How to set in trench drains before concrete.

[zio]

Hey guys. I want to install trench drains in my garage. My concrete guy said he has never done it and the guy that used to do it for him is retired. I can't find anyone else that has any experience. My biggest concern in doing it myself is I do not know how to set the correct height. After the concrete is framed I am not sure how to install the trench drains so they are not too high or too low. Any help would be great.

Thanks
Tom

 

[machsnell]

It is difficult to do if you are doing a monolithic pour. The drains have a tendency to want to rise as the concrete on the sides pushes down and tries to push the drains up.

What kind of drain? Sloped or flat?

For elevation if you don't have a laser you need to string from known elevation and shoot for a half a percent of slope. Pull masonry string tight because it will sag.

I would be leary of a concrete guy that hasn't set a trench drain in concrete.

To set the drain use rebar and wire tie to hold down. Lots.

Pour some concrete to set the drain in so that it is anchored when you go to pour slab.

Send a picture of drain and slab area with dimensions and I can give you diagram with elevations.

Also I will show you a cast in place drain we did a few weeks ago.



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[cbacres]

^^^^^ That pretty much covers it. They can be a lot of work to set, it'll ensure that the drains stay in place while the floor is poured.
In my opion, concreting around the base before the pour is the best way to keep em in place..

 

[Milton Shaw]

You might want to look at slot drains as they would work easier and not move up as the concrete pours around them. Slot drains are 12" galvanized pipe with a slot drain cut into the top of them. They come in sizes for asphalt or 5" concrete slab to be poured around them. Much stronger than trench drains and a lot more water can flow through them.

 

[bedn0009]

You can absolutely do it... and it's not that hard. The results are great. I just installed a trench drain in both a new and existing garage floor last month.

My garage slopes 3" over 28' from back to front. The trench drain I chose can either be pinned/leveled with rebar in the corners, OR... the one I chose had a slot at the base for a 2 x 4 to be put in place for a stabilizing "foot".

The drain installed into the new slab required a "trap" in my county, then into a 12 x 12 drain box, then out to 4" solid core PVC which runs to daylight.

New garage:

Existing retrofit:

 

[zio]

Bedn009 how did you determine the height when setting in the drains? Did you just measure off the base or use a straigh edge from the forming? My biggest worry is getting the night set correctly.

 

[bedn0009]

The concrete guys set a string line at slab grade.... that was essentially the height of the edge of the trench drain. Having rebar tied at the corners allows for fine adjustment.

 

[914wilhelm]

What do you cover the drain with during the pour to keep out the concrete?

 

[bedn0009]

Duct tape....then peel off while concrete is still setting

 

[Matt The Hammer]

Trench drains in the garage? Seems kinda extreme. Why so much water in the garage?

bedn- Nice work.

 

[MagicMarker]

Trench drains in the garage? Seems kinda extreme. Why so much water in the garage?

bedn- Nice work.

Washing cars?

 

[bedn0009]

Snow melt.

 

[coljar]

That looks nice, bed. Any pictures of it completed?