Tim Carter, of AsktheBuilder.com, demonstrates how to prevent bubbles under wallpaper. The water in the glue or paste activator causes the paper to swell. The paper must relax or expand while it is still on the cutting table.

Video Transcription

Modern wall papers like this one often come from factory pre-pasted. That is okay. It is really a good material in that case but the problem is, remember when you get it wet or you used an activator to make it get wet, it starts to expand the paper and you need to make sure that they are expanse on the table not up on the wall. Before you put a piece of paper up and even paste it, you have to go ahead and cut a part of. Do not worry about getting it perfectly straight because you are not sure if the paper wants itself on the wall. If the paper is pre pasted, I get the best results from activating the glue with an activator instead of water. These products just brush on the paper and what to do is you actually mix this product with water, wait about thirty minutes and the final result is really neat gel that is a little thicker than water but bored, is it going to go on the paper easily. This process is called relaxing by the professional wall paper handlers. What is really happening is once you have got the whole piece of paper, glued and you have activated that glue, the paper looks expanded. It just needs to relax. You go ahead and fold the paper back over on itself like this. Do not push down hard and the gel would make a real hard crease. That is not a good thing and then you just sit back yourself and relax for about five minutes till it is ready to hang the paper. I am Tim Carter of Ask The Builder. If you want to discover more home improvement tips, go to askthebuilder.com.