problem manhole cover

[Leadhillite]

I have a selfish eejit for a neighbour.......

I have a brick built rodding chamber behind my house. At the moment, it is covered by a precast concrete slab and its worked fine for the past 50 years or so. Problem is that my eejit neighbour has done works to a plot of ground he owns, (and other ground that he doesn't), creating surface waterflows which now end up in my ground.

The drains have worked perfectly up until now, BUT the concrete slab does not fit perfectly level in top of the brick built chamber, (so if you stand on it you can make the slab wobble a bit by moving your weight around on it). Now when it rains, the surface water is coming down and slowly washing soil and small stones into the slight cracks between the concrete slab and the top of the brick walls of the chamber. These stones and soil end up falling into the drain through the rodding point and my drains get blocked!

The cover is not a standard size, so I cant simply replace it with a shop bought metal one with a rubber seal around it, as the 450x600 standard is way bigger than the dimensions of the chamber.

Does anybody have any advice about what I can do to deal with this?

Is there any product out there that I could use to seal the gap, but still allow me to lift the slab in the future if need be?

I was wondering about some kind of rubber foam that I could fix to the tops of the brick walls, but maybe I'm making a mountain out of a molehill and there is a much easier and more sensible solution out there.

If anybody has any advice it would be very much appreciated.

Thanks.

 

[merlin50]

manhole grease

 

[HERTS P&D]

Large tub of Vasiline from costco.

Andy

 

[noseall]

Buy a 600mm x 450mm precast manhole section and relevant cover & frame.

Drop the precast section over the smaller existing manhole, fill in the void with concrete then bed the new lid and frame to the outer section.

 

[r896neo]

Surely Just bed the slab on mortar its not that big a deal to replace and how often are you going to need to rod?

 

[Leadhillite]

Thanks for all the advice.....I feared I was making a mountain out of a mole hill and so I was!

Re bedding the slab on mortar - I've rodded the drain 4 times now, and from the glugging noise coming back up through the bathroom sink I might need to do it again. This is the first time however that its been ME thats rodded the drain AND the WC hadn't been used for weeks, so the problem wasn't clouded with poo and I could see exactly what had caused it. (From a distance dirt may well be the same colour as crap but up close it disny smell the same!). I'd be terrified to bed the slab on permanently in case I need back in there.

I'll have a think about noseall's idea, as that seems the most correct solution - only problem is I have a wall butting up to the edge of the chambre, so I'll have a think around that. I like how easy the vaseline/grease idea is tho.

Thanks again!

 

[r896neo]

The best thing to do might be to bed the slab on mortar so that it's well supported then after the mortar dries a little (after a few hours) lift the slab off. This will then give you a nice flat solid base to put your thin bed of grease or silicone on rather than having to slather tub fulls of grease all over an uneven surface.

 

[Leadhillite]

The best thing to do might be to bed the slab on mortar so that it's well supported then after the mortar dries a little (after a few hours) lift the slab off. This will then give you a nice flat solid base to put your thin bed of grease or silicone on rather than having to slather tub fulls of grease all over an uneven surface.

That sounds a great idea! However, the slab is about 4" thick and its bloody heavy. The only way anyone has been able to shift it, was by levering it up onto an edge, and then "walking" it away or flipping it over. I really like the above idea, as that sounds like the kind of remedial work that should have been done immediately the chamber was built. Any advice how I could lift and lay the slab vertically so that I don't damage the semi-set mortar when lifting the slab? I suppose I could build a temporary timber cover that would do the same job, yet wrap it in cling film, then when the mortar has set hard, remove the timber frame, apply grease, and reinstate concrete slab. (Mountains out of mole hills again?!?)

Cheers.

 

[r896neo]

A decent 3:1 mortar should take a bit of abuse fine, although to save your back i'd be inclined to replace it with a small 35mm thick type pressed slab. they come in 450x450 you could pick one up in a diy shed pretty easy i'd think

 

[noseall]

If this chamber lid needs to be as portable as you are saying, then not having a lightweight cover with handles would be very tiresome.

A 4" thick greased slab is not at all portable and you will get covered in grease whilst wrestling a slippery dead weight!

Bite the bullet and do it properly and relatively cheap too.

 

[Leadhillite]

I think you're right noseall. Whatever I do, if I keep the concrete slab, I would have to use grease, as the slab is downhill of where the surface water comes, so without the grease there will always be a trickle of muddy water working into the chamber and blocking the drain. Because the slab is so difficult to move, everytime it has been lifted there have always been more stones fall into the chamber as well. Never thought how difficult it would be to lift the slab with it smothered with grease!!

Its in a really tight space as well and its right alongside a public path with no boundary between my ground and the path, so I would be nervous of putting a thinner slab over it for fear of an accident or vandalism.

Thanks for coming back and not letting me take the easy(er) option, as with a standard steel cover it will be a lot easier in the future.....and with the grease applied to the seal there should not be any problems at all!

Thanks again.