off-form concrete surface rectification

[donallan]

Hi all,

I'm working on a building which has, as its major structural and architectural feature, off-form concrete wall. The walls were constructed using 1.2m x 2.4m marine ply formwork and grade 30 concrete. My main problem is that when some of the form work were taken off, they were some surfaces which were not acceptable. The contractor attempted to rectify this by applying skim coat on these areas. Unfortunately this create patches on these panels.

My questions:- (1) is there anything I can apply to the surface to hide these patches? (2)or anything I can do short of hacking the surface again.

Thanks

don allan

 

[RiBeneke]

In most specifications, the intention of using off-form (off-shutter) concrete is that it should have no (or very little) repair work done on the surface. This also assumes a small amount of minor and acceptable blemishes on the final surface. The British Concrete Association (I think that is their name) have recently devised a specification with photographic examples of various classes of off-form concrete.
To answer your question, I do not know of any patching that would still produce an acceptable finish after years of outdoor weathering. The only solution is to break down and start again, unless an alternative finish such as a cement based paint could be agreed for use on the entire wall.

 

[donallan]

I don't think I can break the wall down at this stage since it is the main structural element.

I however have been advised to use KEIM Concretal paint. What do you think?