Fawning Over Foundations

I can’t wait to see this project done. I’m pretty excited about it!

Thanks Brad… we’re pretty excited too!

Jeremy:

Great project, and so far nice description of the materials trade-offs. Neat idea to thoroughly document all phases, write the articles, and do the book.

I have to ask you, though: Did you seriously consider ICF construction for the above-grade exterior walls as well as just the basement?

I would be interested to hear about your rationale. I have been looking at a product called Rastra (www.rastra.com) that can be used in that way.

Michael Clarke

Hi Michael – indeed, we did consider ICF to the roof (I spoke about it here). Quite frankly, I would have preferred to go ICF to the roof – however there were a few complications that came with that decision.

1. I wasn’t aware that ICF was a viable option for all exterior walls until well into the design process, and making that change would have required a great deal of revisions. Given our deadlines, it really wouldn’t have been possible to make these changes and get the plans submitted into the city. We considered submitting what we had, revising and submitting again… but we ultimately decided against it.
2. Because the ICF blocks are wider than a traditional stud wall, we ran into issues with the overall width of the house, particularly in the kitchen. If you look at the drawings, you’ll see that there isn’t a great deal of distance between the kitchen island and the stairs. Had we used ICFs, we would have needed to reduce this even further and we weren’t prepared to loose another few inches. It seems trivial, but that will be a high traffic area.

1. Price was another factor. Taking everything into account, ICFs were more expensive. Now, it wasn’t a huge difference, but it was a difference nonetheless… and we really didn’t have any additional wiggle room in the budget.

   I can’t speak to the Rastra product, but we used Nudura for our foundation and we would have used it for the entire structure had we gone that route.

Hi Jeremy,
 
Very nice job covering the project! Information detailed and well organized. Now to my questions:
 
(1) I am planning on starting on a new 2-storey 42’x38’ open concept house in Toronto this spring. The design is ready, materials specification and structural engineering is the next step. For external walls, I am considering ICF all the way. From one of your posts above, I see you briefly thought about doing the same but decided against it for a number or reasons, one of which was the budget. I do know that building with ICF is on average more expensive than ICF basement followed by traditional framing. However, in my opinion, our design is pretty simple from ICF point of view (the house is rectangular with virtually no other turns, window openings are large and horizontally aligned, there is no split levels, there is no below-grade garage nor walk-out to the backyard) so I think the difference should not be that big. I talked to a few builders and a couple of engineers but no one was able to say how much more expensive it is (percentage-wise, dollar-wise, or both). It sounds like you did your own comparison for your own project and, if you are at liberty to discuss it, I would appreciate if you could say how the two options compared in your case.
 
(2) Have you done any routing of wires or pipes along your basement ICF yet? I am worried about increased wall thickness due to pipes and wires. For this reason, most of our pipes and wires I am planning to route through interior wood-frame walls. However, some wiring and at least one sewage pipe (4’’) will have to go along exterior walls but I am hoping to conceal them in the same “boxes” that will be used for visual separation of open-concept areas. Any thoughts, or experience on this topic?
 
(3) Did you go with floor heating in the basement? I want to put floor heating in the basement floor myself but, since there will be two major areas in my basement, I am thinking of actually having two separate circuits connected in parallel to one heater. One circuit would be always on while the other I could shut off manually when I don’t need it. My designer (not an engineer) hinted that I would need two completely independent systems (i.e. two heaters, too) which, according to him, would be essentially twice the cost. I am an engineer (of a different type) and this is contrary to my engineering gut-feel. Either way, if you did go with floor heating, do you have a rough idea how much it added to the cost of the project?
 
Thanks in advance.
 
Regards,
Vlado

Hey Vlado – I just realized I hadn’t responded to this… so excuse my tardiness.

Regarding the cost difference between ICF and traditional stick construction – I don’t know if I can give you an accurate cost comparison, but if I remember correctly, it was somewhere in the neighborhood of 10-15% more expensive. That said, it would have also been 10-15% faster to construct as well. That said, if your design is straightforward, you should also consider SIPs. Odds are they’ll be cheaper.

Regardless of ICFs or SIPs, you’ll still have the same issues running wires – that is, you’ll have to cut into the panels to do so. In the case of SIPs, you can get the panels delivered with wiring channels already cut through the center (which makes running wire a million times easier). I’m not 100% sure how you’d handle piping though – I suppose you could run everything through interior walls, but I can see how that would have been a pain in the ass for us on the first and second floors. We had a few pipes that needed to be run along exterior walls, but we strapped out wall to conceal them.

We didn’t run in-floor heating in the basement, mainly because of price. To do so, we would have needed a boiler that was completely separate from our forced air HVAC system. I don’t know much about radiant systems, so I’m not entirely sure if you’d be able to do what you’re describing… sorry!

Best of luck.

Hi Jeremy,

Never thanked you for your reply – so, thank you! As usual, congratulations on well-done web site. I also drove by your construction site recently – awesome modern house!

Since my last post, we finalized our own project plans and engaged in construction of our new home. And yes, in the end we did decide to go ICF all the way. I started a web site where I, as much as time permits, I explain, among other things, why we decided to go all-ICF. The site is at http://www.AllIcfHouse.com.

In terms of running wires, pipes and ducts… well, the wires, where they run along exterior walls, I am going to burry in the ICF foam. Pipes are going to be a little bit more difficult but I had to take these matters into my own hands when it comes to making decisions on routing so I think I have solutions with reasonable trade-offs. The greatest concern is the duct work which is mostly not related to ICF but to the fact that the house is an open-concept design, with few interior walls on the main floor. I brought this up at least a couple of times during design stage but was told that will be done later. I regret that I did not push for it as it turned out to have many obstacles. Unless we go for ugly bulk-heads or otherwise conceal the duct work in pretty much EVERY SINGLE ROOM on the main floor. My wife and I (both engineers) already found some solutions but there is more to go. I briefly touch this topic at our http://www.AllIcfHouse.com, too.

And lastly, after much consideration, we opted for in-floor heating in the basement. The main reasons for and against it were that it is either now or never (before basement slab is poured) but then again will not be finishing the basement any time soon. In the end, we decided to get it. One reason is that we thought the extra from our builder was reasonable. The other reason is that we will own the hot water tank anyway (instead of renting it) and will be getting the combo type of the unit. In addition to hot water, it has a coil insert inside the tank that is used for in-floor heating (when turned on).

Best regards,
Vlado