Ronseal Wet Rot Wood Hardener

  4.8/5.0 (8 reviews)
  • A liquid wood hardener designed to strengthen and reinforce wood softened by wet rot
  • For interior and exterior wood including doors, windows, frames and sills
  • A cost-effective, long-term alternative to replacing joinery affected by wet rot
  • Soaks deep into the fibres of rotted wood to strengthen the wood from within
  • Provides a solid base for filling
Brand Ronseal
No. of coats 1
Drying time hrs
Size 250ml, 500ml
MPN 32041, 32042
GTIN 5010214538706, 5010214538713

Ronseal Wet Rot Wood Hardener is designed to soak into the fibres of rotten wood. When dry the special resins harden, strengthening and reinforcing the softened wood, forming a good solid base for wood filler as well as sealing against further moisture penetration.

Ensure that wood to be treated with Wet Rot Wood Hardener is reasonably dry and free from grease, oil, dust and loose particles before application.

  • Remove any completely decayed or very soft crumbly wood until a fairly sound base is exposed
  • For the best results, drill small holes into the damaged area to achieve an even deeper hardening of rotten wood

How To Treat Rotten Wood

Always do a small test area before starting any project and follow the manufacturer's instructions on the tin at all times. If indoors, open doors and windows to provide proper ventilation.

Shake the tin thoroughly before opening.

  1. Decant a small amount of wood hardener into the lid of the tin or other small container
  2. Apply wood rot hardener to the softened wood with a paint brush
  3. Soak the affected area to ensure full absorption of the hardener
  4. Leave for 2 hours then remove any excess wood hardener with a stiff brush
  5. Use Ronseal High Performance Wood Filler to fill and finish the damaged area
  6. Sand off any surface wood hardener prior to painting or finishing

Please Note: Avoid contact with glass, metal, plastic and painted surfaces during the application process. Do not use this product as a surface treatment or primer.

Once Ronseal Wet Rot Wood Hardener has dried fully, the treated timber can be filled as necessary with a suitable wood filler and finished.

8 customer reviews
Really happy with this product by Lee Vaughan

I used this on some old rotten windows and frames it worked really well. I would highly recommend this product.

Reviewed 500ml on: 06/04/17
Very useful product by Colin Pope

Use straight from the can. Dries very quickly. Works without holding you up .

Reviewed 500ml on: 13/10/16
Protection for strengthening wood by M Loring

This is a very good product for reinforcing any wood that looks as if it may be effected by water as it hardens any soft wood that may have been effected so instead of splicing a new piece of wood in this product can save this process.

Reviewed 250ml on: 12/10/16
Wet rot magic potion by Ralf Gunemann

I have used it various times and each time I am amazed how one can save existing timbers with this magic potion. Just remove the worst wet rot, treat the area, wait for drying, once rock hard fill with proprietary wood filler and finish as you like it to blend in with the rest... Very recommendable, worth every drop!

Reviewed 500ml on: 01/10/16
Good by I Williams

Excellent product .. use for rotten wood prior to wood fill .. used many times before.

Reviewed 500ml on: 03/09/16
Very effective product by M Louise Cooper

Product does evaporate so only use small volumes at a time

Reviewed 500ml on: 28/08/16
Works by Iain Robertson

I reach for this as I know it works well and saves a lot of effort.

Reviewed 250ml on: 18/05/16
Again, easy to apply by Neil McManus

Not as successful on badly damaged timbers, but excellent on smaller areas of wood damage.

Reviewed 500ml on: 27/10/15