Brick tower next to drain inspection chamber

[softninja]

Hi,
I've used the forum loads in the past & found some great DIY info. Now I've got a question I can't find the answer to, so thought I should join up & ask the experts

We'd like to put some decking down in our back garden. There's an inspection chamber slap bang in the middle of the area we want to cover, so we're planning to leave that accessible.

The problem is, there is also a brick construction right next to the manhole. It's 3 courses high with a thick concrete slab on top, and is 2 bricks long by 1.5 bricks wide. There's a large vent on one side. I'm assuming this is to vent the drain.

I've tried to find information online, but can't find any mention of the tower thing.

Does anyone know if it's strictly necessary? (no-one in the family has ever seen one, but we're not drainage experts!) If it has to stay, is there any way we could reduce the height of it & vent it in another way (say, across the top) then deck over it?

Otherwise, I'm going to end up with a beautiful methane-venting brick seat!

Any ideas please?

 

[r896neo]

Do you have a traditional soil stack? If so is your stack vented at the top?
Is your house a bungalow?

Also what is in the chamber? and what is upstream of it?

 

[WabbitPoo]

Post a pic.

Do you have a cess tank?

 

[softninja]

Thanks for replying r896neo. Yes, we have a traditional soil stack which is vented at roof level.

The house is a 1930s 2 storey semi.

It's a combined drain (foul & surface water).

Our neighbour's drain branches into it from upstream. We're the end pair of houses in the street, so i don't think anything else is upstream (but i don't know for sure).

 

[softninja]

Thanks for replying WabbitPoo.

Hopefully you should be able to see photos (if I've done it right!)

No, we don't have a cess tank.

 

[softninja]

Hmm, don't think adding pics has worked! I'll investigate & try again...

 

[softninja]

Trying again...

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[r896neo]

Can you lift the lid of the manhole and take a photo or even just describe whats in there?

I would break the slab off the top just to double check what is in the tower too.