Can my deck support a pergola?

Pergola is a structure built to provide shades. The built-up is supported by four vertical posts. Post bases are used to affix pergola to the deck, which hold weight to the entire structure. Precautions have to be undertaken if a pergola is attached to the house, for, e.g. a water-weight connection.  

Size of Pergola

The sizes of the overhead vary, and the lowest boards are the heaviest. Building a pergola is subject to building codes. The structure is built to withstand substantial items, namely snowflakes, which can develop up to 4 inches or more. The snow piling on the pergola is similarly heavy as the pile-up on the roof of the house. Many local building authorities mandated that a minimum of 20 per square feet of live load for the structure to support.

Pergola Installation

Installation of the pergola on the deck sets it up higher and makes the structure vulnerable to the wind’s movement. The pergola’s reliable and robust attachment over a patio is necessary to withstand unpredictable weather, for, e.g. high wind condition. A similar technique as attaching the rail post is used to tighten the pergola beam to the deck’s frame. Most deck builders will bolt pergola support to the deck’s frame using (2) ½” X 6 lag screws with washers per post.  

The heavy top of the pergola would not sway in the wind with the lateral bracing in place, which forces the pergola to act as a sail. Attaching the sections of rail between posts will strengthen the pergola. Installation of braces between the posts and headers would increase the stability of the structure.

The structure is vulnerable to termite infestation when attaching to the deck, according to Sean from Decking Central Coast. The use of insect-repellant wood, namely pressure-treated wood, is ideal for a durable design. No roof should be added to ensure the stability of the pergola attaching to the deck.

These features are to be considered when a decision is made to install a pergola over a deck. The building codes dictate that putting up decking is permitted development and no planning permission is required provided that:-

  • The decking is no more than 30 cm above the ground
  • The decking or platform covers no more than 50% of the garden area
  • None of the decking or medium is on land forward of a wall forming the principal elevation.

In certain areas, additional limitations apply:

  • In the case of any land within the curtilage of the house which is within (a) World Heritage Site, (b) National Park, (c) an area of outstanding natural beauty or (d) the Broads (Listed buildings/properties), development is not permitted if the total size of ground covered by buildings, enclosures, pools and containers situated more than 20 metres from any wall of the house to be greater than 10 square metres, planning permission is required.

Any development at the sides of the Listed buildings/properties requires planning permission. Any outbuildings within the curtilage of listed buildings/properties will require planning permission.

Is it Cheaper to Buy or Build a Pergola?

There is space available in the backyard. Also, there is a surge in the trend to own a pergola as part of outdoor living in home improvement. You think that a pergola would be an ideal spot for you to enjoy with your family and friends during the weekend. It will complement the outdoor landscape and the best hub for relaxation, creativity, meditation and family outdoor activities with the children.  

There are many features to consider before any decision is made to either buy or build the pergola. Some homeowners prefer to buy the prefabricated kit from online retailers or stores. Others prefer to hire a professional builder to custom-made the structure.

So, what is the best option?

Simplicity vs Customization


The prefabricated kit offers a simple structure that professional engineers have designed. The materials and gadgets of the construction would be professionally packed for delivery. It would be simple for you to assemble by following instructions during the assembly and ready for use in a lesser time.

Another consideration that may add to the cost of buying the pergola is digging the post holes. It would require four-by-four posts for the holes to support the structure. The drilling would require renting a gas-powered gadget. A complete tool or ladder is also required. Without experience or skill, the task could be daunting and risky. Minor accidents may happen. 

The most crucial consideration is regulatory compliant. You must ensure that regulations are adhered to to avoid any penalty to be imposed by the authority. In some cases, a building permit has to be applied by the local authority.

The price of 10 X 10 sq ft made of aluminium ranges from US$400 to US$800. The weight of the structure would increase the cost of the pergola. The design made of wood with similar measurement would cost a minimum of US$1,200. The price is exclusive of shipping or delivery charges. It may increase following the weight of the material.

The prefabricated kit may not be able to provide the desired design and styles or customization. You may want to add the lighting, sunshades and other features to the finished structure, which may often incur additional time and money.


Hiring an experienced and reputable contractor or builder will ensure the quality of the finished product. You can ensure that the finished structure is solid, aligned and healthy.

You can create the desired design that suits your lifestyle and budget. Planning is time-consuming, and hiring a professional would lessen the headache. Imagine that you do not have to plan the location, technical aspects of the structure, obstacle of finding the right material, permits etc., as the skilled contractor undertakes the job.  

Most importantly, the finished work would be by the local building codes. You would be able to showcase the finished structure to your friends and neighbours and increase your home’s value.

Is it Cheaper to Buy or Build a Pergola?


It is more cost-effective to hire a professional due to the skill and technical know-how. The expert would be able to handle any untoward incident if it arises. The contractor would have easy access to the necessary tools for the job and the expertise to safely use the tools. The injury could be avoided because of their expertise.  

Overall, your choice is either to buy or build depending on your lifestyle, budget and preference.