Exterior wood protection?

Before it gets too cold I would like to get at least some paint on all the exterior wood I've put up: pressure treated fencing, T1-11 gates, plywood planters (approx 1.5 x 1 x

3').

As far as paint (water based) goes, I heard that exterior gloss is the best, followed by semi-gloss, then flat. Still true?

I read that polyurethane (water based) was not suitable for outside, which never made sense to me. Is this true?

Recently here, someone made reference to wood stains not providing much wood protection. If I use stain, what clear coating can I put over the stain, that will do a good job?

Are "water seals" (the proverbial Thompsons, which I understand is middling in effectiveness) generally clear? Can one mix stain in with them? What is regarded as a better seal, that is generally available?

For non-staining apps, I have tons of exta paint lying around. Is it OK to use any ole paint as a primer, without compromising the final coat? iyr, I kluged together a paint sprayer/pressure pot deal, which worked great on a T1-11 gate. I will be using this sprayer as much as possible. More on my Sprayer Saga in another post.

I heard of something called "edge primer", for the ends, edges of wood. Worthwhile? Good for non-edges?

For the plywood planters, I have some Frontier fibre roof coating, which is like a paintable tar, close to the viscosity of paint. This was recommended by some gardening sources. Should I prime the planters with regular paint before applying this roof coating?

Any advice, tips, experiences, war stories would be helpful.

Reply to
Existential Angst
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The more gloss the longer it looks fresh, the duller the finish the quicker it looks chalky. I would say that noen is better than the other as far as protection.

No! Unless you are painting in the rain. I have been using exterior polyurethane based paint for years with great results.

The above mention will not last as long as a good paint. The more opaque the finish the better the protection.

Not sure if you can mix but it will be a 1~3 year repeat.

What is your time worth? You are painting something that is going to be in a harsh environment. No time to pinch pennies IMHO, buy new paint and use the recommended primer.

You especially want to prime/paint the edges and in particular those near the ground where water will splash or morning dew will collect.

Have you read the directions or asked those that recommended the product?

Reply to
Leon

Gloss shows flaws more than a semi-gloss, and a LOT more than satin. Personally, I dislike gloss very much.

Reply to
Dave Balderstone

This topic is explored by Consumers' Reports every two years or so, when it usually provides encyclopaedic data. Factors include: -- local weather -- horizontal or vertical surfaces (floors and table tops vs. walls) -- finish (smoothness, visible metal fasteners etc.) -- paint or stain?

Anomaly: most stains are not designed to accept a clear topcoat. (This is usual only indoors or with auto paints.)

Timber waterproofing products are secondary to drainage, i.e. design so that water runs off rather than puddles, and availability of drying winds.

Reply to
Don Phillipson

Yep.

Water based? Outside? There is sometimes water outside, you know?

Stains are just a thin color layer. They don't protect the wood from anything.

What do you want to protect it from? Any nicks or hard wear will eventually grind through the stain.

Instead of stain use the wood you want it to look like. Now you are protecting wood.

ehh. pass

no

You first?

Reply to
Richard

I already forgot about exterior paint. Here's my tip on that. Let any exterior wood rot away and replace with new wood to rot away. Use cedar if you can. Lasts longer and looks good natural. Or plastic that doesn't rot. For expensive-to-replace and must-look-painted stuff on the house, have it clad with aluminum or plastic. Exterior painting - except for bridges - is stone-age.

Reply to
Vic Smith

I wouldn't paint any pressure treated lumber until next spring. That's because lumber is pressure treated by forcing water based chemicals into the lumber under pressure, and it takes a long time for that moisture to evaporate.

My experience is that exterior alkyd paints provide the best protection over wood outdoors. If it were me, and you can still buy exterior alkyd paints in your area, I would use an exterior oil based primer and top coat with an exterior oil based paint in a FLAT gloss. The purpose in doing that is that the top coat of paint will dry rough, and so when the time comes to repaint, you won't have to roughen the surface of the old paint to get the new paint to stick better. It'll already be rough enough to provide good adhesion for the new top coat. And, I use a flat paint for the new top coat too.

It's partially true. Polyurethane doesn't have good UV resistance and so it's not a great idea to use it outdoors. A better choice would be a "Spar" or Marine varnish that doesn't dry to nearly as hard a film as polyurethane, but has much better resistance to the elements.

