So I have been working like a mad man getting 5 original tombstones done and then taking old cheapies and thickening them up with more foam and pvc for re bar inserts etc then coating with Drylok. So today I just had a couple touch up spots on one of them and I touched it up with Drylok and set it out side to dry. Its currently 85 F outside and the tombstone was maybe out there 15 - 20 mins. I went to bring it back and it was blistering the drylok off the foam!!! This is going to cause me problems cause it will still be in the 80s come October. Is this a normal issue. Could it be that I did not sand and prep foam well enough to keep it adhered? Just too new of a coat?