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Repairing board formed concrete

tagalong

We have a house in Austin, TX under construction and unfortunately the contractor has really messed up the board formed pour on one of the house's main feature walls. We believe this was due to a combination factors in their improper planning and execution. (13ft long vibrator used on up to 17ft tall walls as one example). Pictures below.

Our hope is to find someone, and concrete artist or restoration expert who can use whatever techniques to patch/fix/repair the areas of honeycombing, and other areas where the wood grain texture did not turn out as intended. That said, we're having trouble finding someone who might have experience with this.

The owner does not want to go so far as tearing the walls down, as that will probably bankrupt the contractor and through the entire build into a tails spin. Short of that, we open to having someone spend months using whatever means necessary to try and correct the eyesores.

Any help with leads / pointing in the direction of someone who might be able to assist with solutions/services would be appreciated. Thanks.


 
Apr 24, 20 3:04 pm
proto

no good solution

repair will look like a repair

learn to love it? or

tear down...do multiple full scale mockups to get process dialed. maybe even consider smaller lifts?

exposed board form is ruthless in that it's all or nothing 

Apr 24, 20 3:31 pm  · 
 · 
archanonymous

Exterior wainscoting?

Apr 24, 20 3:40 pm  · 
1  · 
archanonymous

is the wall structural? If you could carve out or chip away 1" - 1.5" of the surface you could come back with actual concrete and patch it. 


Or you might be able to formulate some sort of epoxy mix with filler that would match well and use it to fill those guys in... not sure how long it would last outside though?


If I were you i'd contact a stone/ concrete repair sub in the area (the people you call when you need to patch some irreplaceable marble in a historic building) and get their take on it. Won't be cheap.

Apr 24, 20 3:43 pm  · 
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threadkilla

combo the chipping away 1-1.5" where possible with re-applied concrete in either a similar texture, or contrast on purpose with a view to break up the board form lines.

throw in other materials - exterior grade plaster or ceramic tiles

you know, make art happen where the mistakes were...

metal you can get crazy with attaching metal panels of any kind right over top, get it welded by local artist or water jet cut to your own design, whatever...

 · 
threadkilla

go nuts and inset some feature travertine stone slabs


 · 
threadkilla

OP, your walls look pretty pretty pretty damn good where the contractor did not fuckup - guess it's up to you and the owner to settle if you want to maintain the overall grain of the wall and try to mask the surface imperfections, or embrace the cover-up as an opportunity for a creative solution

 · 
threadkilla

these guys - https://concretecat.com/ - do some pretty interesting things with tinted and other concrete applications, but they're up in Edmonton, Canada. There just might be a similar outfit or craftsperson somewhere down in Texas.



 · 
Non Sequitur

make the GC redo it. who cares if it costs them a fortune.  It's their fuckup.

Apr 24, 20 4:03 pm  · 
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archanonymous

plants.

Apr 24, 20 4:10 pm  · 
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x-jla

is that a thin veneer of concrete?  I don’t get it from pics? Looks weird 



Apr 24, 20 4:46 pm  · 
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proto

the GC was f***ed the day he accepted the job...board formed is a thankless pursuit where only perfection is deemed success

i've been thru this before and multiple mockups doesn't even really guarantee anything since you ultimately get the single pour at getting it right. You could be successful and learn loads in all the mockups and then get just one oversight in the actual pour & you've got an oddity in the finish

OP, the good parts do look good, if that's any consolation...report back on how it gets resolved

Apr 24, 20 5:08 pm  · 
1  · 
SneakyPete

Is that OSB just filling the hole or are you doing a veneer of concrete?

Apr 24, 20 6:06 pm  · 
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SneakyPete

Also: form liners.

Apr 24, 20 6:07 pm  · 
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whistler

True Dat! Expensive but the only way to get the finish right but that's only one step... mixture has to be right and yeah the virbrator needs to extend the full depth of the forms. I have been afraid to try it on any project, until I meet a concrete trade who can get it right time after time.

1  · 
midlander

whats your landscaping design look like?

Apr 24, 20 8:00 pm  · 
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SneakyPete

*high five*

 · 
thisisnotmyname

Gift the owner with the nicest and most expensive Paul Rudolph monograph you can find, have a few drinks and then convince them to bush hammer all of the concrete.

