Creosote mainly consists of tar, which is a byproduct of the combustion of wood materials.
In other words, that smokey flavor you taste with meats that have been “smoked” is creosote.
You can find creosote lining chimneys and other areas that are exposed to wood fires and the smoke they produce.
Creosote is dangerous because it is quite flammable – especially the third stage creosote which is highly concentrated and thick.
By sticking to surfaces, when it catches fire it may cause considerable damage.
Plus, creosote will quickly build up, especially in conditions where ventilation is poor.
So, can you paint over old creosote to minimize the danger it can cause?
While it is possible to paint over creosote, you will need to use the right primer or base paint and apply several layers over creosote along with at least two coats of finishing paint.
This will ensure that the job is done perfectly well.
How to Paint Over Creosote the Right Way?
Paining over creosote requires the use of the proper techniques to ensure that the creosote can be covered by the primer and paint.
These techniques can also be used to cover other areas that are stained or discolored assuming you are using a petroleum-based product.
Step 1: Preparation
The first step is to scrape away all the loose debris that covers the surface. Use a wire brush on the area that will be painted.
Keep in mind that removing the creosote is not necessary, but you will need to remove all the loose dust, dirt, and debris from the surface before it can be painted.
Step 2: Purchase the Right Paint
To paint the creosote, you will need some aluminum paint.
Plus, you will need a lacquer-based prime sealer and a finish coat.
For clean-up purposes, paint thinner or turpentine is recommended, just be careful as they are flammable liquids.
Step 3: Apply Aluminum Paint
You’ll need to follow the directions and apply the aluminum paint first.
The creosote will need to be totally covered with aluminum paint before you can proceed to the next step.
You’ll have to really stir the paint before applying it, otherwise, it might not work properly.
Step 4: Primer
Next, once the aluminum paint dries, you’ll need to apply the primer.
Use a lacquer-based primer and be prepared to apply at least two coats. This will ensure that you properly seal the aluminum paint.
Step 5: Finish Coat
Once the primer dries, you are now ready to apply the good finish coat of paint. A good oil or latex house paint will do.
Just keep in mind that it will take at least two coats to fully cover the primer. It is possible that you may need more coats to get a smooth finish.
Cuprinol Garden Wood Preserver can be applied over well-weathered creosote for getting a superior long-last finish.
Make sure you clean the surface with a mild detergent solution and get it rinsed well with clean fresh water.
Allow the wet wood surface to dry naturally. And then apply at least 2 coats of wood preserver using a synthetic bristle brush.
Can You Seal Old Creosote-Treated Lumber?
While old creosote-treated timber used in the construction of your property can be used after sealing the lumber, I recommend not to do so.
Because creosote can be nasty and at the same time toxic, if you can replace the timber it’s always the safest option for you.
With that said, if you really wish to use old creosote-treated old railway sleepers in your garden but are worried about the toxic nature of creosote, sealing creosote into the timber can be the solution.
Sealing creosote-treated timber properly will prevent the unpleasant creosote smell and will also make the timber safe for animals, and nearby plants.
This way you can use that old lumber without worrying about the hazardous phenolic compounds that are found naturally in creosote.
The sealer treatment over the creosote-treated timber can be done by following these simple steps…
Step 1- Strip the paint
Using a paint stripper like Methyl Ethyl Ketone remove the paint from the exterior wood surface.
Using a sander is not recommended as it can release contaminated wood dust that can be harmful.
But if you do not have any option other than sanding, be sure to use a face mask, gloves, eyewear, etc for protection.
Step 2- Remove the creosote
After removing the paint, you also need to clean all the creosote from the wood surface.
Use some old rags and solvents (like white spirit or turpentine) for completing this step and make sure you work hard to wipe out all of the creosote patiently.
Also, remember that you may need to use lots of solvents depending on the creosoted lumber. So prepare for the solvent in advance.
Step 3- Treat the wood with CPES
Clear Penetrating Epoxy Sealer™ (CPES™) is a sealer that is made of tough, flexible resin blended in the solvent.
When applied properly the resin system bond to the wood fibers chemically. Plus, it dissolves all the sap, oil, and moisture found in the timber.
For getting effective results, you will need to apply two saturating coats of CPES slowly to the timber.
After applying the second coat leave the timber for a couple of days until the smell goes off completely.
Sealed timber can be finally painted with marine epoxy paint or clear varnish for a more natural finish.
How to Prevent Creosote from Forming in the First Place?
Preventing the third-degree creosote altogether is not an easy task since it is easy for creosote to form and then build upon the surfaces.
Apart from intensive deep-cleaning or simply never using your fireplace again, the only way to fully control the creosote is to have a professional cleaning performed regularly.
However, keep in mind that a little creosote is not all that harmful.
It is when it builds up (for about six to twelve months) that it becomes dangerous.
You can successfully control the creosote and minimize the danger by doing the following.
Both before you start to use your chimney and after the spring season arrives, you should have it inspected for the buildup of creosote.
Even just annual inspections can spot the growth of creosote and lead to its stoppage.
Keeping your chimney well ventilated will help keep the creosote from building up in-between fires in the fireplace.
The chimney should have inner mechanisms to ensure that the ventilation is good.
However, if you suspect that they are not working properly, then you will need to have them inspected and repaired.
3- Fast Cleaning
You can quickly wipe down and clean your chimney between inspections.
If it’s present on concrete, bricks, or cement you can scrub using a mixture of warm water, liquid dish soap, and a bit of vinegar.
Since creosote substitute is moderately soluble in water, this will help wash the creosote off the surface faster.
Once the stains of creosote are removed you can quickly rinse the surfaces with water.
It also pays to keep flammable objects away from the fireplace itself.
4- Dissolving the Creosote
Creosote when it’s still in 1st stage can be dissolved and can be prevented from forming in thick layers.
You can dissolve the creosote either by spraying it directly with water & salt or by burning specially-treated logs.
Sodium chloride (also called table salt or rock salt) does not actually remove the creosote but can work to dissolve small amounts of creosote.
While the fire is burning you can put a small amount of salt with water in the burning wood/chimney.
By doing all of these things, you can minimize the dangers of level 3 creosote and protect your home.
The Bottom Line
Creosote is much like thick soot or an oily substance that builds up in fireplaces, wood-burning stoves, and chimneys with time.
While you can paint over build-up creosote, it’s important that you clean the surface thoroughly before painting.
This will help prevent potential health hazards that creosote can impose.
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Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for over a decade serving customers in areas such as Charleston, Mount Pleasant, Beaufort, and Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques implemented in his profession. You may read more about him here or get in touch with him here.