[Closed] Garage pit - anyone 'built' one?

Yes. There is a reason professional garages use lifts and not pits: fumes that are denser than air. You run the risk of either asphyxiation or explosion.

If you can ensure adequate ventilation/air changes then go ahead, but I personally wouldn't risk it.

It'd be easier to raise the wall plates and lift the roof to facilitate your two-post lift.

If it is to be a pit, it'll need to be much deeper than 1 metre to be of any use. Depending upon how tall you and your boys are, will determine how deep you need to go. Including putting down a membrane, insulation and concrete to make it more pleasant.

When you're digging your trench, go wider to allow for your concrete block walls and think carefully as to how you want to light the work area above, you may want to install recessed lights for example. Or even a tool shelf.

You'll also need to dig another hole, the same size to put all your spoil, of which there will be shitloads. 😉

[i]It'd be easier to raise the wall plates and lift the roof to facilitate your two-post lift.[/I]

Hmm, the building itself is about 45 foot long, with +2 foot thick stone/mortar walls. The roof also overhangs either side by about 6 foot. Huge job to raise it, and tbh based on one of our builders we've renovated, it'd be +£20k as it'd pretty much need replacing (100 year old sarking, nail rot etc). I'll do it one day 🙂

[I]If it is to be a pit, it'll need to be much deeper than 1 metre to be of any use[/I]

The reason for only 1 metre is that I've enough height for a car lifted and 4 foot below as it stands.

Ahhh... Genius! As you were.

😀

make it longer and deeper than you need, allow a rebate round long sides at top of floor level to allow 8 x 3 planks to be put in to make flush floor, also steps, tank seal it eg tanking or it will become a pond,reinforce the top faces around the pit and top face to support jacks etc, you wouldnt want the floor to crack and drop into pit with a vehicle on jacks.

It'll need to be strong on the walls of the pt, especially where the lift bears. You do not want it collapsing. I think you'll need some re-bar in the slab and the pit walls.

Don't forget ventilation and drainage

I'd put a sump and a pump system in there plus ducting for extracting air from the bottom of the pit.

Dig base 250 deeper than required finished depth and 800 wider than finished width. 1 layer a393 with 16mm starter bars 200 centres cast in all round, 2nd layer of mesh on top. Cast base at 150 depth with sump pump at one end. Construct outer 100mm wall with 250 cavity ties every 450 vertical and horizontal. Layer of b503 upright in 100mm cavity build internal skin. Leave 150 down from existing floor and shutter to level. Back fill with 10mm gravel. Fill cavity with concrete. Reinstate floor with metal angle on face of shutter to take chequer plate. Screed 100mm on top of original base found with 100mm linear drain to one edge connected to sump pump. Marvel at the quality and cost....

How much of the time would the lift actually want to be used at full height. Most of them seem to be used at waist high by the guys I know with them. All the way up is just for inspection or double parking.

Timber

Good point, as since I posted I've been considering the 'options''.

I worked on a new garage build a few years ago,groundworkers dug a big hole in middle of garage and a pre made pit was lowered into place and concrete poured round it.I cant remember if it was plastic or fiberglass. Cracking job with no risk of water getting into it as it was

Garagejournal is your friend here. Lifts seem v popular and, while it's a US site, not all garages on there are monster barns.

Look for the thread by "Woody" - he did raise his roof, but lots of detail on the lift install.

Wish I had the room....

Did one in my Mums garage whilst she was on holiday many years ago.
She found out when she noticed the 45 degree lawn borders.
By christ did some bloody soil come out of the thing.

2 post lifts are the best option for working on cars.
4 post lifts are ok for servicing work, but you'll struggle to do anything major like remove a gearbox.
And you'd be as well working on the floor than over a pit with a car. Only things you really do with the car fully up in the air, is drain the oil.

A 2 poster that only goes up a few feet will be of far more use over a solid floor, than having a pit that will inevitably just get in the way. And to meet modern regulations, the pit should be long enough that you can exit it at either end when a vehicle is parked over it, however that's for a commercial workshop.
Fumes are a risk with a pit, however as long as there's air movement in the workshop, and you're not doing something stupid like spilling petrol in it, the risk is very minimal. But you really do want it fully lined. Modern pits are nearly always done using prefabricated inserts, as it's the most reliable method. Dig a hole, position insert, pour concrete around it, job done.

This may be a bit drastic and un-workable depending on the type of cars you work on (too many lows) but why not dig the whole floor down and then have a ramp into it so you could use the lift in a normal way?

[img] [/img]

[i]This may be a bit drastic and un-workable depending on the type of cars you work on (too many lows) but why not dig the whole floor down and then have a ramp into it so you could use the lift in a normal way[/I]

Good idea but the driveway is only about 2 yards from the road, and at the same level as the road - I put a French drain in a few years ago to stop water ingress.

The more I read the more I'm coming around to the idea of no pit, and the (almost) 5ft under a car will just have to 'work'.

Love the vid 🙂