How Do You Seal Outdoor Wood? – A Useful Woodworking Guide

How to seal wood

Wood is a popular building material for many amazing items of furniture and trims works. Unfortunately, wood is easily exposed to harmful elements such as moisture and high humidity.

By sealing the wood, we can protect them from these negative impacts. But, how do you seal outdoor wood? Keep reading our today article to know the answer!

What you need for sealing outdoor wood

  • Sealer
  • Sandpaper (tough and fine)
  • Irrigation syringe
  • Paper bag
  • Vacuum
  • Epoxy (for filling cracks and mumbles of the wood)
  • Clean cloth
  • Clean paint brushes
  • Mask or respirator (for preventing dusks)
  • Latex gloves

How do you seal outdoor wood – A Step-by-Step Guide

Step 1: Prepare the surface of the wood:

How do you seal outdoor wood? Firstly, you need to prepare the surface of the wood.

Ensure the surface of the wood is dust-free and clean by sanding it down.

First, starting with rough sandpaper (80-grit) to get rid of remnants from previous works and any imperfections on the wood.

More: Good quality wood sealer for outdoor furniture

Your wood may carry the cracks and mumbles, so you should fill these with wood filler like epoxy, and use a putty knife to spread the epoxy, or simply coating the entire surface.

For the deepest cracks, use an irrigation syringe to force epoxy into them. Then, leave the wood dry before sealing.

When the epoxy is completely dry, use finer sandpaper to ensure a smooth finishing touch for the surface, then wipe it with a clean cloth to remove all the sanding residue.

Step 2: Apply the first coat:

The next step for sealing outdoor wood, absolutely, is to apply the sealer.

Make sure that your hands are clean and dry by wearing the latex gloves. Now simply brush sealer on the wood with a simple clean paintbrush.

The first coat will begin to dry fairly quickly, so avoid overlapping the places you have applied sealer, and only work your way methodically from one edge to the other.

Step 3: Start sanding

Before applying the second coat, you should check the surface of the wood carefully as you may not want to recoat if it seems tacky. One way to check it is to press a cotton ball upon the surface, if nothing sticks to the ball, then you are ready to go.

But before that, many types of sealants need a second sanding to ensure the next coat sticks better.

This should be done with 400-grit sandpaper, enough to smooth things out without damaging the sealing. And if your paper is gumming up, it’s better to wait for it to dry completely.

When you have done sanding, remove dust with a vacuum and then wipe  the surface again with water or mineral spirits to prepare it for the second coat.

Step 4: Apply more coats

The second coat will not absorb thoroughly like the first one, so put it on a bit thinner, then repeat the process of drying, sanding and wiping and move to the third coat.

For the third coat, wipe straightly from side to side, don’t go back over an area once you’ve left it. If you see a streak in an area you’ve already covered, don’t worry much about it as it will almost disappear when the coat is completely dry.

After the third coat, lightly sand the wood with 600-grit sandpaper, then apply on it the thinnest coat as possible, but still keep the surface wet evenly.

It is recommended that three regular coats and one super thin coat are adequate. Applying more than that number isn’t good. If you apply ten coats, they will not be long-lasting as four applied coats.

Now, do the final buffing with a brown paper bag, which is equivalent to 1500-grit, then leave the wood for curing.


Step 5: Cure

Now you’ve done the hardest part. It’s time to leave the wood to cure for about three days before using it. During the curing process, don’t place any heavy things on the surface, especially plastic, otherwise, it may stick to your finishing.


How do you seal outdoor wood? Now, your problem has been solved. After getting used to our tutorial, it’s important to properly do the sealing step-by-step. Regularly recoat your wood to extend its life and keep it a long-lasting beauty.

Start sealing your outdoor wood like a pro right now! Stay tuned and see you in another tutorial.