Protecting sill beams

Started by eggman, May 07, 2009, 08:02:01 PM

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eggman

I have a 12x24 circa 1950 ballon framed camp. The sills beams were replaced 10 years ago and are in great shape. I want to keep them that way, so I had the camp jacked up. It's on bricks now about 6 inches off the ground. I can get at most of it so I'm wondering if I should stain them with some kind of protectant? I'm afraid ice and water shield would do more harm than good by holding moisture in. Thanks for any advice.

Don_P

If they are unfinished bare wood, I'm a fan of borates. They take care of wood consuming insects and decay fungi but have very low mammalian toxicity. For dry wood one of the glycol based mixes give deepest penetration. Bora-care is the most popular. I'm cheap so mix my own using the ag chemical Solubor, available at real farm supplies in 50 lb sacks for $1-$1.50 per lb.  I mix at 1lb/gallon of warm water and add between a quart and a half gallon of anti-freeze per 5 gallon batch. Anti freeze is ethylene glycol, the glycol in boracare. You can also use rv antifreeze if you want to use a no tox glycol, that would make the equivalent of the mix Shellguard. The glycol simply dries slowly so lets the borate get into dry wood deeper. You can apply it wet on wet until it forms crystals on the surface. I applied it to an 1840's log cabin here for a month. Most folks treat with 2 liberal coats, I had an active infestation and a historic building. It is water soluble and can slowly leach back out. I normally apply a water repellant finish over it. The owner of the old cabin didn't want a finish so I applied until I could see white crystals. I check it every now and then, when the crystals are gone I'll hit it again. It's been several years so far with no loss. All framing in New Zealand is treated with borates and it wouldn't be a bad idea if we did it here. In some places you can get borate treated lumber, I've had it come in on a precast foundation used for the window and door bucks so it is starting to become available commercially.

You are right about the ice and water or in many cases any film forming finish. A small leak can admit liquid water which cannot easily escape as a large volume of vapor. The vapor, unable to escape, raises the moisture content of the wood to a level that will support decay fungi and you have compost in a bag of paint.  I've reached in behind the film finish and scooped out hot rotten wood by the handful.


eggman


eggman

Thanks for the great info Don.

DirtyLittleSecret

Looks like alot of opportunity there!
Thumb, meet hammer...hammer, meet thumb...


eggman

Quote from: DirtyLittleSecret on May 08, 2009, 12:06:41 AM
Looks like alot of opportunity there!
Thanks. I'd love to hear ideas. I just blew out the celing on one half of the camp and put beams on top of the kneewalls. I left the other half for a sleeping loft. All new rafters and roof boards.  Thinking about some winder stairs. Not sure of what to do for insulation. I don't want any moisture in there.. I might go without insulation.There is not and will never be any plumbing due to proximity to water. I've got a incinolet in the barn and a grill on the deck. That's all I need for the weekends..

John Raabe

The main thing I would make sure to do is to have a solid moisture break between any wood and rock or concrete contact. Plastic sill sealer or strips of asphalt singles will stop the migration of moisture from the soil below. Cheap insurance. ;) Borates are a good idea too and will help with air-borne humidity issues, but they will be ultimately overwhelmed if soil moisture can be sucked up into the wood.
None of us are as smart as all of us.

eggman

Quote from: John Raabe on May 08, 2009, 12:33:39 PM
The main thing I would make sure to do is to have a solid moisture break between any wood and rock or concrete contact. Plastic sill sealer or strips of asphalt singles will stop the migration of moisture from the soil below. Cheap insurance. ;) Borates are a good idea too and will help with air-borne humidity issues, but they will be ultimately overwhelmed if soil moisture can be sucked up into the wood.

I plan on keeping it off the ground this much (see pic below). Are you saying I should put plastic sheeting on the ground under the beams to keep moisture from rising? Thanks.