Mitering an ICF Ledge Corner III
July 27th, 2010 | Common Troubleshooting, Lets Get Technical!
If you’ve been reading with us for the last couple posts we are now on part 3 of the ICF Construction- Mitering a Ledge Form tutorial. We decided to get this communicated out there as sometimes it can be tricky in the field if you haven’t done so before. But after you do it once or twice you’ll be a pro.
Altering the ICF Form Teeth
At this point both sides of the ledges are cut now you need to make sure the proper modifications are made in order for forms to stack on top of a regular corner form and a corner form will sit snugly on top. As well as making sure the cavity is conducive to concrete flow and support of the entire ledge.
Notice the raised flat foam areas in the 90-degree corners. The interlocking teeth will not seat all the way down in those locations.
Rasp down half of the height of the interlocking teeth on the interlocking teeth that will bear on the flat raised foam areas so that the ledge form sits down properly on the 90 degree corner.
Now that the ledge form fit snugly on top of the corner form, we need to remove some foam to allow for free flowing concrete. Where the two mitered pieces of ledge form meet at the very corner, trim the foam within the concrete core corbel area at a similar angle of the corbel on both sides.
This opens up the concrete corbel area for sufficient concrete volume.
Cut and remove half of the interlocking teeth on top of the ledge form that will meet the flat raised areas of the 90 degree corner that will stack on top of the mitered ledge form.
Once the mitered corner is cut and dry fit for acceptable appearance and function, glue the mitered cuts together and stack on top of the 90 degree corner.
Lastly, Secure Your ICF Corners!
Use horizontal and vertical wire hooks to secure the mitered ledge form to the immediate straight forms. The mitered ledge could also be taped together to add further support to the glue.
For Thursday on our Mitering a Ledge Form Series we will go over cutting and placing the one and only xLerator- ICF Ledge reinforcement system. And then we’ll go over BRIEFLY how to do an inside miter cut (The principles are the same, just reversed really)
Mitering an ICF ledge corner II
July 22nd, 2010 | Common Troubleshooting, Lets Get Technical!
Our last post we started our ICF ledge corner tutorial and it will continue on today with a couple more steps! Before you know it you will have some clean cut and sturdy ledge corners…maybe even better than our own Darryl U’s!
Cutting the Ledge Form
Now that you’ve cut the ledge side of the block now you have to do the other. Mark and cut the straight foam panel, opposite the ledge side, at the 90 degree bend location where the outside foam starts. (Noted by the arrow)
After the both cuts are made, the plastic tie insert must be cut to separate the two pieces.
Sounds simple enough huh? Now you have one side of your corner cut. Repeat those procedures to cut the other corner return as well.
Cutting the Second ICF Return
Reminder: Make sure ledge form extends past the corner far enough to allow for a 45 degree cut on the ledge side AND make sure plastic furring strips are lined up.
ICF
For the other ledge form for the opposite return, cut at the inside 90 degree bend where the core starts. The cut is to be a square cross cut. After the both cuts are made, the plastic tie insert must be cut to separate the two pieces.
Now use the rasp to smooth out corners edge to ensure a snug joint and even surface to apply foam glue.
For next Tuesday we will go over some slight ledge form adjustments you’ll need to make to make sure the forms will stack correctly on top of the ledge as well as go over the xLerator modifications so it fits in the corner properly.
Mitering an ICF ledge corner
July 20th, 2010 | Common Troubleshooting, Lets Get Technical!
Common ICF Question
We get a lot of questions on mitering our ICF ledge form in order to make inside and outside corners. Most people get hung up on dimensions and measurements but really there isn’t a whole lot of need for measuring. You need the proper tools to get things done correctly and use a little patience while putting your ICF ledge corners together.
In the following posts I will be outlining a few steps each time to successfully miter you corner ledge forms and reinforce them properly. After we cover those items I will go over a proper bracing strategy for ledge forms as well.
Mitering a 90 degree ICF Ledge
The first thing you need to make sur you have is the proper tools. This will ensure you can move smoothly through the process and make the whole task simpler. Tool you need are:
- Saw
- Straight edge
- Speed Square
- Rasping device
- Tape measure
- Also don’t forget- Tape or Glue and a wire cutter to cut xLerator
Next you need to place the ledge form on top of a 90 degree ICF corner. Make sure to place the ledge form far enough past the corner to allow enough room for the 45 degree cut and be sure the furring strips are lined up with each other.
