Sealing Creosote Treated Timber

You might want to use some old timber internally that was once treated with creosote. Perhaps your property has creosote preserved timber in its construction. You might wish to use old railway sleepers in your garden. Worried about the toxicity of the creosote, to animals and plants, and the famous smell it gives. Sealing creosote treated timber effectively allows you to use those old timbers without worry or smell.

Why is Creosote bad?

Creosote is a natural product containing hazardous phenolic compounds. Sale of Creosote to the public was banned in 2003. The odours associated with creosote are not all due to the phenols, and thus do not all carry the health risks associated with the phenols. The odours however are distinctive, and you probably would not want them in your house.

Why Seal Creosote Treated Timber?

One of our customers (Thanks Kenny) wanted to reuse some ancient oak railway sleepers. He had planed those creosoted oak railway sleepers to a clean flat surface, but the smell, and presumably the toxicity as well, remained. Kenny was making a Bass Guitar so he was predominately concerned with toxicity as the guitar will be handled a lot. Kenny wanted a varnish finish so had to remove any oiliness associated with the creosote as well.

Houses built with creosoted telegraph poles exist. All manner of other properties exist with Creosoted timbers in them.

Sealing creosote into timber was clearly a problem worth solving. We asked Steve Smith just to make sure, and his advice forms part of this article.

Seriously Consider Replacing Creosote Treated Timber

If you can replace the timber – my advice would always be to do so. Creosote is a wonderful preservative, but it’s nasty. If you have railway sleepers, it’s probably cheaper to buy new hardwood sleepers (and CPES treat those to enhance longevity) or second hand Azobe sleepers (which will last pretty much forever) than to clean your creosote treated softwood timbers.

Ask yourself – can I replace this or use something else?

Sealing Creosote Treated Wood

The treatment involves the following stages.

• Remove any paint from the surface of the timber. Methyl Ethyl Ketone is a superb paint stripper that will not leave harmful deposits in the wood. If you sand ensure you are fully protected as paint and wood dust contaminated with creosote is very nasty.
• Clean any excess creosote from the exterior of the wood using a volatile solvent such as odourless white spirits or turpentine. This is the hard work stage – you will spend a long time with many different rags wiping. Keep going until you can remove no more. Lots of solvent and patience are key here. If the timber is not part of a house then immersion (multiple times) is highly recommended.
• Prepare the surface of the timber to the state that you wish. Typically this will involve planing and perhaps sanding as well. Creosote stained wood dust is highly irritating to skin, eyes, sinuses and lungs. Use a full face mask, ideally with external air, or a very strong wind at your back when wood working with creosoted wood.
• If you have exposed any more creosote then use solvents again until no more can be removed.
• Next treat the timber with two saturating coats of CPES. Leave the second coat for a few days, or until the smell has almost completely gone.
  • Follow the instructions here if you wish for a natural finish to your sealed timber
  • Follow the instructions here if you are going to varnish your sealed timber
  • We recommend that you apply two coats of a marine epoxy paint if it’s compatible with your required finish (ie you are not bothered about seeing your wood)

What will I achieve by sealing like this?

Well, pictures paint a thousand words, so let’s start from the beginning. This is Laura’s home, where she wanted to seal creosoted timbers to contain the smell. Her testimonial is also reproduced here.

Sealing creosote coated timbers before treatment with CPES

Click to show full size

The same creosoted timbers after treatment

And a matching oak beam also treated

Laura’s testimonial – How she sealed creosoted wood in her home with CPES

Following excellent advice from Steve, I found the CPES (warm) easy to apply using the simple instructions provided. Our old, smelly, creosote-coated ceiling beams were heavily sanded prior to application so it absorbed well and covered smoothly. It has enhanced the grain which looks great and darkened the colour which we like. Once dried/cured, the excess does leave a shine (mainly on the grain or knots) which we removed with a very light sand. The majority of the timber is left with a matt or low sheen finish. The creosote smell is gone! We also used it on some oak beams which had previously been treated for woodworm. Again, good result.
The epoxy is watery, went a long way and we didn’t need as much as expected. I do suggest long armpit length gloves if applying above head height to avoid it running down your arm!

Thanks for your help!

How does CPES cure Creosote smell

Sealing creosote into timber is performed highly effectively by treatment with Smiths CPES. The epoxy resins in Smiths Clear Penetrating Epoxy Sealer react with the toxic phenolic compounds in the Creosote. CPES ties up and renders harmless the toxic phenols from the creosote.

Many different molecules comprise the Organic fragrances in the creosote. Some of the very smaller of these may permeate to a certain degree through the sealed surface. This means that a certain odour, though certainly different to Creosote, may remain. Smiths CPES traps the harmful phenols within the sealed timber, locking them in forever.

Where do I buy the Ingredients?

Copyright Steve Smith and Stephen Dakin. 2020