Hi all – I was surprised to read claims from ICCF makers that regular ICF blocks are not fully pest resistant. Bautex Blocks is one company that made this claim. Are ICF blocks vulnerable to termites or other pests? Have any of you seen this in your builds, or heard about it? I didn't think termites would go after EPS foam. The ICCF blocks, like Bautex, are a combination of EPS and cement. So they're much sturdier and masonry-like, but with lower R-values than pure EPS. I'd want to add an inch or two of polyiso or Kingspan Kooltherm continuous insulation. (By the way, has anyone introduced ICF blocks made of polyiso or other material with better R-values than EPS?) Thanks.

Not sure what people do in the south but yes they have to protect from termites. I am sure others will provide more information, or you my be able to search.

ICF uses EPS because it has strength to hold concrete and cost. Other materials my work but you likely will find they don't work as good and aren't supported in the industry.

Follow the masses and you will be better off. What area are you in? Welcome to the forms....

Polyiso will readily absorb moisture and cause problems. It should only be used in dry locations.

Anything with EPS (ICF or ICCF) may allow pests to tunnel through the EPS. ICF does have a solid concrete core that will prevent pests from tunneling completely through the wall to the interior space. EPS is not a food source, but pests will tunnel into it to get to a food source or to get to a warmer location. EPS is often treated to discourage this in pest prone areas. And this is also easily prevented by several construction methods. Much info can be found on this issue and various ways to eliminate it by Googling. And I would also add that both ICF and ICCF are more robust in this regard than any 2x hollow wood wall construction method.

https://www.icfmag.com/2017/09/termites-and-icfs/

Polyguard makes a termite proof peel and stick waterproofing. There may be more. There are several companies that make forms with a termite additive.

ICCFs that are "EPSCreet" seem to be immune to insects and rodents.

I think there is a YouTube video by Joseph Lstiburek of BSI talking about how ants made a home in the foam insulation of his barn. I don't think it was ICF but it had continuous exterior foam insulation.

The key was that there was an incorrect flashing detail that allowed water in to the wall and that is where the ants were. The dry sections had no ants.

You could say that tells you to build walls that won't ever see water on the insulation but I think that is not as easy as using a material that the pests can't chew through and then doing your best to keep it dry also.

I have been looking in to The Perfect Block and also EF Block. Both are ICCFs, The Perfect Block is available in several core thicknesses of 4 ft^2 blocks, EF Block seems to be less expensive and only available in a 10" thick 5 ft^2 block. EF means more concrete to fill the wall but it's a stronger screen grid. I might use a combo because a thinner block would be convenient in some spots.

When I started thinking about building, I made a wish list of membranes, coatings, insulation and steel cladding to make a super durable wall. After adding it up and comparing to ICCF, I think ICCF with a stucco/plaster finish comes out cheaper, with a superior finished product and potentially less construction labor. Even the best stick built construction has insect and rodent concerns, EPS ICF is better but doesn't eliminate the concern in the EPS, ICCF should eliminate the concern inside and out.

I think the screen grid scares some people and that is why conventional EPS/plastic ICFs are more common. I'm betting if I get an experienced crew to do the grouting, I'll get good pours and no voids. Luckily my build site is roughly between the EF Block and The Perfect Block factories, there are experienced crews pretty local.

If my roof is up to task I should have a 200+ year building. Hopefully I can protect my roof enough to prevent insects. I'm planning to use ZipR sheathing to get a continuous foam and thermal break under my OSB and Zip membrane. I'm going to have to make sure it's protected and the venting under my standing seam steel keeps pests out. I could have a concrete roof poured but that's a pretty big process with less payoff because you still need roofing and insulation.

Since I am building in a desert where rain is infrequent, surviving the sun is my main concern. If my roof steel can last 60 years, I should be dead before it's time to re-roof. Hopefully everything under the steel will last as long as the steel can. I'm going to have about 1,000 ft^2 of roof and I think materials will be around $10,000 including the I-joists, insulation, sheathing, waterproofing, flashing and standing seam steel roofing. Hopefully I'll be able to stretch my budget to include Eastern Red Cedar t&g paneling and some false exposed beams for the ceiling finish. Occasional coats of Cedar oil should make it moth and insect repellant hopefully throughout the building.

