How To Prepare A Deck For Staining

You are here because you have a deck, new or old that needs to be stained or painted.  What steps do you take first?  How do you clean your deck?  Do you need to strip off an old coating before applying a new one?  All of these questions will be answered along with some helpful hints that will save you time and money.  I have separated the article into two sections, new decks and previously coated decks.  Scroll to whichever kind of deck you have to save time.


For New Decks


Pressure treated lumber needs to weather at least 6 months prior to staining.  The coating from the factory needs to wear off before a new stain can be applied.  A good test to see whether your stain will accept stain or not is to take a drop or two of water and put it on the deck.  If the water beads up, the previous coating is still protecting the wood and you should not stain the deck.  If the water soaks in immediately your deck needs to be coated.


Now, lets say your deck is ready to be coated or your wood is brand new and not pressure treated.  Do you need to clean the deck?  Absolutely.   Capital Construction Contracting Inc states that if you install a brand new deck and leave it uncoated for 1 week, you will lose 50% of adhesion when you do apply a deck stain.  In just one week the suns UV rays have damaged the wood enough that you will not achieve the penetration needed for a deck stain to last for more than six months.  The sun's UV rays damage the wood and leave a dead layer of wood on the top of the surface.  In order to get the penetration needed you must clean the surface.


Since your deck is uncoated, you "should" sand and pressure wash the deck.  Most people prefer not to sand their deck because of the work involved.  If you want your deck to last longer than a year I recommend that you sand the deck using 50 to 80 grit sandpaper on a pole sander.  Most people think that you should sand the deck first then wash the surface so you can remove the sanding dust.  This method is absolutely wrong.  You want to clean the wood first so you don't sand mildew, mold, dirt and dead wood fiber into the wood. 


Cleaning your new deck


Use a solution of 4oz TSP (tri sodium phosphate), 1 quart of household bleach and 3 quarts of water.


This cleaning solution is by far the best cleaner you can use on your deck.  Unlike a store-bought deck cleaner, your cleaning solution is mixed and ready to use right before you clean your deck.  Products that have sat on a shelf for a year or two have lost their ability to clean the surface properly.


Use a garden-type pump up sprayer to apply the solution.  Use a push broom to agitate the solution and loosen wood fibers that have decayed.  Rinse the solution off of the deck with a power washer at 500 PSI with the nozzle 8 to 12 inches from the surface.  This amount of pressure is sufficient to clean the surface without damaging the wood.


After the deck has dried you are now ready to sand the deck.  Use a pole sander so you can sand the deck standing up.  Use 50 to 80 grit sandpaper.  Sand in the direction of the wood grain.  You do not need to sand railings, as they are a vertical surface and do not wear as fast.  When the sanding is done you can use a leaf blower, wet dry vac or broom to remove the sanding dust.  Your deck is now ready for stain.  You should stain it as quickly as possible after you have sanded the surface.  The longer you wait, the more the wood will decay and the stain will not penetrate the wood properly.


Since you are ready to stain your deck, head on over to our article: How To Stain A Deck


For Previously Coated Decks


I'll get this out of the way quick, if your deck is stained with a semi-transparent stain that has faded you should continue on with the same type of stain when you do your maintenance coat.  If you are going to switch brands you need to completely remove the previous coating before starting your staining job.  This is because not all stains are compatible with everything else on the market.  We cannot expect manufacturers to produce their products so they can be applied over other coatings. 


Deck strippers are not nearly as hard to use as you might think.  They are typically applied using a paint roller.  Wait the recommended time that the manufacturer suggests and pressure wash the solution off.  Then you need to allow the deck to thoroughly dry before coating the deck.


Should your deck be washed and sanded before you apply the stain?  Absolutely.  Even though your deck has been coated, the wood fibers still need to be cleaned. 


Since you are ready to stain your deck, head on over to our article: How To Stain A Deck

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