Today I added a tag cloud to the website. That's the list of tags in different font sizes in the right sidebar -- the font size reflects the relative frequency of posts with that label. I added the tag cloud in honor of today's post with the unhappy label "Expensive mistakes."
I would love not to share this story, but it's been a big part of our pre-construction process, and it would be disingenuous not to talk about our mistakes as well as our accomplishments.
I'm going to describe our unsuccessful and expensive collaboration with a structural engineer who wasn't a good match for us. It's not Ted's or my goal to criticize anyone here other than ourselves -- I certainly don't want to malign an honest and qualified professional simply because we weren't on the same wavelength. My hope is merely to share our experience so that other owner-builders might learn from our mistakes.
Things might have gone better if I'd had a clearer understanding of what a structural engineer does. I thought structural engineering was simply about doing load calculations and making sure that we're not building something that's going to fall down. Our design has a few tricky bits, including an interior cantilever around the main staircase, and I thought that was the main sort of task a structural engineer performs.
I failed to realize that we needed a structural engineer who is every bit as obsessed with energy-efficient construction as we are. The engineer we hired is very experienced and highly competent, but he is firmly planted in the world of conventional building. This was an unfortunate oversight because structural engineering is heavily concerned with the building envelope and the foundation, which are probably the two most critical aspects of Passivhaus design.
It didn't help that our foundation is turning out to be very tricky indeed. Our building site slopes downhill from west to east and our house design is oblong, but for optimal passive solar performance we want the long side to face south. The engineer warned us multiple times that it would be more difficult/expensive to orient the house that way, and we assured him repeatedly that rotating the house was not an option. He therefore suggested we pay a landscape engineer to do a grading plan, which would detail all the earthwork required to build a frost-wall foundation.
In hindsight, someone should have proposed we build the foundation on piers, since this would minimize the amount of earth-moving and keep the overall cost down. (Also, a foundation on piers would look really cool!) But this never happened, and we instead paid for a grading plan and then a foundation plan that will require heaps of concrete, overzealous bulldozing, and masses of expensive compacted fill.
Was our engineer wrong to propose this? He had suggested numerous times that we reorient the house along the milder grade, and we repeatedly told him that solar orientation was more important to us. It was not ridiculous for him to think that we were prepared to foot the bill for our obstinate tree-hugging ways.
We knew when we hired him that he wasn't experienced with super-insulated construction, but Ted and I thought we might be able to educate him along the way. We were willing to pay for a few extra hours of his time if it would leave him with energy-saving strategies he could use on other projects. Unfortunately, "a few extra hours" ballooned into a lot of revisions when he didn't see the logic of our requests. And to be fair, a lot of our questions and proposals were pretty loopy, so I don't entirely blame him for ignoring our occasional valid points.
Our energy guru Marc met with him last August to discuss the project, and Marc immediately told us that he didn't think we'd hired the right structural engineer for the job. But by then we felt it would be expensive to change course and hire someone new. I suppose this was the "good money after bad" threshold. Sigh... lessons learned.
Other than the grading plan, not much engineering work happened over the winter, and by spring we decided to bite the bullet and find someone else. Marc hooked us up with someone who seems to be a much better match, and we may have a viable and affordable foundation plan before too much longer (blog post forthcoming).
We are wrapping up work with our old engineer, and hopefully there won't be hard feelings on either side. It's been a blow to my pride to discover I'm not immune from making mistakes, and of course it's been a blow to our budget and schedule as well. But we will recover, and if this is our biggest expensive mistake we will be lucky indeed.
Here's hoping that font size in our tag cloud stays very very small!
"In hindsight, someone should have proposed we build the foundation on piers"
You do realize there is a category of construction-industry professionals whose job it is to understand your needs and concerns and make helpful suggestions along these lines? Who will also help you fine-tune your program, improve the layout and orientation of your house, use their experience to develop effective details, and generally help you avoid "expensive mistakes"?
These people are called 'architects or 'residential designers'. I find it hard to understand why you would undertake such an expensive and demanding project without one on the team.
Good design doesn't cost, it pays.
Yes, we're learning that quite convincingly. The good news is that we lost more time than money, and now we have a lot more faith in the people we're paying.
An emerging part of our goal with this blog is to show would-be DIYers that the right professional help is indeed worth the cost.