The method you use to secure the lumber will depend on what kind of roof rack you have.
Transporting plywood on roof rack.
On a roof rack step 1.
4 web ratchet straps in a pair of x formations to hold down the board to the cross bars.
A pair of 20 web ratchets used as a fail safe in case the board slides to the rear of the vehicle.
Ask for help from friends if.
Out of the choices of cheep quick and good you usually only get to pick two.
Place two 8 foot long 2 4 pieces of dimensional lumber on the roof rack lengthwise.
Tighten each ratchet strap to secure the plywood.
Hauled a lot of plywood that way even put longer 2x4 s on once and carried a 10 foot wide garage door.
I transport 4x8 plywood on my roof racks i usually run a couple of 2x4s under the roof racks the full length of the ply and strap to those at the front and back as well as strapping to the actual roof racks.
Secure the 2 4 s to the roof rack by tying it to the front and rear crossbeams.
Drive to your destination slowly and carefully.
In case you have no idea how much weight your plywood sheet is a sheet of inch plywood is approximately 100.
Secure it to the roof rack.
Remember to place a distance of about 3 to 3 foot in between.
Run the remaining three ratchet straps from one side of the roof rack to the other over the plywood sheets.
My car with 4 x8 mdf board on the roof rack.
Oh and remember to.
As an alternative to tying you could attach these with duct tape.
Makes it a lot harder for the winds to lift it up.
Drywall and plywood cartop carrier roof rack.
Second trip 16 2 x4 x6 boards on my roof rack.
This project satisfies all three goals of most of my projects.
Be sure to use straps that are at least 10 cm 4 inches wide to improve cargo stability and decrease the odds of breakage.
I would lay sheets of plywood on these bars and then use a c clamp at the end of each 2x4 to clamp the plywood to the 2x4 s.
Rusticdavid woodworklessons woodworkingforbeginners david shows how to tie wood boards and sheets of plywood safely and securely to your cars roof rack dav.
My car with roof rack with cross bars installed.
There should be a 3 to 3 foot span between the 2 x 4 s.
Use ratchet straps that can handle the weight of your load and check that the roof rack is secure enough to provide a proper anchor.