How to replace driveway drain?

[thomason_peter1]

Hi.I need to replace a grated driveway drain in my driveway. How wide should the cut/ concrete be either side of the new drain (to create the new 'concrete walls')?

Also should there be expansion cuts between the existing drive concrete and the new concrete?

 

[thomason_peter1]

Photo with old drain removed.

[JacobZ]

Hi @thomason_peter1,

A warm welcome to the Bunnings Workshop community and thank you for your question.

Is the plan to install a wider grate than was there before? Or simply to install the same size grate?

Everhard Industries are our main suppliers for drainage grates and their Installation Instructions provide details on installation.

They recommend using 10mm thick expansion foam such as this Sika 10x75mm Abelflex on either side of the drainage grate to allow for expansion and contraction of the concrete. With this being said, the channel should be cut so that it is 20mm wider than the channel you are installing.

With the foam, there is no need for expansion cuts.

Let me know if you have any further questions.

Jacob

[thomason_peter1]

Thanks!. The drain channel i will be using has 25mm sides polly-crete with gal. Grate (not the thin black poly/plastic) - and I am looking at 75mm or 100mm wider cut/concrete on each side of supplied drain channel to drop in and fill -so seems either will do/plenty?

Also what strength concrete is required for  e.g high strength or regular?

Thanks

[JacobZ]

Hi @thomason_peter1,

Unless the concrete on either side of the grate is compromised, you don't really need to widen the trench by so much. I'd suggest checking whether the manufacturer of your specific grate has an installation guide with details of their specific product. They will have an advised method of installation that should be followed to ensure compliance with the terms of their warranty.

As driveways will have vehicles driving over them, you'll want to use high MPa concrete. The MPa (megapascals) rating tells you the compressive strength of the concrete and when the concrete needs to support heavy loads, such as vehicles, having higher compressive strength is certainly worthwhile. This Dingo Hi Strength Concrete is a good option.

Let me know if you have any further questions.

Jacob

[thomason_peter1]

Thanks Jacob. I have decided to allow (cut/widen) 100mm from channel  edge to existing concrete on  each side to allow space for pushing concrete into the channel  side 'keys' (plenty according to manufacturer).

This then wiil give a straightline joint line between new concrete and old concrete. What is the best way to finish the new/old joint to keep it tidy/neat? E.g. 

1: leave the joints meeting (old side neat cut  to new side as it fills) or 2: leave old side neat cut and round-edge new side and fill-in (or not) joint later with chaulk fillwr ? or 3: Option1.with foam filler strip in join when laying the new concrete side?

[EricL]

Hello @thomason_peter1 

I'm putting my vote on option 3 with the foam filler strip in the join when laying the new concrete side. The foam filler strip will act as a shock absorber should any shifting occur in the concrete.

Let me call on our experienced members @Dave-1 and @Nailbag and see which option they'll vote for. 

If you need further assistance, please let us know.

Eric

[Dave-1]

Evening @thomason_peter1 

Sounds like you have done your research I do like the way you have decided and also the option 3 @EricL has spoken about. 

One question as it may save you money. Why do two cuts to expand the holes width when you could leave one side as is and cut the other slab the proper width? That way you could get away with one cut? Tho if the old drain slot lines up with a pipe that may need to be factored in.

Dave

[Nailbag · Accepted solution]

Hi @thomason_peter1 

Both @EricL and @JacobZ have already provided excellent advice on the installation. My only addition is to ensure that the drainage channels are under no pressure during the concrete pour and to ensure the channels grates are installed. This is to avoid any possible deformation of the channels causing the grates to pop or not seat properly. This is a common issue with poly drainage products over other materials. I have one Everhard system and one that isn't. The Everhard grate never sits flush once removed to clean the channel at one end. the other one has no issues. Still go with the Everhard just take those points into consideration.

Nailbag

[thomason_peter1]

R

Thanks @Nailbag , @EricL  @JacobZ and @Dave-1 thanks for the great advice! 

Foam it is!

Great idea on side cuts - i may be able to reduce a cut in one of the 2 drain lines as other links to existing connected  drain and may be easier to widen sides for removing existing trebch bottom concrete. (Vs a minimun cost to get cutters in?) I will have a look.!!

Thanks again all!! Off to Bunnings to help prepare. Wish me luck!