I was contracted to perform a construction clean on a small building and some of the windows are a mess. The masons got a concrete like substance (grey pebble bordering windows)all over the windows, looks like splatters. The windows are etched (actually pitted) and look awful. I have talked to several glass people and most say the windows will need to be replaced and there is nothing I can do to make them look good. One glass store owner said to try jewelers rouge. Has anyone ever come across this problem? The project manager asked me to do the best I can, but it is taking me forever to even get the stuff off the windows. Thanks, Anne

Try soaking the glass with phosphoric acid to break down the lime in the ceament. Phosphoric acid is lime scale remover i.e. lime away. You will need to get a professional strength and use it straight if necessary. Your janitor store will carry it.

Be very careflu scraping the glass, the sand that breaks free from the clumps will want to bite and scratch the glass.

john

Anne I hope you are charging extra for the windows.

Remember post construction cleaning is not responsible for some trades poor workmanship, just construction dirt and grime.

They should have put plastic over the windows.

We have used jewelers rouge before with great results for minor blemishes on glass. It takes time and patience.

Plain old cheap white toothpaste will work as well as jewelers' rouge and usually costs less. Also easier to find. As an added bonus the windows will have that clean minty fragrance! I have used it on a number of windows with very good results.
Good luck.
James

Thanks for all your help. I will be working on the windows on Friday and will let you know how it turns out. The project manager knows that I will try and get them looking good and that he will have to replace them if I can't. Thanks, Anne

Adavis,

I've run into the same problem with lots of mortar splatters on the outside windows on a million dollar home. How did your cleaning turn out? Any lessons or techniques you can share from your experience?

Did you try the 'phosphoric acid trick' the big john suggested to loosen the mortar? If so, any impact on the surrounding brick with the acid dripping down the side of the building?

Thanks, Randy

Hi Randy,
The windows were so badly pitted that they ended up replacing them! We did try acid on a small area which did loosen the mortar like substance but the windows were pitted under the mortar.

Before trying anything, I called and went to a few window repair shops and they all said the same thing - the windows will need to be replaced if the damage is that bad. Other than the windows, the construction clean went very well.

Thanks, Anne