Plumbing question for ADU conversion

[Jacob Jenkot]

Hello BP!

I am considering converting a detached garage to an ADU. Seems like I should be fine my the city, but they are pretty incompetent, that's another story though.

So the detached garage sits on the alley where the sewer runs. It’s an old building and sits on at least 8 inches of a concrete slab (what I have seen visually during some landscape work.)

The structure does not have plumbing, and I would want  plumbing roughed in for 1 bath, kitchen and washer. I am not sure exactly how to ask a plumber for this service, if a plumber even the correct person to call for this. Would I ask for plumbing rough in?

Also, I am thinking this will be my most expensive part of the project. Does anyone have a cost break down from a recent ADU conversion in the Denver area?

Thanks

[Malcomb Stapel]

@Jacob Jenkot  plumbers work under concrete slabs all the time. The correct order of events should be 

1. contact plumber and tell them the scope of work to be performed (have them plan things out).

2. contact concrete cutting service and have them cut exactly where the plumber has detailed. 

3. Get the plumber back out to make the connections.

It could be an expensive job. You might be able to negotiate a discount if your removing the concrete and doing the digging. If your removing the concrete I recommend you have it cut no bigger than one foot squares. 

[Bruce Woodruff]

Yes, you would call either a Plumbing Contractor or maybe better a General Contractor, who would work and manage the whole product and deal with the City.

NOTE - First thing to do though is to go to the City and ask if this is even going to be legal. I used to have difficulty in California converting garages because of the lack of Steel/Concrete PSI/vapor barrier. It may not be possible to do the conversion because of this and you would have to tear down the existing garage and start fresh. You want to know this before you start....

[Jacob Jenkot]

Awesome! Thank you for the advice. I’ll find a few plumbers in my area

[Jacob Jenkot]

Yeah the city of aurora is pretty terrible. Good advice though! I’ll start with that

[Efrain Yakuta]

@Jacob Jenkot if it's going to be a permitted ADU, the city may have a laundry list of requirements beyond plumbing. I would engage with an architect and get all the planning/scope of work dialed and approved with the city. Then you have a clear set of plans to give to contractors for pricing. There's a lot of upfront planning but it will save tons of time when dealing with the contractor and can help avoid misunderstandings. Good luck!