Question is, is it possible (for the right experienced man) to remove retaining wall forms early enough in the game to finish them smooth or is there no way to do this safely?

Yes, but the real question is ..... What is your clients idea of "perfectly smooth"?
I'd suggest you have him show you a completed wall or two he is satisfied with so you can duplicate the finish.

It's not unusual to strip forms while concrete is still green enough to allow rubbing out, patching tie holes, knocking down form fins, etc.
This "rubbed out" finish isn't what I'd necessarily call "perfectly smooth".

I'd call a steel troweled slab surface about as close to "perfectly smooth" as you can make concrete.
It's considerably tougher to make walls look that good.

 

I understand what the client means and will accept. It is within the skill realm of a competent finisher. The plaster guy I spoke of will have a thick slurry mix of cream to use as a floatable finish to fill air holes, seams etc. My concern is trusting these guys know when to safely pull the forms. If they are wrong, we are looking at a catastrophic loss of work and an immense amount of work cleaning up and preparing for a new pour, in the fall of the year. This is not an option.

I'm a fishndude too. Love it. Thanks for the reply.

 

How does the Concrete Sub, (a Structural Steel guy), come with the job ?

If owner hired, the owner is responsible for the finish quality.

Not your concern. Do not insinuate or allow others' any other stance.

 

40 years eh, & you don’t know enough to tell client there is no such thing as a “ perfectly smooth “ finish on concrete? Does the young buck do your retainers normally or the cheapest. You don’t like his forms so what about the finish. You’ve never wrecked forms on green concrete. Sounds like time for a pow wow w/client & have the plasterer in pocket



Mike

 

Love the quotes on "perfectly smooth". If for no other reason but for the fact that my friend and I finished my shop floor, after hours, and while significantly intoxicated. We ran the power trowel all night for no reason but that we thought we were making something "special". We were unfortunately correct, if "special" is a synonym for "extremely slippery and dangerous" for a shop floor. It is possible (at least on horizontal surfaces), but not recommended by my standards. Lol

 

You might want to hit up the engineer and see how he feels about it. I've had engineers spec that the forms stay in place for a week.

 

Haven't had that concern for several years since I've been using ICF's. Lol

 

To respond, the sub's father is a long time friend of the owner. The sub is very good at rebar and has participated in numerous large commercial concrete pours, but I don't see this particular pour/application as being in his experiential wheelhouse. It's like a framer with a construction pencil doing fine finish work. I came onto the job, as a favor, as the last contractor messed up on the shoring and there was a minor earth/wall collapse last winter. This is the home the owner grew up in and has been in his family for 75 years. His goal is to remodel it use it for what time he has left and pass it along to his children for their lifetime use. We are installing an elevator, structural glass floors, and expanding the home into the rear hillside. I turned down the project initially as it is out of town and requires I live here much of the time, but the owner is a longtime client, the project is started and I have proven my trustworthiness over many years and projects to the degree he damned near begged me. I agreed to help him as a man should do. I also consult and troubleshoot for him on his other projects. The owner, who is a doctor, inherited some land/money, handled it well and significantly increased his holdings and income. He participates in his construction projects, always has something going on and personally built his own house. He is not a noob. I told him I would use the existing subs if I liked them, but would replace them if/as I saw necessary. By "perfectly smooth" no one, not even the owner is talking about a glass finish. He is experienced and realistic. Everyone is intelligent and sane here. He is asking for the same thing I or probably you would ask on your own home. The best work product humanly and reasonably possible, but that best product does not and should not include unevenly spliced forms and obvious seams. The forms aren't terrible, they are passable for the average typical retaining well. I just want a better product than average and my work is expected to exceed average. I specialize in design work for designers and architects. Many of the projects I have done have won ASID awards.

I am not proud or egotistical about any of this. It's just been my path in life. All of this is irrelevant to the question I posed but in response to the remarks etc. I submit this information for your consideration.

If anyone has any experience removing wall forms timely enough to float the green concrete walls, please let me know. It would me most efficient to be able to take a smooth finish slurry and use it to finish float the green concrete walls immediately after form removal, if one can reasonably accomplish it. I have never tried.

Otherwise, and where I am headed is, I will cast them as-is, pull them as soon as reasonably practical, scrape any uneven seams, grind as/if necessary and float the walls as perfect as possible. Weld-Crete makes a good bonding agent and finish material and I have access to a man who is a master at such work. It appears this is the most prudent path with minimized risk and maximum potential for a high quality finished product.

Thank all of you very much so far.

 

Personally, I have done it, but not with anything that was of significant height or load bearing capacity that would make me think twice. I understand your reasoning, and I agree with it in the sense that compromising structural integrity for aesthetics is a fool's errand.

