I am just about to put a concrete floor onto an old barn (actually a hangar - no doors), and I thought I would have a go at making an inspection pit.

Question is - what is the best width? A secondary question would be the depth, but that will depend on what I find when I start digging - if it is rock I may end up with a shallow pit that I have to crawl into - but that's still better than nothing.

At a previous workshop I had a home-made pit that was just a little too wide: it could take ages getting a 2CV so both wheels were on either side. Is it a good idea to make the pit narrow enough so it is possible to jack the wheels off the ground from the inside? I mean while the pit is open. That wasn't possible with my previous one. But it needs to be wide enough to work in!

Suggestions would be welcome, thanks

Here's a plastic one.

http://www.mech-mate.co.uk/How-to-Fit-a-Pit.html

Thanks Knightly - that's a help in one way at least - it suggests using 60mm thick boards, and I'll make the rebate at the top about that size.

But the width? Not a word there, and I have no intention at all of buying a fibreglass one (even supposing it was available in France). It'll all be cast in place.

I am sure someone here can say what size their pit is, and whether it ought to have been wider or narrower.

be careful shoring the sides the weight of the concrete is pretty immense even at just a few feet, if you make it narrow enough so you can get a jack under the axle bolts that leaves it pretty narrow for spannering plus there isn't really that much needing attention under the center of the 2cv unlike say a prop shaft classic

how about a lift? some of the hi lift pallet forks come up cheap
http://www.ebay.co.uk/itm/MANUAL-HIGH-LIFT-PALLET-TRUCK-SWEDISH-QUALITY-FORKLIFT-STACKER-/121368786401?pt=UK_Lifting_Moving_Equipment&hash=item1c4224b5e1
thats how id go if i still had the workshop with its flat floor- just make sure you get a polish on the slab

Cheap fork lift truck?

If its just a 2cv going over it then why not mark out with spray paint or chalk on the ground and drive over it to see what easiest to drive over and be practical to work in?

Are you doing it to stand up in? I find working above my head hard work if I'm standing up straight. If you just want a better way to raise a car than a jack then what about a couple of brick built ramps about 12" high so laying under it is easier quicker and safer?

There was a pit in my garage when I bought the place. First thing I did was fill it in.

I am looking for a cheap lift now and thing I found one in Germany.

Trouble is with pits is that you have to get in it and if the car is parked over the top then you're buggered - unless it is a long pit.

Plus it was just too dangerous have a big hole in the floor with planks of wood over the top.

Thanks for all the suggestions. I'm afraid money rules out anything mechanical.

The previous workshop - with the slightly too wide pit - was covered with planks of oak, a little more than 2 inches thick, and despite driving over it frequently over a period of twenty years with cars that are heavier than a 2CV not one of them ever even cracked. Mind you they weren't particularly wide - the biggest was about four inches, so you had to take out twenty or thirty of them when working in the pit.

I had considered the idea of brick ramps, but if properly cemented together they get in the way of moving things around when not in use as a ramp, and I like the idea of an otherwise flat space.

Sean - I wasn't thinking of jacking under the axle bolts on the chassis members. I can see that would dictate a narrow pit. Instead I had in mind jacking on the suspension arms to lift the wheels a fraction to make greasing the kingpins easier.

I've been considering a depth of about 1.25m (4 foot), and about 5m long (the hangar is 9.5m from front to back). There's a second reason for digging out - the hangar slopes down to the back wall, and bringing the ground level up with concrete is an expensive way of making it flat. The spoil I dig out will help reduce the amount of concrete I need.

That sounds like a plan - 5m is a nice long pit allowing access.

I did the opposite, all my building rubble ended up in my pit before cementing over

If you have the mean of digging out and concreting then that is the way to go. I want to go the lifting route as I want to get all my cars in the garage in the winter so going up may get me one more space.

Found this for dimensions - http://www.chatteris.biz/inspection_pit_build.html

Thanks, Ian.

After your previous comment I feel impelled to quote from the Preacher .... "He that diggeth a pit shall fall into it; and whoso breaketh an hedge, a serpent shall bite him."

The link you gave does look rather like the luxury version, and rather deep, too - much too deep for me. I expect mine will be a bit more basic, though it's a useful reminder to put in a conduit for electricity. Luckily I don't need to worry about the water table where my hangar is. The bottom of the pit will be about level with the ground on the downhill side of the hangar.

I'm still unsure about the best width. Could anyone measure a pit in a "real" garage for me?

I helped my Dad dig a vehicle pit at his place about 20 years ago. I'll take some pics and measurements at the weekend.

We learned quite a bit from our build (many of which were from mistakes that we resolved never to repeat).
1. if you're going to build ladder-rung thingies into it, put them at the far end, not the near. Sounds obvious, but we never thought of it at the time.
2. Use a water pipe (downpipe kinda stuff) so you can feed electrical wire into it to supply light to the pit. You can bury the pipe under the garage floor from a socket. Cheaper than faffing around with armoured cable, and easy to thread cable through. Keep the electrical supply as simple as possible. Sorting out wires that you've buried into the ground, then covered over with concrete etc is a pain.
3. Use 90-degree angle iron to house the oak planks that you use to cover the pit.
4. Make the pit as long as you can. Ours was a bit too short.
Hope that helps.

I'll see if I can get to take some pics etc this weekend.