Cost of architect and engineer for 500 sq ft room addition?

Question

hi there

I own a house in michigan and wanted to build an addition 500 sq ft room addition in the backyard, any idea on how much to build a site plan from an architect? Is it something that I can do on my own? Any help would be greatly appreciated, thank you

Brian Rossiter · Answer

Oops...sorry.  I meant Jon.  That was a momentary lapse of reason (any Pink Floyd fans?).

J Scott · Answer

Are you talking about me?  If so, when did I mention that?

Sorry, just confused since I think I'm the only "Scott" that responded, but I definitely didn't say this...

Jon Holdman · Answer

My project wasn't too extensive. I was removing one section, about 8' of a bearing wall.  And moving one wall about 1'.  Unfortunately, that second wall contained a post that was holding up a beam in the attic, so the post needed to move and the beam needed to be extended.  Fortunately, I suppose, I discovered the existing post wasn't well supported, which explained why that part of the house had always been creaky.  Doubling up the floor joists under all these posts was a pain, but no more creaking.  The city was perfectly happy with the letter confirming the work had been done correctly, which I did confirm with the inspector prior to doing it that way.

This project, in my primary residence, is a good example of involving the city from the start.  I've had many, many conversations with the building inspectors and they have been very helpful in keeping me on track.  There have been a couple of surprises, but these have all been resolved.

Brian Rossiter · Answer

As a structural engineer, I'll have to +1 Jon and J Scott's posts.  I can corroborate everything they've stated.  Very well written.

I find the approach used by Scott's engineer interesting.  He just provided a letter to the City stating that work was completed as discussed.  I'm used to the more rigorous requirement such as he describes about Boulder County.  I would end up drawing a set of structural plans for around $1000 - $1500 for a 500 SF addition.  Our hourly rates are about the same as Jon describes, so the plan set probably would have cost him about the same as we charge.

The Building Department website for Ypsilanti is here.  You should be able to find all of the required documents and fees for pulling a permit.  If this isn't the town where the property is, a Google search for "building department" plus the town name will get you the info you need.

J Scott · Answer

Every jurisdiction is going to be different, but in many places, you will need:

-  A survey.  Generally speaking, a survey will be needed every time you do an addition or add on to a house (deck, porch, etc).  This is going to be done by a land surveyor.

-  A site plan.  A site plan generally starts with a survey, overlays the setbacks, may have topographic info, may discuss things like soil/erosion control, and ultimately will overlay the new square footage you plan to add, to scale and where you plan to build it.  This can often be done by the land surveyor, or alternatively, you could hire an engineer or even do it yourself.

-  Construction documents.  These are the construction plans for the actual addition.  They will generally contain the floorplan, the exterior elevations, the building materials/sizes, cross-section, foundation/structural drawings, roof design drawings, etc.  This can be done by an architect, or if you know exactly what you want, you can often have a drafts-person draw it for you (potentially, you could do it yourself).  You may need sign a licensed engineer and/or architect to sign off on the plans, depending on the requirements of your jurisdiction.

Jon Holdman · Answer

Start by calling the building department.  They can tell you what you need to provide in terms of plans and what they require in the way of engineering.  You may well be able to do them yourself, if this is a house you're going to live in.  If its a rental or fix and flip they may require a licensed general contractor.  Certainly they will require permits.

You may also have to review the plans with the planning and zoning commission for things like setbacks and lot usage.

I recently hired a structural engineer for a bath remodel where I was moving several walls around.  He charged me about $100 per hour.  He came to the property.  We discussed what I wanted to do and he examined the existing framing and foundations.  A few days later he called and we discussed the sizing for new beams and posts and where I needed to add floor joists.  And what size of joist hangers to use where.  After I did the work he came out and looked it over.  He then wrote a letter for the city saying I had performed the work as discussed.  This was in lieu of him drawing up detailed plans and then letting the city check the work vs. the plans.  Total was about 3.5 hours.  It would have been more if he had to draw plans.

A friend is building a barn in Boulder county.  They're much more rigorous.  He ended up using the same engineer and has spent a lot more time coming up with a plan the city will approve.  The architect he's using is a friend, so I don't think there's much, if any money, changing hands.  At a guess, if he was paying the same rate I paid for both the architect and engineer, I'd guess he would have spent several thousand bucks.  This barn is quite a bit larger than your addition, though.

Cost of architect and engineer for 500 sq ft room addition?

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