Interesting. What are the R-values for the Perfect Block and EF Block? Bautex was really low, I think less than 15, but they seem to have removed a lot of the information from their website. Have you looked at embedding steel studs on the outsides of the blocks? I've wondered about that ever since I saw ThermaSteel's panels. They use solid EPS, say 5½ inches, like SIPs, but instead of OSB boards on the outside they have steel studs. The key is that the studs are turned sideways, which is brilliant. It eliminates thermal bridging since the studs don't go through the wall, the foam. They're just embedded sideways, so the flanges extend maybe 1½ inches into the foam. It seems like embedding steel studs or straps on the outside of ICF and ICCF blocks would solve some problems re: attachments, siding, etc.

I haven't looked at steel reinforced SIPs all that much.

The ICCFs seem to be in the low 20s R value or higher if you go with The Perfect Block 10" asymmetrical which is in the 30s I think. but they say the thermal mass of the concrete core gives it an effective R value in the 40's.

In the desert environment I will be building in, I'm not sure if the thermal mass will be a benefit because during the summer, overnight low temps will still be higher than my thermostat setting...

I am not sure if the ICCF manufacturing process is conducive to embedding "studs". They say the ICCF surface readily takes stucco and plaster finishes without lath so if you choose that type of surface finish, most of the attachment issues are taken care of. On the interior I am looking for a good way to hang joists and I think I am going to take a lesson from art galleries and embed an aluminum t-slot track high on the walls and hang picture frames from the track. For things like kitchen cabinets, it won't be too hard to concrete anchor a French cleat to the wall and hang things that way. I think I am going to have one articulated TV mount in an ICCF wall which I will also attach with concrete anchors. In some spots I might have to create mounting plates so my anchors can land on the concrete grid but that shouldn't be hard unless I need it to look pretty. I have to attach a deck on the exterior also but it will probably attach the same as my interior floor joists. I think I have found a very good "Cyclone Tie" for attaching my roof joists to the tops of the wall and they embed in the concrete in a straightforward way. I don't think attaching stuff will be much of an issue because I'm planning every detail before I jump in to construction.

You might want to check those R-values the ICCF companies are claiming. They won't be anywhere near the 30s. ICCFs are significantly worse than ICFs in R-value because they don't use pure foam. Even a solid 10 inch ICCF block – one that didn't have any concrete fill – would fall short of 30, because the composite material is not close to R3 per inch. They'd be lucky to achieve R2 per inch. Then you have to factor in the concrete cores, even if only screen grid.

Mixing EPS with cement severely degrades the insulating properties of the resultant material. A normal ICF block is only going to be R20 to R23 theoretical, so an ICCF block will be less than 20 unless it's much thicker. I'm curious if mixing with better materials would make a significant difference. Would XPS or Kooltherm improve the blocks, or would their properties be lost if mixed up with cement?

And termites will tear clean through ICCF using EPSCreet like a hot knife through butter... I got to see that first hand in southwest TX. At least with ICF, they have to go up the entire exterior EPS to get to the interior. But they will certainly do that too if allowed to do so. So it’s always best to place a termite barrier. See the previous link I posted for more about this.

Build Block has a termite shield that installs between a course of blocks. It looks like something that can be fashioned out of coil stock and a aluminum break.

Yes and there is a photo of it and it is discussed in article that I previously posted link. It essentially works by forcing the termites to reveal themselves as this shield and ICF concrete core blocks their path up the external EPS. However, this shield approach likely wouldn't work for ICCF as they could just chew straight through this relatively porous material.

