Halfpipe Ramp Surface Options - Skatelite Masonite SkaterBlend 

Hopefully your budget will allow for a higher grade surface than masonite. Most ramps built use masonite because it's easy to get and cheap. But get ready to replace it once it gets a good soaking.
Masonite - Cheap and easy to get but does not hold up outside.
Renewresources SkaterBlend www.renewresour...
Ramp Armor www.ramparmor.com/
Skatelite skatelite.com/w...