If extremely bad weather is forecast, it is prudent to take measures to protect your greenhouse or glasshouse.
In this article, you will find tips and suggestions on how to go about defending your treasured greenhouse and garden space, to give you security and peace of mind.
Skip to the relevant section
KEEP THE WIND OUT
The most important thing is to secure the structure and make it as airtight as you can. If wind gets inside the greenhouse, it can cause a lot of issues, so secure everything you can and batten down the hatches.
· Keep doors in a closed and secure position. Close all roof and louvre vents.
If you have a lockable door, lock it.
If you have storm locks on your roof vents, lock them. If applicable, refer to the section below on how to disengage any automatic openers before applying the storm locks.
· Disengage automatic roof vents and louvres.
The last thing you need, after all your careful checks, is for an auto-vent to open in the middle of the storm.
Unscrew the cylinder and engage the storm locks, if you have them. Otherwise, tie down the arm of the vent to prevent the hinge from opening. The heavier the window (toughened glass), the less likely it is to be forced open by gusts, but tying it down is a good additional measure.
Keep the wax cylinders in the fridge until you are ready to put them back.
Watch this short clip to see just how simple it is to disengage your autovent and engage storm locks.
· If you have a polycarbonate greenhouse, tape the panels to the frame with glazing repair tape.
Polycarbonate glazing panels are the most vulnerable to wind, being lightweight and flexible. Panels have the potential to come loose from the greenhouse frame, or if the whole structure isn’t anchored sufficiently, the entire building is light enough to lift off the ground if wind gets in. You might want to consider taping the polycarbonate panes onto the frame with a strong adhesive tape such as glazing repair tape.
· Replace any damaged or missing panes, or use glazing repair tape as a temporary measure.
Replace any missing or cracked panes or use tape to cover up cracks temporarily. Take care when handling panes of glass and always wear gloves, even when handling toughened glass with bevelled edges. Replacement panes are often supplied by the manufacturer; or you can contact your local glazier.
If replacement panes cannot be sourced in sufficient time, cover the exposed areas with a suitable, water resistant material and tape it down securely.
· Replace any lost or broken glazing clips.
Spring clips or W-clips are the most common method for attaching horticultural glass panes to a greenhouse frame. They are easily lost and can ping off or snap if exposed to too much pressure. It is worth having more clips for each pane than is strictly necessary when dramatic weather conditions are expected. We’d recommend keeping a stock of spare clips available.
· Tape down over-lapping panes.
It is common practise with small panes of horticultural glass to have them overlapping to cover the entire area. Tape down the places where they meet to prevent wind getting in.
· Are the glazing seals in good condition?
Seals are used on your greenhouse to help secure the panes to the frame and also to keep the wind from getting in. If your seals are starting to perish, try to find replacements. You may be able to get replacements directly from the manufacturer. Again, glazing tape may be used temporarily.
· Ensure your greenhouse is properly anchored down.
This should have been done during installation, but if for any reason your greenhouse is not sufficiently anchored then take measures to make it so, otherwise it could lift off the ground entirely.
Weight down the frame with sandbags or similar; add more anchor points by drilling into the base.
· Check the surrounding environment for other risks.
Do you have any other fixtures in the garden that might be affected by the weather, such as a delipidated shed, a trampoline or rotting trees?
Attend to all other potential hazards by weighting them down or moving to sheltered positions.
Miscellaneous pots, toy or tools should be safely stored in a shed.
Remove dead wood from trees and shore up young saplings.
· Take any precious items out of the greenhouse and bring them inside.
PREPARATION BEGINS BEFORE INSTALLATION
Preparing your greenhouse for bad weather starts when you decide on the location and base of your greenhouse. Choosing an appropriate site is step one, so if you are thinking of purchasing, or are about to start your groundwork in preparation for installation, take these considerations into account:
· Avoid exposed areas of land.
Provide some shelter from high winds by placing in proximity to something that will act as a windbreak, such as a garden wall, fence or hedge. If no shelter can be offered, consider erecting a windbreak of some kind.
· Orient the greenhouse so the gable end faces the prevailing wind.
The front end is the most susceptible to high winds, while the gable end (or back end) is the strongest side of the greenhouse.
· Keep a clear perimeter.
This will allow you to make adjustments and tackle every side of your greenhouse (both inside and out) if any extra reinforcements are needed.
· Keep away from overhanging trees.
Gales, storms and hurricanes might bring down branches - or even the entire tree.
· Ensure the base and door are square and level.
A well-built greenhouse should be level when installed, as it is essential to the overall structure and integral to the lifetime of the building as a whole. If the greenhouse isn't properly level all round, then it is likely to create gaps in the framework and between the panes that will let the wind in where it’s loose or ill-fitting.
If your greenhouse isn't level when you come to prepare for bad weather, see if you can realign or bolster the worst affected areas of the greenhouse by filling gaps and wedging in loose components as a temporary measure.
Seek advice from your greenhouse manufacturer with regards to appropriate ground preparation.
· Anchor it down well.
The more secure the better! If your greenhouse is sited straight onto soil, then cemented anchors are best. And for those with a hardstanding base, drill down into it as deep as you can. Make sure to place the anchors across all sides evenly to spread the load.
· Hard-standing bases are the most secure – a concrete/paving pad or perimeter supporting the frame of the greenhouse is ideal.
If your greenhouse is partly built, then consider carefully the best way to protect your greenhouse as bad weather approaches.
- If the frame alone has been erected but not anchored down, then move the greenhouse into a sheltered place, preferably inside. If it must be left outside, then weight down the frame as much as possible.
- If the greenhouse is too heavy to move, then anchor it down as soon as possible.
- If safer, consider taking the greenhouse apart and starting again when weather conditions have improved.
CHOOSE A STRONG "STORM-READY" GREENHOUSE
Ultimately, a good quality greenhouse is the best way to defend against extreme weather.
Some greenhouses have features that will improve their storm and wind resistance:
- T-section Bracing (Bracing at the eaves and ridge, creating a robust structure)
- Integral Base
- Window and Door Locks
- Toughened Glass
- Glazing Beads (instead of Spring Clips)
A stronger frame, toughened glass, rubber glazing beads and an integral base are all features that will help to enhance the overall strength of the glasshouse.
Many greenhouses come with a guarantee included and it goes without saying that a longer guarantee means a better greenhouse that is more likely to stand up to difficult weather conditions.
Here are some of our strongest greenhouse models: