Publication date: 06/17/2006

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A cleaning solution may be all that's needed on deck

It's almost summer and we have run out of excuses. Now is the perfect time to clean and seal the deck.

What you do and which cleaners you select depends on the decking surface and the condition of the deck.

The temptation is to say that the deck needs to be pressure-washed. Most decks are soft wood and are especially fragile in early summer when they have not dried thoroughly. Cleaning solution and a little agitation with a good, stiff, short-bristled brush are all that is needed. Pressure washing grinds away the surface and can cause major splintering and gouging.

Man-made decking

Man-made decking, such as vinyl, plastic or a wood/plastic composite, has to be cleaned with a deck wash or a mild cleaning solution such as a Simple Green solution of 1 part cleaner to 10 parts water. If it's very dirty, increase the strength to 1 part cleaner to 3 parts water.

If you have a mold or mildew problem, use a mildewcide such as BioKleen Prep from Kleen Sales, (866) 319-3600, www.kleen -tech.com, or a house cleaner such as BEHR No. l62 Multi-Surface Deck-Prep Cleaner & Mildew Stain Remover, Oxi Brands O2 Algae and Mold Remover, (800) 745-5186, www.theo2system.com, or Zinsser, www.zinsser.com, (800) 899-1211, Jomax House Cleaner or Mildew Killer and household bleach.

We have used BioKleen on our test deck and found it quite effective. This is one of the times that the manufacturer actually recommends rinsing with a pressure-washer up to 1500 psi.

The mixture for Zinsser Jomax should be mixed 1 quart Jomax, 3 quarts bleach and 4 gallons water. No pressure washer is needed with either of the Zinsser or Oxi Brands products.

The directions for cleaning grayed and stained composite decking are the same as those for cleaning grayed and stained real wood decking.

Wooden decks

Wood decks can be new or old, stained or natural. If decks are left natural, they gray until they look like driftwood. Stained decks may just have to be cleaned or stripped and re-stained. Each of these is a distinct cleaning problem.

New decks

New decks need to be cleaned and sealed. I recommend they be given an oxalic acid bath to neutralize the surface so that it accepts a sealer evenly. I'll cover that next week.

Gray decks

Some people want their decks to look like driftwood. If that's the look you want, all you ever have to do is clean it. If your deck has never been sealed, I would suggest you seal it after cleaning with a clear wood sealer to protect the wood.

Graying is caused by ultra violet rays from the sun, which destroy the uppermost wood cells. The only way to remove the gray is to remove those cells. If you want to remove the gray, clean away the accumulated winter dirt with a light cleaning solution such as a 1 to 10 mixture of Simple Green and water, or a solution of 2 ounces dry measure of trisodium phosphate per gallon of water, then remove the gray with an oxalic acid or phosphoric acid bath.

An acid bath sounds strong but it isn't. Oxalic acid is found naturally in asparagus, broccoli, cabbage and carrots. Phosphoric acid is used an as antioxidant in food and as a flavoring agent in jellies.

You can find oxalic acid at home centers and hardware stores in such products as BEHR Wood Brightener Conditioner No. 63, Flood Dekswood, Cabot Problem-Solver Wood Brightener No. 8003, Wolman Deck & Fence Brightener for Cedar & Redwood and Superdeck Wood Brightener and Rejuvenator. Phosphoric acid is found in Bio-Wash Simple Wash and Penofin Weatherblaster.

Stained decks

Stained decks may get dirty from winter weather, or the stain may have deteriorated and needs to be removed before re-staining. If the stain still looks good, just wash it with a gentle or medium-level cleaning solution.

Mildew stained decks

If a stained or unstained wooden deck has mildew, you may want to use BEHR No. l62 Multi-Surface Deck-Prep Cleaner & Mildew Stain Remover, Oxi Brands O2 Algae and Mold Remover, or Zinsser Jomax House Cleaner and Mildew Killer and household bleach. Use the same formulation recommended for man-made decks.

Bleach is usually not recommended on wooden surfaces. Jomax includes ingredients that neutralize the bleach and makes it safe on wood. You will find BEHR products at Home Depot. Other products can be found at OPW Decks, (866) 856-3325, www.opwdecks.com or independent hardware stores and Ace, True Value, ACO and N.A.. Mans.

Come back next week for tips on stripping and re-staining your deck.

Note: This article was accurate at the date of publication. However, information contained in it may have changed. If you plan to use the information contained herein for any purpose, verification of its continued accuracy is your responsibility.

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