HOT MELT STRUCTURAL WATERPROOFING TECHNICAL GUIDE 75 bauder. co. uk ¦ Suitable Substrates 76 ¦ Concrete Curing and Drying 76 ¦ Surface Preparation 77 ¦ Priming 77 ¦ Method of Application 78 ¦ Access and Protection Layers 79 ¦ Equipment 79 ¦ Testing and Inspections 79 ¦ General Detailing 80 TECHNICAL GUIDE

CONCRETE CURING AND DRYING CURING COMPOUNDS These additives are a popular method of speeding the curing time of concrete, due to their ease of application, and low material cost. Typically, the liquid type curing compounds tend to form a film on the concrete surface that significantly slows the evaporation rate of retained moisture. Below is an indicative listing of types suitable for use in conjunction with Bauder Bakor 790- 11 and also those considered unsuitable. ACCEPTABLE COMPOUNDS Sodium Silicate Based Compounds – These compounds when properly applied do not leave a film or residue on the concrete surface which would otherwise affect the bond strength of the membrane to the concrete surface. Resin Based Compounds – These form a residue that can take between 45 – 60 days to oxidize and flake off, when exposed to the elements. The residue can be removed by brushing down the surface with a wire brush, or washing the concrete with a light solution of muriatic acid or trisodium phosphate ( TSP) Resin based curing compounds therefore may be acceptable as a curing method, but only on the proviso that they must be completely removed prior to the application of the membrane. UNACCEPTABLE COMPOUNDS Wax Based Curing Compounds – These cease to be an effective curing compound after about 28 days, but take 90 – 100 days to fully dissipate when exposed to the elements. The wax residue will weaken the bond of the monolithic membrane, and is also difficult to remove. Therefore wax based compounds are not acceptable. Acrylic Silicate Based Curing Compounds – These form a permanent film on the surface of the concrete, and could prevent the monolithic membrane from forming an acceptable bond with the concrete. These compounds are therefore not acceptable. The use of any liquid curing compound in conjunction with Bauder Bakor 790- 11 monolithic membrane must be approved by Bauder Ltd. Please contact our Technical Department on + 44 ( 0) 1473 257671. It is imperative that the concrete substrate is allowed to cure sufficiently to ensure that it forms the required adhesion with the membrane. British Codes of Practice consider that it takes approximately 28 days for concrete to cure properly using the standard methods of curing. Concrete decks constructed using profiled metal as formwork will take longer to cure and dry and this process can take up to 60 days. 76 bauder. ie SUITABLE SUBSTRATES Not every form of deck substrate construction is suitable to receive the Bauder Bakor System. Listed below are the types considered suitable and also those to be avoided: - ACCEPTABLE SUBSTRATES Structural Concrete Deck - The concrete deck should be properly cured. The recommended curing time is 28 days. Depending on site conditions and weather, it can be possible to install Bauder Bakor 790- 11 monolithic membrane onto a concrete deck after only 14 days curing – provided the membrane has successfully passed a bond strength test. Lightweight Structural Concrete Deck - The lightweight concrete should have a wood float finish. The recommended curing time is 28 days. A bond test is carried out to confirm proper adhesion to the deck. Concrete Deck Installed into Vented Profiled Metal Deck – A wood float finish will be required, and may have to cure for up to 60 days before proper adhesion is achieved. A bond check must be carried out to check for the correct adhesion. Plywood, OSB or Dens- Deck ( gypsum) - are acceptable decks for the application of the Bauder Bakor 790- 11, provided the correct preparation has been carried out i. e. fixings counter- sunk, joints properly taped, and the deck correctly supported to withstand the inverted build- up loading weight. UNACCEPTABLE SUBSTRATES Lightweight Insulating Concretes Concrete made with aggregates such as Perlite, Pumice, Vermiculite will have a very low density and by their very porous make up, will retain a high degree of moisture. This high moisture content can create a problem in achieving a good bond with the deck surface. However, this type of lightweight concrete can be modified with a suitable latex, resin, or polymer treatment to provide an appropriate surface onto which membrane will adhere satisfactorily. Screeds Please note that Bauder Ltd discourages the specification of screeded surfaces, because although a good adhesion can be obtained once prepared, they will permit water to track and become absorbed beneath the system in the event that the waterproofing is damaged.