8/11/2008
9:58:41 AM 

Roland, I grind out an area about 24 inches by 24 inches a day prior to setting the tests like they specify. Even though I do not agree with astm's explaination as to why you should. And thats a good topic I can't get an answer too by the big boys. That in itself takes another day, an extra trip if you will. If I check for sealers on the slab and there are none, no paint and all that jazz, and I am going to adhere my flooring to that substrate to which it is NOT going to be grinded.....then why should I have to grind my test area? That grinding is changing the surface structure and going to let VE flow through the top faster giving me a higher reading.

I think they put that in the astm to make us all pay for more vapor retarders.

Not sure if I took that picture which shows some reflective areas on the concrete or next to the test area to tell you the truth. I know on the saw cut area I did set the meter inside the test area after the test.