GacoDeck Application Instructions

View the GacoDeck application DVD before beginning your deck. All surfaces must be dry and clean, without wax, dust, oil, asphalt or contaminants. Do not apply GacoDeck if rain is expected. GacoDeck is not recommended over asphalt coatings.

Surface Preparation

• Previously Coated Surfaces:
  Clean surface by pressure washing or thorough scrubbing with GacoWash concentrated cleaner and water. If applicable, prepare all cracks and seams following “Caulking, Taping & Flashing” directions listed below. Prime surface with GacoDeck Primer at the rate of 1 gallon per 200 square feet over entire surface before applying first top coat. If surface is previously painted and has a high gloss finish, lightly sanding the surface is recommended before applying GacoDeck primer.
• Plywood:
  Grades: Plywood should carry the trademark of the American Plywood Association. Grades "Exterior/APA A/C Group I" and "Exterior/APA B/C Group I" are suitable, as well as "Marine" grade plywood. Unsuitable grades are interior grade plywood with or without exterior glue, and underlayment grade plywood, such as "C/C Exterior," OSB, Waferboard and Exposure I markings. Do no use unsuitable grades and Gaco Deck Kit is NOT recommended for Teak, Cedar, or Redwood.
  
  Installation: All panel edges, except tongue and groove plywood, should be supported on blocking or primary framing. Plywood should be continuous across supports with all edges in moderate contact. Plywood joint should be tight, level, and smooth.
  
  Thickness of plywood and spans should meet the following minimums:
  - 1/2" for plank or other solid substrates only
  - 5/8" for supports 16" OC
  - 3/4" for supports 24" OC
  - 1-1/8" for supports 48" OC
  
  Stagger joints when installing plywood over sheated or dimensional (planked) decks.
  
  Repairs to Plywood:
  Plastic wood patch materials may be used to repair damaged plywood. Sanding before taping, especially at the joints, will improve the final appearance of the deck.
  
  The deck should be sloped so as to freely drain, preferably to a drain or gutter. One-quarter inch slope per foot is recommended. slope is a function of structural design, and the GacoDeck Kit cannot be used to provide such a slope where it does not already exist. A deck that lacks adequate slope may experience leaks at low thresholds, standing puddles, or surface stains from ponded water and debris. Avoid soiling the fascia by incorporating a gutter or drain into your design. Insert drain flush with plywood. Install a positive drip so that drainage is outside the fascia.
  
  If you are coating a new plywood deck, please consult the “Caulking, Taping & Flashing” section below. No primer is required for standard or pressure treated plywood applications. If it is a previously coated plywood deck please see “Previously Coated Surfaces” above.
• Concrete
  Concrete surfaces to receive GacoDeck coating must be structural concrete which is properly ventilated. “On Grade” concrete slabs must be poured over minimum 4” pea gravel base or equivalent. Concrete must cure and dry four weeks before GacoDeck application. Concrete surface should be smooth and free from rock pockets or voids without being burnished. Etching of concrete is not normally required. If concrete surface shows evidence of dusting or chalk, then etch surface prior to coating application as follows: Apply diluted muriatic acid (3 parts water/1 part muriatic acid) at a rate of 75 square feet per quart following label directions and precautions. Allow the etching solution to work for 2-3 minutes. Scrub with stiff brush and flush with clean water to rinse from surface. Allow to dry (no rain or moisture) for at least 2 full days.
• Metal 
  Metal surfaces must be primed. Lightly sand surface and prime with exterior metal primer.

Caulking, Taping and Flashing

Apply high-quality 50-year, water-resistant, paintable acrylic caulking to all joints and cracks. (Use only Acrylic Caulking.) Apply caulking according to manufacturer recommendations. Smooth the caulk flush with deck surface. If caulking is allowed to dry more than 24 hours, wipe with a damp cloth prior to application. Joints, cracks and changes of plane must be taped (For details, see Figures E, F, G and H). To begin taping, brush a 5-6” wide stripe of GacoDeck coating, centering the stripe over joints or cracks. Work in small sections, since latex coatings dry quickly. While the coating is still wet, embed polyester tape smoothly into the coating. Brush another layer of coating over the tape, smoothing out any wrinkles. Allow the surface to dry. For a seamless finish, lightly sand the edges of the coated tape with medium grit sandpaper before applying the first coat.

All flashing must be flush with surface. If installing flashing nail or screw every six inches. Care should be taken to not buckle the flashing during installation. Prime all metal flashing with appropriate exterior metal primer. All flashing must be taped following the directions above.

If the GacoDeck coating will terminate where there is no natural break, use masking tape to create a clean, sharp edge.

Application

First Base Coat

Apply uniform coat of GacoDeck, using 3/4 gallon per 100 square feet over entire surface, including taped or flashed areas. Unlike paint, apply a heavy coat in order to create the waterproof elastomeric membrane. Allow surface to dry until it can be walked on, 2-4 hours in ideal conditions. While the first coat dries, wrap the roller cover in aluminum foil or plastic.

Second Base Coat

Apply another uniform coat of GacoDeck, using 3/4 gallon per 100 square feet over entire deck surface, including taped or flashed areas. Allow the surface to dry until it can be walked on, 2-4 hours in ideal conditions. While the second coat dries, wrap the roller cover in aluminum foil or plastic.

Top Coats

GacoGrip texture granules create a decorative and slip-resistant finish for your deck. Add all of the GacoGrip granules to the remaining coating. Stir thoroughly. After adding texture, apply two topcoats at 3/4 gallon per 100 square feet per coat. Best results are achieved by applying texture coats in parallel overlapping roller passes, either North-South or East-West. Allow the first coat to dry before applying the final coat. If you must wait more than 72 hours between coats, wash the surface with detergent, rinse well and allow to dry completely. GacoDeck must be applied at the proper rate (100 square feet) per kit to ensure proper coating thickness. Failure to do so voids the warranty and may result in the products failure to provide a waterproof membrane.

Special Circumstances

During hot weather (above 90 degrees) apply coating in morning or evening. Do not apply at temperatures below 50 degrees, or when temperature will fall below 50 degrees within 6 hours. Wait two or more days before using deck or placing heavy objects on surface.

In extremely cold climates (10-15 degrees over three month period), GacoDeck Primer must be used in conjunction with GacoDeck. If GacoDeck Primer is not used with GacoDeck, your deck could experience surface cracks. There are two modifications to the instructions above for extreme cold weather climates. First, all taping and flashing details must utilize GacoDeck Primer instead of GacoDeck coating. Second, apply one coat of GacoDeck Primer at rate of 1 gallon per 200 square feet over entire surface prior to the first base coat. After primer is dry, you can follow normal GacoDeck instructions starting with "First Base Coat."