Step-by-Step Application Guide

Application Instructions for Flexstone / Tufflex coatings

**For easy to understand application instructions download the" how2apply.PDF" file in the box called Downloads to the right**

Here are step-by-step instructions on how to apply Flexstone / Tufflex to any surface that you wish to waterproof, be it a sundeck, walkway, garage floor, boat deck or the like. This instruction manual will guide you through surface preparation (for new / old plywood, concrete and old membranes), base-coat application and finish coats.

For a complete list of equipment requirements, please consult the equipment page found in the Tech section or download "equipment_checklist.pdf" from the documentation section.

You can jump to any section of the How-To Guide by clicking on the corresponding link from the following menu.

Surface Preparation

Perimeter Application

Mixing and Tufflex Base-Coat Application

Top-Coat Application

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Surface Preparation

Surface Preparation Warnings - READ THIS BEFORE STARTING!!!

The odorless solvent-free Flexstone Tuff base base will adhere to almost any surface including wood, concrete, metal, old vinyl, tile and fiberglass.

Flexstone/Tufflex DOES NOT, adhere well to smooth plastics and IS NOT recommended for over asphalt-based coatings. #3 Primer/Sealer can be used in above situations or when PTD plywood exists.

When in doubt, test the product on a small area for adhesion.

***For a simplified set of Application Instructions go to "Techs & Specs" top menu and download the PDF file called "how2apply.PDF" in the box that says DOWNLOADS.***

Cleaning / Priming

The first step is to prepare the surface in order to ensure a strong bond.

1) Make sure that the surface is clean and free of debris. Vacuum the debris from between any cracks or gaps on the deck.

2) The surface must also be dry.

New surfaces like plywood and concrete do not require any priming.

If the surface is contaminated (damp, dirty or weathered), or smooth concrete, or PTD plywod you should use our #3 primer/sealer gor maximum adhesion and also to block any contaminates or moisture from gassing off or seeping upwards into the coating.

Old Membranes / Existing Coatings

When applying Flexstone / Tufflex over a pre-existing coating or covering such as vinyl, fiberglass or ceramic tile, special precautions must be taken.

1) Ensure that the existing covering is not lifting in any areas. Tap with a wood pole to see any any areas sound hollow and use some small ring nails like you use for drywall and flatten out these areas prior to Flexstone Tuff base application.

2) Remove or staple down any Vinyl areas peeling up.

3) It may be advisable to, cut out old vinyl around the walls and posts where vinyl has a tendency to shrink and let go. Same applies to over top of old drip flashings.


1) Use foam backer rod to fill any large gaps between the deck and the wall.

Cant strips are not needed since Tufflex is extremely pliable and can comfortably bend 90 degrees up walls or posts. If cant strips exist just go over top.


1) Where water drains off the edge of the deck, nail down a 2" x 2" metal drip-edge.

2) Use small ring nails or flat-head galvanized nails to secure the drip flashing. Keep the nails 4"-5" apart offset to the inside edge so that there is no need for seam tape.

3) Rough up the top of the drip-edge with sand paper to ensure a strong adhesion with the Flexstone Tuff Base coat.

Now apply the special Flexstone 2"x180' Red poly tape to the outside of the drip flashings so it sticks up 1". This ensures no coating will drip over the edge and this tape is strong enough so it will not tear on removal and can be left on for several days in the sun and the special adhesive will still release easily with no glue residue.
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Perimeter Application

After the surface has been prepped and the drip flashing installed, the next step is to mix a small amount of Flexstone Tuff Base to apply around the perimeter of the deck - filling in imperfections, sealing walls / posts and covering seams.

Mixing a Small Amount of Flexstone Tuff Base

1) Pour a small amount of raw Flexstone Tuff base into a pail.

2) Add 1 part water for every 4 parts of raw Flexstone Tuff Base.

3) Stir the mixture a few minutes until all the water is absorbed by the white base for a consistent thickness.
It is not advisable to mix more than 2 gals of base at a time as it sets up quickly and you need to move fast to trowel it out before it starts to set up and thicken.

Surface Imperfections

1) Fill any imperfections in the surface such as knot holes, splinters and deep screw holes with a small amount of mixed Tufflex base and a spatula or trowel.

Walls and Posts

1) Seal 2-3" around any posts and up exterior walls where there is no stucco or siding. If it is a permit job inspectors want it up the walls 8" and using our seam tape as wall reinforcement is also something inspectors like to see.

