Perhaps practice differs in your community.

But as a builder of luxury infill homes up to 5,600 sf. the only extra design services I've used have been for HVAC. The HVAC company will do it, but I feel more comfortable with an independent designer.

The plumber--and septic and well installers if you're not on municipal hookups--must submit their plans to the authority having jurisdiction.

For electrical, you can, of course, have a designer or the architect designate every last outlet, switch and light. Or you can have the electrician provide them to Code and add whatever you want. In the framing stage, I just walk around with the electrical contractor and he marks the rooms as we go. If it's a custom home, the client accompanies him.

This post was edited by worthy on Mon, Mar 4, 13 at 19:13

My husband wanted electrical plans, so we paid our architect to draw them up. But if we hadn't done that, it would have been exactly what Worthy describes.

The septic design was done by our septic installer. The septic design had to be submitted to get a permit. The impression I have is that the plumbing and HVAC will be designed by the installer.

We are using a forced air furnace, and that makes our house fairly standard in our area. Is the in-floor heat the reason your architect wants you to hire an engineer for the design?

We hired an HVAC designer who designed the cooling and ventilation for our home with corresponding duct plan -- his price was about $1000.00. He works outside of Toronto. We too will have in floor heat, and that was designed by Uponor (the company that makes the in floor equipment we are using) in conjunction with the contractor. We were left out of the in floor design process, and Uponor and the in floor constractor spec'd for much higher end equipment than we would have liked. I am sorry that we were not consulted with the in floor design as we would have asked for less costly equipment. Our architect did an electrical plan, and we tweaked it with our interior designer.

Good luck

Carol

I really have no idea why she want to hire an outside engineer, maybe it's a liability issue. Pretty much all the info I've found online mentions MEP engineers for large commercial buildings, not typical residential homes.

We are on the local county water, so no septic. So other then radiant heat we're not doing any out of the ordinary

I suppose it varies, depending on what is or isn't important. If the systems are in the bidding documents, one knows exactly what one is getting for the money. If the systems are left for the subcontractors to work out after bidding, an owner is left holding the bag, not knowing what was bid and open to all sorts of extra costs for "upgrades.

As an architect, I always did a lighting (interior and exterior) plan with controls. That's because I consider lighting to be of utmost importance.

I also planned the location of controls, diffusers and returns for all HVAC because I was concerned about their appearance and integration with the design of the house.

I also speced all plumbing fixtures, fittings and finishes if it was important to the owner. If there was a well and septic system, I always indicated where these were to be located. It was always important to me.

The detailed design of the actual HVAC system, capacity and equipment I left to the mechanical bidders, based on the architectural drawings and specifications. Similarly for the electricians and plumbers to design systems of sufficient capacity, including well and septic systems where used.

I would hardly expect a lumberyard drafter to do any of this. And if they did, I'd be concerned.

So in the end I guess it all depends on what's important to a home owner.