Spar or marine varnish.

In my time on the internet, I haven't heard much good said about Thompson's Water Seal. People tend to like Cabot products for their decks.

That depends on the kind of paint you have. Wood is a natural material and swells and shrinks with changes in it's moisture content caused by seasonal changes in the humidity. Paints that dry to hard films (like interior oil based paints or interior polyurethane "varnishes" or hardwood floor finishes) simply don't have the elasticity needed to stretch and shrink with the wood as it expands and contracts with the seasons. The result is that hard paints will start to crack and peel on wood outdoors fairly quickly. So, the primary difference between interior and exterior oil based paints is the hardness of the film they dry to. The harder the film, the better it protects the underlying substrate, but the less elasticity it has to remain stuck to wood outdoors as it stretches and shrinks.

So, don't use an interior alkyd paint as a "primer" because then, no matter what you put over it, it's gonna crack and peel.

Latex paints (both interior and exterior) have plenty of elasticity to stretch and shrink with wood outdoors, and so the primary difference between interior and exterior latex paints is that exterior latex paints will have more additives (like mildewcides and UV blockers) in them. I would use a flat or eggshell interior or exterior latex paint as a primer outdoors.

it's grain. Also, water evaporates from the wood end grain 15 times faster than it evaporates from the sides of a board (per unit area).

It's that differential absorbtion and evaporation that causes two problems:

a) it causes boards exposed to the weather to split at the ends. That's because after the rain stops and the water that's been absorbed into the wood end grain is still being drawn by capillary pressure into the wood when the sun comes out and starts drying out that end grain. So the wood a few inches from the end grain is still swollen with rain water while the wood at the end grain is trying to shrink as the water evaporates from it.

Worthwhile? Good for non-edges?

b) When it comes to staining wood, the end grain aways stains much darker than the rest of the wood, and that's undesireable in furniture where you want to wood to look uniform. I've heard of woodworkers diluting their wood stains in mineral spirits or denatured alcohol and applying diluted coats of stain to the end grain before staining the rest of the wood. I've also heard of wood workers painting mineral spirits onto the end grain of the wood first, and then staining the furniture while the end grain is drying so that it doesn't absorb nearly as much stain. I expect this "edge primer" you're talking about is for use with water based stains, and it's meant to reduce the rate at which water based stains are absorbed into the end grain of wood. I'd only use them on the end grain. If you use it on the sides of the board, it's likely those areas on the sides of the board won't absorb any stain at all.

Reply to
nestork

*I have personally found that for exterior painting of new wood, it is best to start with an oil based primer. After that you can put whatever color latex finish on that you want after letting the oil primer dry for a few days.
Reply to
John Grabowski

You realize that once water based paints cure that it is no longer as susceptible to moisture? And or that most homes exteriors are painted with water base.

Reply to
Leon

Do you live in Arkansas?

Reply to
Leon

Before it gets too cold I would like to get at least some paint on all the exterior wood I've put up: pressure treated fencing, T1-11 gates, plywood planters (approx 1.5 x 1 x

3').

As far as paint (water based) goes, I heard that exterior gloss is the best, followed by semi-gloss, then flat. Still true?

I read that polyurethane (water based) was not suitable for outside, which never made sense to me. Is this true?

Recently here, someone made reference to wood stains not providing much wood protection. If I use stain, what clear coating can I put over the stain, that will do a good job?

Are "water seals" (the proverbial Thompsons, which I understand is middling in effectiveness) generally clear? Can one mix stain in with them? What is regarded as a better seal, that is generally available?

For non-staining apps, I have tons of exta paint lying around. Is it OK to use any ole paint as a primer, without compromising the final coat? iyr, I kluged together a paint sprayer/pressure pot deal, which worked great on a T1-11 gate. I will be using this sprayer as much as possible. More on my Sprayer Saga in another post.

I heard of something called "edge primer", for the ends, edges of wood. Worthwhile? Good for non-edges?

For the plywood planters, I have some Frontier fibre roof coating, which is like a paintable tar, close to the viscosity of paint. This was recommended by some gardening sources. Should I prime the planters with regular paint before applying this roof coating?

Any advice, tips, experiences, war stories would be helpful.

Reply to
BobS

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