For vertical application higher than 8", Tufflex can be thickened by adding our fine powdered black rubber filler a fine 20-30 silica sand into the mix. In this case, slowly add small amounts into a small batch of mixed base and stir with a stick until you can feel it thickening You are now turning the Tuff base into a vertical grade.


Unless "Tongue and Groove" plywood is used, there should be a 1/16" expansion gap between square edge plywood so wood can swell in cold moist weather.

DO NOT allow any liiquid or caulking into the plywood expansion gaps as when gap closes you will see a slight ridge from caulking pushing up.

1) Cover all expansion gaps with special Flexstone 3" adhesive backed white seam tape. Stick the tape over clean dry plywood gaps then pour a bit of Tuff Base over tape and press along the seam tape with flat edge of trowel so the tape absorb base and sticks directly to the plywood.

3) You can also use this absorbant adhesive backed seam tape for gaps and reinforcing at base of walls if needed. Inspectors like to see reinforcing tape at walls as they do not appreciate how strong the Tuff base coat is so his is a good idea when permit inspections take place.

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Mixing and Flexstone Tuff Base-Coat Application

After the perimeter of the deck has been sealed and any imperfections have been addressed, the deck is now ready for field application of the Tufflex Base.
"It's not a good idea to mix more than 2 gals of base at at time as it needs to maintain its self-level mode so trowel marks disappear as it sets up."


Mixing Warnings - READ THIS BEFORE MIXING!!!

Start with a small amount. Once water is added, move fast. The base will begin to set immediately after water is introduced into the mixture. You want to maintain a wet edge to flow into so you need as much time as possible to apply the base.

Always use a new or extremely clean pail for mixing a new batch the Tufflex base.
Have three empty 5 gal pails: 1 for water and 2 for mixing the base into.

With the flat edges of the Trowel scrape out the residual base on the side walls and bottom of the pail then put it upside down to drain on the next area to be coated.
Use the other pail for the next mix and this way you can alternate the pails and avoid a chunky mix.

**TIP: Don't add water to the next mix until the prior mix has been troweled out**

Mixing Instructions

1) After opening the pail of raw Flexstone Tuff base, stir the base in order to reconstitute any resins and polymers that could have settled during transit. Mix all the pails you will be using at the start of the job so you don't waste time mixing them when swithing to a new pail.

2) Pour the raw Tufflex base into a clean bucket.

3) Add 1 part water to every 4 parts of raw Tufflex base.

4) Use a slow speed drill (to avoid bubbles) and paddle to stir the mixture.

5) Keep the paddle deep in the pail and move up and down slowly to draw the material from the bottom trying to avoid mixing air into the solution.
Trapped air or bubbles may cause the cured product to blister.

6) Stir the mixture slowly and consistently for 3-5 mins.

Once the mixture feels thick and consistent, begin your field application immediately.

Base-Coat Application Warnings

Try to avoid installing the base on really hot surfaces as this speeds up the curing. It is best to coat early in the day or later when the surface has cooled down. The base sets up fast and hot temperatures speeds this process up even more. *Adding a block of ice to the pail of water for mixing helps a lot to slow down the set up time in hot weather.*

Rough surfaces and old membranes may need more base membrane than usual. Normally on plywood you should get 150-160 sq ft per pail. Putting it on thicker is just wasting product as the base coat is incredibly strong even if it is a bit thin.

When using the trowel, DO NOT interrupt the self-leveling process by "playing" with the base. This slows down the installation so just keep the trowel moving.

DO NOT worry about ridges or defects. After the product cures and hardens, any defects can be grinded out with a slow speed drill and grinding stone.

Base-Coat Application

1) Pour the mixed Tuff base over an area of the surface no larger than the expanse of your reach.

2) Spread the mixed Flexstone Tuff base with a 3/8" x 3/8"" (V-depth) V-notch trowel. After the self-leveling process, this will result in a base-coat thickness of approximately 64 mils or 1/16" on new plywood, concrete or similar surface. You should cover 30 sq ft per gallon of base with water added.

3) Angle the trowel down to ensure you are getting 30 sq ft per gal of mixed base coat and spread the base with a minimal number of passes.


Applying Over Large Areas

When applying Flexstone Tuff base over a large area, it helps to have two people present - one dedicated to mixing the product while the other(s) applies the product over the surface area. Never add the water to a new mix until the applicator has finished spreading the previous batch so you have as much time to spread the product as possible. Remember, water is the Catalyst.

