360 Winnett » ICF

Poured Foundation

jeremybell — Mon, 22 Sep 2008 23:46:14 +0000

It’s been a few weeks, and we’ve made quite a lot of progress on the house. We had evaluated a number of manufacturers, but ultimately decided upon Nudura for our ICF foundation. Paul Stevens and his crew from Stevens Construction handled the formation and pour of the foundation, and by all accounts they did a smashing job.

The Nudura product comes shipped in a collapsed state, which I believe reduces shipping costs and makes it easier to handle by the workers. The ‘blocks’ look to be about 7’-8’ long, and they basically just snap together. For the odd sizes, the blocks are simply cut with a handsaw. A crew of 3 guys assembled the wall, and the process looked to be pretty straightforward:

First, the footings are formed and poured. The footings are basically a short concrete wall that the ICF blocks will sit on, and their main purpose is to displace the weight of the structure above.
Once the footings have cured, the forms are removed and 2 metal strips are attached. The strips were used to keep the bottom row of the ICF blocks straight and true.
The ICF blocks were then assembled and wood planks are added (in certain areas) for additional support. Permanent wood forms are also built to create the window wells.
The blocks themselves have a “mesh web” built into them, but additional horizontally and vertically rebar is also placed inside.
Large metal braces are temporarily installed to support the wall during the pour. These braces acted as a walkway for the crew during the pour, plus they were also used to fine tune the straightness of the walls once the concrete is poured.

Additional wood bracing was also added throughout to ensure the structure is maintained during the pour.
This isn’t exactly on par with the demolition video, but here’s a little video that illustrates how the foundation walls came together.

Once everything was formed, supported and ready for concrete, I made a point of calling our architect and setting up an inspection before the pour. Nothing too major was out of place, but there were a few things that needed to be adjusted to ensure we maintained the aesthetic we were trying to achieve (one wall was jutting out about 6 inches further than it should have and would have resulted in an unsightly ‘hump’ in front of the stairs). We also decided to abandon the window in the study under the garage. I had raised concerns about this earlier on in the design process, but we made the decision on-side because it quickly became clear that the window well would have been too large for the space along the house. Once these oversights were corrected, it was time for concrete.

A relatively liquid concrete was poured into the hollows of the ICF walls, which allowed it to easily slide through the webbing and rebar. The crew would walk around the walls and fill it up a few feet, and then continue around to fill it another few feet. Every so often they’d stop and use a large vibrator to ensure all air bubbles were worked out, and the concrete made its way into every crevasse. I definitely have to give some credit to Paul and his team – lugging around the pumping house didn’t look like much fun.

The walls stayed untouched for a few days to allow the concrete to cure, after which the the weeping tile, crushed gravel, sand, and backfill were added. Sand was used because it allows for better drainage, and the weeping tile is basically a plastic, sock-covered tube that wraps around the perimeter of the house. It’s sole purpose is to capture any water that seeps into the ground, and move it away from your foundation. In our case, we have a “soak away” pit in the backyard which will capture most of the rainwater runoff and allow it to dissipate naturally into the ground.

I’m definitely glad we’ve moved past this phase, as there were a few hiccups we encountered along the way which increased the foundation budget by about $2000. In particular, we had a little turbulence between the trades and the structural engineer, but I’ll explain this in another post soon.

Construction Drawings

jeremybell — Mon, 04 Aug 2008 18:58:01 +0000

Our construction drawings were submitted to the city a few weeks ago, so we’re in a bit of a holding pattern while we wait for our building permits. This process usually takes around 10 business days, so we’re expecting we’ll receive them this week.

These latest set of drawings are quite comprehensive and illustrate in great detail how we’re planning on building the home. In particular, the cross sections really put things into perspective and give you a decent idea of how the house will look when things are completed (such as the 23’-9” ceiling height when you enter the house.)