Using the speed square and straight edge, mark and cut the LEDGE side at 45 degrees from the INSIDE edge of the 90 corner form.
Come back on Thursday for Mitering a Ledge Form part II, as we continue on our ICF ledge form corner tutorial.
ICF Concrete Placement: Boom Pump Safety
June 29th, 2010 | Lets Get Technical!
ICF Concrete Boom Pump
An important aspect that insulating concrete form contractors must always be cognizant of is safety when working with concrete boom pump trucks. A successful ICF project can be ruined if a major catastrophe or injury would happen to occur. Safety should always be a top priority. The concrete pump operator and contractor must be aware of potential dangers and take proper precautions.
Setting Outriggers
The contractor must evaluate the site conditions and communicate them to the pump truck dispatcher and operator. They need to know the size of pump needed, back-filled areas, underground obstructions, soil conditions, muddy or soft areas, and site restrictions. The outriggers should be firmly placed before unfolding the boom. Cribbing is used to spread the load out to the soil from the outriggers. The general rule is to use as much cribbing as is practical; too much is better than too little. After placing the cribbing on even soil, place the weight of the truck on each outrigger one at a time. If the pad starts to sink, retract the foot and add more cribbing. Continue setting each outrigger using the same process.
Do not place the outriggers on a hill or too close to an excavation or cliff. The one-to-one rule must be followed by keeping the outrigger back one foot from the edge for every one foot of vertical drop. If necessary, move the truck to a different location to avoid any of these areas.
When unfolding the boom, continue to keep an eye on the outriggers for any shifting or sinking into the soil. Keep people out from underneath the boom whenever possible.
Operating the Boom and Pumping Concrete
The pump operator should show the contractor the locations of the emergency stop switches. It is important to wear personal protective gear such as goggles or safety glasses, hard hat, ear protection and rubber gloves. Never stand between the ready mix truck and the pump. Stand off to the side where the driver can see you. Always be aware of overhead electrical power lines. If the pump or boom becomes energized with high voltage, anyone or anything that touches it will be at risk of electrocution. Be sure someone is always monitoring the location of the boom and that it stays at least 17 feet away from electrical wire.
Do not let the concrete level in the hopper become so low that you can see the top of the valve mechanism. If this occurs, immediately stop the pump as air can be compressed into the cylinders. This creates a dangerous situation; as the air is expelled from the hopper or pump line it could act as a cannon shooting out concrete. Slowly restart the pump with caution.
The person at the end of the hose should hold the hose loosely with both hands, keeping it out away from him. He should also be sure not to hug the hose. Spend as little amount of time as possible standing under the boom. Two important issues to avoid at the end of the hose include never kinking the hose and never hanging heavy devices from the hose. If the hose becomes kinked it will cause the pump to have maximum concrete pressure. A heavy device at the end of a hose can cause extreme hazard to the individual holding the hose. If the hose were ever to whip, it could easily knock him down. A heavy device at the end of a hose can cause extreme hazard to the individual holding it. If the hose were ever to whip, it could easily knock the person down.
Read our series on Concrete Placement in ICFs to get a good understanding of the type of concrete to use and the proper placement in insulating concrete forms. Remember if the concrete is not what was specified: SEND IT BACK
Frank Theatres York, PA Update
April 8th, 2010 | Project Showcase
Here’s an updated on Frank Theatre in York, PA. This is a very popular project that is being followed on our blog so we wanted to post an update before the grand opening on the horizon. If you didn’t catch the first post, check out the beginning ICF construction of Frank Theatres.
We visited the theater last week with Chris P of Construction Supply Centers. They are progressing quite nicely now. The various aspects of finish work are well underway and it’s really starting to look like a theater now. Tim Boos, Project Manager with Warfel Construction said they had had some delays with the weather and were expecting to be ready to open the before the first week in June.
