The best stains should last three to five years on a deck and even longer if applied to siding or fences, which don't get as much abuse.
Done right, an exterior paint job can last 10 years; stain needs to be reapplied more often, anywhere from two to 10 years, depending on the type of stain. One key to how long an exterior finish lasts is how well the surface is prepared.
Stain Application Frequency
Exterior deck stains last longest when they cover the most wood grain. Sunshine, specifically UV rays, and rain wear down a protective stain. Although some stains may last longer, in general, you'll need to re-stain your deck every 2 or 3 years.
A good maintenance coating is one coat of stain of the same color every five years. There again, if you are looking to do a color change or you had prolonged maintenance, you're probably looking at two coats of stain every eight years.
Oil-based stain can be kept for 1 year if the cans have been opened, but unopened cans will last 2 - 3 yrs. Water-based stain will last 1 year, if opened, and 2 years, if unopened. Oil-based varnishes will be good for 1 year, opened or unopened.
A change in texture is the biggest visible sign that something has gone wrong. Traditional wood stain should still be a liquid. Gel stain should still be a pudding-like texture. Any indication that the stain has separated, turned stringy, dried up, or had any other change in texture is a sign that it's gone bad.
Most people use sealers or stains to protect exterior wood from the elements. Surfaces such as decks, wood siding, fences, and so on need a protective coating to keep from weathering so fast.
Paint tends to last a little longer than most stains, coming in at around 8-12 years before you will likely have to repaint. Stain, on the other hand, typically has to be refinished every 5-10 years.
Because stain requires a dry deck for a secure application, a week of dry fall weather is ideal for staining your deck than in summer or spring humidity. More specifically, the moderate temperatures of early fall are optimal for staining, as the later fall weeks may bring colder days that are too chilly for your stain.
Staining your home's exterior
Because stain seeps into the wood, it's more protective than a coat of paint which is a coating that simply sits on the top of the wood. Solid stains look almost identical to paint but are more protective to the wood because they seep into the porous wood fibers.
The best options for exterior stains for wood homes are semi-transparent, semi-solid, and solid. You can use them on siding and trim. Their main differences are how much of the natural wood and color you can see through the stain and how often they need restaining.
To properly answer your question of “Do you have to seal stained wood?”, the answer is no. However, if you want to protect your wood and give it a polished finish, it's smart to do so. It's worth taking the extra steps and applying a wood stain sealer.
Extremely dense hardwoods may only be able to absorb one coat of wood stain. The general rule of thumb is to apply only as much deck stain as the wood can absorb. Typically this will be 2 coats, unless you are dealing with extremely dense hardwoods which may only be able to absorb 1 coat of wood stain.
Most stains can be applied from about 50° F to 90° F — but many people don't realize this range refers to the temperature of the wood surface, not the air. A day that's 70°F and sunny can push deck surface temperatures above 90°F leading to application challenges and shortened open times.
The new stain you are applying over the old stain should be compatible. For instance, if it's an oil-based stain, apply another oil-based stain. If it's a water-based stain, apply another water-based stain. Incompatible stains can lead to poor adhesion or blotchy and uneven finish.
Method 1 – Apply an outdoor-rated finish: polyurethane, lacquer, varnish, or epoxy. You have several options for outdoor finishes. Four of the most popular are polyurethane, lacquer, varnish, and epoxy. Application techniques vary depending on the product, but we'll give you a general idea of how to apply your finish.
You want to apply the stain when the wood surface and air are in the temperature range of 50° – 90°F. You also want to avoid the direct application of sunlight. Lastly, do not apply a stain if there is a forecast of rain in the following one to two days, or all your hard work could end up being washed away.
Most oil-based stains must dry for at least 12 hours before they are exposed to any moisture/rain; however, Ready Seal, if properly applied to prepped and dried wood, can get wet within a couple of hours, and it won't wash away. Oil-based stains will generally take 24-72 hours to fully cure.
A general rule of thumb is that stain can be applied when the outside temperature is between 40°- 90°F.
The Cons of Staining Wood
While some stains can last up to five years, postponing re-staining a wood surface for too long can cause the job to become more complex and labour intensive. Even decks that are stripped and re-stained will still require maintenance every couple of years.
Outdoor wood stains are water repellant, so they make the wood waterproof, that is protecting it against water and, as a result, against mold. The only problem is that it is a short-term protection. As the stain wears out, the water easily finds a tiny crack to penetrate the wood.
Stain is typically less costly than paint and comes in fewer colors and options. It is typically used for wood projects but there are some options available for concrete as well.
If there is too much stain, it restricts the moisture from evaporating away, so peeling can occur. Often times this problem will be most evident in the spring time when the deck begins to dry out after all of the winter moisture. This is even simpler. The stain has not adhered sufficiently to the wood.
Stain offers little to no moisture protection, while sealant offers tremendous moisture protection.
Although a wood stain is more expensive than a sealer, it can last up to 5 times longer and looks more professional. So you certainly get your money's worth.