Almost every wood floor will show some separation between boards particularly in the winter months when homes are heated and the air is dry.
Floor boards separating in winter.
A 5 inch wide plank will shrink twice as much as a 2 inch strip.
Cracks and separations can be alarming to the proud owner of a new hardwood floor especially when it looks nearly flawless in the summertime when by winter some noticeable cracking and separating of the floor boards appear.
Narrow boards will shrink less than wide boards for a given change in moisture content mc.
Filling large gaps with natural fiber rope is a traditional method commonly used on wide plank floorboards in very old homes.
So using engineered flooring may be an option for reducing winter time floor issues but check the manufacturer s recommendations and warranty.
Like jim mentioned you need to check your humidity level.
Often it s a floor owner concerned with new hardwood floors separating or gapping.
The wood shrinks because it loses moisture and gaps.
Be sure to use natural rope such as jute or cotton because synthetic rope won t accept a stain.
I usually try to keep my house around 40 in the winter.
While the rope doesn t look like wood you can stain it to blend with the floorboards and the filled gaps will be much less noticeable than the dark empty gaps.
It is normal in the winter month for gaps to increase in general because the humidity in your house is lower and causes the wood to contract.
In some cases these changes in the floor don t occur until years after installation.