My building sills are 8x8 and sitting on treated 2x10 that will sit on 2ftx3ftx1ft pads. I have crushed rock filled in around the pads, then put a layer of base material on top to bring it up to within a inch of the pads. My plan is to cover this all with heavey guage poly (15 mil) to keep ground moisture from off the timbers. I am wanting to use something on the timbers to add to their protection. These sill timbers will be covered completely by plywood flooring on top and on the exterior. The rest of the timbers I would like to finish as well with something to preserve them. Any ideas on the sill timbers?
Maybe Boro-Care? It is a solution of borate salts in water and a glycol. No odor, nothing toxic to vertebrates, resists insects and some fungi. Since the salts are inorganic they last forever. That's what I am using in a somewhat similar situation.
A search for Boro-Care or borates or Tim-Bor here may give you more insight.
What species of timber? Some are naturally bug resistant and will last centuries as long as they are kept dry / away from ground contact. We don't bother treating heart Cypress / Port Orford Cedar or even Douglas Fir, because it's naturally more durable than Borate treated pine to start with. But if it's something bugs might like, then Borate is your simplest option.
Your plan with the treated 2x10s isolating your sills sounds sensible. Main thing is to keep those dry.
Copper Naphthenate can be rolled on. it is like solutions for pressure treatment, without the vacuum or pressure.
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it has a green color and a period of smell briefly.
The timbers are wester/mountain hemlock. With the 10ml plastic the ground moisture will be kept away. I do have borate material which I could spray the timbers. I am in the Regina area of Saskatchewan, not to bad for bugs, and as a rule relatively dry. This building will house the firewood processor, in bay 2 tra tor in bay 3 and 4. Bay 1 is storage for mis. Items,tools etc. We just got a couple of inches of snow last night and this morning but tomorrow and next couple of days above freezing, so will see if it all goes
Quote from: rjwoelk on December 04, 2023, 10:13:02 PMThe timbers are wester/mountain hemlock.
Not regarded as naturally durable, and can be attacked by bugs. Keeping it dry as you are planning will prevent decay, and spraying it with a borate solution will discourage bugs. Borate will leach out of wood if it gets wet, but as long as it stays dry it gives some protection.
I haven't seen it mentioned but keep anything other than ground contact treated wood a minimum of 6" above grade, structural members at least a foot above grade. Borate treated lumber is approved for sills as it is not wet or ground contact, if done as above.
Thanks for the input folks, I may just cover the beams up for winter, and then go at it when I have the rest cut. I need to get all my kneebraces and headers cut for the top sill and posts on the side walls, then we can put it up.