Question for plumbers/Owner Builders/other knowledgeable readers in regards to plumbing design for the building permit: We are Owner Builders and were applying at the City for the building permit with the requested set of plans from our architect. After the first review one of the redlines said: Provide a comprehensive plumbing plan (waste, drain, vent, gas, hot and cold water etc.) based on 1994 UPC w/AZ State Amendments. We were asking the examiner what exactly they expect from us, since obviously the plumbing plan from our architect wasn't sufficient for them. He recommended that a licensed plumber would prepare these plans for us. In order to proceed with the permit but not want to commit to a plumber yet, we hoped to hire a neutral person to do the plans. I've asked an engineer who offers exactly that and his original price for our 5000 sqft livable space home was $1600. We already have an HVAC design and floor heating design in work from engineers for the same redline reasons and we got discounted prices of $750 and $500 for that. Btw... the engineer's price for the plumbing design dropped down to $750 now, but I feel that this is still too much? Or am I wrong? Does anybody have an idea how to get this task done cheaper? Our budget melts away with all these extra soft fees. Thanks everybody.

You can get a plumber or you can study up real quick on plumbing code so you can draw it yourself. I'd recommend putting that money towards hiring the plumber that will do the work.

This isn't entirely busywork. Subcontractors who aren't familiar with ICF are often over their head when they go to do the work and end up doing things that stretch the inspectors patience.

I designed my own plumbing, along with everything else, and found the drain and vent system to be the most frustrating element of the whole house. The code books are rather vague, and I couldn't get useful help on-line or in person. I finally figured it out, but I would recommend having a plumber design it. Plumbing seems to be the one thing that inspectors really key on. Here locally, they spent far more time looking at my drain system than my framing and electrical work combined.

Thank you guys for your feedback. We've tried to find plumbers and as you said, ICFHybrid, we also tried to put that money towards the plumber who would do our work, but it didn't work out well. Plumbers seem to be too busy these days, and didn't come back to us, or they had no clue what we needed, or tried to talk their way out to not doing it. We don't have the knowledge to do it ourselves nor would the plan examiner be happy about us doing it as he always emphasizes to use licensed professionals having our plans done. We hired the engineer for the plumbing design now, just to have it done properly and hopefully right the first time. Any necessary reviews after the second one will be expensive also and will delay starting our project even more. One benefit we hope to get out of that hopefully will be, that the proposal solicitation will be easier and we'll be able to compare the quotations better. Thanks for your help though.

I think it would be a good idea to show the code official the engineer's plumbing plan before getting quotes.  Some changes may need to be made to the plans before approval.

Alton, that's a good advice. Thank you.

I would use "air admittance valves" where possible.

Posted By jonr on 20 Apr 2014 10:29 AM
I would use "air admittance valves" where possible.

Good call. Those plumbers LOVE putting all those R-0 holes in your roof. I believe by code they will be required to have at least one plumbing vent stack but the others can be done by AAVs.

There is a love or hate relationship with AAVs with the plumbing world. In Europe they are much more common and were actually developed in Sweden due to the large snow loads on roofs that blocked the vent stacks. They are also used in high rises. I plan on using AAVs since I don't want all these R-0 holes in my roof and potential roof leaks later on.

I would also advise on going with an ERV or HRV system for the bathroom vents. Don't poke a hole in the roof to run a bathroom vent fan as those are just more R-0 holes and a notorious spot for bugs & critters to drop into your home uninvited. As the saying goes, the less holes in ones head and roof - the better.

Jonr and Lbear,

Thanks for your advice. I've done my research and understand what AAV's are and how they work. And I like the idea not to drill in ceilings either. I also learned about the love or hate relationship what Lbear describes here. I've discussed it with the engineer who is doing the design for us. Although he is from Europe, and so am I, he couldn't say anything about AAV's. He will proceed with the design as per codes, which were switched due to easier calculations from 1994 to 2006 plumbing codes now after approval of the City. I am honestly confused about the use of AAV's. I think I will ask the examiner at the City whether we still have a choice even after the designs are accomplished and approved.

@Lbear: We also planned to have an ERV system installed, but the HVAC designer is suggesting a different solution which is called a Smart Ventilation system with outdoor temperature sensor.

Posted By Rafi on 22 Apr 2014 05:59 PM

@Lbear: We also planned to have an ERV system installed, but the HVAC designer is suggesting a different solution which is called a Smart Ventilation system with outdoor temperature sensor.

Studor AAV's are some of the best valves out there.

With the Smart Vent system. It appears to be a type of HRV system but maybe without the heat recovery. Looks like a well designed system but I am not familiar with it.

The Smart Vent System appears to be essentially an Economizer like we have been installing for over fifty years on commercial systems. They are built into most rooftop single package systems today. The better ones will measure enthalpy and not just absolute inside and outside temperatures.
http://hvacissues.com/energy-conservation/energy-conservation-measures-by-hvac-system-type/economizers/

Its the 5,000 SF mark that necessitates plans for all the trades. Let that be a bench mark you don't cross if 4,990 SF will do. Often one can leave bonus rooms or the like unfinished during the first phase of the build to keep SF down.