Greenhouse Base Options & Groundwork

Greenhouse bases form the foundation for any long-standing greenhouse structure. Without a solid base to build from, you’ll probably find that your greenhouse will encounter problem after problem, so it’s essential that your base is prepared perfectly. Groundwork must also be taken into consideration when totting up labor costs and longevity of the structure.

What Greenhouse Base Options Are There?

Deciding what kind of base you want to go for is a choice made early on in the buying journey, and will determine how much labor goes into the installation process.

Most common options:

1. Metal Base – Integral or Separate
2. Brick Base – Plinth or Dwarf Wall

As a general rule, metal bases are considered to be easier to install and more reliable long term. Brick bases and dwarf walls require a lot of labor and precision at the time of installation, but some choose to take this option for aesthetic reasons – or when a metal alternative isn’t available, it is perfectly serviceable.

Metal Base Options

Integral Base

This is by far the easiest option, as it does not require any further building or construction, as it forms part of the frame itself. The greenhouse can be set straight down onto a level, solid surface and secured into place. No mess, no fuss, job done.

The other benefit of an integral base is that it adds structural integrity to the entirety of the greenhouse.

Integral bases are less common, but when found can often be relied on as an indicator of quality and strength.

Separate Metal Base

This is a common option, as the majority of metal greenhouses do not have an integral base. A separate base is therefore purchased that fits the exact specifications of the greenhouse. This is generally assembled separately and anchored in place before the greenhouse itself can be mounted.

This is still an easier option compared with brick bases, as all the measurements have been taken care of.

Brick Base Options

Brick Plinth

If you don’t have a metal base, you will need a brick plinth to lift the frame off the ground and to anchor the greenhouse into position. You’ll need to build a level plinth to the exact measurements required so the frame can be mounted on top, with the lip of the frame sitting down over the top.

Dwarf Wall

There are those who prefer a brick dwarf wall for aesthetic reasons. A dwarf wall is a striking visual choice on a greenhouse – not the same as a brick plinth that is only for the purpose of levelling and securing a greenhouse into position. It more nearly resembles a traditional style of greenhouse and can be suited to more rustic locations and premises.

If you do wish to go for a dwarf wall, consider this carefully as it will have knock-on effects for building the rest of your greenhouse if the measurements aren’t perfect. You’ll need what is called a ‘Drop Door’ as well, which isn’t available on every greenhouse You may also find that irregular subsidence and shifting of the ground beneath can cause structural issues in the future.

Groundwork

Once you know what sort of base your greenhouse will have (integral, brick plinth or dwarf wall) you can start preparing the site so that the greenhouse has a solid foundation that will keep it secure and level for many years to come.

Essential Requirements and Concerns for Greenhouse Groundwork:

1. Keep it Level - It is absolutely essential that a greenhouse be installed onto a level surface so that the structure fits together cleanly. Without a flat surface, tiny gaps between pieces will cause big issues when it comes to fitting the glazing and it will cause long term problems with the integrity of the building as a whole. If installing directly onto soil, employing a whacker plate or similar compacting tool is advisable.
2. Drainage - If flooding is a problem in your garden then this should be a high priority. You may wish to integrate drainage into the design of your groundwork or consider siting your greenhouse on higher ground.
3. Growing Plans - What do you plan on growing in your greenhouse? If you want to plant directly into the soil, you'll want access that won't be achieved by a complete concrete pad.
4. Water & Power Supply - It is worth well the effort of laying plumbing and electrics during the groundwork stage before the greenhouse has been installed.
5. Cost - If cost is a concern then the cheapest option is a soil base - but be warned that not all greenhouses can be sited onto soil.

Siting & Foundation Options

Once you know what sort of base your greenhouse has, you can then look at groundwork options.

Broadly speaking, you have 2 options for siting:

1. Hard-Standing
2. Soil Base

You can site your greenhouse directly onto soil or onto a hard standing. Not all greenhouses will have both options available so take care when looking at specifications.

Soil Base

Unlike most other brands of greenhouse, Rhino’s can be sited directly onto soil. This is a huge positive over other brands, as it offers a level of flexibility not afforded to you by the vast majority of other retailers.

This is only possible because the Rhino greenhouse is so strong. Its combination of a sturdy base and framework means it will happily sit on a properly prepared soil site for years to come.

In most situations soil is a perfect foundation, so long as it is level and fully compacted down (freshly dug soil will shift too much to create a stable foundation on which to build). Whilst you do need to take time and care to properly prepare a soil site to the required standard, it does have the considerable advantage of doing away with the extra cost and time of building hard standing foundations. Take note of the quality of the soil itself - very heavy clay, waterlogged or very sandy soil can cause problems; a good amount of loam is ideal.

The greenhouse is held in its permanent position by concreting it in place using the specially supplied brackets and J shaped ground anchors.

N.B. The ‘low threshold door’ feature on the Rhino greenhouse is most easily incorporated onto a soil site, by the use of paving slabs (please note, these are not supplied or laid with the greenhouse).

Here’s a few examples of Rhinos on a soil base:

Hard-Standing Base

The versatility of the Rhino greenhouse also allows installation on a hardstand. There are several different types of hard standing bases, all of which must be smooth and level:

• Paving Slabs: must be laid flat and level and should ideally create a site that is slightly larger than the greenhouse footprint size.
• Concreted Area: same as above.
• Brick or Block Perimeter Plinth: must be laid on suitable footings so that it is level, square and exactly to the correct greenhouse footprint size.

N.B. The ‘low threshold door’ feature on the Rhino greenhouse is most easily incorporated onto bricks or blocks, by using a protective timber strip (please note, this is not supplied with the greenhouse).

On all types of hardstand base, the greenhouse is held in its permanent position by plugging and screwing down using the specially supplied base brackets and, wherever possible, the supplied rawlbolts. However, please note that some hardstand bases may require a different fixing, which is the customer’s responsibility to source and use. We also strongly recommend that the top course is laid ‘frogs down’ to give a smooth surface on which to sit and fix down the greenhouse and that bricks/blocks are of a type that will allow drilling without cracking or splintering.

Rhino Greenhouses do not recommend the use of Hardcore or Hogging as base materials, due to issues surrounding levelling and securing the greenhouse.

Here’s a few examples of our customers’ Rhinos on a hard standing base:

You can find lots more groundwork inspiration here.