The meninges are three layers of connective tissue that surround both the brain and spinal cord to form a complete enclosure (Fig. 6-3) . The outermost of these membranes, the dura mater, is the thickest and toughest of the meninges.he meninges are three layers of connective tissue that surround both the brain and spinal cord to form a complete enclosure (Fig. 6-3) . The outermost of these membranes, the dura mater, is the thickest and toughest of the meninges.
These are generally made of wood, steel, or concrete. While concrete is the most durable, it is also the most expensive and the most difficult to install. Steel ramps are more durable than wooden ramps, though they tend to be heavier, more expensive, and heat up in the sun. Wooden ramps are the most aesthetically pleasing, but need to be weatherproofed and treated in order to last. Depending on the type of wood and other specifications, a permanent wheelchair ramp used to reach a height of 30 inches (30 feet long) can cost between $3,500 and $8,000, or between $100 and $250 per linear foot.
Building the ramp from composite decking, aluminum decking or a synthetic wood material will increase costs and might be more attractive and durable. The materials for a project like this will cost $500-$2,000 depending on what material you use, how long and wide the ramp is, and other factors.Widening Doorways. Widening an exterior door will generally cost more than widening an interior door since siding or brick is harder to work with and more costly.uilding the ramp from composite decking, aluminum decking or a synthetic wood material will increase costs and might be more attractive and durable. The materials for a project like this will cost $500-$2,000 depending on what material you use, how long and wide the ramp is, and other factors.