For the most part everything is the same as it was, however we have made a number of refinements since I posted the previous drawings. For instance:

The length of the clearstory has been reduced significantly to stop it from encroaching into the living room. It now sits flush with the front bedroom, while the en-suite continues to extend about 4’ past it.
We’ve reintroduced a step down into the living room. This means the ceiling height in the room below will be about a foot shorter, but Altius was insistent that we eliminate the bulkhead that would have resulted from the en-suite bathroom above. I think that’s a fair tradeoff, no?
Each bedroom now has an updated window arrangement. The master has a larger set to better fill the space, while the others now have windows on adjacent walls for improved cross-ventilation.
Because of grading restrictions we needed to decrease the pitch of our driveway, which unfortunately has caused a few adverse side effects:
- The garage now sits slightly lower, which means it will have a generous 10’ 4” ceiling while the rooms below now stand at a paltry 6’ 11”. I can’t say I’m particularly happy about the lower ceilings, but our options are limited at this point. We’re planning on using INSUL-DECK for the slab floor in the garage (which isn’t illustrated in the latest drawings at the moment). Hopefully that’ll allow us to reclaim a few inches.
- We also needed to add an additional step into the house at the front door and in the garage door. Again, not exactly ideal but not the end of the world.

It looks like we’re going to need a small retaining wall along the north side of our driveway. I assumed it would just be a small block wall, but Altius has illustrated it as a wall + planter instead. Much better, if I do say so myself.
At the moment, the drawings illustrate the use of ICFs for the foundation only, with stick framing and spray foam for the floors above. We really wanted to use ICFs to the roof, but it appears as if it’ll fall outside our budget. Sigh.

As usual, the updated drawings can be found in the documents section for your viewing pleasure.

Shades of Green

jeremybell — Fri, 27 Jun 2008 22:43:42 +0000

To date, the number one question, comment and critique of this project has been about our “green” commitment. Are we really being “eco-friendly”, or is this all just a vanity project? I suppose one wouldn’t put this all online if there wasn’t a hint of narcissism involved, but I like to believe I’m a little more humble than that. Regardless, I welcome all of the comments and I hope the criticism keeps us honest.

So what are our green strategies? As I’ve mentioned before, we hadn’t originally set out to build a green home. We simply wanted a larger home, and while this remains true, our priorities have changed along the way. We’ve come to realize we should be building a smarter home and not just a bigger home. We’ve also come to appreciate our eco responsibilities and felt it was important to document the realities that came with this decision. And there are realities that come with those decisions. Financial realities. We’ve evaluated a variety of eco-friendly solutions-~~and I’d love to use all of them~~-but we simply cannot afford to.

Many of the specifics are still in the air and won’t be finalized until we’re well into construction, but I thought I’d take this opportunity to shed some light on what green features we’re planning for:

Energy Star certification
Compact house footprint that fell below allowable coverage
ICF foundation
Closed cell, medium density spray foam insulation
Low E II insulated, argon-filled windows
High efficiency furnace + heat pump + HRV
On-demand hot water
Passive heating & cooling (solar chimney + cross ventilation + window shading)
Daylighting (clerestory + internal windows)
Energy Star appliances
Rainwater collection

CFL and/or LED lighting
Similarly, we’ve also had to abandon a variety of other green solutions as a result of their costs:
Green roof
SIPs
Geothermal heating & cooling
Grey water collection (although we haven’t completely ruled this out…)

Solar & wind power
I plan on discussing each of these topics in greater detail as we progress through the project, and I’m sure things will evolve as we continue to evaluate our options.

I’m assuming we will continue to face accusations of greenwashing, but hopefully this clears a few things up and illustrates that we are indeed trying to build the greenest home we can. Even if that shade of green isn’t as bright as we’d like.

Under The Garage

jeremybell — Mon, 23 Jun 2008 13:07:10 +0000

I don’t believe this is particularly common, but we’re planning on building two extra rooms in our basement by excavating the space under our garage. In a typical garage, the floor is simply a concrete slab that sits on top of soil, however we’re going to approach things a bit differently.

Because our foundation will be built with ICFs, we’re planning on utilizing a “deck” system that will integrate a structural concrete slab directly into the foundation itself. This means we’ll be able to pour concrete for the foundation walls and the garage floor at the same time. When everything cures we’ll have a structurally sound garage floor capable of supporting the weight of a car, plus a completely insulated 10×20 space below it.

The decking system is pretty straightforward to install—Once the ICF blocks have been assembled, the foam deck panels are placed across the span that makes up the garage floor. These panels are then supported from below with temporary shoring and reinforced with rebar.

Obviously this approach is going to cost a little more, what with the additional concrete and rebar and foam panels and labour, but we’ll be gaining an additional 200 sqft of space that would have otherwise been inaccessible. If you take a look at our floor plans, you’ll see that we’ll have a very generous “study” and additional storage down there… which I’ll say is a decent use of that space, no?

For those itchin’ for the nitty gritty of how a system like this is installed, I also dug up a PDF aptly named Pouring A Structural Slab that explains it all.