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Protecting Interior timber from stains and damage simply

Protecting interior timber from stains, water and other damage can be achieved using a variety of different finishes.

  • Waxes and oils in various formulations may be used for floors and decorative surfaces.
  • Varnishes can of course be used (and of course this includes things in cans that are sold as oils, like OSMO, which sit on top of wood like a varnish)

I have used many of these finishes in my house. The interior of my windows are treated with OSMO oil. It has lasted well internally, as it get’s no real exposure to UV light. Moisture from condensation has proved to be a bigger problem for it when used internally, as it is prone to going mouldy in damp areas.

I have used hard floor waxes to very good effect on some oak flooring. It’s a very hard wearing and durable finish.

A friend (Gerry) made me a beautiful set of oak shaker doors to conceal my shoe cupboard following the refit of my house.

Bare unfinished internal oak doors requiring protection from stains

protecting interior timber

I had originally planned to wax them and Gerry insisted that I used a sanding sealer before waxing, so that should I wish to paint them later I could actually remove the wax from the doors to allow a different finish to stick.

I decided that rather than use a sanding sealer and then wax, I could probably achieve a nicer finish, with better protection with just Clear Penetrating Epoxy Sealer.

I wanted a non glossy finish on the timber, either satin or a full matt, so decided to apply the techniques described in our ‘how to achieve a natural finish while protecting wood‘ article.

The slate floor was covered in paper for protection, and the materials were assembled.

The doors measured 0.75 * 1.85 m, giving a total area of around 3 sq metres to protect. Anticipating coverage of around 10sq m / litre on new hardwood, 400ml of WW CPES was mixed by weight in the jam jar. I used WW CPES as the cupboard houses the underfloor heating manifold, and is actually pretty warm even in winter. Note the CPES was cloudy when first mixed, as the containers were stored in a garage at near freezing. Epoxy Cleanup Solvent (ECS) and a clean tub are to hand, along with Blue Roll to remove any glossy areas of finish.

As well as protecting interior timber from staining, CPES enhances the grain and beauty of the wood

CPES enhances the grain and protects the timber

The Clear Penetrating Epoxy Sealer has penetrated into the wood and has enhanced the grain in it. It has had the same effect on the good quality oak veneered plywood panels in the door as well.

Clear penetrating epoxy sealer enhances the beauty of the wood

If you want to see what wood will look like when treated with CPES, wet it lightly. The darkening and enhancement of the grain comes from light travelling further into the timber before it gets scattered by the wood fibres. The effect is permanent with CPES, and of course the timber is now impermeable to water – thus protecting interior timber from water and stains.

Glossy patches on protected interior timbers

The process of painting the doors with CPES took around 1 hour. Once I had finished the doors looked like this.

gloss and matt patches on still uncured epoxy treated timber

Following painting the timber with CPES to protect it from staining, there are some localised areas with gloss finishes, some with matt finishes. I have protected the interior timber from stains, but I have a little more work ot do on the surface finish.

Localised shiny areas following protection of timber with CPES

And the odd near dribble of Clear Penetrating Epoxy Sealer.

Protecting interior timber and achieving a natural matt finish

A 100ml or so of our new slower evaporating formula Epoxy Clean Up Solvent (ECS) is poured into a clean container.

Wearing rubber gloves, a clean lint free piece of cloth, or a decent piece of blue roll (my personal preference) is generously wetted in the ECS.

This is then wiped, with the grain, along all of the surfaces of the timber that have been protected. There was not a great deal of CPES sitting on the surface of the timber (ie not many glossy patches) so the rag covered a good distance before it was turned or replaced.

All surfaces are then left to dry out. This photograph is taken ten minutes after the solvent wipe. The protective paper was removed from the floor following a spill.

oak interior doors protected and wiped with ECS

Clear Penetrating Epoxy Sealer sets slowly – you have time to work

4 hours after the initial cleanup had been done, I went back to investigate the doors closely. The solvents had had time to evaporate, and what was left was likely to represent the final surface finish if allowed to cure fully.

There were a few glossy patches present.

The odd shiny patch on sealed stain proofed timber

Once more some blue roll was wetted with our Epoxy Cleanup Solvent, and the shiny areas given a light rub.

shiny patch removed 4 hours after CPES applied

The glossy patch has come away from the wood without any problems, as the CPES has a 2 – 5 day cure time.

Protected Interior timber doors – The results

These doors now have a beautiful consistent low satin sheen. I could have achieved a full matt with a bit more rubbing with the clean up solvent, but I am very happy with them as they are. Protecting interior timber doors from staining was fast and easy, the total working time for the surface finish was under two hours, in two patches of work performed over one day.

The cost of these bespoke doors

The cost of my fully protected interior timber oak shaker doors breaks down as follows (in 2022)

protected interior timber oak shaker doors

Time for a little purgatory – straighten the doors for a nice tight fit.

I purchased the oak for the doors from my usual supplier, Scawton Sawmill, and there was clearly an ordering problem as when I phoned up to see where the timber was, it hadn’t been cut. The timber was then cut and despatched, but was not as good quality as I had requested and expected from prior orders.

As the quality of timber for making shaker doors is paramount, you need good joinery grade timber, the doors had a little twist on them once manufactured. The cure for this is to put them into purgatory – apply force to distort them beyond straight, so that when they relax they become straight.

The photo below shows the doors in purgatory. The left one is having a bend at the bottom of the frame straigntened. The right one is having a gentle twist over the entire door removed. The process took under two days and was done with the doors in the door frame.

The finished article – protected interior timber doors

Now – I could choose to wax these doors, but I think the surface finish that I have obtained is preferable to wax. The protection is probably permanent without maintenance in the low UV light environment of my hall as well, so for now at least. I am done with the surface preparation. I will update this with a maintenance record, and photographic proof as time goes on.

For now – I hope that this offers another fast and above all beautiful way for protecting interior timber from stains. It is clear from the enhancement of the grain that the CPES has penetrated significantly into the timber doors, and the finish is, to my mind anyway, quite beautiful. The finish left by Clear penetrating epoxy sealer on timber is microporous yet waterproof. It breathes yet prevents the ingress of liquid water, and  has been a quick and beautiful way of protecting interior timber.

Time to fit some nice handles to match my kitchen and find another project.

finished protected and sealed interior doors

I need somethign to go under the stairs to use that otherwise useless space, and somewhere to store my wine too…

Note – Protecting Exterior Timber

Clear penetrating expoxy sealer does not have enough UV protection to survive eposure to sunlight. All epoxies are degraded by the UV in sunlight.

If you wish to protect exterior timber you have two options:

  • Use CPES as a primer, and apply paint or varnish to protect from UV light. CPES is the perfect primer and can significantly extend the life of your top coat. You can get up to 20 years from a varnish finish if primed with CPES first.
  • Recoat with CPES on a periodic basis. This option is often used to protect Teak boat decks, which have to have a matt finish for safety when wet.