When walking through the individual theaters there is a unique “quietness” to them which is easily attributed to the mass of the insulating concrete forms walls. There was no need for any sort of spray foam on the walls dividing the individual theaters because of the use of Reward’s iForm. We would presume that was a significant savings in terms of labor and materials for the owners. The painters were in, touching up the main corridors and lobby area and there were contractors setting the big decorative columns in the main lobby. There’s a nice restaurant area in the front which will be an excellent convenience for the patrons of the theater.
We are looking forward to visiting the theater when it’s completed and excited for the Frank Theatre’s upcoming Grand Opening. Here are some follow up pictures with the exterior getting closer to completion, taken back in January.
Concrete Consolidation for ICFs 3
March 29th, 2010 | Common Troubleshooting, From the Field
As we have discussed so far there are three main components to proper consolidation of concrete in Reward ICFs. We have already addressed the proper mix, and the placement, and now we’ll go over the actual consolidation.
- Concrete Mix for ICF
- Placement of Concrete for ICF
- Consolidation in ICF
Concrete Consolidation
The concrete placed into the Reward walls needs to be consolidated. Consolidation is required to prevent voids, prevent honeycombing and to ensure that there is solid contact made between the concrete and the steel reinforcement. It is important to consolidate the concrete during each concrete lift. Consolidation can be accomplished by using internal vibration.
We do not recommend other types of consolidation as they are not as effective and the iForm can handle internal vibration. The Reward iForm has plastic webs 6 inches on center making the form very strong for concrete placement and consolidation. Additionally with the webs 6 inches on center, there is less EPS foam area being supported by each webs making the form strong during concrete placement and consolidation. This results in a very consistent flat wall with no pillowing or bulging at the horizontal and vertical seams that is typical with forms that have ties 8” or greater on center.
Internal Vibration
This is the best method for consolidating the concrete. A light-duty pencil with a maximum 1″ diameter head size, the lowest frequency or revolutions per minute, a lower motor size of 3/4 to 1 maximum horsepower and the shaft length to meet the wall height vibrator is recommended. The head can be either the squared headed or round head. Darryl U prefers the square head vibrator. The concrete should be stung on each lift and in such a manner that the multiple lifts should be boned together. This can be accomplished by internally stinging thru the current lift and just into the previous lift by a few inches 6” approximately, thus bonding the two together.
Do not use an internal vibrator unless it meets these guidelines. Consolidation using internal vibration method should be done with care to avoid placing excessive internal pressure on the forms.
In order to achieve the best results when using an internal vibrator, it is important to place the head of the vibrator into the concrete fast and remove it slowly from the concrete. This will do the best job of removing the entrapped air from the fresh concrete. Once the head is in the fresh concrete it should be moved slowly but consistently through the concrete.
Around areas of high reinforcement concentration special attention should be given to ensure proper consolidation of the concrete. The rule of thumb for stinging concrete is steady and deliberate when stabbing into the concrete and withdrawing at approximately 1’ per second. The rate of withdraw of the vibrator is also determined by the release of entrapped air in the concrete. and loosen the amounts of congestion inside the form at any given area. Caution should be taken so the vibrator doesn’t touch the sides of the forms. The frequency and amplitude will determine the spacing between the insertions and the rate of withdraw also.
In summary, all three of these aspects must be monitored for each pour. Internal vibration is a must to ensure that the concrete inside of the form work be consolidated to achieve structurally sound walls. These are only guide lines as experience will play into the methods of good technique of internal vibration.
One thing to stress. The most important element of all three is the proper concrete mix. If the mix shows up at job-site at a level not specified…REFUSE the concrete and send it back.
Concrete Consolidation in ICFs 2
March 23rd, 2010 | Common Troubleshooting, From the Field
Last post we went over the proper concrete mix for insulated concrete form walls. Depending on the forms’ size and the concrete core width, the concrete aggregate size and slump should be adjusted accordingly. The ultimate goal is to get the correct compressive strength for the concrete as specified.
Insulated Concrete Form Concrete Placement
The concrete should be placed in 4′-0″ lifts to ensure proper concrete consolidation. Typically if there is more than one concrete pour per project, the walls are poured a story at a time. Concrete is placed in 4′-0″ lifts using several passes around the perimeter of the building plan until either the top of the wall is reached or until the first pour is completed. Concrete should be placed below every window opening through the opening left in the sill of the window buck.
