Plan your ramp location. Measure the height from the entry door’s sill to the ground in inches. The height in inches will equal the required sloped ramp length in feet. A 16-inch height requires a 16-foot ramp. The entry door needs a level landing 5 feet on a side and ½ inch below the door sill. Ramps must be at least 3 feet wide, with a handrail top 34 inches above deck level.
Cut posts to the lengths required to support each corner of the landing plus 34 inches above the deck level for the handrail. Set each post on top of a 12-by-12-inch square of plywood. Cut joists to 5 foot lengths to frame the landing’s edge.
Fasten the landing’s two outside joists to the posts with lag screws and the two cross joists to the outside joists with metal corner brackets and 1 1/2-inch screws. Using joist hangers, install two more support joists perpendicular to the landing’s deck boards, which run parallel with the ramp’s deck boards.
Cut three joists to the length required for the ramp. Angle-cut the tops to fit snugly to the landing frame. Either bury the bottoms in the ground or cut them at an angle so the deck will touch the ground. Install a pair of posts every 5 feet along the ramp. Cut posts to the heights required to support the ramp plus the railing, and set each post on a plywood square. Cut a piece of joist equal to the width of the ramp plus the width of the posts. Fasten this cross member to the upslope side of the posts with lag screws, at a height that allows the ramp joists to rest on the cross member.
Fasten the joists to the landing with joist hangers. Rest the other end of the ramp joists on a post cross member. Fasten the outer joists to the posts with lag screws. If you are joining multiple joist lengths at posts to make up the ramp, set the joint’s cross member upslope on the posts at the same height as the joists. Use joist hangers to secure the upslope joists. Use lag screws to secure the outer downslope joists to the posts and a joist hanger to secure the middle downslope joist.
Cut the deck boards to span the landing and ramp. Set the deck boards on top of the framing joists and use the 2 1/2-inch screws to fasten them. Use 2 1/2-inch screws to fasten other joists vertically to the inside top of the posts for the railing. Cut the 1 1/4-by-1 1/4-inch furring strips into 42-inch lengths. Fasten them to the outside of the joists and railing with 2 1/2-inch screws, leaving 2 inches between the railing top and strip top and a 2-inch drip leg at the bottom. Space the furring strips 4 inches apart.