Milled hemlock question

[rangeroad]

Hi folks,

I have the opportunity to purchase some pre-milled 1x4 hemlock for a project I'm working on. Can anyone tell me what these curved runs in the photo are for, or why they were milled like this? The current owner does not know the story on the boards.

Thanks.

 

 

[Jim_Rogers]

I've seen flooring cut like that.

Jim Rogers

[rangeroad]

Thanks Jim, is the reason the grooves are there to help with attaching to subfloor?

[fluidpowerpro]

Maybe the grooves are for asthetics? I've seen trim around doors and windows with grooves like that.

[Peter Drouin]

Release stress so not to cup.

[rusticretreater]

It depends on what the wood is used for.  If its trim, its just decoration so everything is not just a flat surface.

There are a multitude of reasons given for the coved runs in flooring and trim.  

It makes the wood more flexible and able to conform to uneven surfaces
It makes the wood more flexible and able to handle uneven temperatures on opposing sides.
It relieves tension in flooring wood as one side is finished and sealed and the other side isn't
Air and vapor circulation
It reduces the weight of the wood making it less costly to ship
It gives the roaches a place to get out

[Bruno of NH]

It's a back relief. 
To limit cupping and also so when it's used for trim it lays flat. It helps for variation in drywall or plaster.

[Don P]

Yup, flooring relief grooves, supposedly helps with cupping. When the icemaker fails, they are of no help  :D.

[711ac]

Is hemlock flooring "a thing" somewhere? 

[Fern Wood]

That is some exceptional hemlock!

Is hemlock flooring "a thing" somewhere?

[SwampDonkey]

Western hemlock? Our eastern hemlock here gets hard when dried and not even possible to drive a nail without splitting or shattering the board, including turning the nail into a crooked snake. :D :D

But as to the grooves, looks like for flooring. But western hemlock makes exceptional moulding to. I would not say that is a pattern for moulding work though.