How To Remove Oak Beams Stains Properly

Oak Beams adds an architectural appeal to your house. However, beams tarnished by stains are quite an eyesore. Not to worry, this article can help you in removing the stains on that beautiful oak beam properly without damaging the original features.

Why Does Oak Turns Black?

You might be asking yourself why does your oak turn black. Well, it has something to do with the ferrous fixings (screws, hinges, or nails) used on the timber. The ferrous fixing will react to the tannic acid, a component that makes the wood long lasting, which will result in the dark blue staining, known as ferrous ironmongery corroding.

Removing the Black Stains from the Oak

In dismissing the black stain from oak or other timbers, we use Oxalic Acid. Before starting, please make sure that you read the safety data sheets first. Wear the following:

  • Wear Safety Goggles
  • Wear a mask
  • Wear latex gloves
  • Use in a well-ventilated area

You will also need the following:

  • Clean metal container for you to mix the solution
  • Paintbrush to apply the solution
  • Scales to weigh the crystals
  • Wooden to stick to stir the mixture

Usually, the Oxalic Acid comes in crystal form ready for mixing. You can use water or with Methylated Spirit, which can give you a quicker drying time for the mixture.

Mixing the Oxalic Acid and Applying it

Once you have the safety gear on, you can now move on to mixing the solution. Here are the steps.

  1. You need to around a pint of water to 60 grams of Oxalic Acid. Adding more Oxalic Acid will not make it any stronger.
  2. Mix the solution in the metal container using the wooden stick as a stirrer. Add the water first then the Oxalic Acid. Keep stirring until you have a few undissolved crystals.
  3. Once the mixture is ready, you can now apply it to the stained oak using a paintbrush, be careful not to drip the solution to you or anywhere else. Just brush the mixture as if you are painting.

It depends on the timber that you are trying to remove the stain, if it is badly stained, then you may have to repeat the process. Once you have applied the solution, you will have to wait and see the result for yourself.

When you are pleased that you have removed the stain, you can wash off any residue and leave it to dry.

Repair Options for Water Stains

If it is a water stain, here are some options that you can do to repair options for exposed wood beams with water stains.

  • Sanding Smooth-Surface Beams

Sanding can help you remove water stains on most beam surfaces, but it can also get rid of existing wood stain topcoat and color. If it has a nonglossy finish, then you can sand away the stain and retain the wood. This method though has a better chance of success with original colored beams that were never stained.

  • Rough-Surface Beams

You can’t sand rough surface, but you can consider sandblasting the stain away. It can be a messy process, and you may have to remove all the furniture away, cover the floor and wear a respirator mask and protective eyewear.

  • Refinishing the Beam

Probably, the best solution for water stains is refinishing the beam. For smooth-surface, you can use a random orbital sander to remove the old finish, restain and re-apply a protective sealer or topcoat. For rough-surface, you can do sandblasting or scrubbing the entire beam using the Oxalic Acid bleaching agent and if necessary, use a brass brush, before re-applying a protective sealant or stain/sealer combo product.

  • Painting

The last resort is by painting the wood beams. If the stains though are a bit stubborn or if you don’t delight in a lengthy process, painting is a good solution.

To achieve the best result, you should clean the beam thoroughly using a solution of Trisodium Phosphate mixed with warm water. Let it dry and apply a coat of stain-blocking before applying two coats of quality paint.


Beams are not just your primary support in your house, also as an architectural design that you should not take for granted. It would help if you took care of it and as much as possible save it from being tarnished. It is costly to strip the beam and cleaning or to remove the stains is the most practical way to do it!