For Simplified instructions: Download "2-Page Install Guide"

Detailed Application Guide

Here are detailed 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. These instructions will guide you through surface preparation (for new / old plywood, concrete and old membranes), base-coat application and top-coat application for the standard system.
For a two page simplified set of instructions just download the how2apply.pdf flie in the download box at the right side of this page (Techs & Specs). This condenses everything down to two pages of easy to understand application instructions. .

For a list of equipment needed - Tthis is also included in the two page how2apply.pdf file at the right side of this page under Techs & Specs..


Surface Preparation

Perimeter Application

Mixing and Flexstone / Tufflex Base-Coat Application

Top-Coat Application

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Surface Preparation

Surface Preparation Warnings - READ THIS BEFORE STARTING!!!

The Flexstone / Tufflex base will adhere to almost any surface including wood, concrete, metal, old vinyl, fiberglass and ceramic tiles. Rough up smooth metal flashings with sandpaper for good adhesion.

Tufflex DOES NOT, however, adhere to extremely smooth surfaces like plastic and IT IS NOT compatible with asphalt or-tar-based coatings.

If in doubt, test the product on a small area or contact the Flexstone / Tufflex distibutor or dealer for technical advice.

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. Fill and seam tape where needed.

2) All surfaces must also be clean and dry. If new plywood is installed just use standard grade ply and not G!S (good on side) or PTD (pressure treated) ply.

For smooth concrete surfaces it is advisable to use our Tufflex 2-part primer.

If the surface is contaminated (damp, dirty or weathered), it is also advisable to use the Tufflex 2-part primer.

Old Membranes / Existing Coatings

When applying Tufflex over a pre-existing coating or covering such as vinyl, fiberglass or ceramic tiles but certain precautions should be taken.

1) Ensure that the existing covering is not lifting in any areas. If it seems to be loose all over it is best to just remove the old coating.

2) If only a few areas seem loose you can staple or nail them down. Tap fiberglass surfaces to see if some areas sound hollow then use small drywall ring nails to secure these areas prior to coating with the Tufflex Tuff base coat.

3) Also, cut out old vinyl below the walls and around posts where vinyl has a tendency to shrink and fail.

4) If you go over surfaces that are contaminated or too smooth it may be advisable to use Tufflex 2-part primer to ensure good adhesion.


1) Useround 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.


1) Where water drains off the edge of the deck, nail down a 2" x 2" metal drip-edge. Rough up the top of the drip-edge with sand paper to ensure a strong adhesion when you apply the Tufflex Tuff Base coat. Use small flat-head galvanized nails (drywall ring nails work well) to secure the flashing. Keep the nails 6" apart and a bit off center away from the outside edge.

2) There is no need for seam tape - just apply the Tuff base with the flat edge of the trowel so it is smooth so no ridges are visible when you apply base to the rest of the deck. Press hard where you terminate the base coat past the drip flashings so it is thin and smooth.

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Perimeter Application

After the surface has been prepped and the flashing installed, the next step is to mix a small amount of Tufflex Base to apply around the perimeter of the deck - filling in imperfections, sealing walls / posts and covering seams.
Tufflex "Tuff" base coat can also be thickened into a caulking consistancy for those tricky hard to get at areas. Use fine rubber or fine silica sand as a filler.

Mixing a Small Amount of Tufflex Base

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

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

3) Stir the mixture until it feels consistent.

Surface Imperfections

1) Fill any imperfections in the surface such as screw holes, knot holes, splinters etc. with a small amount of mixed Tufflex base or even a generic 1-part polyurethane caulking.

Walls and Posts

1) Seal around any posts and up exterior walls as needed. At the base of the wall you can apply a heavy bead of 1 part urethane caulking to bridge the gap. Where big gaps exist some people even install a wall flashing which should be roughed up with sandpaper before applying the base over top. Seam tape is another option at walls where big gaps exist. Round foam backer rod is often used to fill gaps.

For vertical applications Tuff base can be turned into a caulk grade or vertical grade by thickening it with fine silica sand (20-30 grit) or some fine rubber powder. After adding the water slowly pour in the sand or rubber and stir until you can feel it getting to the desired thickness.

Seams & when to use our special 4"x 180' Seam Tape

Unless "Tongue and Groove" plywood is used, there should be a 1/16" expansion gap between square edge plywood. We don't want any open gaps in plywood.

DON'T allow any membrane to fill the gaps between plywood because when the wood expands and the gap closes it will force the membrane up causing a ridge.

1) Cover all open gaps with our 4" seam tape using the following procedures..

2) Apply a thin skimcoat of base on either side of the gap with a brush, roller or trowel. Stick the seam tape over top and stretch it out so it is smooth. You can even staple the ends if you wish to keep it flat and even.

3) Now you can use a brush, roller or trowel to apply another skimcoat of base over top the seam tape to sandwich it between the two skimcoats of base. Once the base coat is trowelled over the deck the seam tape should not be visible. It will set up quickly so you should not have to wait very long before you coat the whole deck.

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Mixing and Tufflex 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. This involves mixing a larger amount of the Tufflex Base, applying the base and allowing it to cure, followed by the application of either the 2 Finish options.

Mixing Warnings - READ THIS BEFORE MIXING!!!