For large areas you can use a special custom squeege with 3/8" x 3/8" V-notches available from your Flexstone & Tufflex distributor.

Use a long pole attached to the squeege so you can spread the base quickly while standing up. Lower the handle significantly to angle the V-Notches so you get full coverage of 30 sq ft per gallon.


1) Allow to cure overnight. Depending on the temperature the Base coat should cure in on full day. If you can walk on it you can apply the finish coats even if the base coat is a bit tacky.

Speed Up Curing

In special cases, such as applying Flexstone Tuff base in cold weather, it may be ideal to speed up the curing time.

To speed the curing time, use warm water and/or add a vial of RBC accelerator into the mixture. Use a maximum of 2 vials of RBC per 5 gallon pail of base.

Using these measures, the Flexstone Tuff base-coat can cure within 4-6 hours in warm weather.

This step is recommended for more experienced applicators.

*DO NOT add more water to change the recommended mixture as this will shorten the time you have to spread the base coat. Flexstone / Tuff Base coat is water-catalyzed and requires the exact proportions specified in the mixing instructions to cure properly (1-part water to 4-parts raw Tuff base). On damp plywood you can add less water (5-1 mix) so the base will absorb the moisture. Never add more than a 4-1 mix as this will adversely affect the curing process giving you less time to spread the base coat.

Dealing with Imperfections

1) After the product has fully cured with the surface hard and dry, you can feather grind out any hig spots or skim coat some base to fill in low spots.

2) Feather out / flatten all edges of each batch to ensure that there are no raised areas when you tie in the next batch. Push the base coat over the drip-edge and bring back past flashings then feather out so there is no lip that can prevent water from flowing over the edges or pooling. Base coat is so thick you should not have a lip from the drip flashings.

Clean Up

1) Wipe away any wayward product with a rag as soon as possible.

2) If the base has partially set, use a small amount of Xylene on your rag to help dissolve the base.

3) Clean your tools with Xylene. Discard used brushes and roller sleeves.

If Xylene is not available, try to find Acetone, Toulene or mineral spirits may help to perform clean ups and splatters.

4) Allow leftover base to set in the bucket and peel it out after it has set.

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Top Coat Application

Now that the Tufflex Base-Coat has been applied, we have the option of applying either the Standard Colour coat Finish or the Flexstone Textured Stonefinish.


The Standard System consists of: a colour top-coat that protects the base from UV damage and provides an attractive colour finish; and granules interlaced within the top-coat to provide traction.

Before applying the colour top-coat, make sure that the base has fully cured.

If the base has not cured properly, the top-coat may blotch or separate.

1) If the base-coat has been exposed to the sun for a prolonged period of time, especially in a hot weather. It hardens the surface and for proper adhesion it may be advisable to wipe the surface with a small amount of Xylene on a rag. This will soften the surface a bit to ensure you attain good adhesion of the top coat.
Check with the distributor if in doubt or do a test patch.

2) It's a good idea to stir the pail of AL Colour Top-Coat a bit before use.

3) Pour a small amount of AL Colour Top-Coat into the roller tray.

4) Roll on a thin layer of AL Colour Top-Coat with a roller sleeve.

5) Broadcast silica sand (20-30 Grit) across the surface – akin to feeding chickens. The amount of silica sand depends on the desired texture of the deck. Proceed with caution. Too much silica sand may cause the top-coat to "fish-eye." This is more common with darker colour coats and another skim coat may be required to eliminate fish eye issues.

6) Roll over the silica sand with another layer of top-coat.

One layer of top-coat is sufficient to protect residential projects. For heavy traffic areas, use two coats.

7) Allow to cure. At room temperature, the top-coat takes 1-2 days to fully cure.

8) Pour leftover top-coat into a air-tight plastic pail to save for future use. Keep used top-coat in a cold-dry place.


The FlexStone System consists of: a colour coat that protects the base from UV damage and provides a wet substrate for adhesion with the colour flakes; colour flakes that give the surface a luxurious aggregate look; and a clear multi-glaze coat that protects the colour flakes from wear and tear. Use standard 10mm nap roller sleeves for Colour coat and a thick 19mm sleevefor the Clear coat and do not let roller sleeve get empty to avoid having areas where clear coat is thinner as it will not be a shiny. You want an even thickness everywhere to prevent flashing or an uneven shine. After a month or two everything will dull down and look even. "Let your clients know this so they understand they need to be patient.

For instructions on how to install the Flexstone System, please contact your Flexstone / Tufflex distributor.