How to Build a Pergola

Discover the key "How to Build a Pergola" ingredients that help make building a pergola an easy construction with solid foundations.

Find out how to make this addition to your home become an asset to your home with a build that is up to code.

How to prepare your pergola building plan so that the design and timber you use suit your home and surroundings...

How to Build a Pergola:
The Benefits of an Attached Pergola

A Pergola is a wonderful addition and is an ideal open cover to complement any deck or patio area outside your home.

Even though a Pergola is not a totally enclosed roof cover like a porch, it will change the way that you use an otherwise uncovered outdoor living space.

Without a doubt a deck or a porch covered by a Pergola is more inviting, while still allowing you to enjoy the outdoors.

Climbing plants and the addition of lattice or trellis to the roof will give you more shade while adding planting and lattice or trellis to the sides can give your pergola more privacy and some protection from the sun and wind.

Once you have build you basic pergola construction their are many possibilities to further adapt this new space to create your own perfect idyll.

How to Build a Pergola:
Preparing your Pergola Building Plan

By taking the neccesary steps to ensure that the general size, height AND location of your proposed pergola building plan is acceptable to your local building office, you pave the way for this construction to be an asset to your home.

You will also need to determine if an attached pergola is permitted or if you have to build a traditional four post pergola construction a certain distance from your home.

Your local building office will also advice you on acceptable methods of securing pergola posts in your area.

Designing a pergola building plan on your home design software or simply by using a pencil and paper will help you to convey the look and scale of your intended project and may help speed up any necessary planning permissions.

Once you get the green light to go ahead, it's time to concentrate on how to build a pergola.

Before breaking ground it is vital that you know where all of the underground utilities are running to and from your home. Although building an attached Pergola usually only requires digging footings for two pergola posts, it could be costly if you burst a pipe!.

How to Build a Pergola:
Measuring for Square

Now that you know where you can safely dig, it's time to measure out the area to make sure that your pergola will be square.

The traditional method of placing stakes or boards into the ground and extending mason string raised off the ground and along the extremes - is still the easiest and best way to get it right.

how to build a pergola - measuring for square

(In this diagram we have used red to denote mason's string.)

  • Length 1: runs along the wall of the house the full length of the proposed construction. It should be exactly the same length as side 2.

  • Length 2: represents the outer beam of a parallel beam attached construction, and should be the same as length 1.

  • Length 3: is the distance the pergola will extend out from your home and should match length 4.

  • Length 4: is the distance the pergola will extend out from your home and should match length 3.

At this point we can measure the diagonals to make sure that our pergola building plan is square.

When you are planning how to build a pergola - having a square construction is not only important to the look of the finished build, it's stability and potential value - but will also make it a lot easier for you when you come to fitting beams and rafters of equal length.

*Note the alphabetical letters is each corner of the diagram:-

  • Measure diagonally from corner a to corner d
  • Measure diagonally from corner b to corner c
  • If both diagonal measurements are the same you can be confident that your plan is square.

This is the same measuring method used for any like construction - including building a deck.

How to Build a Pergola:
Preparing Pergola Posts

There are many ways to secure posts for your pergola, what is important is that the method used is up to your local code and provides you with the best possible solid foundation.

We believe that by far the best way when considering how to build a pergola is to prepare a solid concrete foundation into the ground which reaches below the frost level in your area.

building a pergola - footings options

Figure 1: The concrete foundation rises up to a couple of inches off the ground and the top is rounded off for good drainage-

A galvalised steel metal post anchor is pushed down into the cement and placed into the exact center of the footing before it dries.

These tall two sided metal post anchors provide more strength than the shorter versions used for anchoring posts of low level decks.

It is important that they are placed square and facing the right direction for the posts to be placed square to the build once the cement is dry.

Leave a small gap between the post and cement footing to allow for good drainage then the posts are secured with 4" machine bolts or as otherwise directed.

Concrete footing will take about three days to fully set unless you are going to use pre-prepared and bagged - quick drying cement which can take mere hours to dry - as per instructions given on the product used.

Concrete footings for a pergola to be build over a deck or patio will mean that the pergola will extend just beyond the surface deck or patio - to where you can dig post holes.

We have more indepth information for you here with another article on the best method for Digging and Cementing in Pergola Footings

Figure 2: Here the post is embedded into the cement. Cedar is really the only wood that I would use for this method to ensure that the construction would be reliably long lasting.

Once the hole is dug, small stones are placed on the bottom before pouring in the cement - the stones mean better drainage out of the bottom of the hole. once the post is in place it will need to be braced until the cement has completely set.

Figure 3: This is not a favourite with us, but I will explain how it works - this is a method used to secure pergola posts directly onto decking. The post anchors are later covered with wood post trim to hide them.

Although the post anchor is placed directly onto a decking board - the board must rest securely ontop of a under-supporting joist and with additional blocking between surrounding joists to provide a strong base.

Figure 4: This is a more secure way to anchor posts to the strongest part of your under deck construction. Here the posts extend below the level of the deck and are bolted directly into main joists.

We would then still use trim and moulding around the base of the post at the deck surface for a neater finish.

How to Build a Pergola:
Post & Beam Options

There are a few different methods for attaching a beam or beams to your post - deciding whether to notch your posts of not - this article on Building a Pergola - Post and Beam Options will help you decide which is the best construction method for your home.

How to Build a Pergola:
Prefered Pergola Timbers

Unless you live in a really dry climate where treated pine is used successfully for outdoor projects - we prefer to use Redwood or cedar for strength, durability and the natural resistance to decay and insects - also they shrink less than other timber throughout climate changes.

All treated timber that has been cut to size should be re-sealed at the new ends before construction.

Adding a water repellent wood preservative will help the longevity of the timber.

Only recommended hardware and fasteners should be used depending on the timber type you choose to work with. The best quality hot-dipped galvanised fasteners work best with redwood and cedar, sub-quality products will cause a bliush staining around the fasteners or hardware which cannot be removed.

We hope you found this "how to build a pergola" article useful, for more information on your pergola construction options, tips and ideas please read the following additional articles...

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