Last night marked the first construction milestone: I cut the last check for the concrete work: $1,191.60, bringing the total to approximately $5,950. This was about $350 more than the estimate, but you may recall that I was warned in advance we might go over by 300 – 500 due to the slope of the land. The contractor was Charlie Record (Record Concrete of Chester, VT), and I’d recommend him without hesitation.
What would I do differently on the foundation the next time? Nothing, fortunately, and that surprises me. I’ve heard enough horror stories about contractors that I have to admit I expected to have at least small problems with anyone I hired. The fact that both the concrete and excavating work has been quick, professional and good quality has been encouraging. Of course, the fact that I researched the work up front, asked a million questions, and went in with a good idea of what I wanted probably helped. Here’s where experience as a business analyst and project manager pays off outside of work.
So far, at least.
Next up: Floor framing. After reading up and consulting a number of Internet Joist Span Calculators (including this one), I called Lavalley Building Supply expecting to order 2 x 10 x 16 Douglas Fir joists that I would space at 12” on center. And here’s where one of those pesky assumptions jumped up and bit me:
Salesman: What’s the span?
Me: 16 feet.
Salesman: You sure you want 2 x 10? Most people want 2 x 12 for 16 feet.
Me: The joist calculators I’ve been using say that Douglas fir should be good for 16.
Salesman: Oh – Doug Fir – yeah that would probably work. But we don’t have it – we’ve got spruce.
I told him I’d call back. After some research and a few questions, I determined that the framing lumber they had was lumped into a category that some calculators call ‘SPF’ – Spruce / Pine / Fir – which can be either northern (Lavalley’s was from Canada, eh?), or southern. It looked like I could still span 16’ with SPF 2 x 10s, but I was troubled by the comment that ‘most people want 2 x 12 for 16 feet’. The difference in price was about $9.50 vs. $16.50. My options:
1) Put in a beam and lally posts at 8’, and cut my span in half. This would be more work, but would allow me to use smaller joists.
2) Take Lavalley’s advice and go with 2 x 12s, which – according to the span calculators – should be much more than adequate. These would be heavier to work with and more expensive.
3) Take a chance on 2 x 10s, and insert a beam later if they proved inadequate.
What’s at stake? ‘Deflection’, apparently – the amount of flex or ‘sponginess’ in the floor. Apparently, we’re most comfortable with a deflection of about 1/2”; less and the floor is uncomfortably hard, more and there is too much bounce, causing the plates in your hutch to rattle when anyone moves.
In the end, I compromised by going with the 2 x 12s, spacing them 16” on center (which is standard) instead of 12”. This allowed me to reduce the number, saving a little work and minimizing the cost increase. The floor would have probably been fine with 2 x 10s at 12” oc, but the $200 savings wasn’t quite enough to risk it. And who am I to argue with experience?
Delivery is tomorrow, and we'll have about 14 hours to lay the sills, frame the floor, lay the decking, and then cover it with plastic until the next visit. Now the real fun begins!