Yes, any company that uses thermal mass and effective R-value in their marketing may be grossly exaggerating what you will actually experience. You only get a significant beneficial thermal mass effect when the outdoor daily temp varies both above and below the desired indoor temp. If your outdoor daily temp is always above or always below your desired indoor temp, you won't see a significant beneficial thermal mass effect. Standard ICF has a conventional R-value of about R21, but our actual effective R-value in Summer is about R60 because of our southern Oregon diurnal climate (daily 100F high and 50F low). But in Winter our actual effective R-value is only about R21 because the daily high temp is always well below 70F. You can accurately determine what your ICF effective R-value will be in your location by using this calculator:

https://www.borstengineeringconstruction.com/ICF_Performance_Calculator.html

Posted By sailawayrb on 24 Nov 2020 12:35 AM
And termites will tear clean through ICCF using EPSCreet like a hot knife through butter... I got to see that first hand in southwest TX. At least with ICF, they have to go up the entire exterior EPS to get to the interior. But they will certainly do that too if allowed to do so. So it’s always best to place a termite barrier. See the previous link I posted for more about this.

Do you have any pictures of this termite damage?

I would like to believe that EPSCrete would be impervious to insects at least as much as Aerated Concrete which is another ICF option (EZ Block). Once it is coated with stucco/plaster, that should give you an additional barrier and I think there are some flashing details that can be done around the foundation to protect that junction of foundation to wall.

As for the R value of ICCF, the asymmetrical 10" block has 50% more EPSCrete insulation than their R21ish 8" block so R30 is very likely accurate.

Compared to leaky standard construction, I think R21 and air tight should be fine for walls in a desert. My roof is going to be at least R40 with a thermal break, radiant barrier and portions shaded by solar panels. To me the roof seems like the bigger issue for summer time solar heat gain (and winter heat loss to some extent).

Any way, the desert has things like scorpions, rattlesnakes and possibly some poisonous spiders that I would prefer to keep out. With the lack of water, I'm not too worried about termites and like I said, I'll do my best to keep water out of the wall despite the lack of water.

I was largely responding to the OP who created this thread and who apparently needs to deal with termites and is considering options.

No, I don’t have photos of ICF or ICCF termite damage that I had occasion to witness, but a little research should uncover some. Termites can pretty much get to wherever they want to go if given enough time. And while I would like to believe in many things too, reality keeps getting in the way…

I don’t think R20 walls and R40 ceilings will be nearly enough in an extremely hot location if you are looking for any energy efficiency. There was a guy (perhaps ICFbuild?) who built his off-grid place somewhere remote of the Phoenix AZ area many years ago and he posted here frequently for a time (often complaining about geothermal). He considered ICF, ICCF, CMU and several other options. He ended up doing a double wall design…perhaps stone/CMU exterior side, steel stud drywall interior side and filled the cavity between these double walls (which was something like a 24” wide) with rock wool (which he somehow sourced for low cost). And his ceiling was something like R100 if I remember correctly. He reported needing only a very small HVAC footprint. Anyhow, I think he has since retired, moved to New Zealand and he doesn’t post here any longer.

The stated r-value for a Rasta block is 1.7 per inch. So that would make a 10" block r-17 by third grade math.

Exactly and when you factor in the lower concrete R-value your total wall R-value will likely be something under R15.

Smart Shop, you're missing the point on the R-values. The R-values you're quoting are false. The reason we know that they're false is that the material has much lower R-value than pure foam. There is no "R21-ish" 8-inch block of EPSCrete. It doesn't exist. You've got to wrap your head around the fact that EPSCrete isn't an insulation material. It doesn't have normal insulation performance – it's much worse than any known insulation product. And then there are the concrete cores, so you'll have to revise downward from an already low R-value. This means you'll need much thicker walls if you want to use it as your only material. 16 inches or so might get you around R21. Otherwise, if you use the regular 10-inch or 6-inch blocks, you'll need to add a couple of inches of rigid foam or mineral wool to get a decent R-value. By default, an EPSCrete house has much worse insulation than a normal 2 × 6 wood frame stucco house in Phoenix. Even regular ICF is sort of mediocre, but ICCF is well below average.