I am in the process of installing hardwood steps in my house. I did the first three and thought they looked pretty good. The temp outside was 80, so i turned the furnace off. Unfortunately, I went out of town without turning it back on. As a result, I came home to this today (please see attached picture): I did not face nail the front of the steps as I was hoping the liquid nails glue and nails under the risers would be enough. (I see that is a big mistake now). I have turned the heat back on, do you think the steps will level back out? Is there any way to fix this? If they do flatten back down, I will face nail the front of them. How many nails do you all recommend? Will face nailing them prevent this from happening in the future? I did a lot of research online and didn't find anything saying I needed to lay a vapor barrier or anything under the hardwood before putting them on. Do I need to do this?? Any advice and insight would be greatly appreciated!! Thanks in advance.