What Does It Mean Wet Damaged Cover

Ok, when I find water damaged covers with undamaged looking stamps on them, is it wrong to presume that someone went whole hog immersing the envelope to get the stamp off and then put another or that stamp back on? Why else does this happen?

Houses get flooded in storms, houses are not kept up and roofs leak, houses are built in low-lying areas and basements get water in them, pipes burst in cold weather, water lines to toilets or washing machines or hot water heaters get old and burst, etc. etc. etc. One well known example is that a large portion of the existing West Indian Aerial Express first flight covers were in the possession of man who founded that airline and who was living in Florida. A big hurricane hit the area in which he was living and a large trunk in which he had kept these covers was destroyed making WIAE flight covers rarer than the reported numbers that were flown.

Thank you Kimo for that response.
I think that I did not ask the question clearly. I have seen covers where the envelope dried wavy paper like water damage. But, the stamp looked fine. I want to know why the stamp does come out looking so fine under this circumstance. If the envelope were pressed then it would not be so wavy. It looks like the stamps in some of these situations may have been removed. Why would that be?

More than likely they are just water damaged as noted by Kimo.

I have several canadian covers from a collection that was stored in the attic of the house. Obviously the roof leaked, the envelopes got wet and show a brown tone line from where the water ran on them, leaving some a bit wrinkly looking, some with ink running on envelope. Not unusual to come across envelopes in the condition noted and also many with stamps washed off the covers.

Edit: And as far as the stamps being put back on the covers, it is certainly a possibility that someone may have done that.
Mike

Thank you both.

Interesting discussion.

Also, most stamps tend to be made of a higher quality paper than most envelopes. This is so they can take the wet ink that is printed on them and come out flat and looking good. Most envelopes are made of relatively cheap paper that does not have the kind of stability that the paper on which stamps are printed have. Sometimes if the wavy-ness of water damaged (or high humidity damaged) envelopes can be flattened by putting them in elevated humidity for a while then putting them in a paper press or between the pages of a book with some heavy books on top and coming back a week later, but mostly that does not work well. Especially on envelopes that show more noticeable waves since those waves indicate that the paper has stretched and cannot be put back very easily. Trying to flatten envelops with an iron or spritzing water mist on them or leaving them in high humidity can wind up making things much worse.

You have to look at how the stamp is tied to the cover. If the cancellation marks line up then it is probably legit. If it is an expensive cover there are more concerns.

Louise, You ask a very general broad-brush theoretical question. Yet, each water-damaged cover could have a different cause. Do you have a specific cover or two to post for discussion?

In reply to John Becker;
No I do not. I have been looking at more covers and noticed this and wanted to know why as it seems to happen not infrequently. The replies were very helpful. Thank you all.