Granite inlay clearance

[Brent Romero]

I am going to do inlaid granite in a cypress top. Much much clearance should I leave for expansion/contaction?

Thanks

[Jerry Miner]

It depends on several factors:

1. The expected seasonal change in relative humidity in the location where the piece will be.
2. The relative humidity at the time of construction
3. The grain orientaion of the wood (flat grain expands/contracts about twice as much as quarter-sawn)
4. The width of the inlay

To be safe, if you are using flat-sawn lumber, allow 1/4" movement per foot of width (the length will not change appreciably). If you're feeling lucky you could try cutting that number in half (remember though, if you are building in the humid season, the wood will shrink when the air dries out. If you build in the dry season, it will expand)

The whole expansion/contraction issue is why it's not a great idea to inlay a large piece of stone into a solid wood tabletop. A frame-and-(stone)-panel system would be a better choice, IMHO

[Brent Romero]

The expected seasonal change in relative humidity in the location where the piece will be...down in South Louisiana, drastic changes
2. The relative humidity at the time of construction...high humidity
3. The grain orientaion of the wood (flat grain expands/contracts about twice as much as quarter-sawn)...not sure of the meaning of these terms...sorry
4. The width of the inlay ...18" square

[Jamie Buxton]

There's a really good book by Bruce Hoadley, called Understanding Wood. It should be on every woodworker's bookshelf. It will educate you about wood movement, terms like flat grain and quarter-sawn, and help you decide how much clearance you might need for your project.

[Brent Romero]

I would say that the grain orientation is more quarter sawn than flat sawn.

[Jerry Miner]

I would say that the grain orientation is more quarter sawn than flat sawn.

That's good. You will get much less movement. So if you allow 1/8" per foot of stone (half of the amount allowed for flat-sawn), and you've got 18" of stone, you will need 3/16" clearance.