Most Reward builders have found that an overhead boom pump truck is the most efficient method to place the concrete in the Reward walls. With the overhead boom pump truck it is important to slow the velocity of the concrete by reducing the diameter of the hose to 3″ near the end of the line.
During placement, the ICF contractor must keep a close eye all the time on how the concrete is flowing through the forms and around rebar. Be sure the concrete is not getting hung up on rebar or any embedments.
During cold and hot weather, the concrete mix may need to be adjusted to modify its flowability and the rate of concrete placement may also need to be adjusted.
Next post we will cover the actual concrete consolidation and use of internal vibrators with insulating concrete forms.
Concrete Consolidation in ICFs
March 18th, 2010 | Common Troubleshooting, From the Field
Concrete consolidation is a very critical component in the construction of ICF buildings. The consolidation of concrete in the ICF wall is more difficult to inspect after the pour because the forms stay in place. That is why internal vibration and proper concrete mix and placement is important to ensure that there are no voids or honey combing in the wall.
There are three main components that must be evaluated and addressed. Consolidation is a function of all three components.
- Concrete Mix
- Placement
- Consolidation
Concrete Mix Design for ICF
One of the most important aspects of concrete placement is the proper concrete mix design. The flowability of the concrete is crucial. A quality concrete mix can go along way to assure a successful and efficient concrete placement. Proper concrete mix will save time on labor, facilitate concrete consolidation and provide for a successful Reward wall pour. Cutting corners on the concrete mix can add cost and problems when you go to place concrete into the Reward walls. Concrete mix can vary from region to region throughout the country, as the raw materials are different in various areas. Because of the variance in materials and the importance of a quality concrete mix, the best advice is to work closely with the local concrete supplier. Explain to the concrete supplier that you will be placing concrete in Reward insulating concrete forms. Reward cannot provide the specific concrete mix design; we can only provide guidelines for the mix.
A proper Reward concrete mix will incorporate the following guidelines. These guidelines must be conveyed to the concrete supplier. They will have the most knowledge about the materials in the area to design the best mix for the Reward projects.
Concrete Compressive Strength
The 28-day compressive strength of the concrete must be specified to meet the strength used in the design of the Reward walls. The minimum strength that should be specified is 2,500 psi. A slightly higher compressive strength of 3,000 to 4,000 psi can help the flowability and pumpability of the concrete and provide additional strength to the walls with minimal or no additional costs.
Slump for Insulating Concrete Forms
The slump is an important criterion in the concrete mix to allow the concrete to flow and be pumped at an efficient rate. Inadequate slump can create voids and honeycombs in the walls, or put excessive pressure on the forms during concrete placement. Reward generally recommends a concrete slump of 5.5 to 6.5. The core size of the forms will help determine the slump, and the smaller the core size the higher the slump. For example, the proper concrete slump for each size is listed in the table below.
| Form Sizes | 9″ | 11″ | 13″ | 15″ & 17″ |
|---|---|---|---|---|
| ICF Concrete Slump | 6.5″- 7″ |
6″-6.5″ | 5.5″-6″ | 5.5″ |
| Course Aggregate Size | 3/8″ | 3/8″-1/2″ | 1/2″-3/4″ | 3/4″ |
The slump specified must be the slump that arrives in the cement truck at the job site. Water should not be added to the concrete at the job site. Additional water will reduce the compressive strength of the concrete and affect the water to cement ratio.
Aggregate Size for ICF
The aggregate size is also important in providing concrete with the proper strength that will flow well through the insulating concrete forms. A maximum aggregate size of 3/8″ to 1/2″ is recommended for the best results. The risk of too large of aggregate in the forms could create the damming of the concrete within the forms resulting in a void.
As an example, again the smaller the core size needs the smaller aggregate. The proper aggregate for each size of core is listed in the table above.
