Greetings all! I'm in my late 40s, and have been on the "property ladder" my whole life. In other words, I've bought cheap, run down houses and fixed them up while my family lived there, and while I work my "day job". Then after a while we sell the house and shift up to something more expensive, and do it again. It's a way to gain equity over time. This has required small and medium-sized renovations including full kitchens, bathrooms, foundations, siding, stairs, roofing, flooring, drywall, HVAC, plumbing, electrical, everything except main sewer and water lines (knock on wood!). I've done this using a combination of DIY and contractors. My experiences with contractors has taught me to be careful- there are many good ones out there, but also many bad ones that create more problems than they solve. I'm planning a major ICF addition to a house. The addition with be a 4-story, 28x21 ft "accessory family suite"... a house of it's own really. I plan to use ICF, because I can do it mostly DIY but with a 25-yr ICF contractor checking my work before pours, and being on site during pours. I can be in control of most aspects, which I like. I'm looking for ways to minimize risk in the build. The question I have for the forum is about plasticizers in concrete for ICF builds. It sounds like plasticizers are ideal for ICF concrete because you get better flow without adding water, and some even say you don't need to use vibrators, which some say is beneficial because it reduces the chances of blowouts caused by somebody holding the head against EPS too long or too aggressively. Seems like a great investment to minimize risk during the pour, which is a "low-control" situation. What do you experienced folks think? Are plasticizers as good as they sound for ICF? Is there a brand that's better than others? Any tips on using it? Do I need to personally monitor it being added to the mix? Thanks!

In regards to plasticizers. Best place to answer your question would be to visit your local concrete plant and speak to the plant rep. Since your concrete will be coming form them, they will add plasticizers to your mix based on your needs. Plasticizers will help the mix flow to the slump required.

Depending on your location (city/rural/distance from plant), a lot of factors at play. You can order a 3,500 psi mix with 6-8 inch slump using plasticizers. Some concrete plants use ONE person who is in charge of doing all the mixing and then dispensing them into the waiting concrete truck. Other plants leave the mixing up to the DRIVER of the concrete truck. Find out what your plant does.

So let's say the truck leaves the plant at a 6 inch slump and it's 90F outside and it's a 30 minute drive from the plant to your site. By the time the truck pulls up, the grout pumper guy gets setup, it can be pushing 45-60 minutes since the mix was added to the truck. That 6 inch slump is now maybe 5 inches or maybe even 4 inches. That will not flow well into an ICF wall full of rebar. So the guy in charge of running the hose will ask the driver to add water to the mix to get it to flow at 6+ inches once again. That might be 25+ gallons of water to the 10 yard drum.

In a perfect world, the ordered slump will arrive perfectly at that slump ordered to the site, but we don't live in a perfect world. Every ICF pour I have been on, water had to be added. Concrete trucks carry water on-board for that reason. Being a rural area, it's a 45 minute drive to most sites. Pouring in the summer heat vs winter, changes everything also. I am not an expert but all the flatwork guys I know, they all add water to their mixes to get them to flow at the site. Especially in the summer heat. The summer sun beating on the concrete trucks steel drum and the 90F dry air temps will play havoc on most concrete mixes.

Over-vibrating a wall causes problems also, with blowouts. A good flowable mix should flow into all areas with minimal vibrating.

That's my take on it...Others can chime in but that's what I have experienced.

Ok thanks. So what you've seen is usually just water is added to get a flowable mix, and it doesn't cause any trouble strength-wise for ICF. Maybe plasticizers make more sense for high-spec concrete applications or something. I'll take your advice and talk to the concrete yard my contractor recommends. For only $5-$6/yard, I'd be happy to try it unless there's a reason not to, since voids in a 4-story build would ruin my sleep! ha

It is never a good idea to add water to a mix to increase flow. It's a filler that evaporates leaving a weaker concrete. I use ad mixes in my pours depending on the conditions. I dose on the job to make sure it's in the mix. The water reducers have a somewhat short time they are effective so I find it easier to load at the job. One additive to use to increase flow is fly ash. It gives gives you stronger concrete.. Where I am it's included in all mixes, but I increase the percentages. Regardless of mix all icf pours need to be vibrated. No vibration means voids.

