I have a post tension slab and notice the parging crumbled in some places and exposed some post tension cable end caps (plastic caps)
I called my builder and they came out. They said it’s just cosmetic and it’s fine that the end caps can be exposed like that. I believe the end caps need to be covered. They said that should be up to code and no need to do anything. Is there any code regarding this? What can I use to cover these?
I’m sure someone with more knowledge will chime in… I’ve never inspected a tension slab but did take a class once and remember the guy just kept hammering that they need to be labeled to keep people from inadvertently cutting them. Did you see any labels?
I bought the home right after it’s finished with flooring installed so I couldn’t see the labels. I didn’t see any labels in the garage as well. However, I’m sure it’s a post tension slab because the builder had an engineering report (they had to pass an engineering inspection from the engineer designed the slab).
The “Building Codes” do not specifically or remotely cover Post Tension Cable (PTC) reinforced foundations. There are other standards that do cover these however what standard was used is typically defined in the engineered foundation plan for the home. The Engineer will make references from that standard(s) and list them.
One very frequently/mostly used standard is the Post Tension Institute (PTI) manual “Construction And Maintenance Manual For Post-Tensioned Slab-On-Ground Foundations”. Unfortunately this standard can not be viewed for free but is available for purchase on the PTI site here Post-Tensioning Institute > Publications > Store > storeresults.
What you are viewing there is what is called the “Live End” or “Stressed End” of the PTC (also called tendon). Once the tendon is stressed and locked down (anchored with a specialty anchor system) they will thoroughly clean the cavity of dirt, debris, grease (used on the cable) and then reach into the pocket and cut the cable to create a 1" space between the face of the slab and the end of the cable. It is then grouted in with a specialty grout used for this purpose to provide a 1" cover over the cable end.
If they are unable to achieve the 1" spacing they can reduce that down by using the white cap you see there. However they should still have at least a 1/8" space between the end of the white cap and face of the foundation. Again they use the specialty grout to fill in the pocket and cover over the cap.
This is not a cosmetic issue. Those caps will deteriorate and eventually can expose the cable end to the elements. Even before it deteriorates water/moisture can enter around it and to the cable and cable mounting hardware. Exposing these cables and mounting hardware to water/moisture can naturally cause corrosion of the cable and mounting hardware. If the corrosion becomes severe enough the cable anchoring can fail either through broken cable strands or failed anchor hardware. These cables are under a high level of stress and if they release the results are unpredictable. It can be from minimum damage to fairly severe damage and also requires significant repairs just for the failed cable.
Typically if there is one cable exposed this way they did not properly finish them and there may be more in this condition.
This is something that should be corrected by the Builder if you are still in a warranty period. The correction is very simply removing the failed grout material and reapplying it. Failing to perform the correction can contribute to a potential failed cable later.
What I recommend is you demand the Builder display the engineered foundation plan and the actual standard documents they used to build it. Have the Builder show where this is supposedly a “cosmetic issue” as it is not.
Yes I have inspected after Engineers supposedly inspected slabs and seen many significant issues ignored. I would not rely on any Builder Third Party inspection report, nor any City inspection report, no matter who performed the inspection. It is akin to the saying “The Fox is guarding the hen house!”.
Where are you located?
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Thanks for the detailed explanation! I’m in North Dallas, TX
Is the specialty grout you’re referring to hydraulic cement? I’m still in the structural warranty period so I’m trying to get them to fix the issue. I just want to make sure they do it correctly.
No hydraulic cement is a typical patch for cracks when the area is wet like a leaking crack in a concrete wall. It is made to cure rapidly when applied even with moisture/water present and it hardens well. It is also considered a temporary only patch material until the problem can be fully corrected.
The specialty grouts are grouts that are chloride-free, non-shrink grouts that will not damage the cable and will not shrink and crack. PTI actually has a FAQ No. 11-Proper Filling of Single-Strand Tendon Stressing Pockets which can be viewed for free here with other possible useful FAQ’s in lieu of the PTI manual.
https://www.post-tensioning.org/faqtechnicalnotes.aspx
Gee whiz, surprise, surprise! I had an idea you were here in Texas somewhere. I’m about 35 - 40 miles Northeast of you. This is unfortunately typical of what we see here.
