There are different strength levels of treatment usually classified from h1 through to h6 being the most effective and best preserved.
Treated pine or hardwood sleepers.
If you want to use pine wood for retaining walls use logs or wing splits as the sapwood is on the outside.
Avoid treated pine sleepers if they are to be in contact with the ground.
2 625 in x 3 75 in x 8 ft pressure treated landscape timber.
Both have similar properties and one can expect 15 to 20 years of use.
And never use sleepers longer than 2 4m without extra uprights as these extra uprights will prevent the sleepers from bowing.
Their advantages are obvious.
Expect them to last about as long as treated hardwood sleepers.
Increased strength and durability and a much better ability to withstand the elements.
Pine on the other hand from which our softwood sleepers are constructed are less resistant to decay and are henceforth treated with either tanalith green or tanatone brown.
Concrete sleepers which come in fixed 2m lengths are becoming a popular alternative to traditional timber sleepers.
Hr5 highly water and pest resistant treated pine sleepers are estimated to last for up to 20 years.
These sleepers do not treat as well and regularly fail in the landscape.
If you want to use sleepers use class 1 hardwood sleepers.
Hardwoods have a natural protection against pest and fungal breakdown because they are hard and softwoods like pine are easy targets for pests because they are easier to eat.
Treated pine logs have a shorter estimated lifespan than treated pine sleepers.