A plasticizer is a substance added to concrete to improve its workability without significantly affecting its strength. It achieves this by reducing the water-cement ratio, making the concrete mixture more fluid and easier to pour and shape. This increased workability is especially beneficial when concrete needs to be placed in tight spaces or when a smoother finish is desired. Plasticizers are commonly used in various construction applications to enhance the handling and placement of concrete. On the other hand, superplasticizers, also known as high-range water reducers, are more potent additives that offer superior control over the flow and workability of concrete. Unlike plasticizers, superplasticizers can greatly reduce the water content in a concrete mix without compromising its workability. This results in a more densely packed and durable concrete with improved strength and lower permeability. Superplasticizers are particularly valuable in applications where high-strength, self-consolidating, or low-permeability concrete is required, such as in high-rise buildings, bridges, and marine structures. What is Plasticizer? A plasticizer is a chemical additive that is commonly used in various industries, including the production of plastics, rubber, and concrete. Its primary function is to increase the flexibility, workability, and pliability of materials, particularly polymers like plastics and elastomers. Plasticizers achieve this by reducing the intermolecular forces between polymer chains, which allows them to slide past each other more easily. As a result, the material becomes more flexible and less brittle. In the context of concrete, plasticizers are used to improve the workability of the concrete mix. By reducing the water-cement ratio without sacrificing the mixture's ability to flow and be shaped, plasticizers make it easier to pour and mold concrete, especially in situations where intricate or tight forms are required. This helps in achieving a smoother finish and enhances the ease of handling and placement during construction. What is Superplasticizer? A superplasticizer is a specialized chemical additive used in the construction industry, specifically in the production of concrete. Its primary function is to significantly improve the workability of concrete mixtures while simultaneously reducing the water content needed for the mixture. This unique property distinguishes superplasticizers from regular plasticizers. Superplasticizers work by dispersing and deflocculating the cement particles within the concrete mix. This action allows the particles to be more evenly distributed and keeps them separate, resulting in a highly fluid and workable concrete mix without the need for excessive water. As a result, superplasticized concrete can achieve a much lower water-cement ratio compared to traditional concrete mixes, which typically results in higher compressive strengths, improved durability, and lower permeability. https://www.engr.psu.edu/ce/courses/ce584/concrete/library/materials/Admixture/Link-sup.htm Though more expensive the Superplastiicizer is the way to go IF they are compatible with the cement being used by the concrete plant . adding about 20% flyash will also create a more flowable concrete and reduce the amount of cement required reducing cost without affecting concrete strength. And you should always vibrate your concrete in ICF using Helix 5-25 micro rebar in the mix will also reduce aggregation problems in the concrete. With Helix you can eliminate Horizontal rebar placement . You will still need Horizontal rebar in the corners , over Lintels and at the tops of walls to anchor anchor bolts in the concrete. Helix will increase the flexural strength of your concrete by 300% it will also increase your concrete’s ductility by up to 30%. We use MST-bar in the corners over lintels, at the top of the walls (horizontally ) and vertically in the walls and helix through out the mix. MST is a fiberglass rebar, light weight and never rusts, it is the only fiberglass rebar that can truly claim that it is 3 times stronger than steel rebar. There are many copy cats but none are as strong as MST-bar. The concrete will actually adhere to MST-bar better than steel rebar. While there are certain instances that steel rebar is still required MST-bar and Helix 5-25 can handle most of ICF concrete reenforcement. And reduce aggregation problems in the process

Understanding your weather conditions and distance from the concrete plant to the job-site and the height of your wall pour all play a role in deciding what additives to use and having additives on hand at the job-site to ad to your add mixture plays a crucial role in how your concrete performs. In anddition to andding 20% flyash, All superplastizers are not created equal! We use Supercizer 7 from Fritz-pak. You can reduce your water content by 40%. If you are 45 min from the concrete plant and it is 90 degrees.outside, We would add Fritz-pak’s standard delay set to the admix. When the concrete arrives on the job-site and we are pouring the bottom of a 24’ tall ICF.pour (which we routinely do) we will add Fritz-Pak’s Non chloride accelerator to the mix (if standard delay set has been added we have to use more NCA.). But you have to know your concrete and when to add what! We do this to accelerate the concrete setting up in the bottom of the wall to get early strength in the tall wall pour. There is a lot to managing this process, timing of your trucks is critical too!

Understanding your weather conditions and distance from the concrete plant to the job-site and the height of your wall pour all play a role in deciding what additives to use and having additives on hand at the job-site to ad to your add mixture plays a crucial role in how your concrete performs. In anddition to andding 20% flyash, All superplastizers are not created equal! We use Supercizer 7 from Fritz-pak. You can reduce your water content by 40%. If you are 45 min from the concrete plant and it is 90 degrees.outside, We would add Fritz-pak’s standard delay set to the admix. When the concrete arrives on the job-site and we are pouring the bottom of a 24’ tall ICF.pour (which we routinely do) we will add Fritz-Pak’s Non chloride accelerator to the mix (if standard delay set has been added we have to use more NCA.). But you have to know your concrete and when to add what! We do this to accelerate the concrete setting up in the bottom of the wall to get early strength in the tall wall pour. There is a lot to managing this process, timing of your trucks is critical too!

Understanding your weather conditions and distance from the concrete plant to the job-site and the height of your wall pour all play a role in deciding what additives to use and having additives on hand at the job-site to ad to your add mixture plays a crucial role in how your concrete performs. In anddition to andding 20% flyash, All superplastizers are not created equal! We use Supercizer 7 from Fritz-pak. You can reduce your water content by 40%. If you are 45 min from the concrete plant and it is 90 degrees.outside, We would add Fritz-pak’s standard delay set to the admix. When the concrete arrives on the job-site and we are pouring the bottom of a 24’ tall ICF.pour (which we routinely do) we will add Fritz-Pak’s Non chloride accelerator to the mix (if standard delay set has been added we have to use more NCA.). But you have to know your concrete and when to add what! We do this to accelerate the concrete setting up in the bottom of the wall to get early strength in the tall wall pour. There is a lot to managing this process, timing of your trucks is critical too!

