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How to permanently block a floor drain?

I need to permanently block off this laundry floor drain, which last week filled my house with storm water.
My plumber suggested inserting a dmv in pipe plug into the 50mm drain. However the metal grate opening is approx 42mm diameter and the dmv plug is rigid, so it wont fit.

I am thinking of gluing a rubber plug to the metal grate. What solution would you use?

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MitchellMc

Hi @PeterE,

It's important to note that permanently blocking a floor drain can lead to several potential issues. If this area is classed as a wet area under building codes, the drain may be required to remain functional as part of compliance. Blocking it could also create a risk of flooding in the event of a burst pipe or overflow, and might cause insurance complications if future water damage occurs.

Another concern is that floor drains should be connected to the sewer system, not stormwater. Stormwater pipes are only meant to carry rainwater from roofs and outdoor areas. If stormwater has been backing up through this drain, it suggests a plumbing connection issue that needs professional correction rather than a DIY blockage.

I’d recommend discussing the situation further with your licensed plumber, explaining what happened and asking how the underlying pipework could be corrected or rerouted to prevent another flood. Attempting to block the drain yourself, especially by gluing or sealing it, could lead to serious water damage or compliance problems down the track.

Please let me know if you have any questions.

Mitchell

PeterE

thanks Mitchell

my plumber came to the property and inspected the drains

his advice was to permanently plug the laundry drain and said that doing so in a laundry does not compromise regulations

so if you have any plug suggestions, please let me know

MitchellMc

That's great to hear you've verified that with the plumber @PeterE. Just didn't want you to get into a sticky situation.

I'm sorry, but I'm not aware of any plugs that can fit through a 40mm opening and then expand to block a 50mm pipe. Does the plumber have access to the pipe under the house or outside it? They could cut the pipe and disconnect it, and then cap off the stormwater line.

The only other option I can think of would be to cut out the grout to release the drain cover surround and lever it out. Block the pipe and then reinstall it.

Let me tag @Dave-1 and @Noyade to see if they have any thoughts.

Mitchell

PeterE

thanks again,

yes the plumber assured me I can do this without compromising regulations

at present I am considering inserting an appropriately sized plug and gluing it; either into the metal grate, or if the plug is flexible into the pvc pipe

https://www.bunnings.com.au/boston-50mm-white-large-ultra-grip-plug_p0027943
https://www.bunnings.com.au/gorilla-59ml-glue-bottle_p1662678

MitchellMc

What amount of stormwater came up through the grate, @PeterE? Stormwater can have a tremendous flow and pressure, especially if other routes out of the property are blocked or have limited flow. Your idea of gluing in a plug could work, but I have concerns that if it fails, you could end up with a flooded home.

I would suggest you have the plumber disconnect and cap off the plumbing work, as that would be the only real solution I'd be comfortable with.

Mitchell

Dave-1

Good afternoon @PeterE

I like the idea of the plug you mentioned, but not really keen on the gorilla glue lol Mainly because if you ever have to open it back up again the gorilla glue will be a pain and a half. How about silastic instead?

I do have some concerns that stormwtar is connected to the drain, I dont have a drain in my laundry and I had the same question to the plumber years ago. Back when the laundry wa sbuilt there was no rule, now the rules have changed so Iam in the "inbetween" time.

Dave

PeterE

a huge amount of water came into the house, so any plug would need to be fail proof and ideally removable if required

disconnecting the pipe is our last option because the pipe sits under a slab and pavers

PeterE

thanks for the reply Dave,

the house was built in 1995, so perhaps the rules were different back then

as for the glue, I need something strong enough to hold the plug under water pressure but not so strong that I cant remove it if required ..... will need to research silastic adhesives

Jason

Do you still use the laundry @PeterE?

Obviously the point of having a drain in a laundry is so that if you have an internal plumbing issue, water can escape and won't damage the property. I have previously experienced the ramifications of a burst pipe in an apartment in which the drainage was insufficient, and the property damage was very significant and expensive.

I would be inclined to get a second opinion from another plumber about how to rectify this issue.

Jason

Noyade

G'day @PeterE

"What solution would you use?"

For me - I would definitely want to be able to screw and unscrew some form of waterproof lid involving a homemade washer or O-ring.

You mentioned a 42 mm diameter hole?

I tried to draw it out to scale - and an R31 was best fit O-ring wise which has a cross sectional diameter of 3.55mm

Or a custom washer from thin rubber.

The lid would be stainless steel or aluminium cut to fit.

The tricky bit will be the threaded holes for the counter sunk M6 bolts.

It would involve a M6 tap, 5.5mm cobalt drill and possibly a 5mm masonry drill.

Screwing the plate down will create the watertight seal and that molded lip on each corner will prevent 'crushing' the O-ring or washer.

All theory of course. 😁

Let me know what you think.

Cheers.

Noyade

Having said all that - I wish my old house actually had floor drains in the laundry and bathrooms. So I'm not sure why you're having these problems @PeterE ?

PeterE

Thank you Noyade for your indepth reply.

Yes, being able to open and close the drain lid would be ideal. I will give some thought as to how I can manufacture the lid. As for the threaded holes, perhaps I could do without those if I can find a suitable masonry screw; although lid depth is only around 3mm.

PeterE

due to an enormous amount of rain in a short period the storm water entered via the laundry drain and flooded my house

it is the first time after living here for 10 years despite numerous Brisbane storms ...... so we now know the laundry drain is connected to the storm water

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