Start with a small amount of mixed base to determine how quickly you can apply the product. .Once you mix in the water move quickly as the base is designed to set up fast so if it rains in a few hours it will have a skin and not be damaged. Only mix what you can apply in around 20 mins. and try to maintain a wet edge to flow into for the new mixture. You don't want to mix too much as when it starts to set it will not self level and you will waste material..

Using 2 pails allows you to trowel out the residue in the first pail then put it upside down on the next area to coat so it drains. Then use the next clean pail with the new mix to keep the application moving along by rotating the 2 pails...

If one pail is used trowel out as much of residual base as possible. Any leftover base in the pail could set up and cause the new mixture to turn "chunky"..

Mixing Instructions

1) After opening the pail of raw Tuff base coat stir the base thoroughly to mix the polymers and resins that settle at the bottom of the pail during storage.

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

3) Add 1 part water to 4 parts of raw Tuff base.(1 quart water / gallon base)

4) Use a slow speed drill and paddle to stir the mixture for a few minutes.

5) Keep the paddle deep in the pail and draw the material from the bottom in order to avoid mixing air into the solution. DO NOT "bounce" the paddle up and down. Trapped air may cause the cured product to blister.

6) Stir the mixture slowly and consistently.

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

Base-Coat Application Warnings - READ THIS BEFORE APPLYING THE BASE-COAT!!!

Rough surfaces and old membranes may need more base membrane than usual.

When using the trowel, DO NOT interrupt the self-leveling process by "playing" with the base.

DON'T worry about ridges or minor defects. After the product cures defects can be easily removed with a small angle grinder and a coarse sandpaper disk (25-30grit). As the disk turns barely touch the surface and imperfections disappear.

Base-Coat Application

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

2) Spread the mixed Tufflex base with a 3/8" V-Notch Trowel. After the self-leveling process, this will result in a base-coat thickness of approximately 3/16" on new plywood, concrete or similar surface.

3) Keep the trowel straight and spread the base with a minimal number of passes.

4) Stop 1/2" from the edge of the flashing. (The top coat will be applied to the edge.)

Applying Over Large Areas

When applying Tufflex over a large area, it is recommended to have at least two people present - one dedicated to mixing the product while the other(s) applies the product over the surface area.

For detail areas like up walls and around the perimeter use a V-notched Trowel.
For the large areas you can use a 24" gauge rake which can be adjusted to control the thickness. It's a good idea to have spiked boots as well with a gauge rake.


1) Allow to cure overnight. Under optimum conditions, the Tufflex base-coat will cure in 6-8 hours. A vial of catalyst can also be used to speed up the cure time.

Speed Up Curing

In special cases, such as applying Tufflex 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 Tufflex base-coat can cure within 4-6 hours in warm weather.

The above step is for experience applicators as you need to apply the base fast.

DO NOT add more or less water content of the base mixture to try and affect curing time. Tufflex is water-catalyzed and requires the exact proportions specified in the mixing instructions to cure properly (1-part water to 4-parts raw Tufflex base). Adding or subtracting water will adversely affect the curing process.
*Note - if the surface contains a bit of moisture you can go a 5-1 mix as adding a bit less water will allow the base to soak up some moisture from the substrate.

Dealing with Imperfections

1) After the product has fully cured, feather grind over any defects with a small angle grinder and a 7 inch 25-30 grit sandpaper disc. Keep the disc moving as you barely touch the surface so you do not heat up the coating. This can be done over the base coat or even the top coat if anything needs smoothing out.

2) Ensure that the edges of the base layer are flattened out with the smooth edge of the trowel when installing over drip edge flashings. This way no lips or raised areas will exist and the base flows evenly into the perrimeter providing a smooth surface allowing water to flow freely over the drip-edge. Feather grind any raised areas.

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 a rag to help dissolve the base.

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

If Xylene is not available, try Toulene, mineral spirits, or perhaps acetone.

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 Textured Stone Finish.

Flexstone Standard Colour Coat Finish

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 and there is no dust or oils on the surface to inhibit adhesion..

1) If the base-coat has been exposed for a prolonged period of time, especially in a hot climate, it may be advisable to wipe the surface with a small amount of Xylene. This will soften (etch) the surface a bit to ensure you obtain good adhesion of the top coat. Check with the distributor if in doubt or do a test patch.

2) Always stir the pail of AL Colour Top-Coat before use.

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

4) Roll on the AL Colour Top-Coat with a thick nap roller.

5) Broadcast silica sand (20-30 Grit) evenly across the surface (similar to to feeding chickens). The amount of silica sand depends on the desired texture of the deck. Proceed with caution. It's a goo idea to do a test area first to get the desired grit.

6) Then back roll over the top coat with the silica sand to even out the sand..

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

7) Allow to cure & in the summer with warmer temperature, the top-coat takes 1-2 days to fully cure. Once the surface is not tacky it is ready to walk on.

8) Pour leftover top-coat into a air-tight plastic pail to save for future use as the metal pails are hard to re-seal. Keep used top-coat in a cold-dry place.

FlexStone Textured Stone Finish

The Textured Stone Finish consists of: a the base coat, a colour coat for UV protection, special blended colour acrylic flakes and a rugged 1 part clear urethane top coat. The colour flakes gives you a luxurious simulated aggregate stone look and the durable clear multi-glaze coat protects the colour flakes from wear and tear.

For more detailed instructions on how to install the Textured Stone System, please contact your Flexstone / Tufflex distributor or local dealer.