[How do I?] Q's about preserving wood against relentless rain and sun- my shop staircase

[pontiac428]

I built my shop to be two levels with 13' between decks, so I have a big outdoor staircase that didn't count against my square footage built outside rather than in.

I know very little about doing anything with wood. I think it is a terrible material, full of hard and soft spots, it warps, splits, and can't be welded. I act as if I have an allergy to cellulose, and only cut 2x4s when the world says I have to. I also have lived most of my life where it does not rain (California) or where it doesn't rain and nothing rots either (Nevada). I have been living in two different temperate rainforests that each get over 72" of rainfall per year, and my ineptitude with the inferior building material is starting to show. The stair treads are cupping, the planks are lifting, and all the stuff that used to fit together is moving apart. Nails are pulling up under the strain of warping wood.

Here's pics after 3 years. The pressure treated material is great, but the sun and moisture is causing it to twist, lift, and separate. Metal doesn't do that! I even think that my camera is fond of woodwork, since it didn't seem to pick up the number and severity of defects that I can observe from the same spots the pics were taken from. Things are starting to move, and the surface isn't holding up to treading on it.


I want to put some protection on this wood, but I'm nervous about not letting pressure treated breathe as it ages. I need to put something on the treads and decking to protect against the sun at minimum. What I don't want is to rebuild this staircase five years from now because I waited too long.

What should I use to ensure this staircase lasts as long as I do? Thompsons? I don't want whatever I apply to turn to s--t and have to re-do it every other year. I also don't like foot long splinters sticking out of the hand rails, so there has to be some way to preserve these tree bones. Please post your advice, experience, or just to profess your undying love for fir or pine. I feel I will regret not doing anything come winter.

 

[mickri]

You probably chose the wrong wood for the job. Redwood would have been better. My experience with pressure treated wood is that it is very wet from the pressure treating, maybe not the best grade and loves to warp and twist as it dries out..

Nails really aren't very good at holding exterior wood together. That's why you use exterior wood screws when making a deck. Screwing the deck from the underside is best. Any fasteners on the top will eventually cause the wood to rot around the fasteners no matter what you do.

Any type of sealer that you use will need to be reapplied every year or two. IMHO all sealers do is to try to preserve the color of the wood. I have always let my decks age.

Looks like the posts are set in the ground. If so eventually the posts will rot at or just below ground level.

As for splinters sanding helps. The warping and twisting will happen in the first couple of years. Then you can sand the deck and railings back to somewhat level.

Typically decks have a life span of 15 to 20 years before needing major reconstruction.

 

[rabler]

I want to put some protection on this wood, but I'm nervous about not letting pressure treated breathe as it ages.

Almost any treatment (paint, stain, varnish, oil) will allow some moisture to pass through, allowing the wood to breathe somewhat. Ideally you'll treat the top and bottom surfaces so that the boards maintain a somewhat uniform moisture throughout the board. Differences in moisture content (think rain and sun on the top vs bottom) cause differences in swelling which is what causes splitting and warping/cupping. So you want to significantly reduce but not completely eliminate moisture absorption and evaporation, allowing the wood moisture level to stay more homogeneous.

Water sealers and stains do help but they are not magic. One advantage is that most of them can be applied easily with a cheap garden sprayer. But you'll need to re-apply every couple of years. I'd probably sand the handrails and paint those to avoid splinter issues.

editted to add: clear sealers work better than stains in a garden sprayer, the stains are a suspension that can get clumpy in garden sprayers.

 

[matthewsx]

 

[rabler]

Another compromise solution is to replace the horizontal boards (deck and stairs) with the composite/plastic (simulated wood) decking. It's waterproof. Quite a bit more pricey than wood per sq ft, but longer lasting and no maintenance. Only thing I use, held up well in coastal Georgia.

 

[pontiac428]

Thanks for the replies so far, guys.

John M, I'll comment on yours first, because that's naturally what I had in mind. It would solve all my problems save for hot handrails on sunny days. Unfortunately, I'm a little behind the power curve to be able to apply your excellent recommendation!

The idea of applying a finish with a pump sprayer did occur to me, and this seems like a good piece to try it on. Is there a preference for sealer types? There are the polymerizing oils (linseed, etc), there are oil finishes, there are polyacrylics, polyureas, spars, so many to choose from. I want it to not crack and peel if possible, last in the sun, and of course manage water and foot traffic.

I didn't build the staircase, I specified one and the framing crew built it, which is why they used pressure treated and nail guns. That is all direct-burial rated material, and the posts go from 9' to 15' down. They are wrapped, preserved, and each pole was inspected at 3 stages by the city during the build. They took at least some precautions for the $150k I paid them, even if they didn't offer me teak or apitong. I don't want to tear it down and replace anything, I just want to get more time out of it because the weathering it shows at 3 years is making me nervous.

Composite would be a great option for re-building, as would redwood (at grandpa's prices) but I hope to delay that for now by applying some measured triage.

 

[rabler]

Hopefully you don't have to deal with carpenter bees in your current climate.

 

[DavidR8]

I hate to say it John but keeping any kind of film finish on outdoor wood in our climate (north of you on Vancouver Island) is a loosing battle.
My preference would be a semi-transparent stain.

 

[Flyinfool]

Pressure treated only needs around 6 months to dry out. Depending on rainfall and humidity levels can add a few extra months. After 1 year it will be fully dried no mater where you live. After 3 years you should be plenty dry to put on any finish you want. As to what that finish should be, The only thing I have heard is that Thompsons is one of the worst, but they have the biggest add budget so everyone knows the name.

If the decking was installed correctly it would warp with the center high so that you do not have the edges sticking up, the edges are a lot more noticeable than the center of a board being high.

 

[pontiac428]

Hopefully you don't have to deal with carpenter bees in your current climate.

Carpenter bees didn't come around this year, but last year they came looking for stuff to dig. My house is sided with cedar shakes, I've seen bees fly in a crack, make some awful scraping noise, and spit out a pellet of wood- they are fast at it too. Luckily, it's just black coconut ants and moss for the most part. The stairs are on the western wall, so it's not too extreme.

I hate to say it John but keeping any kind of film finish on outdoor wood in our climate (north of you on Vancouver Island) is a loosing battle.
My preference would be a semi-transparent stain.

I've had to consider that doing nothing is an option too. If that won't lead to later regrets, I'm okay with it. I can sand down the hand rails and call it good. Should I run around with the screw gun and try to hold down anything that's twisting, or is that going to be a fight later on?

Pressure treated only needs around 6 months to dry out. Depending on rainfall and humidity levels can add a few extra months. After 1 year it will be fully dried no mater where you live. After 3 years you should be plenty dry to put on any finish you want. As to what that finish should be, The only thing I have heard is that Thompsons is one of the worst, but they have the biggest add budget so everyone knows the name.

If the decking was installed correctly it would warp with the center high so that you do not have the edges sticking up, the edges are a lot more noticeable than the center of a board being high.

It was really moist when built, but after a year it was plenty dry. I was more unnerved by the cupping and pulling at joints than the finish. I wish to preserve its function as long as I can before breaking down and rebuilding it right. I just got the dang thing paid off last September, so... yep.