No-Rot Gel



Tested in Australian conditions and approved for commercial and domestic use. Learn more about APVMA approved.
No-Rot Gel is a ready-to-use, water-based brush on wood preservative, to control the spread of decay. It is formulated to penetrate by diffusion into the timber, while still allowing the surface to be painted over. No-Rot Gel can also kill surface mould, algae or fungi. It can also be used on timber, masonry or concrete surfaces.

Key Points

  •  Can be applied on damp timber and structural timber that has been affected by floods.
  • Ready to use.
  • Suitable for both indoors & outdoors. (outdoors to be an undercoat only)
  • Designed to protect the wood from biological growth and prolong its lifespan.
  • Acts as a barrier against fungi and inhibits their colonisation.
  • Can be painted over with either oil or water-based paints.


Recommended Uses

No-Rot Gel can be used as a timber treatment where it has been affected by decay, mildew or insect attack. No-Rot Gel is ideal for use in external areas such as timber window frames and posts that are intended to be painted with oil or water-based paint. It is also ideal for use in internal timber framing where moisture is a problem, such as in bathrooms or under subfloors with poor ventilation.

RESTRAINTS. No-Rot Gel is not to be used on timber exposed to rain (ie without a painted finish or surface coat), timber in contact with the ground, or surfaces that come into contact with foodstuffs or drinking water.


No-Rot Gel will not restore timber severely damaged by rot and termite attack. Unsound wood within any timber structure should be replaced. The new wood must then be treated with No-Rot Gel to prevent deterioration in the future.

Areas Where Decay And White Ant Attack Normally Occur

Decay attacks occur in timber that becomes wet for prolonged periods. Key situations in which timber becomes wet and therefore should be treated with No-Rot Gel are:

  • If timber is subjected to long wet periods or high humidity
  • Interfaces and joints that trap moisture
  • Around drill and bolt holes

Directions For Use

Apply No-Rot Gel to the timber surface using a brush, roller or spray gun. If the timber is very dry, it is best to dampen the timber with water to allow better penetration of No-Rot Gel. For effective treatment against decay, mould and insect attack, use the following table apply the correct dosage to the timber.

Required depth of diffusion into the timber surface 0-25mm 25-50mm 50-100mm
Amount of No-Rot Gel required per square meter 500ml 1 litre 2 litres

For correct dosage rates, No-Rot Gel will require 2 coats. Allow 2-3 hours between coats.

Painting Over No-Rot Gel

Timber treated with No-Rot Gel can be painted over with either oil or water based paints, primers and undercoats. For best results, allow 5 – 8 days for the timber to thoroughly dry.

Technical Data

Active Ingredient Boron (Disodium Octaborate Tetrahydrate) and Benzalkonium Chloride
Active Concentrations Elemental Boron 52g/L
(Boric Acid Equivalent 174.6g/L)
Benzalkonium Chloride 12g/L
Appearance Clear Liquid
Boiling Point > 100°C
Odour Low odour

Pack Size

Available in 1 Litre, 5 Litre, 10 Litre, and 20 Litre drums.

Storage And Shelf Life

Store in a cool dry place out of direct sunlight. Keep out of the reach of children. No-Rot Gel has a shelf life of 18-24 months depending on how it’s stored.

Safety Directions And First Aid

Avoid contact with eyes and skin. When handling No-Rot Gel, wear protective clothing, gloves, eye protection and a vapour mask if spraying. Wash contaminated skin or eyes with copious quantities of water for 15 minutes. If ingested, give water to drink. Do not induce vomiting. Seek medical assistance and contact the Poison’s Information Service on 13 11 26.

SDS and Tech Data

No Rot Gel SDS
No-Rot Gel Tech Data



Karen H.
Review by Karen H. on 7 Jul 2022 review stating Great product
Really soaks in and on and kills all fungi/mould and penetrates to ensure long lasting protection. Been a life saver after all the rain!

Ross W.
Review by Ross W. on 17 Dec 2021 review stating Great Service
It was easy to apply and I am very happy with the product. More importantly I was really pleased the the patience and service offered by Kieran when I asked a dozen inane questions and then got my account mixed up.

Barbara S.
Review by Barbara S. on 10 May 2021 review stating No Rot
Works well.

George S.
Review by George S. on 23 Apr 2021 review stating No Rot Gel
Excellent product and excellent service.

Related Products

No Rot Gel Wood PreservativeTimber Preservatives Decking Oil


Can I paint over Preschem’s No-Rot Gel?

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

What is Timber Decay (rot)?

Timber Decay/ wood rot is a biological attack within the wood by certain species of fungi. The fungus can lie dormant in the timber for years until the right conditions present themselves, most causes of timber decay occur due to an increase in moisture or damp conditions.

Can I Prevent Timber Decay (rot)?

Yes, you can we have a range of products that can prevent and treat it. They protect your timber against decay, rot, fungicide, termites, borer and insect attacks.

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