How to repair overflow relief gully concrete?

[lm4]

Hi all, 

I've recently noticed some damage to the concrete surrounding our overflow relief gully. Is this something that can be repaired DIY or would it need support from a tradesperson? Does this also need to surround and "fix" the plastic grill in place (it currently is jammed in to the drain however not completely secured)

Thanks very much

[EricL]

Hello @lm4 

Thanks for sharing your question about concrete repair of your relief gulley. It appears that this gulley used to have a concrete pipe collar and parts of it have deteriorated. I think its possible to rebuild the collar using concrete. I suggest removing all the broken and loose pieces of concrete before you rebuild the collar. Before you add more concrete to fix the collar in place, I suggest spraying the plastic sides with vegetable oil, this is to ensure that the grill does not bind with cement and allowing you to remove the cover. 

Let me call on our experienced members @Nailbag, @Dave-1 and @AlanM52 for their recommendations.

If you need further assistance, please let us know.

Eric

[AlanM52]

Hi @lm4,

Check this out-

We live in South East 'burbs' of Melbourne and our water mob is Yarra Valley Water.

Google AI reports this:

Yes, you can and should repair an overflow relief gully (ORG) in Victoria, as it's the property owner's responsibility to maintain it for safety and to prevent internal sewer spills; however, due to complex plumbing codes (AS/NZS 3500.2), repairs, replacements, or alterations must be done by a licensed plumber, who will ensure it meets height, access, and installation standards and obtain necessary consents from water authorities like Yarra Valley Water.

Meanwhile back at the job I agree with @EricL's suggestions and..

When I have dobbed on and shaped about 80 percent I then run chook wire around a couple of times and embed in the mortar, then finish off the job. My general thoughts are that at some point in time there is likely to be movement and (if there is) the chook wire will at least keep things in place.

Cheers

[lm4]

Thanks @EricL and @AlanM52 

Is there a guide you would recommend for performing this repair of the concrete pipe collar? So far, as I understand it, I would clear out all the broken pieces/debris, build up a pyramid shape up to the top of the grill (or 3/4 up?), wrap with chicken wire to hold in place and then finish off / shape into more of a curved finish?

I haven't worked with concrete before so keen for a step by step guide if that is available.

Thanks

[Dave-1]

Good Morning @lm4 

Yeah I must admit I get nervous working with concrete Something about it going off and then I have a lump to get rid of

So here is a suggestion. Using Australian Builders 20kg Sand And Cement Mix Bag 

We are going to "play" with the mix to start with. So if you have some old timber sheets, hard/waterproof surface type deal to set the concrete on.

Mix about 2kgs of the mix together, this is to show how east it is to mix and form, Id mix it in a bucket. Keep to the ratios on the side pof the bag for mix + water. When you pour it out onto the hard surface (even black plastic over concrete) then you can use an old paint scraper to mould. Id try making a rectangular block out of the mix, it will show if the mix is to sloppy/wet or to dry by the way it slumps when you pour. If you see water around the base id say you have used too much water, add a bit more concrete mix to it. You want the mix to be firm with very little slump.

Once you are happy with the "block" let it dry, then repeat the process the next day but this time we are forming a ring around the colar. The Chicken wire that @AlanM52 has mention would definently help hold it together but may be fiddly to instal. "Wiggles hand" as to having it in the concrete or not.

The Vegetable oil suggestion from @EricL I like, Ive heard of WD-40 as well to help things not stick.

The practice is meant to give you confidence in mixing the cement and using it. My first concrete was for a letter box install And all my mistakes were under the ground Practice gives us the nerves of concrete for more jobs down the path

Dave

[EricL]

Hello @lm4 

I'm sorry but I don't have a video guide on building concrete collars. I suggest having a look at this guide - How To Mix Concrete. Please note that you are going for the consistency of peanut butter or toothpaste. If you add too much water it will turn into a slurry and you'll have to wait for that water to evaporate while continuously mixing the concrete. My best advice is to take your time, mix it well and do not add too much water. Too much water will result in the concrete not holding its form and it will slump. 

If you need further assistance, please let us know.

Eric