Insulated Concrete Form Admixtures
Admixtures are ingredients in the concrete other than portland cement, water and aggregates. Some of the effects of admixtures are to improve the pumpability, durability and workability of concrete and for weathering purposes. There are many different types of admixtures available in different parts of the country. Some of types of admixtures include air-entraining, water-reducing, superplasticizers, retarding and accelerating. Fly ash, air, plasticizers and superplasticizers are common admixtures used in concrete in the insulating concrete form industry. The concrete supplier should address admixtures at the concrete mix design stage. The goal should be a good flowable concrete mix.
Be sure to thank our in-house ICF engineer Kelvin D and Darryl U for contributing to these posts. Next post we’ll go over concrete placement techniques.
|
|
9″ iForm |
11″ iForm |
13″ iForm |
15″ & 17″ iForm |
|
Concrete Slump |
6.5″ – 7.0″ |
6.0″ – 6.5″ |
5.5″ – 6.0” |
5.5” |
|
Course Aggregate Size |
3/8” |
3/8”-1/2” |
1/2”-3/4” |
3/4” |
Architect & Designers ICF Toolkit
March 2nd, 2010 | Marketing
ICF Marketing Support
Thought I take a post to announce a newly created brochure that is now available. This brochure, has been created to show our company history, major product lines, highlight benefits of ICFs, showcase a few projects and most importantly declares our pledge as the industry’s best in customer support- from conception of the ICF project until the walls are completed.
Too often we sell ourselves short on our service and support, however with current tough times and the better times ahead, its the innovation and service that will define our industry. Reward has a corporate office with sales and product delivery support, regional sales managers, marketing personnel, technical specialists (remember Darryl U?) and an engineer on staff- all which are corporately employed.
See here our new Toolkit for Designers and Architects to help communicate the benefits of Reward and insulating concrete forms.
Click to launch the full edition in a new window
ICFs vs PIP: Rebar requirements (Correction)
October 20th, 2009 | Common Troubleshooting, From the Field, Lets Get Technical!, Marketing
I needed to re-post this article that was published in our newsletter last week. When I edited for space requirements I switched a couple sentences around in the second paragraph and in turn the paragraph made absolutely no sense. So to please our on-staff engineer and Darryl U as well I am re-posting that article with corrections made.
If ICFs produce a higher strength concrete and ICFs and poured walls both follow ACI 318, why do ICFs require significantly more rebar than a poured-in-place wall? This is a question we have heard many a time, and there are two different issues that each requires a separate answer.
ICFs do have a higher concrete compressive strength. According to Portland Cement Association (PCA) testing and information a concrete wall that is moist cured 100% of the time will end up having a higher concrete compressive strength than a concrete wall where the forms are removed. Standard walls will cure quicker due to more air and less moisture. A structural engineer can not rely on this in the design calculations, so it is not used in the design. This is only an inherent strength of the concrete ICF wall.
An ICF wall designed by a structural engineer will and should have the same rebar requirements as a poured in place wall designed by that same structural engineer. There should be no difference (assuming the same concrete wall thickness and everything else being equal). This is especially true with commercial construction. People may see the differences with residential construction and primarily with below grade basement walls. For residential below grade basement walls, it may be that ‘traditional’ walls are designed using prescriptive tables found in the building codes. These tables can show less reinforcement to zero reinforcement when compared to the ICF tables in the IRC Section 404.4 or Reward’s prescriptive tables.
It is important to compare the same wall thickness. These tables may not require reinforcement for an 8” PIP wall but someone may be trying to use a 6” ICF with rebar and trying to compare the two. So the choice is – an 8” wall with no rebar or a 6” wall with rebar.
Temperature & Shrinkage (T&S) for crack control may come into play as well. The ICF industry tables basically will always show #4 at 48″ o.c. no matter what for T&S. The difference being a PIP wall may not need rebar structurally and does not put T&S rebar in the wall.
It is important to know and remember that an ICF wall is a PIP wall and there should be no difference. So if you are ever in that situation, there should be no difference assuming everything else is equal.
Our ICF walls can be designed to the SAME tables as the PIP walls in the building code. Our ICC ES ESR-1552 report refers to these tables. They can design to the traditional prescriptive tables in the building codes, the ICF tables in the building code, Reward’s prescriptive tables or ACI 332 prescriptive tables for residential concrete
In conclusion, it is due to a combination of these factors why why an ICF wall ends up erring on the side of “more” rebar than a PIP wall.