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Concrete Restoration

Concrete Restoration

New postby phil327 on Fri Aug 23, 2013 1:17 pm

This is probably more of a ' Is this the right way to do this work '
Three items
The company is behind schedule and they are starting to hurry things up.

1. They did repair work on the concrete and smoothed it over with a layer of stucco. They then painted the stucco a 4 days later. Most information I have seen suggests 2 weeks minimum for the stucco to cure. Is this painted to soon?

2. They are sandblasting some of the rebar and old concrete. There is no containment and the sand blast material is blowing all over. They are also painting some of the exterior of the building at the same time. ( I do woodworking and one thing you don't do is create dust and paint at the same time )

3. Cleaning up they are using a leaf blower to clean up the debris. This afternoon they had to remove a wooden frame, with fiberglass insulation from one of the balconies. This framework must have had a significant water leak, because the wood was rotted and covered with black mold. There were also termites present. They chipped away some of the concrete on the balconies above and below. They are working on scaffolding and there are workers on 3 other scaffolds down wind from this particular unit. So - they start up the leaf blower creating a dust storm of concrete dust, black mold and fiberglass insulation. This went on for over 30 minutes as they went down each balcony to remove the debris. The workers downwind were treated to all this airborn debris, as well as any one who happened to be out side at the time. I would have thought that an industrial vacuum would be the way to clean this up, slower that a leaf blower, but much better.

Are these just "ROOKIE" mistakes - this is a fairly new company.
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Re: Concrete Restoration

New postby phil327 on Thu Sep 05, 2013 11:16 pm

I am starting to feel like the 'Negative' person here. Or maybe one of a few who has some background and sees what is going on. The latest adventure concerns pouring in the concrete into those areas on the walkways that did have some damage. I'll make up some numbers because I am not going to count all the small separate areas, They put wood forms around the repaired areas leaving the top open. let's say there were 100 spots to pour concrete into and only 2 workers - this is not an accurate number. So, they started on the upper floors and did a fairly good job getting everything level and smooth. As the day progressed and they worked their way down, the repaired areas got much less level and not smooth at all. Someone commented that it looks like they put the concrete in with an ax. We are being told now that those areas will have to be ground down and 'polished' to make them level with the existing concrete.

It seems to me that the concrete has started to set up and cure as the day went on. Looking at it now, it appears they had too few workers and too many areas to fix. Simply put, they either should have gotten a separate concrete delivery in the afternoon, had more workers available, or not tried to fill as much as they did. I wonder about the stability and strength of the concrete that was put in place later in the day - I'll bet there are air pockets and the concrete will not bind all that well to the existing concrete.

Any comments would be appreciated.
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Fri Sep 06, 2013 1:16 pm

phil327 wrote:I am starting to feel like the 'Negative' person here. Or maybe one of a few who has some background and sees what is going on.


You may be the only one who understands and who cares?

It seems to me that the concrete has started to set up and cure as the day went on. Looking at it now,
.
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I wonder about the stability and strength of the concrete that was put in place later in the day - I'll bet there are air pockets and the concrete will not bind all that well to the existing concrete.


Typically, concrete has an 'open time' of 90 minutes between when it is batched at the plant, mixed while the truck is driving, and the setting/waiting time on-site until the concrete needs to be dumped out and the truck cleaned out. There are admixtures which can be added to the concrete mix which will speed up the initial cure time (setting-up time) and different admixtures which will retard the initial cure time, the temperature of the water, of the concrete mix, of the sand, and of the aggregate will also affect the initial cure time with cooler/colder ingredients slowing the initial cure time and warmer/hotter ingredients shortening the initial cure time. You can contact the batch plant where the concrete was batched and ask them what time it was batched and the time after which the concrete is no longer considered usable.

There are also trucks which 'batch on-site', making the concrete as the truck sets there, making as much as is needed for use when it is needed - is it possible that one of those trucks was used?

From your description of the work I am guessing that one of the batch on-site trucks *was not* used. If that is the case, then as you stated, there may be problems with the concrete placed after its usable life time expired and the concrete was not dumped and fresh concrete brought in to replace it. Those problems could include bonding to adjacent material (steel, bonding agent, existing concrete, etc), not being placed properly and having voids in the concrete, the strength of the concrete could be affected negatively, and other potential issues. If there is a doubt, insist that the engineering firm overseeing the project have the concrete in the questionable repairs core sampled and crush tested for concrete strength - if the concrete comes in at or above the required specified strength in the contract documents, then that eliminate one of the more major issues. The CMT lab (Construction Materials Testing lab) core some samples where the new concrete meets the existing concrete and do a crush test - if the bond between the two breaks before the required minimum strength then that is an issue, if the bond holds and the concrete breaks (or the bond breaks) above the minimum specified strength, then that removes an additional issue. They could also do the same core drilling and crush test where there is steel in the concrete to check the bond of the concrete to the steel, this would require those areas to be chipped up and additional steel added before repairing the concrete core holes,
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Re: Concrete Restoration

New postby phil327 on Fri Sep 06, 2013 10:02 pm

We surveyed the repairs earlier today. About half the repairs have cracks where the new concrete meets the old. These are about 1/16 inch all the way around the repaired area. It also looks like the concrete is depressed towards the center of the repair. If I had to guess, there was water added to the mix, then the water evaporated effectively shrinking the new concrete. Some of the repaired areas are extremely rough.

thanks for your earlier answers
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Sat Sep 07, 2013 6:14 pm

The cracks all the way around basically indicate that the new concrete underwent shrinkage, quite often from too much water, as you suspect.

