concrete/sewer lid advice.

[wiley coyote]

My sewer lid has cracked and I need to fix it before I, or someone else, has a cold, smelly swim. But I can't work out how many bags of cement I need to make a new one. It's 1800 long, 1300 wide, and, 75 thick. Does any one know how to calculate the correct amount of cement for this? 0ne Bunnings store said 8 bags. Another said 20 bags. So they're no help either. Any advice appreciated. wiley.

 

[Hippyty79]

If it rectangular 0.175m3

 

[Mackka]

21 bags of 20kg concrete mix.

 

[woomera]

My sewer lid has cracked and I need to fix it before I, or someone else, has a cold, smelly swim. But I can't work out how many bags of cement I need to make a new one. It's 1800 long, 1300 wide, and, 75 thick. Does any one know how to calculate the correct amount of cement for this? 0ne Bunnings store said 8 bags. Another said 20 bags. So they're no help either. Any advice appreciated. wiley.

https://www.theconcretecalculator.com.au

 

[wiley coyote]

Many thanks Guys

 

[Hippyty79]

If your close to a batch plant, I’d get a quote for 0.2m3, particularly if the company takes orders direct, here in Wa they use to charge m3 ordered plus a pro rate rate upto 3.4m3, if it’s trafficable I’d go 100mm thick with sl 82 mesh

 

[critters]

A sewer pit lid, or a gatic lid is usually made of steel with concrete infill. At the very least it should be reinforced with reo/rebar. A storm water pit lid is usually made of reinforced concrete. In regards to the calculation for concrete mix, there are concrete calculators on the internet. You also need to take into account the MPa, or strength of the concrete mix, especially if there is likely to be vehicle traffic going over it. Would highly recommend having a plumber take a look.

 

[HarryHoudini]

My sewer lid has cracked and I need to fix it before I, or someone else, has a cold, smelly swim. But I can't work out how many bags of cement I need to make a new one. It's 1800 long, 1300 wide, and, 75 thick. Does any one know how to calculate the correct amount of cement for this? 0ne Bunnings store said 8 bags. Another said 20 bags. So they're no help either. Any advice appreciated. wiley.

Thats a pretty big lid buy 20 bags and take the ones left back. Nothing worse than running out part way through job. Don't forget the reinforcement. But also remember it’s going to be very heavy so get help to lift back. cheers HH

 

[Unitedphil]

Thats a pretty big lid buy 20 bags and take the ones left back. Nothing worse than running out part way through job. Don't forget the reinforcement. But also remember it’s going to be very heavy so get help to lift back. cheers HH

It will weigh about half a ton so you may need a little help lifting it.

 

[axtyr]

That is a huge cover. What is it covering? Is it over a pit or a septic tank?

Here in Victoria it should have been a Gatic cover, a steel cover inside a steel frame with concrete in-fill, and it should have multiple sections so you're not lifting a half ton of concrete.
A single cover that size doesn't make sense because of the weight. You would need a crane to life it. The sewerage authority might have to come around to replace it.

If you have to repair it yourself then I would be looking at covering the hole and then just concreting over the top. That will leave you with a concrete slab sticking above ground which you may not want and it could be in an inconvenient spot.

If you go that way, you should get some 50mm angle iron and dynabolt it across the cover as reinforcement, then concrete over the entire lid. Good luck lifting it after that.

Unfortunately you have a quandary.

Regards Axtyr.

 

[Unitedphil]

That is a huge cover. What is it covering? Is it over a pit or a septic tank?

Here in Victoria it should have been a Gatic cover, a steel cover inside a steel frame with concrete in-fill, and it should have multiple sections so you're not lifting a half ton of concrete.
A single cover that size doesn't make sense because of the weight. You would need a crane to life it. The sewerage authority might have to come around to replace it.

If you have to repair it yourself then I would be looking at covering the hole and then just concreting over the top. That will leave you with a concrete slab sticking above ground which you may not want and it could be in an inconvenient spot.

If you go that way, you should get some 50mm angle iron and dynabolt it across the cover as reinforcement, then concrete over the entire lid. Good luck lifting it after that.

Unfortunately you have a quandary.

Regards Axtyr.

Thinking about this more, you are only responsible for it if it is your feed to the main sewer which should not have such a bit manhole. If it's not yours it will be an easement and belong to the sewer authority. Do a before you dig australia search. This will tell you who owns it. And if the sewer authority call them. They will fix it. Good luck.

 

[wiley coyote]

It's a septic tank lid. The shire inspected all the towns septic tanks and the drainage lines from them about 8 years ago. Mine passed the inspection.

 

[Unitedphil]

It's a septic tank lid. The shire inspected all the towns septic tanks and the drainage lines from them about 8 years ago. Mine passed the inspection.

Ahh ok missed that.

 

[axtyr]

G'day Wiley, although I've never installed a septic tank I have seen a few. I suppose there are different regulations for different States. The ones I have seen have a cover over the sections of the baffles inside. You couldn't expect anyone to lift a cover of that size. Maybe yours was built in the ground as opposed to a drop in one. If they have placed a cover of that size over the top then there should at least be smaller access panels within that larger cover you can lift to see inside.

If the cover only has a crack in it and not a hole then the danger isn't that bad because the cover SHOULD have reinforcing in it. Unless whoever made the cover did a dodgy.
If it has a hole then you probably have concrete bits inside the septic already but don't worry, it doesn't float, unless it is lightweight concrete, LOL.

Either way I think your cheapest solution is with angle iron running the length or width of the cover and dynabolting it to the concrete then concreting up to the level of the iron.
You will get extra reinforcing on the cover. Just build up the ground to the new concrete level around the cover.

Regards Axtyr.