 

An experienced finisher may know the answer most of the time. Even very experienced concrete guys can pull forms a little too early. My buddy did this on a retaining wall, and it developed a bow or tilt. Had to flòod the footing with water so it could move with the wall, then push it all back in place.

Given you're looking for a low risk vs low cost, I wouldn't strip early.

 

I love and work about 2 hrs north of SF
While I see guys pull riser forms early for stair risers all the time. A tall retaining wall could be much more nerve-racking. Not to mention the method of having to strip the form when it’s early could be much more difficult. I agree with Hdavis if you’re wanting to keep risk factor low. Find that stucco Plaster dude who’s got 1 billion YouTube videos in Oakland his family will come out and probably make that wall look stunning with a skimmed finish coat. Or the plaster guy you got I’m sure good enough. But if you’re overseeing the project and your guts telling you to not be too risky with the retaining wall, then that is the route I would take with the owner like King said have a powwow before it’s all done.

 

Live and work, not love.

 

If you can’t get the vibrator down into the concrete from above, can you vibrate the forms frommthe outside? Hold a sawzall shoe against the form, without a blade.

 

Keep the forms on and schedule the plaster guy.

 

Hah! I've seen that guy on YouTube. You are right HDavis. A good experienced finisher knows what he is looking at and doing. After a point, a reasonably man knows his trade. I have no experience with these finishers and have not yet insisted on speaking to them personally. The walls are varying heights and thicknesses so someone's is going to have to be on their game to avoid a problem, and I'm just not "feeling" it. I'm the kind of guy who is not scared of anything. I genuinely believe I can accomplish, build or create anything, but my gut says don't take this risk in this instance and a ruined wall in this case means tremendous work and time to get it reformed and poured when it is late in the year and in the end. As you guys know, if it goes bad, the concrete guy is going to come up with every "reason" possible to avoid the expense of the repair and it is going to reflect on me no matter what, and who needs that mess? I can leave the forms and float the walls afterwards.

It this was common practice it would be commonly done and more people - yourselves - would have more experience with it. It's not commonly done and there are reasons for that.

Thank you all very much.

 

You talk a good game & write a good book. Sounds like helping out a buddy is right up your alley 40 years & got some greenhorn pulling forms on a green wall….. I’m a Russian fighter pilot…



Mike

 

Congrats Mike! I didn't know you were taking lessons.

 

I don't think you understand the concrete subs intentions. He is not going to strip forms an hour or two after placement and have the walls collapse.

Depending upon temps, concrete mix and a few other things, you can strip forms on a wall the next morning after pouring and the surface is still relatively "green" so that it is workable and allows material to bond to it well. You then remove wall ties, patch tie holes, knock down the form fins with a rubbing stone, and rub out the entire exposed wall surface. The "rub out" can be done with with a portland cement mixture and sponge trowel to get a pretty nice finish. I've seen guys do a really slick job rubbing out walls with a wad of burlap -vs- the sponge trowel.

It's common to strip forms on smaller pours like steps pretty quickly after pouring and rub the vertical surfaces out while still quite green.

I'll go back to what I said originally ...... You better have the client physically show you a wall surface he is satisfied with, then show your sub the same and tell them that is what is expected.
Sub also needs to know that if he screws it up, removal and replacement to satisfaction is on him. If you don't trust this sub, draw a line in the sand with the client and insist on a sub you do trust.

 

From what you said, I wouldn't trust that sub to do it, forget about when he wants to strip the forms. One thing with concrete, once it's there it's there, hard to fix after the fact. I'd look for someone with experience in doing a smooth finish or decorative walls and demand to see pictures of their work. If you can't find anyone, do it yourself. I'd ask your engineer about designing a concrete mix with plasticizers and an 8" slump to help with the smooth finish. Also, make sure there are no guarantees in your contract, explain to your client you'll do what you can but it's hard to say how it turns out or if it will meet your expectations. Go over plastering or stucco options too, lots of ways to make a wall look good.

 

All good points. Thank you gentlemen. You have been a help.

 

...and thank you for your understanding and wisdom fishindude. You completely got the picture.

 

Concrete may be a fickle B&tch, but it's not difficult to ascertain when it's stiff enough to pull forms. If the timing and conditions are right, it's even possible to work the finish by hand 24 hours after the pour with the proper tools and experience. That being said, if the structure being discussed is meant to be structural, yet aesthetically appealing, I would assume that a post form finish would have been taken into account in the bid.

 

Thanks ICF. I get what you are saying and see you have more experience than I. You confirm my consideration the viability of the endeavor rests in the skill and experience level of the finishers - something one has to have a comfort level with. Thanks again.