OR

Bondo all the bad parts and then paint everything black to look like shou sugi ban.

Apr 24, 20 10:40 pm  · 
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PandasAreSexy

Get a hold of Matt Risinger or these guys: http://bootheconcrete.com


Apr 24, 20 11:35 pm  · 
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threadkilla

well, I just spent about 4 hours down that youtube rabbit hole, so thanks!

1  · 
Haha Hadude

Sucks that the contractor is going to have to redo everything because they tried to cut corners

Apr 25, 20 2:44 am  · 
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justavisual

its a story, leave it...and learn to love it. and then dont do it again. ask for a price reduction on the work

Apr 25, 20 5:27 am  · 
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Wood Guy

If you want the look, you have to control the risk and expectations. It's concrete--sometimes you get rats' nests. I don't think any applied finish is going to fix it.

Board-formed concrete is very difficult to get right. My brother was a PM for a builder and they did a 20+ foot tall board-formed fireplace, all in one pour in an almost-finished house. Just as they got to the top of the pour, the bottom of the forms blew out. Quite a mess.

Business idea: clear concrete forms. 

Apr 25, 20 9:10 am  · 
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I’m pretty ruthless when it comes to concrete subs not able to do their job. Make them tear it down and do it again. Concrete isn’t that difficult to get right if you don’t cut corners. I mean who thinks they can consolidate the concrete at the bottom of 17’ tall forms with a 13’ long vibrator!? Yet we let them get away with it again and again and again.


Disclaimer: No project I’ve ever been involved with has forced a contractor to redo the bad concrete. They always just sack and patch it to a smooth finish (no issues yet with board form though). To demand otherwise would always create other problems that the owner doesn’t want to deal with, like delays. I just want one project where the crappy sub is held accountable. 

Apr 25, 20 9:53 am  · 
1  · 
Wood Guy

If it makes you feel any better, on a new house I designed a couple of years ago, with a concrete slab, I had spec'd WWM since fibers can be tricky. The concrete sub wanted to change to fibers, so I verbally ok'd it to the GC and mentioned to make sure they use extra-fine fibers. Apparently the batch plant used the wrong fibers (at least that's the subs' claim) and the finished floor was full of fibers sticking up.

Instead of pouring a 2" slab over that one, which would have been a simple fix, the concrete sub convinced the builder that they could put down a heavy sealer, let it cure, and buff it out. This was a near-Passive House, all low-VOC materials, Zehnder ventilation system, sensitive clients. Well, the concrete sub used a sealer labeled for exterior use only and it REEKED, similar to diesel fumes. And after it was dry enough to buff, they found that it didn't fix the issue. SO THEY APPLIED ANOTHER COAT. And it reeked. And didn't work. So then they had all that mess ground down to bare concrete, which sort of took care of the fibers. 



1  · 

I wish that story made me feel better, but it just shows how the simplest solution (follow your WWM spec to begin with) would have probably produced the best result, but you (really we collectively) let them propose something else without a real upside, and they screw it up.

I haven't looked into it, but I've heard that with the right type of fiber you can simply take a flame to the floor to burn off the fibers (though I've also heard that fuzzy floors really isn't an issue with fibers if finished with care). It would make me feel a little better if that is true and this sub would have found this out say a week after paying to grind the floor down to bare concrete ... yeah, that would put a smile on my face. 

1  · 

I disagree Rick

 · 
Wood Guy

EA, I don't think I've heard that about burning off the fibers. I wonder if that would have worked on my project. Supposedly the issue was that they used heavy-duty, "commercial" fibers instead of superfine fibers. But I'm sure they would have melted. Hopefully without spalling the aggregate.

In my work--mostly higher-performance but on tight budgets--I need to be able to work with contractor requests. They often save time or money, or propose an elegant detail. So I like having an open door for changes. But sometimes it backfires. 

1  · 

I agree for the most part. When a trusted knowledgeable contractor has a better way of doing something, or can save some money without sacrificing quality ... I’m all ears. I think learning from each other is one of the best parts of the job. And yes, sometimes things backfire. Your example was like three backfires though. Which is why, on the other hand, when a contractor is out over their skis ... I wish they’d pull up and proceed with caution. Same thing should apply to architects.