Understanding your weather conditions and distance from the concrete plant to the job-site and the height of your wall pour all play a role in deciding what additives to use and having additives on hand at the job-site to ad to your add mixture plays a crucial role in how your concrete performs. In anddition to andding 20% flyash, All superplastizers are not created equal! We use Supercizer 7 from Fritz-pak. You can reduce your water content by 40%. If you are 45 min from the concrete plant and it is 90 degrees.outside, We would add Fritz-pak’s standard delay set to the admix. When the concrete arrives on the job-site and we are pouring the bottom of a 24’ tall ICF.pour (which we routinely do) we will add Fritz-Pak’s Non chloride accelerator to the mix (if standard delay set has been added we have to use more NCA.). But you have to know your concrete and when to add what! We do this to accelerate the concrete setting up in the bottom of the wall to get early strength in the tall wall pour. There is a lot to managing this process, timing of your trucks is critical too!

Understanding your weather conditions and distance from the concrete plant to the job-site and the height of your wall pour all play a role in deciding what additives to use and having additives on hand at the job-site to ad to your add mixture plays a crucial role in how your concrete performs. In anddition to andding 20% flyash, All superplastizers are not created equal! We use Supercizer 7 from Fritz-pak. You can reduce your water content by 40%. If you are 45 min from the concrete plant and it is 90 degrees.outside, We would add Fritz-pak’s standard delay set to the admix. When the concrete arrives on the job-site and we are pouring the bottom of a 24’ tall ICF.pour (which we routinely do) we will add Fritz-Pak’s Non chloride accelerator to the mix (if standard delay set has been added we have to use more NCA.). But you have to know your concrete and when to add what! We do this to accelerate the concrete setting up in the bottom of the wall to get early strength in the tall wall pour. There is a lot to managing this process, timing of your trucks is critical too!

We also pre panelize all our walls and floors (above the concrete basement or first floor slab). The ICH walls have your window and door buck framing and buck bracing installed, we pre-wire and pre plumb them and install a new type of drywall made of Magnesium Oxide ( water and mold and mildew resistant, has an excellent fire rating, high impact resistant, a green building product-carbon negative, has sound proofing qualities, and the material will not cause fasteners to corrode.). We used steel stud framing for internal walls all prepanelized at our shop- pre wired, pre-plumbed, with MgO drywall installed we build our floors in cassettes ( 12’ wide by up to 30 ft long ( all clear span) using steel floor joists and steel ledger boards with MgO drywall installed on the bottom of the joists and MgO sub floor panels installed on top of the joists. We install a Radiant heat and radiant cooling system just above the ceiling drywall in the cassettes ( no duct work required). And we install a MgO sip roof R-60 with max wind load of 230 mph they are installed in panels 8 ft wide by 24 ft long. They do not require rafters or trusses. The whole process takes a week to 10 days with occupancy permit in 3 weeks from start of site work.

We also pre panelize all our walls and floors (above the concrete basement or first floor slab). The ICH walls have your window and door buck framing and buck bracing installed, we pre-wire and pre plumb them and install a new type of drywall made of Magnesium Oxide ( water and mold and mildew resistant, has an excellent fire rating, high impact resistant, a green building product-carbon negative, has sound proofing qualities, and the material will not cause fasteners to corrode.). We used steel stud framing for internal walls all prepanelized at our shop- pre wired, pre-plumbed, with MgO drywall installed we build our floors in cassettes ( 12’ wide by up to 30 ft long ( all clear span) using steel floor joists and steel ledger boards with MgO drywall installed on the bottom of the joists and MgO sub floor panels installed on top of the joists. We install a Radiant heat and radiant cooling system just above the ceiling drywall in the cassettes ( no duct work required). And we install a MgO sip roof R-60 with max wind load of 230 mph they are installed in panels 8 ft wide by 24 ft long. They do not require rafters or trusses. The whole process takes a week to 10 days with occupancy permit in 3 weeks from start of site work.

I'm curious how do you pour the bottom of a 24' wall?

MeasureTwice, I am wondering if you are located in Southeast, USA.

So I had to prove to a building inspector ICF didn't need sheer walls.....(head hitting wall)

Did an example of the strength of a shear wall against an ICF wall of the same size with a garage door opening in it....

The ICF 6 inch wall was over 10 times stronger even with the 9 foot opening in it....

My question is why do you need it stronger and for the cost.....put in more insulation or spend money on things that are going to save you money in the long run.....

Did you know that concrete that sets underwater can be stronger than concrete that sets in open air? In an ICF wall, the concrete is protected from air/wind/sun, so it cures very slowly and the water evaporation rate is very slow. The slower the rate of evaporation of water, the better the result of the concrete will be. The "vulnerable" spots are on top of the ICF wall where there is no insulation and it is exposed to the environment. The claim is that it take around 30 days for an ICF wall to cure out.

On exposed slabs, one of the most common methods for curing concrete is to hose it down frequently with water, 5x daily, up to the first 7 days. Moist curing allows the moisture in the concrete to evaporate slowly. The slower the water evaporates from the mix, the better.