How To Build a Carport

A Quick Guide to Building a Carport

Many people see the benefit of buying a carport to protect their vehicles. But one of the main questions they then have is how to build a carport. You can make and build your own carport from scratch using stock length materials of the shelf, or you can buy a carport kit. A carport kit is by far the better option because apart from saving you time and money, it simplifies the steps in building. We also supply construction and installation guides with all our carport kits, making the process even easier.

But for the purpose of this article, let’s have a quick look at how to build a carport.

When you look at the basic steps of how to build a carport is essentially the same for all the different roof types and designs, it’s just the amount of time and effort that changes.

• Step 1 – Install the Posts
• Step 2 – Connect the Frame to the Posts
• Step 3 – Concrete the Posts
• Step 4 – Install the Fascia Capping
• Step 5 – Screw the Roof Sheets to the Frame
• Step 6 – Screw and Fix the Guttering and Flashings to the Frame and Roof
• Step 7 – Clean Up

Let’s now go into some more detail on this.

STEP 1.  Installing the posts

– There are 2 options to installing carport posts:

1. Concreting them directly into the ground – the Preferred Option

Concreting the posts into the ground is the preferred method and has several advantages. One is that you get a stronger structure overall because of the increased bracing achieved. In simple terms it will move less in windy conditions. Secondly, it looks better as you don’t have footing plates and sometime angle braces in the way. It’s also more practical as you don’t have footing plates to get in the way of anything, or kick your toe on!

Note: Before you place the posts into the footing holes, remember to fit the 2 length lengths of rod through the bottom of the posts. This will tag the concrete in the footing to assist with uplift etc.

2. Fixing them with footing plates onto existing concrete

The main reason people want to use footing plates is because they already have existing concrete to bolt onto. This can potentially speed up the installation. However, in most cases, there is not enough concrete to fix to. A typical concrete driveway that is 100mm thick is not enough to anchor a carport to. You need proper footings under each column. Footing plates cannot be used in high wind areas such as cyclonic wind regions. There are also size and height restrictions, such as under 3m high.

Marking out the Post Hole Locations

First, you will need to go to the ‘Post and Footing Layout’ in the engineering drawings. This will give you the dimensions of the post locations. Please note: The layout uses running dimension lines. Your post centres are the second measurement minus the first meausrement in each direction (ie. do not assume the zero point).

– Once you know the post location (yes it is different to the carport size), simply start at one corner and work off there. Whether it is 4 posts, 6 posts or more, you will need to ‘check the square’ of the holes. This means making sure that all posts are in the correct spot in relation to the the posts. There are 2 common methods and we suggest that you use both to double check your measurements.

1. Measure Both Diagonals

Measure the diagonal measurement between the outside posts. The 2 measurements must be the same. Look at the example drawing below. This is typical post hole layout for a square carport that is 6m wide and 6m long. Notice that the diagonal measurements are exactly the same. This same principle applies for a rectangular carport as well (see 2nd drawing).

2. Use the 3-4-5 Rule for a 90 Degree Corner

You can also use the ‘3,4,5’ rule. Start in a corner of the carport. Your measure one way in a multiple of 3 (eg.3 metres) and mark the spot. You then come off the same corner and measure in a multiple of 4 (eg. 4 metres) and mark the spot. Then measure across the 2 spots you have marked. If the corner you started with is at 90 degrees, this measurement will be a multiple of 5 (eg. 5 metres). You can then simply the measurements of the sides out to the dimensions of the other post hole locations.

By using these 2 methods, you can ensure that your carport will be at 90 degrees in the corners and will be square.

We also strongly suggest that you connect some of the frame and brackets to the posts before concreting or fixing the posts in, to ensure the posts are in the correct orientation and location and that everything fits. Note: Only connect what frame is needed to get the posts in the right orientation before fixing/concreting (no roof sheets etc), as the footings/fixings are needed to keep the carport fixed and anchored to the ground (from wind etc) and are required to be concreted/fixed before any more frame or roof sheets etc. Once the frame is connected, simply square and level the posts and frame.

You’re now ready to concrete the posts into the ground. Follow the instruction in your guide. You can also contact us with any questions you may have.

STEP 2. Bolt the frame to the posts

With decent quality carport kits, you should find that the main frame simply bolts together with no cutting or drilling needed. Start by bolting the main perimeter or fascia beams to the posts. Then connect the rafters or purlins to the beams with the supplied brackets. In the case of the gable, hip and dutch gable carports, you will now need to screw the purlins to the rafters, ready to take the roof sheets.

STEP 3. Concrete the Posts into the Footings

Once you have installed the posts and frame, it’s now time to square and level everything, brfore concreting the posts into the footing. Always use the correct concrete, as noted in the engineering drawings. It’s also beneficial if you can dome the top of the footings, so that any water or rain will run off away from the posts. This will minimise the chance of corrosion long term. Wait until the concrete has cured, before moving on with the rest of the carport.

Step 4. Install the Fascia Capping

The next step is fitting the fascia capping. This mimics the fascia capping on your house and enhances the look of your carport overall. Typically ther will be 2 sides that are cut to length and 2 sides that need some simple cutting and folding to cover the corners of your carport.

STEP 5. Screw the Roof Sheets to the Frame

Now simply use the supplied roof screws to fix the roof sheets to the purlins. Care must be taken to start in the right place. You don’t simply start at one end for every carport. Follow the instructions in your installation guide so that you get the correct sheet layout.

One other note: In the case of a gable, hip roof or dutch gable carport, you may find it easier to fix the fascia flashings to the carport before the roof sheets go on. This is because they sit under the bottom edge of the roof sheets.

STEP 6. ­– Screw and Fix the Guttering, Downpipe and Flashings to the Frame and Roof

This involves fixing off of the guttering, as well as various flashing which may include the ridge capping, barge capping, hip flashings and infill flashings. As mentioned above, the fascia flashing are better to be done earlier.

If your fascia flashings are on then do the guttering. After this you can look at fitting the barge cappings and ridge capping.

This involves fixing off of the guttering, as well as various flashing which may include the ridge capping, barge capping, hip flashings and infill flashings. As mentioned above, the fascia flashing are better to be done earlier.

If your fascia flashings are on then do the guttering. After this you can look at fitting the barge cappings and ridge capping.

Step 7. – Clean Up

A couple of things we suggest to do also. Make sure that there are no metal shavings or what is called ‘swarf’ on the roof sheets or in the guttering. These are formed when you are screwing the roof sheets and flashings on. Either sweep them of the roof or use a blower tool to blow them off the roof. If you don’t they will rust over time and potentially mark your roof etc.

Then have a complete look over your carport and make sure every bolt, screw and rivet has been put in.

That’s it. Your carport is finished!

We hope this information has been helpful. If you’re still not sure exactly about what’s involved in building a carport or diy carport kit, why not give us a call on 1300 011 191. We’d also welcome the opportunity to give you a quote on a carport kit to suit your house or property.

Thanks very much.