Thursday 22 August 2013

Durisol, FastFoot, EPS vs. XPS, PHPP, and Enginners - Oh My!

Sorry for the absence, been pretty busy of late.  I thought I would provide a brief update as to where we are.

1) Our testing of the Durisol ICF continues: after 8 months of continuously drenching the outer panel with water, we still do not have significant inward capillary action.  We will now fill the bays with concrete and see what difference this will make.  (8 month Status Video).

2) We are also progressing our testing of the fabric footing from Fab-Form called FastFoot. This product is used to replace the typical framing of footings and then provide a lasting protection from rising damp.  After 6 months of testing, there has been no noticeable moisture penetrating through the fabric.  However, we have realized that if the capillary flow was small enough, it would evaporate out the top as fast as it penetrated through the fabric.  So we will modify this experiment by creating a sealed envelope of the product around a paper towel and submerging it in water.  We will then open it in a few months time to determine if the paper towel has seen any observable wetting. (6 month status video)

3) The next experiment we will start is to compare the water uptake and thermal performance of EPS vs. XPS.  It is generally accepted knowledge within the building science community, that XPS is more water resistant than EPS. But there recently has been some discussion on LinkedIn that disputes this claim (LinkedIn Posting).  The post points to a 15 year case study performed by a EPS foam company that  may call into question the standard test (ASTM C 272) may not be accurate when taking into account long term moisture take-up. In a discussion I had with a local engineer, they advised that XPS is more moisture resistant, but EPS dries faster.  So I speculate that if the foam is only periodically getting wet and then is able to dry between wetting (granular layer below slab), then EPS may perform better than XPS depending in the cycles of wetting.

In order to try and come to some conclusion on this, I will run the following experiment:

- 12"x12"x2" samples of both 30# XPS and 30# EPS will be buried in my back yard in an area they will get wet often or just stay wet (near a fish pond).  They will be down around 4-5ft.
- Equal number of samples of each will be submerged below water in a sealed Tupperware container
- Equal number of pieces will be sealed inside a large zip lock back and put on a dark shelf in a conditioned space (no UV).
- Finally, an equal number of pieces will be just left loose on the dark shelf.

I hope to bury these samples within the next week (I am just waiting for some FoamGlass samples from Pittsburgh Corning to also include in the test).  All samples will be then tested for thermal resistance at the end of approx 6 months time to determine any changes to the control (samples sealed in zip lock bag).

4) I would like to accurately model the planed dwelling for heating and cooling loads.  I am a certified Residential Hydronic Designer, but have never been satisfied with the rather gross estimation calculations provided in the TECA manual.  The best software I have come across to date, is the PHPP produced by the Passive House Institute. Unfortunately, it has been a couple of years since I took the week long training course in PHPP and now do not remember enough of the nuances to correctly navigate my way through it.  A posting on a few of the LinkedIn groups netting over a dozen offers of help including several for free.  Once I solidify my design (see next topic), I will do the bulk of the entry into PHPP (entails entering in the volume of all of the surfaces like floors, walls, ceilings, windows, doors, etc.) and then choose the best of the respondents to work with.  One of the key needs will be to model many of the details in THERM to calculate the thermal bridge credits to enter into PHPP (it for instance presumes a fairly poorly detailed exterior corner and if you build with continuous insulation, you actually get a credit).

5) It appears that once again, I am in the need of a structural engineer.  I have had the worst luck I have ever had finding a vendor for this task.  I initially chose someone last spring who came recommended by two different people.  Initial communications had gone well, but on the first day of actual design, the project went south really quickly.  In hindsight, I believe the engineer was unfamiliar with ICF foundations (concrete poured inside permanent forming).  My first clue was when he insisted in designing a standard 8" foundation INSIDE the ICF.  This would have bumped me up to the 12" Durisol block instead of the planned 10" (costing substantially more for the block, freight to Vancouver, and the extra concrete). As a comparison, the BC Building Code allows for a 5.5" concrete core in an ICF.  The next issues was an insistence that I must use 2x6 studs for structure. When I tried to point out that only 2x4 Studs were required for structure and that the bump up to 2x6 construction was actually to meet the insulation needs of the 2006 code, and that as I had continuous EXTERNAL insulation, this was not applicable to me, they just stated that they only designed in 2x6 studs.  At this point the engineer suggested he step aside and I was in full agreement.

This was a very low point for me, because of this and a topic I will talk about in an upcoming post, my goals to start building in 2013 was not going to be met.  My wife and I came to a realization in March that it was not going to happen and that putting off for one more year made a lot more sense.  Of course this meant that I sloughed off from designing for a while and got out of the habit of working on it.  I picked it back up in earnest in June.  I decided to look for ways yet again to shrink the structure.  The District of North Vancouver building bylaw for my neighbourhood is VERY restrictive.  There is a rule that the upper floor cannot be larger than 75% of the lower floor.  Of course this goes against sound building envelope principles that dictate a cube as the 'perfect' structure, as it represents the smallest building envelope.  Anyway, I was able to shrink the upper floor enough so that I could meet the 75% rule if I added all my left over FSR to the bottom floor.  I will then go for a variance asking them to waive the 75% rule and not make me make the dwelling bigger than I need or want.

