Geelhoutvlei Timbers
Grading, Treatment & Coatings

Grading

• All products go through some level of grading whether formal or informal. Where a formal grade is applied, the product will be stamped with a grading South African National Standards mark.
• The fact that a product does not carry a National Standards Grading mark does not necessarily mean that it does not conform to that standard, but rather that the formal certification has not been applied. For example, all our sawn board is informally graded using SANS1783-3 as a guideline, but is not certified in terms of the standard. (See Sawn Board Grading).
• Poles are graded to SANS 457-2:2018
• Lam Beams are graded to SANS 1460:2015 and fingerjointed in terms of SANS 10096:2013

Treatment

• Lam Beams are graded to SANS 1460:2015 and fingerjointed in terms of SANS 10096:2013
  • H2 Internal above ground
  • H3 External above ground
  • H4 External ground contact
• Certain certification authorities are able to monitor and certify particular producers to treat in accordance with SANS standards.
• At Geelhoutvlei Timbers we are certified by the SABS to treat with CCA in hazard classes H2, H3 and H4 in accordance with SANS 1228:2020.
• We outsource our H2 Vacsol clear treatment.

Coatings

Coatings is a mine field and whereas we have our own preferences, we feel that our customers need to do their own research and experimentation. We can make the following personal observations:

• Being dry and porous by nature, wood responds very well to oil. In particular, linseed oil makes a very good coating and we apply it thinly to all indoor product including joinery and furniture. It can be thinned with turpentine to achieve better penetration. You can also apply oil-based coatings on top of it. For instance, on flooring and other internal product, we use it as a first coat.
• A three-part mixture of linseed oil, mineral turpentine and methylated spirits, applied with 0000 steel wool can be used to clean and restore any wooden surface, including fine furniture.
• Linseed oil is a fantastic organic coating.
• We like the Woodoc products. Woodoc 10 (polywax) gives a very natural good natural interior look finish and Woodoc 25 (polyurethane) is very durable. The trick is to ensure you layer them up in thin coats burnishing with 0000 steel wool in between.
• External coatings need to be water repellent.
• Decks can be left uncoated and will weather, but if correctly fastened, can last at least 15 years. Alternatively, they should be thoroughly oiled and sealed. If sealed, a really good deck sealer needs to be used otherwise it will crack and flake. Once again, we find, if correctly applied, the Woodoc Deck Seal is highly effective.
• Exterior exposed wood surfaces can also be sealed cost effectively with Waxol. This will darken the timber and is slightly oily and sticky, but is very effective long term maintenance.
• Whatever coatings you use or choose, please be aware that periodic maintenance will be required. In particular, if you choose a varnish type sealant that is not oily and malleable, it will crack and flake and will need re-sanding and new application. For this reason, we prefer to use the products as above but we encourage you to look deeply into the matter yourselves.