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View Full Version : Help! for stopping green wood shrinkage



Keith G.
07-11-2003, 09:08 AM
I have just become the recipient of a bunch of white spruce slabs. I want to build a walkway across my lawn with these slabs, which are about 3 inches thick and 20 inches across. They are really fresh and really green.

Any advice to prevent cracking and splitting? I have considered automotive antifreeze, PEG (Lee Valley sells it here (http://www.leevalley.com/wood/page.asp?SID=&ccurrency=1&page=20080&category=1,190,42942) , and Thompson's Wood Sealer.

Keith G.
07-11-2003, 09:08 AM
I have just become the recipient of a bunch of white spruce slabs. I want to build a walkway across my lawn with these slabs, which are about 3 inches thick and 20 inches across. They are really fresh and really green.

Any advice to prevent cracking and splitting? I have considered automotive antifreeze, PEG (Lee Valley sells it here (http://www.leevalley.com/wood/page.asp?SID=&ccurrency=1&page=20080&category=1,190,42942) , and Thompson's Wood Sealer.

Keith G.
07-11-2003, 09:08 AM
I have just become the recipient of a bunch of white spruce slabs. I want to build a walkway across my lawn with these slabs, which are about 3 inches thick and 20 inches across. They are really fresh and really green.

Any advice to prevent cracking and splitting? I have considered automotive antifreeze, PEG (Lee Valley sells it here (http://www.leevalley.com/wood/page.asp?SID=&ccurrency=1&page=20080&category=1,190,42942) , and Thompson's Wood Sealer.

Bruce Hooke
07-11-2003, 11:27 AM
Trying to keep them from drying is likely to be pretty futile. PEG would do it but you would need a HUGE quantity of it because the wood needs to be soaked in it for a long time (as in probably months for boards that size).

I would focus on controlling the drying process to keep the wood from checking. The key to this is sealing the end grain. Trim off enough wood to get rid of any checks that have already formed and then paint the end grain with aluminum paint, epoxy, or one of the products designed specifically for coating end grain. You can then either stack the wood with spacers (stickers) and let it dry, but with 3" thick slabs that would take quite a while, or you could build the walkway and let it dry in place. If you do that you would need to allow for the boards shrinking as they dry, which could make fastening a little tricky.

I would recommend painting the wood with some sort of wood preservative because spruce has very little rot resistance.

Bruce Hooke
07-11-2003, 11:27 AM
Trying to keep them from drying is likely to be pretty futile. PEG would do it but you would need a HUGE quantity of it because the wood needs to be soaked in it for a long time (as in probably months for boards that size).

I would focus on controlling the drying process to keep the wood from checking. The key to this is sealing the end grain. Trim off enough wood to get rid of any checks that have already formed and then paint the end grain with aluminum paint, epoxy, or one of the products designed specifically for coating end grain. You can then either stack the wood with spacers (stickers) and let it dry, but with 3" thick slabs that would take quite a while, or you could build the walkway and let it dry in place. If you do that you would need to allow for the boards shrinking as they dry, which could make fastening a little tricky.

I would recommend painting the wood with some sort of wood preservative because spruce has very little rot resistance.

Bruce Hooke
07-11-2003, 11:27 AM
Trying to keep them from drying is likely to be pretty futile. PEG would do it but you would need a HUGE quantity of it because the wood needs to be soaked in it for a long time (as in probably months for boards that size).

I would focus on controlling the drying process to keep the wood from checking. The key to this is sealing the end grain. Trim off enough wood to get rid of any checks that have already formed and then paint the end grain with aluminum paint, epoxy, or one of the products designed specifically for coating end grain. You can then either stack the wood with spacers (stickers) and let it dry, but with 3" thick slabs that would take quite a while, or you could build the walkway and let it dry in place. If you do that you would need to allow for the boards shrinking as they dry, which could make fastening a little tricky.

I would recommend painting the wood with some sort of wood preservative because spruce has very little rot resistance.

Bob Smalser
07-11-2003, 10:28 PM
With your cold climate like mine, you might get away with spruce in contact with the ground for a few years...but preservative or no preservative, I don't think you'll get 10 years out of them. Surface-applied preservatives don't penetrate sufficiently to do much good - especially in 30pct+ M/C wood like yours.

PEG is a probably a waste of money for this project....you could buy cedar with that money instead.

I'd paint the ends (anything will do - cheap latex paint or paraffin wax/solvent slop are fine) stack, sticker (each board deck - no boards touching another) - cover the slabs with tarpaper (open sides) and dry them a season, first. It'll take 2-3 summer seasons to air-dry them to 18-20pct M/C.

Then you might try the preservative.

Another alternative is to run them on cedar or P/T stringers to get them away from those soil microbes.

Better yet, see if your slab source can score some cedar for you....or come visit me - I save WRC bark-edge slabs from my sawmill for use in outdoor woodsy furniture and have a hundred or so on hand...you can have all you can carry gratis....

...and there may be a small sawmill operator near you who'll do the same.

[ 07-11-2003, 10:35 PM: Message edited by: Bob Smalser ]

Bob Smalser
07-11-2003, 10:28 PM
With your cold climate like mine, you might get away with spruce in contact with the ground for a few years...but preservative or no preservative, I don't think you'll get 10 years out of them. Surface-applied preservatives don't penetrate sufficiently to do much good - especially in 30pct+ M/C wood like yours.

PEG is a probably a waste of money for this project....you could buy cedar with that money instead.

I'd paint the ends (anything will do - cheap latex paint or paraffin wax/solvent slop are fine) stack, sticker (each board deck - no boards touching another) - cover the slabs with tarpaper (open sides) and dry them a season, first. It'll take 2-3 summer seasons to air-dry them to 18-20pct M/C.

Then you might try the preservative.

Another alternative is to run them on cedar or P/T stringers to get them away from those soil microbes.

Better yet, see if your slab source can score some cedar for you....or come visit me - I save WRC bark-edge slabs from my sawmill for use in outdoor woodsy furniture and have a hundred or so on hand...you can have all you can carry gratis....

...and there may be a small sawmill operator near you who'll do the same.

[ 07-11-2003, 10:35 PM: Message edited by: Bob Smalser ]

Bob Smalser
07-11-2003, 10:28 PM
With your cold climate like mine, you might get away with spruce in contact with the ground for a few years...but preservative or no preservative, I don't think you'll get 10 years out of them. Surface-applied preservatives don't penetrate sufficiently to do much good - especially in 30pct+ M/C wood like yours.

PEG is a probably a waste of money for this project....you could buy cedar with that money instead.

I'd paint the ends (anything will do - cheap latex paint or paraffin wax/solvent slop are fine) stack, sticker (each board deck - no boards touching another) - cover the slabs with tarpaper (open sides) and dry them a season, first. It'll take 2-3 summer seasons to air-dry them to 18-20pct M/C.

Then you might try the preservative.

Another alternative is to run them on cedar or P/T stringers to get them away from those soil microbes.

Better yet, see if your slab source can score some cedar for you....or come visit me - I save WRC bark-edge slabs from my sawmill for use in outdoor woodsy furniture and have a hundred or so on hand...you can have all you can carry gratis....

...and there may be a small sawmill operator near you who'll do the same.

[ 07-11-2003, 10:35 PM: Message edited by: Bob Smalser ]