1  · 
x-jla

Rick, I’m so happy I decided to go design/build. All of that conflict goes away. If I don’t like how something looks, I simply tear it out and redo it.

 · 
Wood Guy

EA, in this case I totally trust the GC and I had actually recommended the concrete contractor, who I know and had only had good experiences with, when the GC's regular guy couldn't do it for schedule reasons. But they brought in a flatwork sub neither the GC or I were familiar with. It's always something... I agree with your sentiment, though--I don't understand why contractors take any more risks than they're already dealing with.

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x-jla

If you can stay in business for a month as a D/B or GC form you are competent. Any foolishness can land you in the negative digits. One big project gone wrong can end your business and bury you in debt. It’s a very risky business. The reason contractors don’t like getting adventurous is because they pay for problems. Architects have far far less financial liability.

 · 
x-jla

Not to mention being responsible for the Safety of workers. DB is nice, building other designers work is a complete shit show.

 · 
BabbleBeautiful

think wabi sabi

Apr 25, 20 4:05 pm  · 
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citizen
  1. demolish wall; set new forms 18" apart
  2. take GC/sub out for (many) drinks
  3. drop GC/sub between new forms
  4. re-pour


Apr 25, 20 6:07 pm  · 
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citizen

5. for fun, site-specific decoration, selectively remove portion of forms prior to full cure

Han Solo Frozen in Carbonite (Original Prop) | Star Wars Ide… | Flickr

 · 
bowling_ball

Plants. Furniture. Artwork. 


We once made a GC tear down an entire board formed public building (beach washrooms) twice because their work sucked. TWICE. And they tried to sue but lost. We've never done it again. 

Apr 25, 20 11:17 pm  · 
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Your best choice is goodbye concrete, hello stucco.

Apr 26, 20 3:01 am  · 
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Volunteer

If you are in Austin, just use thick limestone veneer over the wall. More appropriate to the region anyway and goes with classic and modern homes. 

Apr 26, 20 10:14 am  · 
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tagalong

There's some interesting options mentioned above, related to removing a certain amount of depth within affected areas and coming back with something else..the thinnest wall is 8", what you were seeing with the plywood is an oculus (which turned out ok now that all the wood is off).

It'll require a composition study but we may look designing another layer of material to cover the problem areas...if we can make it look intentional and not like a cover up.

The GC is currently proposing a concrete slurry coat over the affected areas, one board-width at a time, and then pressing a board, against it...they are going to mock that up on an area that will eventually be below grade, so we'll see. Not sure if that will hold up over time.

I've found a couple concrete restoration artists and pinged them with emails. One responded requesting more info..

@Pandasarsexy -funny you should mention it - we're in this mess because Boothe walked from the job after they poorly performed on pouring the slab/foundation and took most of their profit on the project. They will never step foot on one of our projects again.


Apr 27, 20 3:23 pm  · 
1  · 
proto

slurry will chip off through enough temperature cycles [sacking a wall always has adhering issues over time]

a carefully composed covering layer is your best option for leaving it in place...could be 2" of conc, stone veneer, stucco, anything really

what about bead/sand blasting the lower section of wall? it might even be enough to smooth over a patch zone made where you got air pockets & bug holes

re: length of vibrator [huh huh huh]...I think what I saw on the last job we did board formed, the sub touched a stinger to the rebar and that was how they vibrated the conc (but they weren't doing 17' tall walls...maybe 12 or so?)...that said, they still had repair/patch issues

Apr 27, 20 3:45 pm  · 
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x-jla

I think the board formed texture would be a perfect surface for any creeping vines that do well in your area.  The pits are mainly on the bottom.  The vines would be denser at the bottom.  A careful landscape design can really hide those mistakes.  The imperfections will be nice with plants taking it over.  You can do a juxtaposition (can’t believe I used that word) of clean modern planes and the more rustic eroded overgrown planes.  My 2-cents.  I’d rather have a house over taken with plants than patches or veneers.   

Apr 27, 20 5:34 pm  · 
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