I built a wooden block when when we got our first travel trailer to provide enough lift to unhitch without any problems. My first 2 travel trailers, the tongue jack was just too short to lift high enough to unhitch. And if hitching, was not high enough to get the ball under the coupler.
I built a "temporary" block. It was just a trail-and-error experiment out of scrap treated lumber: 2 - 2x8's criss-cross 2 more 2x8's and then put single 2x8's on top of that, two layers deep, for a total of 4 layers.
A little heavy, so I drilled a some holes and attached a couple kitchen cabinet handles to each end (There again, it was scrap stuff I had around the house).
Well, here we are more than 11 years later and I'm still using the same block. I've considered building a new one. I've considered purchasing something else, but I've not found anything any better and since this pile of lumber works so well, .... well???.... why make another one?
If I need even more height, I can simply add a another board on top (If parked on a bad hill. And if parked on a hill flowing the other way, a single board works just fine.
Cinder or concrete blocks are not recommended, however, I have used cinder blocks before and never had a problem. But the wood is still best. It's solid, firm, and has no "give".
You may find something made of plastic, but you've got to consider all the weight being supported on that single post, and all that weight is focused to a single point of contact under it. YOU WANT something solid. I would never trust "anything" plastic under the tongue jack.
I also use wood under my stabilizer jacks too. People sing praises about Lynx block. I have a set. Wood is better.
If you are using wood, stick with it. If you have to, take several pieces and just stack them on top of each other. That way, you are not having to handle any one single heavy item. That's still more support than anything plastic can support.
I had to do some back-searching through my Photobucket images, but finally found a good picture of my "temporary" block that's lasted over 11 years now! This is our Springdale camper, not our current one.
