WITANFLEX AluMet

Preparation of the substrate – general information: Loose, brittle or non-sticking parts as well as paints, rust and separating materials must be removed. All surfaces to be treated must be firm, clean and dry and must not be covered with a moisture inhibitor. If there is any doubt concerning possible residual moisture, it is necessary to wait for the substrate to completely dry out; in addition, special vapour barriers for liquid products (art. 0818 002 951) can be used. Uneven substrates such as plaster, rough blasted plaster, holes, gravel beds, cracking etc. must be repaired and/or suitably smoothed. Water drainage points (drains) must be checked and restored and/or replaced as necessary. In the case of wall outlets, the installation of special elbow fittings for sealing liquids must be provided (art. 0818 002 952).

Cement-based substrates: Pretreatment of the surface with primer consisting of WITANFLEX ALUMET diluted with BITUMUL DIL to 50% (1 kg WITANFLEX ALUMET – 0.5 kg BITUMUL DIL), quantity 250–300 g/m2. New cement substrates must fully cure before proceeding.

Thinner (with BITUMUL DIL): Required for use at low temperatures (< 10°C) and when applied with a sprayer and/or brush. Application on undried bitumen-based substrates or on residues of bitumen can lead to an aesthetic change in the form of yellowish blooming of the sealing coating.

Bitumen-based substrates: Bitumen coats peeling off must be repaired in advance. Any protective paint that may be peeling off must be removed.

For bitumen polymers, the substrates should be prepared as follows: WITANFLEX ALUMET can be applied directly to unprotected old bitumen polymer membranes without applying a primer beforehand. In the case of old and self-protecting bitumen polymer membranes with slate granulate, pre-treatment of the surface is required with a primer consisting of WITANFLEX ALUMET thinned with BITUMUL DIL to 50% (1 kg WITANFLEX ALUMET – 0.5 kg BITUMUL DIL), quantity 250–300 g/m2.

In all cases, all bitumen substrates must be sufficiently cured and dried (at least 6 months). Otherwise, the appearance of oily efflorescence on the WITANFLEX ALUMET layer is possible.

Metal substrates: Rusty metal surfaces must be treated with rust converter after careful cleaning and repair of damaged areas (art. 0893 110). Rust protection primer Roststop (art. 0890 191) or a suitable primer must then be applied. Suitable mechanical reinforcement must be provided at overlapping points or at joints.

Plastic coatings: Tarpaulins made of TPE or EPDM must be clean and repaired if they exhibit surface tension or cracks. Due to the wide variety of materials, it is generally recommended to perform an adhesion test in advance. This is especially true for PVC tarpaulins. Provision should be made for the use of non-woven material between the two applications of an insulating layer.

Application: After preparing the substrates according to the above points and the complete drying of any pre-treatments, WITANFLEX ALUMET can be applied undiluted. In the case of sealing or subsequent sealing including of old bitumen polymer membranes with clear signs of micro-cracking, at least two layers must be applied using at least 2 kg/m2. PLEASE NOTE! If mechanical damage may adversely affect the sealing surface (large surfaces, unstable surfaces, encroachments on plastic surfaces etc.), the use of SOLVENT-PROOF NON-WOVEN reinforcements is recommended (art. 0818 100 051).

Sealing cycle with complete non-woven reinforcement: Prepare the substrate according to the above procedures and pretreat according to the instructions described. Once the primer has dried, WITANFLEX ALUMET is applied undiluted once with a roller, brush or sprayer at a quantity of 1–1.2 kg/m2. Before drying, the solvent-proof non-woven material (100 cm) is applied, taking care not to form bubbles or air pockets. The individual webs of the non-woven material should overlap 10 cm. Wait for the layer to dry and then apply WITANFLEX ALUMET a second time undiluted at a quantity of 1 kg/m2.