Solid Hardwood, Engineered and Laminate Flooring - Gaps in Hardwood Floor

I posted this info under someone else's thread. Reposting here in hopes of getting some help We purchased our home in 2004. I think the house was built in 1997. When we bought the home, the floors were fine. Since 2004, little by little, gaps have been showing up in our formal dining room and now in the living room. Our formal dining room have 3 gaps that are 1/2" wide. Living room gaps are 1/4" wide. We've had several people look at the gaps and don't know what the problem is. Just last week, I filled the gaps with wood filler and painted the filler with varnish to match the wood. No, its not perfect, but it's much better than the gaps. Oh, we have oak floors. I'm posting links to 4 picture I took of the gaps. Any help is greatly appreciated. Thanks!

http://teezpics.shutterfly.com/26

http://teezpics.shutterfly.com/27

http://teezpics.shutterfly.com/24

http://teezpics.shutterfly.com/25

Have you tried moving the boards back into position?

I know they are supposed to be secured with nails or staples, but maybe the installer missed a few and these boards are slowly moving.

Just a thought.

do you have floor vents? can you remove the cover and look at the wood floor and the subfloor. if you have a concrete subfloor then you might have a moisture problem and the glue released from the floor. if the subfloor is wood the glue failed and/or the installer left out some nails. if the boards can move it can be is a easy fix.

OK mommatee you have 1/2" gaps. :)

It makes more sense that they are butt joints. I thought you were saying the side joints were 1/2" gaps. I'd like to see a pic from about waist high. Your showing the macro shot of the gap but what is happening at the other end of the plank? Is this the last plank before a wall?

You definitely have an engineered oak floor (engineered planks shrink at the end - solids do not). How was it installed? Glued or stapled? Are you on concrete or a wood subfloor? Its not a moisture problem with concrete. If you had excess moisture your planks would be swelling up not shrinking. Also when was the floor installed? and when was the problem first noticed? You didn't just wake up one morning and see 1/2" gaps so how long did it take to get that big? Lets start with that stuff and see where it leads.

The floor could have had a flood at one point in time, and now it is shrinking, as it drys from a drought, and very low humidity.

Is the areas hollow when you tap on them?

By looking at the pics it apears to me that this is an engineered oak glued on concrete.It looks like there is cutback
adhesive on the concrete and that a transparent adhesive like Dritac was used to glue the flooring. It is impossibale for moisture to have caused this large of gap. My bet is adhesive failure do to the cutback not being removed prior to install.