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Building a pergola with ground screws

Are you keen to give your garden an added dimension?

A pergola in the garden gives you an additional space where you can sit down for a cup of tea, have something to eat or socialise with family and friends and enjoy summer.
A pergola gives your garden a boost and creates a lush extra space. But what is a pergola actually, and what should you consider if you are about to build one?

What is a pergola?

The word pergola is Italian and means colonnade or garden alcove. A pergola can have many different designs and fulfil several different purposes. Many people see it as an outdoor space where family and friends can gather to talk, eat and enjoy time together. Climbers are perfectly suitable plants in a pergola and create a lush and opulent impression, while providing shelter and shade. It is also possible to attach a sail on top to protect against the weather.

Choosing the right timber

Once you’ve planned and measured where you want your pergola, it’s time to choose timber. As it is a permanent structure, you should choose impregnated timber. This will make the maintenance of your pergola easier – you just don’t want to cut back your climbers every year to clean the timber. If you think you might add a roof to your pergola in the future, this must be taken into consideration when choosing the timber. It must withstand both the weight of the roof and any possible snow cover. However, many people prefer to let the climbers grow and form a natural and lush ceiling. Keep in mind that your climbing plants will not only wrap around the rafters but will also hang down. Therefore, you have to allow for extra ceiling height.

Positioning the pergola

There are many suitable places for the pergola in the garden. If a wind screen is added, this can create a lush and cosy garden alcove. Most common however, is to place the pergola as an extension to the house. This creates an atmosphere of an outdoor room. As many of the plants in the pergola thrive in the sun, a south facing position is excellent.


01 Why use the ground screw?

Stop Digging’s ground screws provide a secure and stable foundation that saves both time and money. They make construction easier and smoother; no more lugging heavy concrete blocks or laboriously digging holes and shifting piles of soil to make way for the foundations. Ground screws are easy to place and move if a site needs to be adjusted due to an unforeseen discovery or for better support. Ground screws are ready to use after they are installed – no waiting for wet concrete to harden, and they can be installed in all soil types and weather conditions.

A ground screw from Stop Digging should not be confused with the lightweight ground anchors and pile foundations you find at B&Q, Wickes and other hardware stores. By comparison Stop Digging’s robust ground screws are delivered and installed by our experienced and certified installers.

02 When can you use ground screws?

Ground screws can be used to support most types of construction. This includes underpinning decks, pergolas, sheds, children’s playhouses, carports, conservatories, greenhouses, hen houses and much more. We offer several different models and sizes such as the adapter, pipe, pillar and beam screw, all designed to tackle tricky terrain and soils. In addition, ground screws are ideal for flagpoles, signage or solar panels and for inaccessible locations where alternatives are not an option. By selecting from a range of models, you can tackle even the most challenging of terrain with our versatile screws – the question isn’t when you can use a ground screw, but when you can you not?

03 How deep can a ground screw go?

How deep a screw needs to be depends on the terrain and the required load. We offer screws between 580 mm to 2500 mm long, much deeper than conventional concrete foundations. Anchors typically need to be between 400 mm and 650 mm deep to meet U.S. building regulations, which we can easily surpass if required. Our experienced fitters will choose the right screw for each project and site, providing stable and long lasting foundations for your project.

04 How many ground screws do I need?

How many ground screws you need depends on the size and weight of the particular construction project. For example, when installing decking it is advisable to mount the supporting ground screws at 2 metre intervals when the rim joist is at least 45 × 170 mm in size. For a decking terrace of 4 x 8 meters, for example, that would mean installing 15 ground screws.

05 How long does the ground screw need to be?

This depends on the soil type, load bearing required and the nature of the project. We offer four basic models – adapter, pipe, post and beam screw – in a variety of lengths to meet your specific needs. In addition, we can install ground screws with our special attachments that are designed to support installations such as flagpoles or solar panel systems and other unusual projects. All of our screws are robustly designed with northern climates in mind, and meet building standards for depth.

06 How do you use ground screws in difficult terrain?

Just as we would pre-drill hard stone for fixing a normal screw, we always drill a pilot hole before installing our ground screw in tricky terrain. This forces smaller stones or gravel aside and our equipment is powerful enough to split medium-sized rocks. If you are building on solid or large enough rocks, our installers can anchor with a drilled steel stud and use ground screws where the ground is more suitable. We offer a complete service with no need to wait for another specialist.

In newly excavated, soft or disturbed soil, our installers are trained to assess the ground and select longer screws if necessary to provide a secure and stable foundation. Our installers are specially trained to select the right screw for your project, install it correctly in whatever terrain they face and finish with the minimum of disruption.

07 When do we install the screw?

We can mount ground screws all year round, even during a cold, hard winter. Our screws were originally developed to cope with the harsher conditions found in Scandinavia, and the U.S. climate, by comparison, is much gentler! Do you want to know more? Feel free to ask your local installer, who has a specialist knowledge of your area and useful reference materials.

08 How do ground screws handle slopes?

Easily! Our ground screws are ideally suited to work on slopes to anchor, for example, decks or stairs or other structures. Our equipment can install the screws in difficult to reach locations at the required depths. Furthermore, by combining the various ground screw sizes and models produced by Stop Digging, together with our attachments such as plates and L-supports, we can create a tailored solution whatever the terrain or slope your project faces.

09 Do ground screws settle after installation?

Just like concrete supports, a ground screw can be affected by the ground settling over time, but they are not generally affected by other forces such as frost heave. Settlement of soil is especially an issue with freshly excavated or disturbed soil and our installers are trained to identify this and select longer screws to provide a deeper, more secure, fixing as needed.

10 How do you calculate the screw load bearing?

You can employ the same calculations which you use to work out the load bearing of concrete supports. Our ground screws can replace concrete in every way and follow building standards. As a result you can safely use standard centre to centre measurements and calculate the span and strength just as for concrete. In the case of larger projects and heavier loads, we recommend that we undertake a tensile test so that our installers can provide you with the correct type of screw.

11 How much load can a ground screw bear?

All of our screw models have been rigorously tested to cope with load, pressure and tension bearing and you can read more about our screws here. Our tests were made in normal arable land which we use to calculate the performance of our screws in different soils and terrain. We can test your ground to provide precise feedback for your project planning.

Our steel ground screws (ISO 630 FE 3604) are specially developed and adapted to northern climates in terms of thickness (4 mm) and surface coating. All of our CE marked ground screws are hot-dip galvanized according to ISO 1461 and manufactured by ISO 9001 certified production facilities. They all come with a 25 year warranty.

12 How much do ground screws cost?

We offer a fixed price per installed ground screw. However, our prices vary depending on which screw you need to use and where in the country you are located.

Our vision is not only to provide a high quality product, but to deliver and install it to the highest professional standard. A ground screw from Stop Digging should not be confused with the lightweight ground anchors and pile foundations you find at B&Q, Wickes and other hardware stores. By comparison, Stop Digging’s robust ground screws are delivered and installed by our experienced and certified installers.