While the steel is what provides the strength (versus the strength of the bond) the strength of the bond and tightness of the bond is what helps keep moisture out of the joint between the existing concrete and the new patch concrete.

Your description indicates that water may have been added to the mix, and (for most mixes) the tickets will state either 'no water to be added' or 'X amount of water may be added by driver' and then that 'x amount' of water should not be exceeded. If no water is authorized on the batching and delivery ticket then no water should have been added - by anyone, not the driver and not the concrete workers. I recommend getting a copy of the batching and delivery ticket and see what it says about the mix, the maximum time between batching and use, and the addition of water.
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Re: Concrete Restoration

New postby phil327 on Mon Sep 09, 2013 12:52 am

Just a quick picture or two to show what I am talking about

Image

this one is the walkway edge, where they will attach the new railings. The swirl marks are from the grinder they used to level the repair. I have more pictures, but this is representative of the most of the work.

Image
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Mon Sep 09, 2013 9:03 am

You say that they used forms?

Looks like they applied it by the handful and then tried to pat it out with a trowel - like it was already setting up as you said.
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Re: Concrete Restoration

New postby phil327 on Mon Sep 09, 2013 10:09 pm

I got into a discussion earlier today. I had seen a lot of concrete poured into foundation forms in NY. Basically the basement of a house below ground. The forms were 4x8 panels spaced 6-8 inches apart and set on previously poured footings. The transit mix truck poured the concrete into the forms. The workers would 'jitter' ( not sure if that is the right word) poured concrete to make sure the concrete gets into all the areas and there are no air bubbles ( Jitter - vibrate the concrete, or tamp it while it is still fluid ) The top is leveled by scraping a board across the top of the form, then smoothing it with a wide trowel. A few days later the forms are removed.

At this point in time the concrete is smooth on the top and sides, no additional work is needed.

The work here, including the work poured into forms, gets a layer of stucco, then a grinding to make it smooth. It seems to me that if the work is set in the forms correctly, no additional work would be needed.
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Mon Sep 09, 2013 11:14 pm

"It seem to me that if the work is set in the forms correctly, no additional work would be needed."

Typically, only limited work is needed to remove concrete irregularities due to the forms and/or tightness of the form joints.

Concrete work is considered 'rough work', not 'finish work', and therefore has liberal tolerances. Nonetheless, though, what I see in the photos exceeds even those tolerances (from my perspective of just looking at the photos).
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Re: Concrete Restoration

New postby phil327 on Tue Sep 10, 2013 9:19 am

This is not completely on topic but does fit in with concrete forms. There were a few commercial buildings in NY that used very rough saw lumber for the sides of the forms. When the forms were removed, the concrete had the look of rough cut lumber, even down to the grain pattern of the wood. Visually appealing, but don't brush up against it, like sand paper.
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Re: Concrete Restoration

New postby phil327 on Tue Sep 10, 2013 9:18 pm

And today they were grinding the balcony edges, and to keep the dust away from the worker - a 3 foot industrial floor fan aimed at the person doing the grinding, blowing all that dust and dirt into the pool area......
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Tue Sep 10, 2013 9:27 pm

Sounds like someone lacks common sense, does not care, does not think, does not know what they are doing, or maybe a combination of the preceding ... now they need to clean the pool, filter, deck, chairs and everything else they got that dust on - maybe they just have so much money that they don't care how they spend it?
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Re: Concrete Restoration

New postby phil327 on Tue Sep 17, 2013 10:22 am

Just to keep this interesting. They finished grinding the stucco that was applied over the concrete that was poured into forms. These are open balconies, a ceiling, floor, and three walls, with one area open for windows or screens. Hook up the power washer and power wash, with water, the walls, floors, and ceilings. This would be fine if the entire enclosure was just concrete, but, they are not. Some have ceiling fans, still in place. I doubt if the the blades are suitable for out door use, plus the motors are not water proof. Additionally, there are a few units that appear to have painted wood paneling.

I am not 100% certain, but, some water got into the fans, some water got behind the wood paneling.

Just unbelievable....
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Tue Sep 17, 2013 12:05 pm

phil327 wrote:These are open balconies, a ceiling, floor, and three walls, with one area open for windows or screens. Hook up the power washer and power wash, with water, the walls, floors, and ceilings. This would be fine if the entire enclosure was just concrete, but, they are not.
.
Some have ceiling fans, still in place. I doubt if the the blades are suitable for out door use, plus the motors are not water proof.


