Home plans update (one of many)...

(Brendan)

Again, it's impossible to adequately follow the previous post, so this post will seem kind of silly. Nonetheless, we are excited about closing on our house and getting started on our new house, and I thought I'd do some posts on things that have changed since our set of bid plans. For the best background for this post, I'd recommend re-looking at where we were at the end of the bidding process (including known cost-cutting measures at the time).

This post specifically regards the elimination of the basement that we had originally planned, and our new plans for the home's foundation. Eliminating the basement was certainly done in order to save on cost, but the decision was made very easy when, in further conversations with the city of Ham Lake, MN, we were informed that our original plan would not be allowed since the depth of the basement was below the water-saturated soil level (which, due to the wetland nature of the Ham Lake area and our particular lot, is only a couple feet below the ground level). Never mind that this detail should have been given to us a long time ago on our site plan (and that it was written on a "livability plan" document that the city had, but we were never given), in the end all that matters is that elimination of the basement needed to happen. Due to our architectural sensitivities with this home, we also were not going to go with some sort of large grading effort to create an artificial hill for the home site in order to have a walkout basement (this would also be necessary even to create a simple crawl space). Actually, the neighbors to the South of our lot did that, and it looks a little silly. So the best option for us was to go with a simple slab-on-grade foundation (basically a solid concrete foundation, with frost-footings).

Switching to slab-on-grade is no simple deal when the house was completely designed with a basement in mind. Here's a list of just a few of the challenges this creates:

• Where do we create above-ground storage space?
• All the mechanical systems were going to be in the basement. Where will these go?
• Air ducts were being run through the basement ceiling, how will these be re-arranged?
• It's Minnesota. The first-level floors will be freezing cold in the winter with a slab foundation, won't they?

I'll address these challenges in future posts. The final bullet point I'll address here. We decided, with our general contractor's advice, to go with a hydronic radiant heating system on the first level. This will cost us moderately extra, but not too bad (4 figures, total, for the rough-in of the tubing and the mechanical services). Coupled with the large savings of not having a basement, it's still a big net cost savings. And it will be almost a necessity in the winter simply for livability and enjoyment of the home. No one wants to walk around on freezing cold wood floors. With radiant heat, floors will be toasty warm in the winter and will be a pleasure to walk on barefoot.

Here's how it works. During creation of the slab foundation, tubing is weaved and secured to a grid of rebar (or other support system), ensuring coverage of all areas of the floor. Concrete is then poured over the tubing, embedding it in the slab. The tubing will carry warm water through the concrete floor, warming the floor and eventually heating all of the rooms themselves as the heat radiates upward. It's a very clean, efficient, non-allergenic, and comfortable way to heat a home. The upstairs will still have air services for heating, but hopefully that mode of heating will be infrequent as the lower-level heat will also contribute, indirectly, to heating the second-level (especially with our highly insulated SIP's home construction).


Above: A section view of a hydronic radiant heating system installed in a concrete slab foundation. The water-carrying tubing is embedded within the concrete and is insulated from the bottom to prevent heat being transmitted to the ground. (Okay, the guy with the blue socks is annoying, but the time investment needed to photoshop him out just isn't worth it ;-)

Below: Examples of hydronic radiant heating being installed in new construction.


The case for radiant heating over forced air: with forced air we heat our ceilings (wasted heat) and the floor is the coolest part of the room; with radiant, it's the opposite. Because of the higher efficiency of radiant heat, it also costs less to heat the home. Why doesn't everyone do radiant then? Simply because of the higher up front costs (though you can get your money back over time with reduced heating bills).
One final note, this works ideally with concrete floors, and also does work particularly well with engineered wood floors. It can work with hardwood floors too, but you have to be careful which wood species you go with (the harder, the better). The issue is expansion and contraction of the wood. Engineered wood floors are multilayer constructions that don't expand and contract much, and that's the type of wood flooring we choose for the house anyway.