If you are out of your one year warranty period you are better off doing it yourself than fighting them for it! The warranty past that is typically catastrophic coverage and this is not anywhere near that point. Most likely if they even fix it they’ll send someone over to put some type of patch material over it that may or may not be proper and without even cleaning off any loose pieces first. Then you’ll be in the same situation down the road before long.
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Thanks! I’m already out of the 1 year warranty so I guess I’ll have to do it myself then. Thanks a lot for the explanation.
One last question - are the things that look like rusty nails close to caps need to be covered as well?
It is a real simple job at this point. If you call someone in you will pay for it! Mixing grout and applying it is so simple.
- Find the proper grout mix which most likely you can find at Home Depot or Lowes. You will also need a small mortar pan (the small circular ones are more than enough) and a trowel for applying mortar. Also get yourself a water spritz bottle like the window cleaner bottles and a soft bristle brush (an old toothbrush works well). If you use a window cleaner bottle make darn sure it is thoroughly cleaned of all cleaner inside and the tube/sprayer head.
- Use your trowel to gently scrape the area to knock off any loose pieces.
- Wash the area down and brush it with the tooth brush to get the dirt and crap off. No need to flood it just to clean it. Make sure you clean 6" around it.
- Mix your grout as instructed for a vertical wall face. I like mine about the consistency of a margarine tub type butter. That way it will not drool down and the next step helps add a slight bit of water to it anyhow.
- Use the spritz bottle to spray the area until it runs.
- Give the water a second to stop running but not to long especially in this heat. Use the trowel and spread the grout on like butter no more than about 1/8" thick. Go at least an inch past the original cap material (reason why the 6" cleaning above).
- Clean your mortar pan and trowel good before the mortar dries out.
- Let it dry and inspect it later to make sure it bonded properly.
Trust me when I say it is so simple to do. If you go out and get a quote then subtract your cost of doing it take the difference money and go out and have a beer and nice dinner! I’m sure you’ll have even more money saved than that.
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Wow, thanks a lot! I really appreciate it! Can I use the same grout to cover the rusty nails as well or it’s fine to just leave them like that?
The rusty nails are the nails used to nail the pocket former for the cable to the form boards before concrete pour. Unfortunately even PTI does not cover that in their installation manual. It is my opinion they should be covered over and they can use the same grout as the pocket grout. The rusting nails can expand and cause cracking around them although this is rarely seen. I have also seen them cause rust staining down the foundation wall.
Many Builders will parge the whole foundation wall to cover over small and aesthetic defects. Parging is where they take a cementitious material (typically plain cement) and brush the entire wall with it. Not only does it cover the little defects it covers these nails and also adds to the grout cap cover over the cables. It gives the foundation a clean and even appearance.
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See my statement above.
You are more than welcome to any help we give here. Owning a home can be expensive enough and there are so many things even an inexperienced homeowner can try and do them successfully. Nothing like the satisfaction of saving a big chunk of change on a simple project. Of course be very careful if you are married otherwise your spouse will see how handy you are and your Honey Do list will be HUGE!!
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That is really good info.
Agree! I recently had a bad breaker and contacted the manufacturer and they sent me a replacement for free (life-time warranty!). It took me 10’ (+ 30’ watching Youtube) to replace it while my neighbor hired an electrician for $300 
I know it’s a small job but felt pretty proud of myself lol.
Sorry to bother you again but is this grout suitable for this application? https://www.homedepot.com/p/Quikrete-50-lb-Non-Shrink-Precision-Grout-158500/100318529#overlay. I don’t see they mention chloride-free but they said it can be applied around metal so I guess it’s chloride-free. I couldn’t find anything that specifically says chloride-free non-shrink grout.
Google is your friend!..
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The Quickrete product page does not state what its content is however it appears that style grout is used for horizontal applications because of the way it is mixed.
Jeffrey is on it with the Google angle.
Also a 50 Lb bag of grout is WAY MORE than you would ever need even if you have other points needing attention. Unfortunately Home Depot and others seemed to have stopped being the Homeowner place and offering 5 Lb bags. If you have to resort to a larger bag when you are done each time wrap it in a 13 Gallon trash bag, seal the top, and if possible place it in a plastic bin or bucket. All to try to keep moisture from entering. When done right it can last a long time that way. Of course don’t use the spouse’ nice Tupperware clothes storage bin otherwise you’ll catch hell for that! Been there, done that!
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