Preschem FAQ









Preschem FAQ

Preschem has added a lot of new FAQ to this page. To keep them in a logical order, we’ve added categories and grouped them accordingly. To see the FAQ under each category, please click to expand or collapse the FAQ. Then click on the question to see the answer.

DIY Timber Preservatives

Remove the source of moisture. Moisture will degrade timber and the Preschem preservative system applied over time. If the source of moisture is removed, then Preschem products will remain in the timber almost indefinitely waiting to protect the timber when moisture becomes an issue again. Sealing the timber with a quality paint is the simplest and most effective means of controlling moisture in timber when its above ground.

This is subject the the environment the timber is in and how much persistent moisture is present, but for most normal situations where the preservative is expsoed to the weather unless otherwise stipulated:

Timber Preserver: 4-5 years
No-Rot: 4-6 years
No-Rot Gel: 4-5 years (note that exposed exterior timber must be sealed with a quality exterior paint, otherwise the expected life will be 6-8 months)
Clear Wood Preservative: 12 months
Heavy Oil Preservative: 4-5 years
In-Ground Paste: 4-5 years

Preschem’s timber preservative products will kill, prevent and control rot within reason, but will not restore strength. Badly decayed structural timber must be replaced by a registered professional tradesman.

No-Rot Gel

Yes. For best results allow the preservative to dry for as minimum of 24 hours. Use can then use a “builders bog” type filler and quality oil based primer then your choice of quality exterior oil or acrylic top coat.

Timber Preserver:

Yes, but with caution. Timber Preserver’s active ingredeint, Copper Naphthenate, is also used as a paint drier in oil based paints. As such it can be prone to colour bleed. To paint over Timber preserver we recommend the following:

  • Allow at least 2 weeks to dry. Preferably more if practicable.
  • Use a quality stain block type acrylic primer such as those made by Zinsser or Dulux
  • If colour bleed through occurs with the primer, do not continue painting. Strip back the primer to bare timber and allow a further 2-3 weeks to dry.

No. Heavy Oil Preservative contains a medium paraffin oil, making it amost impossible to paint over.

Call Now Button