An air gap between the siding and sheathing.
Strapping house siding.
Vertical strapping is added on top of the sheathing.
This allows the back of the siding to dry as fast as the front keeping the wood stable and extending the life of the paint siding and sheathing.
This allows for air movement so any water that gets in behind the cladding can evaporate.
The last step is the exterior siding.
As with most home renovations asking as.
Paint lasts longer when the siding is vented.
If the siding is lap siding and it is taken off strapping may be needed just to allow the new vinyl to properly line up with existing trim on the house.
If you currently lack attic ventilation and have difficulty achieving it then there is good reason to consider strapping but you must choose an appropriate product and you may wish to install vertical strapping followed by horizontal and then actively venting the resulting chamber.
Never had a problem with wavy siding as long as the plane of the straping is true the siding should remain nice and strait the 1 2 bend on the butt should hold its shape as for straping i rip 5 8 or 3 4 whatevers on sale presure treated plywood into 3 inch strips i have found plain staping cups and warps and throws out the wall.
I guess it depends on your climate whether the drying to the exterior through the siding is sufficient.
Kaycan gives you 6 tips to help you prepare your home to be sided with vinyl siding.