Cover Inspection Pit - RSJ/Box Section and Road Plate?

[Mr David Cameron]

Hi all - first post with something of an idea. I don't know if it's an AMAZING idea, but if you're passing with an opinion talk me into/out of it? Any comment welcome!

So, bought a house with my dream garage in it. It was INCREDIBLY well built (to my eye anyways) and has water, electric, even a toilet (yes really) BUT there is a problem, in that it has an inspection pit.

I thought to myself first thing I'll do is fill it in with hardcore, 150mm layer concrete over it, problem gone BUT then I kept on thinking and thinking... That is valuable storage space after all.

Cars in the garage will be on dollies, and are BOUND to get caught on any lips in anything as they get shoved around, so I figured on:

- Tank it: I'm thinking pond sealer or paintable DPM. Couple of layers. It is bone dry as it stands but rather pre-empt.

- Hefty box section (maybe RSJ even) in each corner, and box section every 1/2m along the edges not quite the full height.

- Weld them up to feet before they go down, winch them down, drill and bolt them to the brickwork.

- Weld box section across the top to within 16mm of full height.

- Finish the "lip" with some aluminium angle to square the top. Get it flush with the concrete floor at the top to frame the...

- ...steel road plate. One to go over the top (bolt that on into tapped holes just to stop it moving but can ultimately be removed if it HAS to be) and one removable section over the stairs.

- Paint the lot (red oxide primer?) and then store stuff down there so it can grow fungus nicely (I'll have to ponder ventilation...)

That way, the bigger road plate sits across a hefty framework of steel, as does the more removable access bit, and if it's framed to size hopefully not too much lip to catch the dollies. Hopefully. The "permanent" plate I can always seal around the edges with silicone even, and aluminium angle to frame it should last well enough.

Any ideas on it? Thanks all.

 

[Tigercubrider]

Nota car pit but...
A place I worked in had an orchestra pit that was only around 3 feet deep. It was enough to drop the musicians below the level of the audience who were seated on terraced areas.
The floor was spring like a school hall/gym

What was done was a metal rim possibly made of angle iron as support along the perimeter, about 50 mm below the floor.
Then about 150mm below the surface were box section uprights every metre of so. They were built so that more bits of metal running horizontally could bridge the shorter dimension of the pit, and give support for the pit lid, made of sections of timber.
One end of the pit had a recessed handle or hole so you removed one section, then another, so on, then lifted out the support bars.

Obviously cars were't on it but loads of people stood/danced/sat on it. Because it was flush with the floor, it didn't move out of it's rebate.

Road plates made of steel are really heavy. Look at fibreglass ones?
Heavy duty aluminium would do? the height being equal is the key
I wouldn't fill in a pit unless it floods.

 

[Mr David Cameron]

Nota car pit but...
A place I worked in had an orchestra pit that was only around 3 feet deep. It was enough to drop the musicians below the level of the audience who were seated on terraced areas.
The floor was spring like a school hall/gym

What was done was a metal rim possibly made of angle iron as support along the perimeter, about 50 mm below the floor.
Then about 150mm below the surface were box section uprights every metre of so. They were built so that more bits of metal running horizontally could bridge the shorter dimension of the pit, and give support for the pit lid, made of sections of timber.
One end of the pit had a recessed handle or hole so you removed one section, then another, so on, then lifted out the support bars.

Obviously cars were't on it but loads of people stood/danced/sat on it. Because it was flush with the floor, it didn't move out of it's rebate.

Road plates made of steel are really heavy. Look at fibreglass ones?
Heavy duty aluminium would do? the height being equal is the key
I wouldn't fill in a pit unless it floods.

Yes yes - from the sounds of that you're picking up what I'm putting down.

Was a bodybuilder in my younger days... I keep on forgetting 100kg of steel is probably a consideration to shift where it wasn't in years before. Meh, it's pretty much fixed but aluminium for the removable part for access could well be the way.

Thanks for that.