checking the area up during the next major storm. A repair that looks spot on on a dry day may well fail in the rain.

Keeping records makes future maintenance a whole lot easier. If a leak comes back, you can go and check what was done, when it was done, and whether it’s happened before.

A greenhouse in use makes roof maintenance more of a problem, but good records in that situation are even more valuable. Inspections are a great way for the grower to spot ageing seals, damaged glazing, blocked gutters and all the other sorts of things that can go wrong. They’re also very useful for planning. If you’ve got several panels that are wearing out then it’s often far more sensible to replace them all at one go during a crop change rather than do a lot of little piecemeal repairs. You don’t have to get on and fix everything. You can focus on the urgent issues, protect the crop during the repair period, and use a temporary fix where necessary.

The greenhouse roof is part of the growing environment. Looking after it means looking after the plants, the people down below, and the roof panels themselves.