Tuff Industries Inc. has created a simple overview video for the Architectural and Design community to outline the process for waterproofing balconies, decks, patios and walkable roof spaces with Tufdek waterproof roofing-approved vinyl decking materials.
Deck and balcony waterproofing is a unique blend of exterior flooring and single-ply thermoplastic roofing concepts combined to achieve both an aesthetic finished surface and a high performance, pedestrian friendly, waterproofing system.
Single-ply deck membranes are integrated into the building envelope and have the ability to waterproof a variety of applications and construction designs. Always ensure you refer to local building codes for product compliance in your area.
This video is a general overview of the installation process and does not cover all possible details. Slope, as outlined by the manufacturer, must be indicated on the design drawings and a minimum of 5/8” T&G Exterior Grade plywood, glued and screwed into place, must be specified. Structure and joist spacing must meet local building code requirements. Specify a manufacturer that supplies a complete system and use only their components in the application.
Surface Preparation is a critical component of the installation process. All damaged, delaminated plywood, as well as any “hollows” should be removed or replaced as the first step in Substrate preparation. Ensure all fasteners are countersunk below the surface. Blow off all dust and particles. Meters should be used to ensure both substrate moisture levels, and temperature, are acceptable for proper adhesive performance and application. The substrate is sanded smooth to prepare the surface for installation and to discover any potential problem areas. Debris between T&G joints is cleaned out and removed. Again, the substrate is blown clean.
A cementitious filler, or patch, compound is mixed according to the manufacturer’s directions, creating a heavy paste consistency. Within specified working times, the filler is then spread into all T&G joins, hollows, and uneven areas to provide a smooth, even substrate. The filler is left to completely dry and then the substrate is again sanded smooth. 24 gauge metal flashings, coated in PVC, should be used for best waterproof integrity.
The deck edge is first planed down to create a recessed channel for the drip edge to sit flush with the deck surface. That allows free flow of water runoff. The drip edge metal is then cut and fitted into place, then fastened using 1-1/2” galvanized ring shank nails. Galvanized metal flashings should be used at deck to wall intersects where a gap in the substrate exists. That provides solid support for the membrane.
Next, the waterproofing membrane is cut to size and rolled out onto the deck. The membrane is then trimmed and rough fitted into place prior to adhesive application. Compatible adhesives supplied by the membrane manufacturer are then applied. These can typically be either rolled, or troweled on, depending upon the adhesive selected. Local temperature and humidity conditions at the time of installation are taken into consideration when selecting which type of adhesive to use. First one half of the substrate is covered with the right adhesive, then while still wet, the membrane is rolled into the adhesive and all air bubbles are removed and full contact is ensured by the use of flat spreaders or heavy rollers. All verticals and upstands should also be adhered to the wood sheathing.
Membrane flashings are formed and fitted for all doorsills, outside corners, and framing intersects. They’re glued to the wood structure, and finally thermally welded into place using a hot-air welder. Overlap membrane seams are also thermally welded together – as are all terminations to PVC coated metal flashings, creating a totally waterproof installation.
The completed waterproof deck is now integrated into the building envelope and will provide many years of protection to the structure, and a beautiful, low maintenance deck surface for the end-user.