Resealing Cut Ends
Treated timber should not be re-sawn or dressed by the user as this may reduce the protection afforded by the treatment. However, when a piece of timber is cut, notched or rebated, there may be a chance that un-penetrated heartwood is exposed on the cut surface. With low natural durability timber such as pine it is important that these areas are resealed with a suitable “in-can” or “brush on” preservative to ensure that a satisfactory preservative envelope is maintained.
Nails, Bolts & Metal Fixings
Due to the presence of copper and other electrolytes in the preservative, all metal connectors in contact with the treatment should be corrosion resistant. For most situations, hot dipped galvanized steel will provide satisfactory performance although higher grade material such as stainless steel should be considered for the critical connections particularly where there are additional sources of corrosion (salt) or where very long service life is required. Do not put treated timber in contact with, or above uncoated zinc-aluminium roofing sheets as the presence of copper ions may cause severe corrosion.
Painting and Staining
Unfortunately a perception has developed that treated timber does not need painting. While the preservative treatment will protect against decay and insect attack for decades, the timber is still prone to the effects of general weathering such as splitting, warping, fading and surface discoloration. While these factors may not be important in a retaining wall for example, they can seriously degrade from the appearance of a deck or pergola within a few years.
We strongly recommend that all dimensioned timber in weather exposed, above ground situations is painted or stained to maintain appearance and serviceability. There are a wide range of surface coatings available from clear water repellent sealants which require regular reapplication, clear or semi-transparent timber stains that show a natural timber appearance through to fill bodied, opaque acrylic paints that will last for over ten years. Treated timber can be painted or stained like normal untreated timber providing that it is dry and clean.
SAFETY PRECAUTIONS
CCA , MicroPro & LOSP treated timber can be planed, chiseled, nailed or drilled just as easily as untreated timber. Carbide tipped saw blades are suggested when big projects are planned. Nails, plates and bolts should be hot-dip galvanized and/or stainless steel. Good building practices should always be utilised in the application of treated pine to ensure maximum stability and endurance.
- Wear gloves to help avoid splinters.
- Wash hands and face free of sawdust before meals or smoking. Food and drink should not be left exposed to wood dust.
- When power sawing and machining, wear goggles to protect eyes from flying particles.
- When sawing and machining treated wood, wear a dust mask. Whenever possible, these operations should be performed outdoors to avoid indoor accumulations of sawdust.
- Cuts and abrasions should be protected from sawdust whilst sawing or machining timber.
- Sanding operations should be performed in well-ventilated areas. If this is not feasible, use dust protection equipment. A dust mask and goggles will generally suffice. Gloves and overalls in high dust situations are also recommended.
