Just a question,,,wrong forum maybe???

[rcp612]

If MDF is supposed to be so stable, why do you have to leave 1/4" clearance on all sides of a Pergo floor? Is it NOT MDF? Sure looks it.

[mschrank]

Good question and one I wondered about when I was installing laminate flooring a couple years ago.

I'm not sure it's technically MDF, but you are right in that it looks like it and is at least a similar "engineered wood product." The only explanation I could come up with is that pretty much everything swells and contracts with changes in temperature, so that maybe the reason you're supposed to leave the gap. But 1/4" seems overkill to me, especially if the bottom (the part covered by the baseboard) of your walls are comprised of ratty beat up drywall like mine....I can't imagine the wall material could stop the forces of the floor expanding.

[Mr__Bill]

venting of water vapor that gets trapped under the flooring. at least that is the reason given by the manufacturer of the flooring that i put down. so said the documentation.

[gwyneth]

Isn't it to allow for the expansion, contraction of the other things in proximity--which could include subfloor, joists, studs, etc.

[Stytooner]

All of the above would be my final answer.

[jking]

Keep in mind the reason for the "floating floor" setup is to minimize or effectively eliminate the "cracks" in the middle of the floor. With hardwood floors, there is eventually a spot where the joint opens. While the Pergo (or other brands) may be quite stable compared to solid wood flooring, when you get a large room there is going to be some amount of expansion. I suspect 1/4" may have been a result of allowing for the expansion and allowing for whatever wedge or clamping is needed to tighten up the last joint at the wall.