The ceiling fans which are installed in that type of location are required to be listed for outdoor use. Typically, the ceiling fans would be damp location rated and identified as suitable for outdoor use (there will be a sticker on the top of the fan housing or inside the fan canopy covering the junction box which says the fan is suitable for outdoor use).

Pressure washing the balconies would be no different than a driving rain during a hurricane, tropical storm, or even a typical rainstorm in Florida where the rain goes almost sideways - provided the person did not decide to pressure clean the ceiling fan itself (that would be just plain old dumb).

Based on the above, the ceiling likely really should have been rated for wet locations, not just damp locations, as rain WILL be blown onto the ceiling fan during the rain events I mentioned (I'm not sure there is a "wet location" rated ceiling fan, probably just "dry location" (for indoor installation) and "damp location" for outdoor installation where the ceiling fan is far enough back from the exposed edge of the ceiling/overhang to be out of the path of being saturated with direct rain). It would be the OWNER'S responsibility to have the proper rated ceiling fans installed, not the contractor's responsibility ... that said, the contractor SHOULD HAVE checked the ceiling fans for their rating and advised the owner's of the ceiling fan that the ceiling fan was not properly rated for the location and SHOULD NOT BE INSTALLED THERE. If the owner does not take the ceiling fans down, the contractor is obligated to do their contracted job. Either way, the ceiling fans are the responsibility of the owner, the contractors responsibility is to be nice and inform the owner of the issue.

Additionally, there are a few units that appear to have painted wood paneling.

I am not 100% certain, but, some water got into the fans, some water got behind the wood paneling.

Just unbelievable....


Again, unless the wood paneling is intended for outdoor use (pressure treated, exterior glue used, rated for exterior exposure, installed as required for exterior installations, etc), the owner should not have had the wood paneling installed. If the wood paneling is suitable for installation outdoors and was properly installed, then pressure washing around and near the wood should not be a problem - if the pressure washing operator did not pay attention to what they were doing and went over the wood with the pressure washer, then the pressure washer would most likely leave a raised grain trail on the wood - and that would be the responsibility of the contractor.

The contractor should not be held liable for work done by an owner where the work was: a) not permitted and inspected; b) inappropriate materials were used and/or installation was made; c) the owner was advised of the inappropriate materials/work and did not remove same.

In this case, unlike the other items and issues, it sounds like your contractor is not the one who should be shouldering the blame for wood bladed ceiling fans which are likely rated and listed for indoor use ONLY.
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Re: Concrete Restoration

New postby phil327 on Tue Sep 17, 2013 9:28 pm

I should have mentioned that these were originally enclosed balconies, they had jalousie windows installed, I do know that some of the units had permits for the jalousie windows.

I have seen ceiling fans for damp locations, my understanding is that the main difference is that the blades are not made of wood.
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Tue Sep 17, 2013 10:10 pm

phil327 wrote:I should have mentioned that these were originally enclosed balconies, they had jalousie windows installed, I do know that some of the units had permits for the jalousie windows.


Enclosed balconies would mean that the ceiling fan did not need to be even damp location/outdoor use listed.

With that being the case, the contractor should bag the ceiling fans in the balconies which were enclosed prior to pressure washing the balconies (bagging each of the ceiling fans in a plastic bag prior to the construction work would have been even better - and the best thing would have been to have removed all of the ceiling fans prior to starting work - and included that in the contract price as nothing is free).

I have seen ceiling fans for damp locations, my understanding is that the main difference is that the blades are not made of wood.


All of the damp location ceiling fans I have seen do not have any openings in the motor housing so moisture cannot easily enter into the motor housing. I have seen wood and plastic blades on damp location ceiling fans (at least I think I recall having seen wood blades on some).
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Re: Concrete Restoration

New postby phil327 on Sat Sep 28, 2013 11:17 pm

I took a walk on the walkways today to see what was happening. The construction company has put a thin layer of "stucco" on all the cracks and areas that shrunk. I am not sure what compound they used, but is is rough and very thin. These are areas that will be walked on, have hand trucks and all kinds of other traffic rolled and pushed across.

Is spreading a thin layer an accepted method to repair the walk ways? Oh - pretty sure they will grind these down to make them level with the old concrete.
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Re: Concrete Restoration

New postby Jerry Peck - Codeman on Sun Sep 29, 2013 8:00 pm

phil327 wrote:The construction company has put a thin layer of "stucco" on all the cracks and areas that shrunk. I am not sure what compound they used, but is is rough and very thin. These are areas that will be walked on, have hand trucks and all kinds of other traffic rolled and pushed across.

Is spreading a thin layer an accepted method to repair the walk ways? Oh - pretty sure they will grind these down to make them level with the old concrete.


All depends on the actual and specific material they used - in some cases it may be acceptable, in other cases it may not be allowed.
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