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I want to jack up my car so I can work under it. Sadly, the only non-inclined surface I have available is covered in grass paving blocks similar to this:

grass paving blocks sample picture

I have a pneumatic jack that I would use to lift the car up on one side, then I'd put these jack stands under it to secure it better: supports

But I'm worried that the jack or the jack stands might slip off the concrete onto the grassy bits, or maybe crack the somewhat thin concrete area, and become unstable.

What would be recommended to put under them to spread their weight over more area and prevent slipping? My best guess would be "thick wood" or "iron plate with a non-smooth surface", if there's an established "best practice" or maybe even a product to buy, I'd love to hear it.

Location is germany, if that matters.

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  • I would not use these jack stands after looking at some of the reviews at amazon. It seems they are bad, they bend and slip. I would not put my life in the hands of them. amazon.com/product-reviews/B0753MMRN7/…
    – Polygorial
    Commented May 2 at 18:32

4 Answers 4

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I typically use a piece of solid wood large enough to completely fit under the jackstand. Here in the States it would most likely be a piece of 2"x8" or 2"x10" board. I don't know what the bottom width of the base of your jackstands are, but I'd have some amount of "stick-out" which would be even all the way around. The general idea is to spread the weight over the area. With what you are showing, the main idea is for the jack stand NOT to dig into the ground. This is a two fold effort of making sure a jackstand will continue to support the vehicle as well as not messing up the paver stones.

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    This. I use a small square of 1/2" plywood underneath each jackstand unless I'm on concrete. Commented Apr 30 at 19:52
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    @DavidWatson - I've even had jackstands sink into asphalt, so agree, unless I'm on concrete, I like something between the stand and the ground. Commented Apr 30 at 19:53
  • Yes, as @Pᴀᴜʟsᴛᴇʀ2 notes, asphalt can be soft, especially in warmer weather. Commented May 2 at 17:53
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Your problem is a dangerous one. I am very strict with jackstand safety because I'm old and have seen too much. Plywood is definitely out. 2X12 are better, but any give in the soil beneath can cause them to split. Steel would be better if it is thick enough to not flex. You also have to remember that you may be turning some stubborn bolts, which gives your foundation (grass or soil) movement. Based on my experience, if you don't have a level concrete surface or at least a solid gravel space backed up by steel plates, you are not equipped to be underneath a vehicle. I said I'm strict, but I once, not too long ago was helping a neighbor inspect something underneath. We stacked 2 pieces of plywood under each stand and jackstand. While he went to get a tool from the garage the vehicle shifted from a loose foundation. The axle fell to just to my chest. I couldn't get out without using part of the vehicle to pull on. The jack and stands were at a dangerous angle.I yelled for my neighbor and told him to lower the jack and if the vehicle fell to quickly jack it up. Fortunately the stands held and he jacked it high enough to get me out. No more shortcuts for me. The biggest injury for me was knowing the fact that I knew better and tried it anyways. I'm still needed by my family making it one dumb decision.

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    I venture that the problem wasn't so much using plywood (though obviously not thin plywood), but having a loose surface. For example on gravel, the base can slip more easily than if you had wiggled the stand into the gravel. Plywood is stronger than timber of the same thickness. Commented Apr 30 at 14:20
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    I'd also vote for steel here: the crumble strength of those filling blocks if subjected to a concentrated load (edge of an axle stand etc.) is unknown. Commented Apr 30 at 16:40
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    @WeatherVane in particular, plywood is far less likely to split if it's pressed down either side of a high spot in the ground. If I was going to make a habit of something like this I'd glue together 2 sheets of 18mm ply (or maybe even 25mm) but also add a frame of (thinner) ply to centre the jack/jackstand nicely on the base. Some bottle and scissor jacks have such a narrow base I'd want this plate to be attached - but they're not designed for that. Some also have a rather small contact area until they press down into the ground by a mm or two; then steel might be good after all
    – Chris H
    Commented May 2 at 8:51
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Once the load is applied to the jack stands and keeping the jack there, supporting the car too, you might be surprised to see that even on grass, it won't go anywhere. Honestly, I would be more concerned with damaging your driveway than having the jack stands fail or sink. So, using a sheet of material would be a great habit. If you have steel more than 1.5mm thick, you will be fine. Regular "restrictions" and safety habits should still be followed: like, don't try to shake the car free when someone is under it... I usually keep the jack engaged to keep the vehicle up, with the stands as safety measures. For a product recommendation, you could switch to ramps... there are a few models which have continuous ground interaction ( not just a formed metal sheet ) that would help to distribute the load of the car across a larger area.

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I use wooden blocks to support cars I'm going under. I suppose I'm building a crib under the car, even if it feels a bit pompous to call it that. They would have no issue on grass paving blocks.

I haven't met a jack stand or ramp I trust. I do trust my blocks.

Three wooden blocks stacked with one supported perpendicularly by the other two, each block approximately 6 inches by 6 inches by 24 inches

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  • Have you ever considered that blocks not fastened together can roll under the right conditions? Seems a lot more dangerous than a properly used jackstand. Commented May 3 at 0:06
  • @Pᴀᴜʟsᴛᴇʀ2 Believe it or not, I have! You don't stand them up like dominoes, lol.
    – MackM
    Commented May 3 at 2:35
  • You do what you like ... your life, not mine. Commented May 3 at 9:36
  • @Pᴀᴜʟsᴛᴇʀ2 Indeed it is :-)
    – MackM
    Commented May 3 at 12:30

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