Sill gasket - prevent rot or keep out air?

[ontario]

I'm building a garden shed on a concrete pad. The sill plate will be pressure treated wood. Do I need a sill gasket? I really don't care about air infiltration but does the sill gasket keep the wood from getting wet and rotting?

[David]

I don't think you need a gasket if you don't care about air infiltration.

I would, however, do my best to install a bug screen and flash well.

[ontario]

I don't think you need a gasket if you don't care about air infiltration.

I would, however, do my best to install a bug screen and flash well.

Can you elaborate? What is that exactly? I would like to keep the bugs and mice out.

[David]

Here are some photos by a builder in Iowa, named Rollie.
http://imageevent.com/okoboji_images/deloreshouse

Scroll down, click show all, look at images 148-152.

You'll see it's just a standard insect screen, like on a screen door. Just cut 6" strips off of a roll of galvanized insect screen. (You can also get copper or stainless steel if you have a big budget!) For each wall, staple the screen to the bottom of the sill, then assemble the wall as you normally would. After the wall is raised or asssembled, capnail the screen to the sheathing (studs if you have no sheathing).

Also, in TX, many people suggest placing an inch or two of lie on top of the sill in the stud cavities. Not sure if that'd work after freeze and thaw cycles.

[ontario]

Great idea. Thanks.

The inside of the shed will not be finished so can't do the lie. I think I may still do a gasket to keep bugs from crawling under the sill.

[Don_P]

Lye? That's a new one on me, its also a wood pulper, strong base, not sure I'd do that. My sweetwife makes soap and went to get the makings a few months ago. Lye is now a controlled substance around here, the meth heads use it somehow in their cooking ... gee I wonder why their teeth fall out. We're back to store bought soap till I get off my carcass and make a lye trough and drip some out.

I took a quick trip on a smokehouse floor one time. The salt had corroded the nails and when I stepped in that was all it took. The salt had also pulped the wood about 1/4" deep, you could roll the fibers off to that depth with your fingers, kinda neat.

Old time carpenters used to sprinkle borax or boric acid in stud bays for the critters also. I've sprayed several houses with borates, our present client is going to do his shell up this weekend.

Treated can be layed on concrete without trouble if you wish.

[David]

Sorry, it's borax! That's what they use INSIDE the house. They use lye around the perimiter of the property to keep snakes, critters, fire ants, ... off the property. I've heard it works very well.

[tooltroll]

Concrete is porous and wood will wick water from it and eventually rot, especially in a shed situation where the concrete is more exposed to the elements than, say, a basement floor. Sill gaskets are cheap, and isolate the wood from concrete. I don't ever let wood touch concrete.

[David]

Wood touches concrete all the time here. The sill plates are PT lumber, so they aren't gonna rot anytime soon. However, on houses here, we install poly under the slab, so there is a lot less water to wick.