|
I assume you mean 3" x 8" or 4" x 8" sawn timbers. These sizes are commonly used in Australia for rural fencing. Three issues: timber strength, timber durability, and attack by termites. Strength: the denser hardwoods are certainly strong enough for intermediate posts. I'd use something bigger for strainers though - at least 6 x 6 sawn or about 8" diam poles in dense hardwood, or about 12" diam if softwood. Durability: Species vary hugely in durability, and you can't go by density. West Red Cedar is super durable for instance (but not very strong). Have to find out the species you have available, and look on the net, or contact your local forestry dept for data. I have data for some common Nth American species. If timbers are pressure treated, they will last at least 20 years, depending on your soil types and conditions. Termites: Most termites love moisture, so boggy ground is great for them. Some timber species are relatively resistant to termites (tho none entirely so) - again establish species of the timber you have and check its properties. Pressure treatment DOES NOT increase resistance to termite attack (at least in Australia). Also you can use local knowledge to find out whether termites are voracious in your area, and what sort of conditions they tend to go for near you. Email me if I can help further.
David
| 
