Good morning everyone

I am preparing to lay down 1000 ft of unfinished ¾” x 4” Brazilian cherry.
Largest room 28 ft wide.
I had 3 installers come and give me a bid before I decided to do it myself.
2 of the 3 said they Always put penny size expansion spaces in the floor every 3 ft or so, in addition to the 3/4" space at the walls.
The other installer was not experienced with site finish hardwood.
One said the cracks will disappear over time.
I live in very humid South Louisiana; my house is 3’ off the ground, open and very dry underneath.
I have looked over the forum and elsewhere and cannot find any reference of this.

Has anyone seen or done this themselves?

Thanks

I've heard of it before and actually did it once per the request of the dealer I worked for at the time. This was well before I had more experience under my belt. What was strange is the dealer didn't suggest any asphalt felt underlayment. 2 1/4" strip Ash. I wonder if it ever cupped? It's more of a matter of what each installer is accustomed to and what works for them.

Incidentally the conditions were fairly similar. High humidity, open below stilts, Sanibel Island FL, but the floor was about eight feet above grade.

This is often done in the winter time and the wood floor acclimated to the dry heating of the home, shrinking the wood down. At this time of the year, it might not be needed.

Each species of wood has what is call a shrink & swell ratio. That is used to see what the wood will do given how humid the environment is. If the wood is reading above the average moisture content for your region, you don't want to put expansion in the field of the installation. Now, if the wood is reading a low moisture content for the region, some expansion in the field is needed so as the floor does swell, it will not buckle.

Just saying they do it, especially at this time of the year, makes me wonder.

Spacing is still common here in the south. Now that we have moisture meters and better industry guidelines for installing wood flooring, we don’t do it as often as in the past but there are times when spacing is needed.
Your installers may have been at the wood floor distributor’s open house in New Orleans this year. Before the boiled crawfish, poboys and fried oysters were served, the owner had a one hour discussion and slide show on wood flooring and moisture problems. The link below shows his presentation regarding spacing.
http://www.crescenthardwood.com/DYK/SPACINGAFLOOR.pdf