How to Build the Ideal Polycarbonate-Roofed Carport

Exterior additions to your home not only add curb appeal and tonnes of style, but they can also be practical. Carports are some of the more functional add-ons, a good alternative to garages, and possibly the only option in instances where space is tight. If you don’t have either, then this simple guide can help you keep your vehicle protected at all times. Before sitting out in that heavy rain or watching birds practise their art skills, an easy solution is to build your own.

Building a carport can be a simple DIY project if you have the right materials and basic tools. Essentially, carports consist of a roof sitting on a frame. Materials need to be tough enough against weathering while still leaving a pleasing look. The most important detail is undeniably the roof, and here tough plastics do a fine job of shielding vehicles from rain, ice, and UV rays, as well as bird droppings and the usual dust and debris. Frames are usually built around timber rafters and battens, while plastic sheets sitting on top are secured in place with durable glazing bars.

Getting Started

There are a few considerations before building your ideal carport. You need to think of size, placement, and the type of carport that works best for your needs. Average sizes for a single carport tend to gravitate around 3 metres wide and 5 metres long. This can be attached to an existing exterior wall and provide an uninterrupted path from your home to the car, or it can be a standalone carport sitting further forward, often on the driveway.

The next step is to configure exact placement, both in terms of functionality and how this blends in with the rest of the house. Attached carports are undeniably harder to get right but act as a seamless extension of the dwelling, so they are more pleasing to the eye.

Building the frame will be the most time-consuming. Timber posts first need to be anchored into the flooring material (preferably stone or concrete) and then secured with a beam. Another beam anchored into the exterior wall should sit at an angle of 5 degrees and allow for drainage. Both beams are the foundation for the rafters. It is recommended to space rafters at a distance of between 500 and 600mm apart to provide adequate support for the polycarbonate sheets and glazing bars that hold everything tight.

Why Go With Polycarbonate Sheet?

Polycarbonate is one of the toughest materials you can use in any roofing project. It’s almost 250 times stronger than glass, is shatterproof, reflects harmful UV rays, and copes well in extreme temperatures. It’s also easy to work with, so it can be drilled, cut, and used with fasteners without cracking or breaking. Additionally, the material comes in varying finishes, from opaque to frosted to transparent, and a wide range of colours. Keep in mind that colours and finishes not only affect the final look but also the shade they provide.

When considering durability, also keep in mind the varying thicknesses and designs. For carports, the most common is a twin- and triple-wall polycarbonate sheet, usually offered in a thickness of 10 or 16mm. Thinner and cheaper sheets are used in areas like cladding, and sheets of 25 or 35mm offer the best durability and protection in places like greenhouses. While thickness will affect overall weight, all polycarbonate sheets are extremely light, which is good news if you’re building your carport on your own.

Corrugated sheet has been around for ages, but solid poly sheet is the newer design, is internally strengthened, and looks much better in residential settings. This also integrates seamlessly with rafter systems and glazing bars for a neater finish.

Pre-Installation Tips

Poly sheets come in standard building sizes. Keep in mind that larger sheets (3050 by 2050mm) will work fine in frames for single carports, but if you’re building a twin carport, frames will also require midsection battens (or purlins) and are better off with smaller sheet sizes, such as 2050 by 1220mm. You’ll want to measure the rafters and cut the sheet, either with a hand or a circular saw to suit.

Besides this, you’ll need a drill to fasten the screws that hold the bars to the rafters, a mallet to tap the bars in place, as well as the provided accessories like gaskets, aluminium (or poly) side trims, eaves fillers and fixings like end caps. Complete kits can differ from manufacturer to manufacturer, so ensure you’re getting all parts beforehand and all tools ready.

Fitting Poly Sheet Roofing on Your Carport Frame

First, ensure that each sheet is cut to the correct size. You can check this by laying the poly sheet across the rafters and seeing how it works with the glazing bars. For a completely flat, sealed, and watertight fit, there should be no gaps, nor rafters that are unevenly placed. Do any corrections, before moving on to fitting the sheets.

The complete installation process goes as follows:

● Most kits consist of eaves filler, and this is the first component that’s added along the length of the beam.

● Next, cut the rafter gaskets and fasten them at 300-mm centres. Both gaskets and filler prevent vibrations and noises in stronger winds and heavy rain.

● Follow up by placing the poly sheets on the gaskets, ensuring they’re the right side up. This will be clearly marked. Sheet ends need to be flush and clean. Use breather tape for a cleaner fit.

● Attach an end bar to one end of the roof. Proceed by fixing one sheet at a time using a glazing bar between two adjoining sheets, all the while ensuring they line up perfectly with the rafters.

● After installing all the glazing bars, attach the other end bar and add the end caps. At this point, you can remove the protective film from the sheets, drill holes, add fasteners, and tighten to the right torque.

● For attached carports, you can also add flashing to wick away water.

Summing Up

Carports are one of the more versatile and practical additions to any home. They’re also much cheaper than fully-sized garages, are ideal for smaller spaces, and offer great protection for your car. And they’re easy to install, even on your own. All you need is timber, some cheap but durable polycarbonate sheets, and a glazing bar kit. Done correctly, this material combo should last years to come and is one exterior feature both your car and home deserve.