Pergola Construction Materials
In order to design a pergola to be sturdy and beautiful, you first need to know the types of pergola construction materials that you will be working with. The strengths and weaknesses of different materials, and especially in regards to the ratio of weight to that strength, can dramatically impact design decisions such as length of spans, thicknesses of structural components, and even the color schemes that will be available to choose from.
Pergolas can be built from a wide range of materials. Countless types of wood, various metals, and more modern man-made materials such as PVC and vinyl are all options. Before you ever pick your building plans you should at least narrow down the material you are going to use to a general category of construction materials so that you.
Another aspect of construction materials that needs to be taken into account is how they will fit in with the general look and feel of your home. While an industrial steel pergola may look very modern and appealing on it’s own, next to a more traditional house it would look very out of place indeed. While there are some tricks that you can utilize to blend in divergent materials, often it’s just easier to start with those which are visually compatible in the first place.
Wooden Pergola Design Considerations
Wood is perhaps the most common material used in pergola construction. Easy to work with, relatively inexpensive (for most types of lumber that is commonly utilized), and possessing a natural beauty, it’s not hard to see why that would be. Paradoxically, a wooden pergola brings a look that is both uniform due to the structural components, and flowing due to the grains of the wood.
When working with various types of wood though there is a huge variation in weight of the materials, suitability for outdoor use, and the look of the grain. Some types of wood like cherry or rosewood have very pronounced grains with wonderful coloring, whereas others such as teak have much more muted tones and difficult to distinguish grain. (Teak is a very popular choice still for outdoor structures and furniture due to it’s natural resistances to weathering and pests.
In general, because of relatively low strength to weight ratios, wood pergolas end up more stocky than their metal counterparts. This can mean that some styles of pergolas just aren’t suited for wooden construction, especially those which incorporate wide spans with lithe beams and posts. Often though, the type of look one would want with wooden components is easily achievable, as the “natural” look tends to be more substantial.
Using Metal In Pergola Designs
The use of metal structural elements in pergola designs have really opened up a lot of possibilities as far as design features are concerned. That “opened up” is literal in fact, as the types of pergolas that can be constructed by metal can be far more svelte and open than what can be achieved with wood. Beams can be smaller and/or extend further over spans, while posts and even slats can be much smaller dimensions without losing their strength and rigidity.
The main drawback with metal is how to incorporate it into more traditional designs without the look of the material causing dissonance with the style. In some cases, such as with wrought iron, the look actually goes well with more classical or traditional styles. Of course wrought iron isn’t a lightweight material like aluminum or steel, and so will necessarily result in a much more bulky structure.
Classic Design with Stone or Concrete Pergolas
The first pergolas were probably nothing more than some wooden poles extending from the eves of roofs, but the ones that exist from antiquity certainly had to be made of more substantial materials. This is perhaps why when we think of pergolas from Ancient Greek or Roman times, we tend to picture massive stone or concrete columns, arches, and a general sense of solidity.
Stone is a very expensive material to build with in most cases, and very difficult to work with as well due to the weight. With concrete though the difficulty of building large structures is drastically reduced. However, you may end up using more steel in a concrete pergola post than you would in a steel one, due to all the reinforcement necessary!
Often the slats or runners on a pergola of this sort will be made of metal or wood though. It’s only for the posts and beams that stone and cement make much sense. The thickness of the runners would have to be rather substantial to span much more than a couple feet.
Modern Materials for Pergola Construction
More recently man-made materials have become popular for building outdoor structures such as pergolas. Due to very high strength to weight ratios, along with resistance to the elements, uPVC and vinyl pergolas are often available in kit form from local hardware stores and home centers.
Using Varied Materials for their Strengths
When designing a pergola, bear in mind that using the same materials for all components isn’t necessary. Dramatic and beautiful looks can be achieved by contrasting different materials with one another, or by utilizing the suitability of one material for some structural components, and using another for decorative elements. In this author’s opinion, not much can beat the look of wrought iron posts and beams, decked with a rich, dark hardwood for the slats above.
Understanding the relative strengths and weaknesses of the various types of components can help you to visualize and design a truly unique and gorgeous pergola that will be as sturdy as it is beautiful.