In June I received a list of engineers, who all reportedly work in ICF, from my friend Murray Frank.  I started to go through the list contacting each one and asking if they were interested.  Out of the seven names provided, 1 was out of business, 1 did not do residential, 1 was no longer doing ICF (and was actually an expert witness in a law suite against a prominent Foam ICF supplier), 1 was just not interested, 1 was never reached after lots of telephone tag, 1 was too busy, and I just did not get the right vibe from the last one (was too much like the one I parted ways with in March).  SO, so far I was batting 0 for 8.  The people on the list of five, provided three additional names.  Out of those three, 1 was too busy, 1 never returned my initial call, and 1 was not interested in ICF because of water ingress concerns (remember this one, I will come back to them).  This list of three recommended  2 more names and out of those two names, one was too busy (was a person I contacted back in March who was too busy then as well), and 1 sounded again like the fellow I had hired last March and I could see would not be a good match.  Scouring colleagues turned up another  4 names, 1 of which is not interested in ICF, 1 of which was not really recommended unless I had a basic design and did not need to ask questions, 1 which is in Ontario but licensed to practice in BC, and 1 of which looked like they basically only did large commercial work when I went to their website.  If you are keeping score, I am 0 for 16 plus 1 possible who works from Ontario.

I decided to go back to the person who did not like ICF due to water ingress concerns. I talked to him on the phone and assured him, my design with a full torch on membrane and several drainage planes would not have the same liability.  I was able to get his trust back when I explained that the ICF I was using was Dursiol and that yes I could do a full torch on without melting the ICF (something you cannot do with a foam ICF).  He agreed to meet with me and after a productive meeting, I felt comfortable proceeding with him and told him I would like to proceed on July 2.  That has been the last time I have heard from him.  After several follow up emails and phone calls, there has been no action.  I suspect the hold-up is based on some project requirements I have designed to.  I want to chose environmentally and IAQ friendly floor trusses, and for me, this means I want to eliminate the OSB I-Joists. I found a company in Quebec (TriForce) that uses the tops of Black Spruce trees to fabricate industry leading spans of 22ft with only a 11-7/8" deep truss.  This was great, as I have a height restriction in my neighbourhood (so need to keep my floor cavities as shallow as possible) and also want a fairly open floor plan.  This product fit the bill and I designed my floor plan around it.  The engineer had not heard of the product and seems to be reluctant to check it out and approve it.  I suspect he is just too busy to mess with something he is not familiar with.  But meeting my project requirements is important, I would need to redesign the whole floor plan if the 22ft spans was not approved by him,  as my wife and I do not want a bunch of drop down beams cutting off a nice 9ft ceiling space.

SO, it appears that I am back to square one yet again and that the fellow from Ontario may be my last chance at a touch down unless some of the people who were busy in June and July are now available.  I really was not expecting this task to be at all difficult, but it appears that as soon as there is a slightly abnormal quality to your project, a lot of vendors just are not equipped to deal with the extra effort required.  Out of the list of 17, I will re-approach 4 of them.

Lets hope threes a charm.

Thanks for reading - Cheers.


Unknown said...

If I read the Durisol site correctly, they say you can only use the 5.5" cores if you have less than 4' of unbalanced backfill. If you have more than 4', then you need to go to the 6.75" core at least.

From your drawings, you seem to be going 8' deep. So I don't understand how you are getting away with 5.5" cores??

I'm only going 6' deep, and I expect to use the 7" cores/12" block. If I could get away with less, then I need to figure that out!

And if I've signed in with my Google account, why do I need to keep proving I'm not a robot with the Captcha thing?

SENWiEco Designs said...

Not sure about the sign-in thing - are you selecting Google User from the drop down list?

I will be using the R8 configuration of the 10" Block. This has a 6.5" Core. The problem with the R14 configuration is that the core is actually only just above 5" which does not meet the BCBC which requires a min 5.5" concrete core in ICF. You probably do not need to use the 12" block and should be able to get away with the R8 10" block for your needs. Cheaper to put more insulation on the outside than it is to use a larger block and more concrete.

I just recently found a great structural engineer (I still have to do a blog entry on it). Give him a call for your structural needs as he is in Ontario. It is not about what Dursisol show, it is about your local building codes and what the engineer accepts. His name is Nathan Proper and works at Tacoma Engineers (five-one-nine-763-2000 ext. 217 Let him know I sent you.

Unknown said...

Fortunately, our engineer hasn't had a problem with the Durisol. He seems to get it. But it's always nice to have options, so thanks.

Wait until I tell him about Fastfoot, and trying to perch the footings up on a gravel base.

And then when I suggest I might want earthen floors!

It's sad that any departures from "the usual" can be so difficult to communicate and work with. Even if they are better.

Unknown said...

I keep forgetting to ask: why are you using Durisol, when Faswall is just across the border from you (I think). Wouldn't they be way cheaper? Not to take away from Durisol...

SENWiEco Designs said...

To be honest - not sure I came across Faswall when I was researching. Will look into pricing, but I plan to move the Durisol in a train car along with my floor trusses I will get from TriStar. So not too bad in terms of freight costs or embodied energy of the freight.

SENWiEco Designs said...

Did some research re Faswall. An industry insider advised that this originally was to be a Durisol licensee but once they received some proprietary info from Durisol, they split and did their own thing. The product is made with used pallets unlike Durisol that uses new softwoods. There is health concerns re what may be in the pallet lumber and also how this typical hardwood would behave in below grade environments. I have also read on various blogs now, concerns over Faswall's dimension tolerances. I will stay with Durisol and plan on shipping it by train from OT to reduce the freight carbon load.