How To Build a Ramp
DEAR TIM: I need to build a ramp that will allow me to get my lawn tractor into an outdoor shed of mine that has a wood floor system. I've never done this and wonder how it's done, what tools I'll need and what are some great materials to use. Can you help me get started? I want to make sure the ramp doesn't fail and is not dangerous. Lizzie B., Dayton, OH
DEAR LIZZIE: I've built more than my fair share of ramps, so I believe I can help you. The great news is that this is a pretty easy task. You should be able to accomplish this job in a weekend with little effort.
The first thing you have to do is determine the slope of the ramp. If at all possible, try to keep the slope around 11 or 12 degrees. This translates to about 2 inches of rise for every 12 inches of run. Steep ramps can be dangerous when wet and they can be very problematic for lawn mowers that have low-hanging belly mowers.
If the ramp is too steep where it connects to the flat floor of your shed, you can have the bottom of the belly mower scrape at the pivot point. I've seen mowers get stuck because the rear drive wheels of the garden tractor lift up and loose traction.
You'll probably end up using a measuring tape, circular saw, hammer, drill, framing square, spade, level, and a few miscellaneous tools. Most of these are pretty common or can be borrowed from friends if necessary.
I prefer to use all treated lumber for the outdoor ramps I build. I frequently use 4-inch by 4-inch timbers for the ramp supports and then cover this with treated 3/4-inch-thick plywood. Yes, you can purchase plywood that has the same chemicals as treated framing lumber. It can last for years and years getting wet without rotting.
What's really critical is how you attach the ramp to the shed. You don't want the ramp to crash to the ground one day while you're walking on it or a garden tractor is on the inclined plane.
One way that's worked well for me is to engineer the ramp so the ramp plywood overlaps the framing lumber at the doorway to the shed. I try to make this overlap at least 4 inches if possible. This often means you have to nail additional framing lumber to the inside face of the outer floor joist of the shed. The outer floor joist of the shed and the added framing lumber have to be cut away to have the same slope as the ramp will have.
Taking the time to make this connection allows the plywood for the ramp to help hold the ramp supports close to the shed. For the shed to fall away, the plywood would have to rip away from the actual shed joists. That would be very difficult if you use stainless steel fasteners or galvanized ones that will never rust.
I often attach a simple treated 2x4 to the face of the outer shed floor joist. This acts like a tiny beam to support the ends of the 4x4s that make up the supports for the ramp. I notch the bottoms of the 4x4s so they sit flat on the 2x4 ledge. The top of each of the 4x4s is flush with the beveled floor joist of the shed. This allows the ramp to be smooth and in the same plane.
I space the 4x4s two feet on center. This provides plenty of support for the thick 3/4-inch plywood. Where the 4x4's touch the ground, I usually put an additional 4x4 under them. This 4x4 runs perpendicular to the ends of the ramp 4x4s. It acts as a beam to support the ramp timbers and helps keep the ends all in the same plane.
The 4x4 that supports the ends of the ramp timbers needs to be placed below grade so that the end of the ramp ends up touching the ground. You don't want a big drop-off at the end of the ramp. It needs to transition smoothly to the ground.
Most of the ramps I've built are no more than 8-feet long. If you have to build a longer ramp, you'll probably have to add support under the ramp 4x4s as they'll get a little spongy. You can do this with concrete blocks, rocks or other masonry materials that you place on the ground under each 4x4 ramp timber. You want the ramp to be solid, not like a trampoline.
Be sure to use galvanized or stainless steel fasteners. The ramp will be exposed to the weather and you don't want it to fail because your nails, screws or bolts rusted away.
It's important to keep the ramp free of all dirt, algae, mold and mildew. If a ramp has this on it and becomes wet, it can become very slippery. You can add rubber mats that will provide great traction when wet, but be sure the rubber is clean.
You can watch a video that shows the major components of a shed. Simply click on this "shed ramp video" link.