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Monday, July 19, 2010

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Four Common Deck Finishing Pitfalls

Recently, a customer was proudly explaining to me that she stains her deck every year with two coats of semi-transparent deck stain, whether it needs it or not. When we asked how long she'd been maintaining her deck this way, she said, "8 years, and it still looks great!" we were happy that her deck finish seemed to be holding up, but didn't want to tell her that when her finish started to fail--and it would start to fail sooner rather than later--it would really be a mess. Staining a deck takes time and none of us want to do it more often than necessary. So, here are our top four deck finishing mistakes:

Staining Deck

  1. Overcoating. Transparent, semi-transparent, and semi-solid alkyd stains are single coat systems that are designed to penetrate into the wood. Extra coats are often applied in the mistaken belief that they will add more durability, but what actually happens is that the stain just sits on the previously coated surface, leaving a slight sheen because the stain hasn't fully soaked into the wood fibers. As this layer dries out, it will flake and peel away from the decking. So read and follow your stain manufacturer's directions; if your 2-year old finish is still in good shape, don't just throw another coat on--you might end up having to remove everything the following year. 

  2. Moisture. We also cringe when we hear a customer say that they're planning on pressure-washing and refinishing their deck over the weekend. Pressure-washing is a great way to clean a deck, but it also forces water into the wood fibers. If the decking isn't allowed to dry thoroughly, the water will be trapped by the new stain; as the moisture eventually dries out, the stain gets pulled off along with it. That's why it's always better to spread a deck refinishing project out over at least two weekends: do the cleaning and prepwork the first weekend, and then staining the following weekend, allowing a week of dry weather for the decking to dry out.

  3. Hot Weather. Direct sunlight can cause deck stain to dry too quickly, leaving unsightly lap marks. To avoid this problem, start in the morning as soon as the dew has dried off, stopping around 11 when the sun gets high in the sky. Then start staining again in the afternoon when the sun is lower, staining 2 or 3 boards at a time their entire width. A good temperature range for staining is 50 to 90 degrees F--if wood is too hot to leave your hand on comfortably, then it's too hot to stain. Pay attention to humidity too--the higher the humidity, the longer the drying time. And if it's windy, you may find that dust and debris gets blown onto the stain.

  4. New Pressure Treated Wood. To give it rot-resistance, pressure treated wood is saturated with a chemical solution; when you pick it up at the lumber yard, you don't know if the wood is fresh from the mill, or whether it's been sitting there for 6 months. The temptation, of course, is to finish the deck as soon as possible after completion, but if you do that, the  solutions used in pressure treated wood may not have had a chance to dry out. In this case, and in any other case where moisture may be an issue, check the moisture content in the wood with a device called a moisture meter before applying any stain. Moisture content should always measure below 12%, regardless of the type or age of the wood. Probe-type moisture meters are easy to use and can be found at most rental supply stores 


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In response to Dianne Weldy and John:
I had to deal with a badly peeling deck years ago, but didn't have the time to completely strip the old paint (it was on my Father's house). I just striped off what could be easily removed, then put latex stain on the remaining mess. The latex stain adhered to the paint as well as the exposed wood, but, of course, it didn't stop the paint from peeling. Every year I touched up any places where the remaining paint had peeled. Eventually, the peeling stopped and the deck only needed a occasional touch-up work. This is a viable solution for anyone who is reasonably handy and doesn't demand immediate perfection. It won't work for someone who is having all of the work done and doesn't want any part of the maintenance effort.

Thank you for the great tips on staining. A lot of people get really overzealous with staining their decks and try to get everything done a single day.

The new pressure treated wood always seem to be the top pitfall!!

Make sure you only use oil based stains on your deck. They are easy to strip and look great when everything is done right.

A finish coating must contain pigment in order to block, absorb or reflect damaging UV rays. Coating pigment protects your deck's surface much like sunblock lotion protects your skin: both prevent the top surface layer from drying out and aging prematurely.

The new ARBORCOAT® protective clear coat is water base 100% Acrylic latex. When the product is being applied as a refresher coat, remove contamination from the weather stained surface by washing with Multi Purpose Cleaner 318. The clear coat finish can be applied to rejuvenate the surface

I am thinking of covering our deck with BM Arborcoat Semi Solid Deck & Siding Stain 639 and then a coat of Arborcoat Protective Clear Coat 636. My question is this, is the Clear Coat kind of like varnish and eventually will it have to be removed?

In order for you to successfully apply an exterior deck stain to a previously painted porch would require complete removal of all traces of paint back down to a bare wood surface. This can be accomplished with a combination of a chemical paint stripper, a paint scraper, sandpaper, wire brushes, etc. The surface must be dry and in sound condition. Remove mildew, oil, dust, dirt, peeling paint or other contamination to ensure good adhesion. Once all paint has been removed, an exterior deck stain can be applied.

You might also consider removing the peeling paint using a surface preparation machine such as the OnFloor16 Machine.

Transform a worn porch or deck with the OnFloor16™ and Benjamin Moore products. Designed for both residential and commercial use, the OnFloor16™ helps you achieve the look you want in a quick, easy, and cost-effective way, and offers an application-ready substrate every time.

The OnFloor16 Multipurpose Surface Preparation Machine is more than just a sander, Onfloor 16™ helps bring new life to concrete surfaces, decks and hardwood floors.

Our porch is painted with an oil based alkyd deck enamel and is peeling to the point that we cannot paint over it without having the same reaction. We want to remove the peeling paint and coat it with stain. We purchased the stain from a local BM distributor. How do we prepare the porch for the staining process? If the wood does not hold the paint, will it hold the stain?

The best time to stain your home's exterior, deck siding, or outdoor furniture is when temperatures are moderate (above 50°F, but below 95°F), the humidity is low to average, and there is no rain in the immediate forecast. Ideally for a least 12 hours.

I applied Ben Moore Arborcoat solid stain over a clean, dry, previously stained deck (stained a year ago). It is "bubbling" in spots - any ideas as to what could be causing this?

how long does stain take to dry before the rain can affect it

The stain can be removed with product 315 Finish Remover. This product is designed for the removal of peeling oil or latex stain, varnish, and clear-coat wood finishes. It will also remove damaged and discolored wood fiber from all exterior wood surfaces: decking, siding, shingles and furniture. Restores wood to its natural tone and prepares the surface for recoating.

Can opaque stains be removed? Several years ago my husband and I stained our deck with a solid color stain. There are parts of it that have worn off and the wood is coming through. Can we pressure-wash the deck and remove this stain so that we can then reapply a more natural finish?

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