Sunday, January 27, 2013

DIY Roof Rack

Saturday I set out to build a roof rack for the car. With prefabricated racks costing in the $400 - $500 range, I was determined to make one of my own and at a fraction of the cost! I was able to make a highly functional and rather legitimate looking roof rack for around $40 USD. Overall the build was pretty simple and straight forward. The only tricky part is getting all the measurements just right so that all the bolts line up. Well enough rambling, it's time to show you how I did it.

The rack is 4' long and about 40" wide, and will easily support two crash pads.
2 - 1 1/2" X 10' PVC pipes
4 - 1 1/2" 90ยบ PVC elbows
8 - 12-24 X 2" machine bolts (Or whatever size bolt your car requires)
24 - 1/4" washers
1 - Flat black plastic spray paint
PVC cement
A bit of scrap wood ( I had a 2" rip from a deck board, which was nice given its rounded edge)

The mounted nuts my car came with

It is important to note that while my car did not come with any rack or rails, it did have mounts already installed on the roof. If your car lacks prefabricated mounting brackets, it will be a much more involved task to make your own rack. (But if anyone has please share!)

This is the basic premis of my mounting system:
The PVC has a large hole drilled in the top (big enough that the head of the bolt fits through it) and a small hole (the width of the bolt) in the bottom.
The bolt is then run through the washers to create more space (I started with 2, but then decided 3 worked better. You will need to determine the best number for your project.)
Finally the bolt runs through the wood block and then into the mounting bracket.

A mockup I made to test my mounting system

The first step was to cut all the wood blocks. I measured the area where they would sit and cut them down to size using a skill saw. Again I was fortunate enough to have a nice rounded strip of wood laying around, but really anything cut to size would work.

Second I had to drill holes in the blocks for the bolts. So, after carefully measuring the space between each mounted nut on the frame, I marked the blocks and drilled. Be careful to keep track of which place each block came from and its orientation so as not to end up with holes not lining up later. I then placed them in a box and hit them with a couple of coats of black spray paint.

The next step was to make the side rails. It was important to make these first as the length of the cross-bars would be determined by how these sat.
Each cross bar was 4' (a length I decided on because it would hold two crash pads) with an elbow on each end. I cemented the elbows on and used the pavement to make sure everything was square.

The next, and likely most crucial step, was drilling holes for the bolts. I measured the distance between each mounted nut and then very meticulously marked where to drill. It is important to be as precise as possible at this step; if you get off here the whole project will fail. Make sure that the distances are correct and that the marks are in line with each other. Then drill the holes all the way through with a drill bit that is the size of your bolt (do have a bit of space so that the bolt moves through freely and you don't have to turn it to get it through the hole). I chose to do just two bolts at each bracket even though it was set up for three, this was mostly do to laziness... Besides two was plenty strong! 
When marking and drilling these holes do it from the bottom. Inevitably, when drilling through pipe, the second hole you make on the way out the other side will be off center. If the off center hole is on top that's no problem, but if it is your bottom hole, the spacing could prove disastrous!

Next go in with your bigger drill bit and make the top holes larger.  

If you have a sun/moon roof, make sure not to interfere with its operations
After you have the holes drilled, go ahead and pre-mount the side rails. This will allow you to take accurate measurements for the cross-bars. After you have done that, dismount the side rails, cut the cross bars, and cement them in place. Make sure to keep everything square! 

After framing everything up, I drilled a few holes all along the bottom of the rack to keep water from pooling up inside the pipes. You could try sealing up all the top holes instead, but that would make dismounting later a chore; besides you really never see the little holes anyway. 

Then it was just a matter of two simple coats of the spray paint and a little time for drying. 

Finally, with a little brute force, we were able to thread all the bolts, washers, and blocks and mount the frame! 

So there you have it, a roof rack built for only 40 bucks!


  1. Don't tension down any ratchet straps too much, or you're going to bust your new roof rack pretty quickly. All in all, pretty cool.

  2. Yeah, for what I want it for there really is no need to crank anything down too hard. However, the frame was even more rigid than I would have thought.

  3. What do you usually use the rack for, by the way? I hope you didn’t forget about the weight capacity. All the same, it really looks legit! No one would’ve mistaken it for a DIY. :D -->Arlyne

    1. Thanks for saying so! I just use it too strap down my two crash pads. They both sit in really nicely. It's also handy for getting moderately sized loads of lumber home from the hardware store.

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