Classic cars forum & vehicle restoration.

[pauldaf44]

Im very lucky in that I have a full standing height inspection pit in my workshop unfortunatly it lies quite low down the lie of the farm and such if we have a lot of rain in ends up full of water. Over the last year it has spent more time under water than being useable.

Now the water in the pit is not flood water as the workshop above the pit is perfectly dry all of the time what we have is the water table rising to above the base of the pit and thus it flooding. Is there anything I can do to prevent this flooding?

As an interim measure I have purchased a bilge pump 3000GPH to attempt to keep it clear when I need to use it but this is treating the symptom rather than the problem. Unfortunatly I need to do something more permanent soon as the concrete that lines the pit is starting to crumble.

Any advive greatly appreciated especially as I would very much like to put lighting into the pit at some point

[geonot]

This is difficult to cure without ripping out the inspection pit, widening the remaining hole and re doing with appropriate membranes etc. to hold the water back- even then the membranes can fail if not installed correctly etc.
There are water proof renders that can be applied, but if there is any thermal or structural movement, small cracks will appear that will allow water ingress over time.
The easiest way is to control the water entering the pit. Dig a small sump at the lowest point of the pit and install small sump pump with a grill over the sump so that you don’t keep “nearly breaking you ankle”- you can even cut small channels in the floor that will allow the water to drain to the sump.

[pauldaf44]

To be honest if the pit ended up a bit narrower it wouldn't be much of an issue at the moment putting a vehicle with a narrow track over is fun. For instance the track on the DAF is only about an inch wider than the pit.

Also apologies for the double post its confusing me a little as I only entered the thread once, but the same has happened a few times when ive posted. Im using a chromebook if that makes any odds to it.

[peter scott]

Hi Paul,

I've seen glass fibre pit liners at Beaulieu. They are standard sizes so you'd probably need to modify your hole to suit but they should resolve the water table issue.

Something like this:
http://mech-mate.co.uk/How-to-Fit-a-Pit.html

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[Roger-hatchy]

Reminds me of a friend who dug a pit in his garage.

A few years ago he moved house, built a double garage dug the hole for the pit, he used a mechanical digger so it was done in a day, all straight and ready for the floor and lining, next day he went out to the garage saw a shovel in the pit so jumped in to retrieve. got a bit of a shock as he was now waist deep in ice cold water.
The water table was half pit level, it was also so still you couldn't see it in the semi dark.
He never finished the pit.
He still gets ribbed about his small swimming pool

[pauldaf44]

[kevin2306]

speak to a contractor who does glass-fibre roofing systems. with the correct primer applied during a dryer spell you can get the pit fully lined. with the correct detailing it is very successful
i would also consider introducing some external land drains to help with the high water table.

kev

[Bitumen Boy]

I wonder if there's something else going on as well as the high water table - the concrete shouldn't be crumbling just because it's a bit wet! Of course, it could just be that the original mix was lean on cement, it's something that many workers try to economise on but it's always a false economy.

[roverdriver]

In Oz we have lots of concrete tanks for both domestic water supply and farm water storage. Our two are well over 50 years old and starting to show signs of deterioration. There are businesses that specialise in re-sealing the tanks, some use various membranes, some treat the concrete in some way, others use fibreglass.

In your case you want to keep the water out as opposed to us wanting to keep the water in, but if there are similar businesses in your neck of the woods, perhaps they can help.
_________________
Dane- roverdriver but not a Viking.

[kevin2306]

[Keith D]

Be very careful with a sealed fibreglass pit. If the water table rises too high in winter, these will literally float out of the ground. I spent a number of years in the water handling business and the risk of sealed pools floating up through high water tables was a nightmare! Even swimming pools of council proportions were usually built with fire hydrants in the floor to release water trying to lift them, until they were filled with water ready for swimming.

I think the suggestion by GEONOT of putting a sump in the bottom and pumping out when you need to use it is the safest and cheapest option.

Keith

[Peter_L]

An old cast iron bath tub and just lay back and tinker while "madam" moves the vehicle into the perfect position. After all guys, how often have we heard about the importance of position ?

[Churchill Johnson]

Many year's we [father and me] had one on a high water table when me old dad was digging it i asked him if he was going to put a membrane in, no he replied my mate down the road said it will be ok,you can guess, it filled to the brim so we had a hand pump to empty it but it took age's then of course it was wet and muddy to get into so it never got used very often.

[pauldaf44]

Well I set about pumping it out yesterday and it seems my 12v 3000GPH bilge pump is not up to the job it flattens the battery at about 1/2 empty to by the time its charged again the pit has refilled.

As I really needed the pit we resorted to the old fashioned bucket. Once empty it seems to take about 12 hours to refill.

[buzzy bee]

Hi

Could you dig a sump at the bottom and put a pump in there with a floating switch, then it will not have all the concrete wet all the time, then see about renderings the sides and sealing them, or building new sides and sealing them?

If you do, maybe make it so the pump doesn't send water straight to the stream or the drain as if you drop a sump of oil in it, or a diesel tank etc, it will cause you issues.

As a side note, always make sure timber bridges are in good condition on pits if you use them, we had a traction engine over one, big rail sleepers for bridges and it was fine, or so we thought, brought the digger in to push the engine and it fell in the pit, through the bridges. Lol

Cheers

Dave